International Symposium on Uranium Raw Material for the Nuclear Fuel Cycle: Exploration, Mining, Production, Supply and Demand, Economics and Environmental Issues (URAM-2018)

25 Jun 2018, 09:00 → 29 Jun 2018, 14:40 Europe/Vienna

Vienna

Michel CUNEY (CNRS - GeoRessources - CREGU - Universite de Lorraine), Olga Gorbatenko (Inkai JV)

Adequate services, expertise and modern technologies are needed to ensure a sustainable supply of uranium raw materials to fuel both operating and future nuclear power reactors. Effective regulation, sound environmental management, training and education are required to minimize the impact of uranium mining and production and to contribute to public acceptance of the global nuclear industry in general. In 2005, 2009 and 2014, the International Atomic Energy Agency (IAEA) hosted International Symposia on Uranium Production and Raw Materials for the Nuclear Fuel Cycle1 at its Headquarters in Vienna, Austria, to discuss all aspects of uranium raw materials for the uranium fuel cycle to ensure the long term sustainability of a nuclear power programme. In response to a challenging economic environment, the industry is currently seeking new and innovative ways to improve efficiencies in producing uranium. Since 2016 the long term median forecast envisages the growth of nuclear power worldwide, thereby leading to an eventual increase in uranium demand and in turn the price of uranium. In the last few years uranium supply has exceeded consumption, leading to historically low spot prices for uranium oxide. This has resulted in decreased exploration activity as well as in some mines being placed in care and maintenance. Looking forward, secondary uranium supplies are expected to dwindle. This, combined with the exhaustion of some active uranium mines, requires that the uranium resource base and global production capacity be further advanced in order to meet current and future demands. The current oversupply could potentially lead to undersupply in the medium to long term. Due to long lead times from discovery to production, the re-evaluation of uranium resources is required now.

The long term sustainability of nuclear power will depend on, among several factors, an adequate supply of uranium resources that can be delivered to the marketplace at competitive prices. New exploration technologies and a better understanding of the recognition criteria and genesis of the uranium ores will be required to discover and delineate increasingly difficult-to-locate uranium deposits, particularly those of low cost. In addition, exploration, mining and milling technologies should be environmentally benign, and site decommissioning plans need to meet the requirements of increasingly stringent environmental regulations and societal expectations. The purpose of the symposium is to analyse uranium supply and demand scenarios and to present and discuss new developments in uranium geology, exploration, mining, milling and processing, as well as the environmental requirements for uranium operations and site decommissioning. The presentations and discussions at URAM-2018 will:

• Lead to a better understanding of the adequacy of uranium supply to meet future demand;
• Provide information on geological models, new exploration concepts, knowledge and technologies that may potentially result in the discovery and development of new uranium resources; 
• Describe new mining and processing technologies that have the potential to support a more efficient and sustainable development of uranium and related resources; and 
• Consider the environmental compatibility of uranium production and the overall effectiveness of progressive waste management, decommissioning and remediation of production facilities.

URAM-2018 is intended to bring together scientists, managers, exploration and mining geologists, mineral economists, engineers, operators, regulators, community representatives, social scientists, nuclear fuel cycle and environmental specialists and young professionals to exchange information and discuss updated research and current issues related to uranium geology and deposits, exploration, mining and processing, production economics and environmental and legal issues.

More info can be found here: https://www.iaea.org/events/uram-2018

 

notes cn261_Extended_Abstract_Guidelines(v1).docx cn261PosterGuidelines.docx

Monday, 25 June

OPENING SESSION

Conveners: Dr Michel CUNEY (CNRS - GeoRessources - CREGU - Universite de Lorraine), Ms Olga Gorbatenko (Kazatomprom)

1 Opening addresses

2 World Nuclear Association 2017 Fuel Report

The World Nuclear Association has published reports on nuclear fuel demand and supply at two-year intervals since 1975. The 2017 report is the 18th edition in the series and looks at scenarios for uranium demand and supply to 2035. *The Nuclear Fuel Report* considers three scenarios (Lower, Reference and Upper); the projections are based on assumptions of electricity demand growth, nuclear economics, public acceptance, government policies and electricity market structure within each country. From 2000 until the Fukushima accident in March 2011, successive editions of *The Nuclear Fuel Report* projected increasing nuclear capacity. But since Fukushima, the reports have reduced nuclear capacity projections year-on-year, with a corresponding reduction in uranium requirements. The extensive range of mining projects that were developed over 2000-2010 have largely fallen away in the light of historically low uranium prices. The World Nuclear Association believes that nuclear energy can make a greater contribution to clean and reliable electricity generation and presents a vision for the future, called ‘Harmony’. In this vision, 25% of global electricity in 2050 would be provided by nuclear energy. We can be confident that sufficient uranium resources exist in the world to allow such a rapid expansion.

Speaker: Ms Olga Skorlyakova (World Nuclear Association)

3 Nuclear energy and uranium: looking to the future

In recent years, nuclear power continued to supply significant amounts of low-carbon baseload electricity, despite strong competition from low-cost fossil fuels and subsidised renewable energy sources. However, there is ongoing debate on the role that nuclear energy will play in meeting future energy requirements. Key factors that will influence future nuclear energy capacity include projected electricity demand, public acceptance of nuclear energy and proposed waste management strategies, as well as the economic competitiveness of nuclear power plants. Concerns about the extent to which nuclear energy is seen to be beneficial in meeting greenhouse gas reduction targets could contribute to even greater projected growth in uranium demand. Key issues in terms of nuclear market developments will be discussed in this presentation and how they could impact the broader nuclear and uranium industry.

Speaker: Dr Luminita Grancea (OECD Nuclear Energy Agency (NEA))

4 The Impact of Global Nuclear Fuel Inventories on Forward Uranium Production

INTRODUCTION The March 2011 Fukushima accident has not only led to a significant reduction in global uranium demand, but it has resulted in the enormous growth of nuclear fuel inventories. Uranium producers have been unable to compete with the current situation of large and growing nuclear fuel inventories and have recently begun to curtail primary production as these low-cost inventories have pushed uranium prices to levels below the production cost of many uranium projects, making these projects uneconomic in the near- and medium-term. DESCRIPTION Global nuclear fuel inventories are held by numerous entities, including: • End-user nuclear power utilities and their relevant nuclear fuel procurement/management subsidiaries, • Suppliers throughout the supply chain, including uranium producers, converters, enrichers, fabricators, and even reprocessors and mixed-oxide (MOX) fuel fabricators, • Investors, traders, and financial institutions, as well as other non-end users, and • Governments that have historically been involved in the production of nuclear fuel for both civilian and military applications. Among global utility inventories, UxC data shows that the desired level for 2017 was 392 Mlb U3O8e (150,769 tU), with actual inventories amounting to 759 million pounds U3O8e (291,923 tU), or an excess of 367 million pounds U3O8e (141,154 tU) [1]. The U.S. Energy Information Administration (EIA) reported in its 2016 Uranium Marketing Annual Report that U.S. utility inventories held nearly 129 million pounds U3O8e (49,615 tU) at the end of 2016, up 43% from 90 million pounds U3O8e (34,615 tU) in 2011 and 182% higher than the historical low of 46 million pounds U3O8e (17,692 tU) in 2003 [2]. The Euratom Supply Agency (ESA) shows that European Union (EU) utility inventories increased from 123 million pounds U3O8e (47,308 tU) in 2011 to a peak of 142 million pounds U3O8e (54,615 tU) in 2013, but have since decreased slightly to 134 million pounds U3O8e (51,538 tU) [3]. Interestingly, given numerous reactor closures since 2011, EU utilities now hold more inventories per reactor than just a few years ago. Given the highly uncertain situation regarding the future of reactor restarts in Japan, the question of the country’s utility inventories has become even more important to the uranium market. UxC estimates that Japanese utility inventories total 126 million pounds U3O8e (48,462 tU), with very little consumed since 2011, and enough fuel to last most Japanese utilities through most of the next decade and some utilities even beyond 2030. UxC’s Base Case reactor restart/operations forecast for Japan assumes that only 21 of 40 operable units will eventually restart [4]. China’s three main utilities – China National Nuclear Corporation (CNNC), China General Nuclear Power Corp. (CGN), and State Power Investment Corp. (SPI) – are estimated to hold 450 million pounds U3O8e (173,077 tU) at the end of 2017, an increase of 151% compared to an estimated 179 million pounds U3O8e (68,846 tU) in 2011. Starting in 2010, the import of uranium supply tripled, and net uranium imports have surpassed domestic uranium demand by a huge margin in every year since. Supplier inventories have also built up inadvertently to the extent that global uranium demand has dropped off and utilities cancel out of previously contracted commitments. Traders hold inventories as well, although they do not produce or consume uranium. Since traders facilitate the flow of supply in the market, in some cases with offtake agreements, they end up holding inventories. After Fukushima, traders also became heavily involved in mid-term contracting wherein they purchased low-priced spot uranium to hold in inventory for future delivery. Another recent development stemming from the Fukushima accident and subsequent reactor shutdowns has been the use of excess SWU capacity to underfeed enrichment plants and/or re-enrich depleted tails to natural uranium. This underfeeding of enrichment plants has caused the need for newly produced uranium to decline even further. Thus, enrichers have been “creating” or accumulating uranium inventories and have turned around and sold this excess uranium into the market. Additionally, depending on how enrichers elect to use their excess capacity, they can choose to build inventories in the form of enriched uranium product (EUP). UxC estimates that inventories from all the world’s suppliers, traders, and investor-related entities totaled ~231 million pounds U3O8e (88,846 tU) at the end of 2017, with this group holding 53 million pounds U3O8e (20,385 tU) more than it did in 2015. Governments, including the U.S. and Russia, continue to hold uranium inventories for military purposes. Much of the uranium is held in the form of highly-enriched uranium (HEU) contained in nuclear warheads and strategic stockpiles, which can enter the market if it is considered excess to national security interests. U.S. Government inventories, declared as excess or commercial, total ~145 million pounds U3O8e (55,769 tU), but its disposition of natural UF6 and HEU inventories are expected to be largely completed by the end of this decade. The true wildcard going forward is the success of the U.S. Department of Energy’s proposed tails re-enrichment program. The Russian government is the holder of an estimated 368 million pounds U3O8e, (141,538 tU) although most of its material must undergo some type of processing to be utilized. A large portion of the inventory consists of depleted uranium. Furthermore, tails that are deemed to be suitable for re-enrichment have low assays, but with Russia’s large excess enrichment capacity, the volume of re-enriched tails has increased since the Fukushima accident. Two other major components of Russia’s inventory are slightly irradiated uranium and reprocessed uranium. Among the country’s inventory that does not require further processing is primarily natural UF6 stemming from the monitored inventory that became available following the end of the HEU Agreement. DISCUSSION AND CONCLUSION Although current inventory accumulation has taken several years to take shape, it has clearly become a major concern for market participants in the post-Fukushima environment. There is clearly no single opinion about the inventory situation, but most market participants agree that dealing with the growing level of inventories is crucial to rebalancing supply and demand fundamentals and creating a more sustainable future. In early 2017, the world’s largest producer Kazatomprom stated that it would reduce planned 2017 production in Kazakhstan by ~10%, noting that its decision “was based on the current glut of the uranium market [5].” And in late 2017, Kazatomprom announced its intention to further reduce Kazakh planned uranium production by 20% under Subsoil Use Contracts of Company enterprises for the 2018 through 2020 period, “in order to better align its output with demand [6].” More importantly, the cuts come to a country with the majority of its production in the lowest cost tier, with UxC showing a weighted average full cost of ~$15 per pound U3O8 across Kazakh operating uranium projects in 2016 [7]. Other producers have not been immune to the impact of inventories on the market. In November 2017, Cameco Corp. elected to suspend production from its low-cost McArthur River mine for a period of at least 10 months starting in January 2018 [8]. A primary driver in cutting production by ~16 million pounds U3O8 (6,154 tU) in 2018 was the fact that Cameco’s inventory position had ballooned up to ~28 million pounds U3O8 (10,769 tU), which is nearly twice the level of its preferred 6-month inventory position. More than a year earlier, in April 2016, Cameco suspended production at its Rabbit Lake mine in Saskatchewan and began curtailing production at U.S. in-situ recovery (ISR) operations, resulting in the aggregate decline of ~6 million pounds U3O8 (2,308 tU) per year [9]. In Africa, AREVA has reduced production from its two operating projects, SOMAIR and COMINAK, in Niger by 25% since 2015, citing difficult market conditions. Meanwhile, Paladin Energy made an adjustment to its Langer Heinrich mine plan in August 2016, choosing to process stockpiled low and medium grade ores through 2019 and effectively shift higher-grade ore processing into later years when uranium prices may be higher [10]. As a result of the change, Langer Heinrich production was about 1.6 million pounds U3O8 (615 tU) lower over the last year. Going forward, the mostly likely scenario entails additional inventory growth in the near-term, followed by the gradual disposition of utility, supplier, and trader inventories, which cumulatively will be greater than any additional buying on the part of utilities or other market players in the post-2020 period. Inventories will displace primary uranium production on a larger basis, especially after 2020, and as such, they will continue to have a price suppressive effect on the uranium market as existing supply outweighs new demand for inventories. However, this situation should slowly dissipate by the late 2020s, especially with significant uranium resource depletion projected in the mid-2020s. Accordingly, any new production decisions within the next several years will likely be premature unless market fundamentals change significantly in that timeframe. REFERENCES [1] THE URANIUM CONSULTING COMPANY, LLC, Global Nuclear Fuel Inventories, February 2018. [2] U.S. ENERGY INFORMATION ADMINISTRATION, 2016 Uranium Marketing Annual Report, U.S. Department of Energy, June 2017. [3] EURATOM SUPPLY AGENCY, Annual Report 2016, European Commission, June 2017 [4] THE URANIUM CONSULTING COMPANY, LLC, Nuclear Power Outlook, Q1 2018 [5] KAZATOMPROM, Kazakhstan To Reduce Uranium Production by 10%, January 10, 2017, https://www.kazatomprom.kz/en/news/kazakhstan-reduce-uranium-production-10. [6] KAZATOMPROM, Kazatomprom Announces Further Production Cuts, December 4, 2017, https://www.kazatomprom.kz/en/news/kazatomprom-announces-further-production-cuts. [7] THE URANIUM CONSULTING COMPANY, LLC, Uranium Production Cost Study, September 2017 [8] CAMECO CORP., Cameco To Suspend Production from McArthur River and Key Lake operations to reduce its dividend, November 8, 2017, https://www.cameco.com/media/news/cameco-to-suspend-production-from-mcarthur-river- and-key-lake-operations-an. [9] CAMECO CORP., Cameco Announces Operational Changes in Saskatchewan and the United States, April 21, 2016, https://www.cameco.com/media/news/cameco-announces- operational-changes-in-saskatchewan-and-the-united-states. [10] PALADIN ENERGY LTD, 2016 Annual Report and Financial Statements, August 24, 2016, https://www.paladinenergy.com.au/sites/default/files/financial_report_file/160630-paladin- 2016-annual-report.pdf.

Speaker: Mr Nicolas Carter (The Ux Consulting Company, LLC)

5 Foundational fuels of the 21st century: Evolving socio-economics of sustainable energy systems

The last few years saw the end of the commodity super-cycle, the gradual fall in oil and gas prices, the carbon crunch and the wide-ranging revolution that is going on in technology, often termed Industry 4.0. Rapid digitization, which is taking over all areas of the industry and the society, including transportation, means that energy in general will be increasingly electric. How the electricity will be produced, stored, distributed and utilized will depend on the acceleration of this change and bare realities of economics. Three fuels assume importance as foundational fuels in this scenario - natural gas, uranium and renewable resources. This paper will discuss the socio-economics of energy transformation, the comparative advantages and disadvantages, especially focusing on the role of nuclear energy in the post Paris Agreement era.

Speaker: Mr Harikrishnan Tulsidas (UNECE)

6 Uranium One development outlook

The Russian State Corporation Rosatom has acquired Uranium One in 2010 to secure long term uranium supply for its nuclear fuel cycle chain and consolidated on its basis high quality uranium assets in Kazakhstan and in other countries. Uranium One has increased annual production almost 5 times during the last 7 years and became a fourth global U producer. It has a diversified production base in Kazakhstan, the US and a development project in Tanzania. Known resources and mining capacities secure further sustainable uranium production growth at favorable market conditions. Through its shares in five joint ventures and six mines, Uranium One owns 20% of attributable uranium production and 17% of attributable resources in Kazakhstan, being the second after Kazatomprom and the first among the foreign companies. The designed production capacity of six uranium mines is 12 ktU, half of which is attributable to Uranium One share. The successful innovative technical policy in conjunction with the unique by its geological and technical characteristics deposits, provide significant competitive advantage for Uranium One as the global company with the lowest cost uranium production.

Speaker: Mr Vasily Konstantinov (Uranium One Group)

12:40 Lunch Break

Uranium Markets

Conveners: Mr Nicolas Carter (The Ux Consulting Company, LLC), Ms Olga Skorlyakova (World Nuclear Association)

7 Regulations for the diversification of partners as part of the security of supply policy

In the current uranium industry conditions, the stable and sustainable natural uranium and uranium fuel supply is becoming crucial. It can be achieved through the mandatory diversification of uranium suppliers portfolio regulations issued by IAEA for the utilities. Some countries and utilities experience such constraints, when they are not able to procure uranium through different sources, because of some regulations of their arrangements with strategic counterparties. We can take as an example some utilities working in the market, the natural uranium supplier portfolio of which is diversified by means of their own corporate policies, e.g. where they allow not more than 10% of their needs to be fulfilled by the uranium producers with a single mining source, and not more than 20% of their requirements procured from the producers with more than one sustainable mine. Given the prevailing situation on the market, the international political situation, as well as ensuring the stability of fuel supplies for sensitive facilities such as nuclear power plants, it seems advisable to introduce international rules on the mandatory diversification of supplies of natural uranium and uranium fuel for the needs of energy companies.

Speaker: Mr Riaz Rizvi (Kazatomprom, Republic of Kazakhstan)

8 Uranium Resources and Perspectives for Nuclear Supply in Argentina

INTRODUCTION In 1992, due to the low prices in the international market, the import of uranium concentrates began from South Africa, a situation that gradually led to the closure of local production in 1997. Since then, there has been no production of uranium in the country, while the uranium needs from operating nuclear power plants have been met with raw materials imports from abroad (i.e. Uzbekistan, Czech Republic, Kazakhstan and Canada). However, despite the fact that international uranium market has been depressed in recent years, the Free On Board (FOB) prices that the country has paid for the purchase of yellowcake in the spot market have not necessarily been trivial, mainly due to the increases in transportation charges, insurance premium and taxes [1]. This paper attempts to present a comprehensive vision of and uranium projects, updated resources, and project statuses and the perspective of local production of uranium oxide concentrate regarding the foreseeable demand for nuclear energy generation in the country. Besides, the eventual row material supply from the Latin American region is briefly discussed. DESCRIPTION Argentina has three heavy water reactors, namely Atucha I with a gross electrical power of 362 MWe that is fuelled with Slightly Enriched Uranium (SEU) (0.85% U-235), and Embalse (CANDU) and Atucha II, both based on natural uranium fuel with generation capacities of 648 MWe and 745 MWe, respectively. At present, Atucha I and Atucha II, located in Buenos Aires province, are in commercial operation, while Embalse, located in the province of Cordoba, has been out of the generation system for two years for refurbishment tasks designed to extend its useful life for a term of 30 years, which includes an increase in its power by an additional 35 MWe [2].With an approximate installed capacity of 1.7 GWe, nuclear power sources have a 10% share in the national electricity matrix, with natural uranium requirements of about 220–250 tU per year. Additionally, at the Atucha site, the Argentine prototype small modular reactor CAREM (27 MWe net/32 MWe gross) is under construction and is planned to come into operation in 2020–2022 and in the future plans are to increase the scale of the unit to a higher capacity of possibly 120 MWe. As part of the nuclear development in Argentina, China and Argentina signed an agreement for the installation of the fourth (CANDU Pressurized Heavy Water Reactor) and fifth (Hualong One Pressurized Water Reactor) nuclear power plants in the country, with construction planned to start in 2019 and 2021, respectively. Based on various nuclear growth scenarios, it is estimated that by 2030 there will be a generation capacity of some 3,470 GWe, for the low case, and about 4,070 GWe, for the high case. Therefore, the raw material needs would consist of 525 tU and 620 tU in the respective scenarios, which is about double the current consumption. In 2017, CNEA reported about 19,000 tonnes of uranium (tU) as identified resources (Reasonably Assured Resources + Inferred Resources) for the production cost category <130 USD/kgU in the OECD-NEA/IAEA classification scheme [3]. Approximately 11,000 tU of Canadian National Instrument 43-101 (NI 43-101) certified resources have been reported in recent years by the public mining company named U3O8 Corporation [4] and the private mining company named UrAmerica Limited [5]. The total uranium resources of Argentina are thus 30,010tU in the aforementioned Identified Resources category. It can be highlighted that if the higher production cost category of <260 USD/kgU is considered there is no substantial variation and identified resources account for 31,060 tU. In the Cerro Solo Deposit (Chubut Province), the tonnage and grade estimated are expected to ensure sustained uranium production in the future. The identified resources are 9,230 tU at approximately 0.1 to 0.2 per cent U, which are included in the < US$260/kg U production cost category. The reported resources correspond to the most studied mineralized bodies, and the available geological knowledge indicates excellent potential to develop new uranium resources in this mining property. In connection with pre-feasibility studies, in 1997 the CNEA retained NAC International to complete the Preliminary Economic Assessment (PEA) of the Cerro Solo uranium deposit [6]. Recently, a programme to complete the technical feasibility study of the deposit has been formulated and started. Also, the social-environmental baseline is being surveyed in cooperation with national universities and research councils. In the Laguna Salada project (Chubut Province) uranium identified resources have been evaluated at 3,880 tU at grades ranging between 55 and 72 ppm U, while vanadium identified resources have been assessed at 21,330 tV at grades ranging from 308 to 330 ppm V. Recently, the NI 43-101 PEA, where U-V comprehensive recovery concept is reinforced. Uranium and vanadium would be extracted from the fine material after screening by alkaline leach, in which the reagents are sodium carbonate (washing soda) and sodium bicarbonate (baking soda) at an optimal temperature of 80°C [7]. Sierra Pintada uranium Deposit (Mendoza Province) [8] has been the focus of the most significant uranium production in the country, with a total of 1,600 tU produced from 1975 to 1997, after which, the mining-milling facility was put in stand-by status for economic reasons. The level of uncertainty in the estimation of remaining resources in is medium to high, which are evaluated to be 10,010 tU recoverable identified resources at a production cost below US $130/kg U. Therefore, feasibility has been partially demonstrated by the fact that this deposit was previously in operation, using an acid heap-leaching mining method. Given the possibility of the reopening of the mining - milling complex, all available data have been processed to redefine the geological model and formulate a more suitable mining design. Meseta Central project (Chubut Province) is located in the vicinity of Cerro Solo and comprises the Graben, Plateau West and Plateau East deposits. The total inferred resources for the project are 7,350 tU at an average grade of 260 ppm U. As reported by UrAmerica Ltd., about 75 per cent of the uranium resources evaluated occur in confined aquifers layers [5]. Therefore, further geological and hydrological studies will be undertaken to determine amenability to in situ leaching mining. The results of these studies could play a relevant role regarding the socio-economic viability of this project. It must be noted that in January 2018, the Ministry of Science, Technology and Productive Innovation of Argentina, Uranium One Group, subsidiary of State Atomic Energy Corporation of the Russian Federation (ROSATOM), and UrAmerica Argentina S.A. signed a memorandum of understanding whose main purpose is to promote cooperation and joint development on uranium exploration and production focused on In Situ Leaching. Planned investment in this project amounts to USD 250 million [9]. The Don Otto (Salta Province) uranium deposit was in operation from 1963 to 1981 and produced 201 tU at 0.1 to 0.2 per cent U grade [10, 11]. The reminding identified resources are 430 tU and current exploration/evaluation studies yielded very encouraging results. Additionally, enlargement of the mining property and resource augmentation are considered key factors to ensure the project feasibility. A comprehensive study that includes updating environmental impact assessment (EIA) reports, block-leaching research and development studies, feasibility of underground extraction, use of a mobile ionic exchange plant, hydrogeological studies to define in situ leaching amenability, vanadium resource evaluation and extraction feasibility, and uranium recovery from the former heaps and remediation of the site, are all factors that would aim to increase project viability [12]. Laguna Colorada is located in the Chubut Province with evaluated resources of 160 t U at 660 ppm U [13]. The limited resources of the project make it difficult to envisage extraction at present unless the characteristics of the ore will allow treatment in a plant that may in the future be located in the area of Cerro Solo. At the exploration level, there are several projects such as Golfo San Jorge, Amarillo Grande, Alipan, Mina Franca and Laguna Sirven within the basins of great interest in the country that are carried out by both the private sector and the government. Initially, it will be necessary to advance the delineation of resources and raise their level of confidence through preliminary economic assessments of these projects, taking into account that, as general rule, the integral exploration at basin level has not been carried out and resources have generally been evaluated with a low level of confidence. In sedimentary environments, particular attention should be given to those sandstone-type deposits that are amenable to in situ leaching to recover uranium. Also, there are some unconventional sources of uranium that could provide sustainable alternatives for nuclear supply in the foreseeable future, such as rare earth projects, phosphates, and lake and sea waters. DISCUSSION AND CONCLUSION Despite the apparent growth prospects of the use of nuclear energy for the generation of electricity in the country, which would lead to double the uranium needs by 2030, there are no immediate prospects for the provision of nuclear raw material for fuel fabrication from the local production of uranium oxide concentrates at Argentine deposits. This has implications for supply and energy security [14]. One main concern is that the identified uranium resources in Argentina are mostly located in the provinces of Chubut and Mendoza. These are areas where no metallic mineral mining projects are in operation, and also, the provincial legislations markedly restrict uranium production. These factors need to be taken into account when studying the socio-economic viability of the projects. However, it could also be assumed that the mining laws could be amended as necessary if a requirement of uranium and other critical materials for clean energy projects becomes very important to Argentina. Also, projects with a higher degree of maturity must complete technical feasibility studies for the recovery of uranium. In the case of possible future production of U, other valuable materials such as V and Mo, can be assumed to be produced as a by- or co-product, contributing to the mineral sector development in Argentina. While U is used for nuclear fuel, V and Mo have critical applications, especially in the renewable energy and steel industry sectors. In the Latin America region both Brazil and Paraguay could be consider as potential uranium suppliers for Argentina. In Brazil, in the short - medium term, domestic needs would be covered and even significant uranium surpluses could be produced that could contribute to nuclear supply for Argentina. On the one hand, with the expansion, the Lagoa Real deposit would produce about 670 tU/ year. On the other hand, some 1700 tU / year would be obtained as a by-product of the extraction of phosphates in the Santa Quitéria deposit, from 2020-2022. As a recent precedent, in 2016 Industrias Nucleares de Brasil (INB) and Combustibles Nucleares Argentinos (CONUAR) signed an agreement for the provision of four tons of low enriched uranium (1.9% - 3.2% U-235) produced at the Rio de Janeiro facility in Brazil to be used for the fuel of the initial load of the CAREM reactor which is under construction at Lima site in Argentina [15]. While in Paraguay there are two projects of interest found in the eastern part of the country, related to sandstones in the western flank of the Parana Basin: Yuty project, with about 4,290 tU of NI 43-101 certified resources, and Coronel Oviedo project, which constitutes a NI 43-101Exploration Target ranging 8,900 to 21,500 tU. In both projects hydrogeological testing indicates that the uranium bearing unit has aquifer characteristics that would support operational rates for ISR mining. These projects are waiting for better market conditions to be developed and as Paraguay has no prospects for the use of nuclear power, these resources could contribute to the supply of nuclear fuel resources for Argentina. To this regards, it must be highlighted that Argentina is constructing a new uranium purification plant located about 200 km far away from Paraguayan uranium projects. Therefore, the transportation of pregnant resins or elluants could be consider as the best economic and technical option, rather than yellowcake to be precipitated in Paraguay ISL facility and to be dissolved at the uranium purification plant in Argentina [16]. REFERENCES [1] MINISTERIO DE ENERGÍA Y MINERÍA, Informe especial, Mercado del Uranio (2016) http://scripts.minem.gob.ar/octopus/archivos.php?file=6939 [2] NUCLEOELÉCTRICA ARGENTINA S.A. , Web pages (2017) http://www.na-sa.com.ar/ [3] BIANCHI, R., GRÜNER, R., LÓPEZ, L., Argentina - Country report, Prepared for Uranium 2018: Resources, Production and Demand, OECD Report, the ‘Red Book’, National Atomic Energy Commission (CNEA) internal report, unpublished (2017). [4] COFFEY MINING PTY LIMITED, NI 43-101 Technical Report Laguna Salada Initial Resource Estimate, Prepared on behalf of U3O8 Corporation, 30 p. (2011) www.sedar.com [5] PEDLEY, A., CONSULTING GEOLOGIST, NI 43-101 Technical Report on the Paso De Indios Block Property Within the Central Plateau Project Located in the Chubut Province of Argentina, Prepared For UrAmerica Ltd., 92 p., unpublished (2013). [6] NAC INTERNATIONAL, Cerro Solo U, Mo Deposit, Chubut Province, Argentina, Pre-feasibility study prepared for the CNEA, 169 p., internal report, unpublished (1997). [7] TENOVA MINING AND MINERALS PTY LTD, Preliminary Economic Assessment of the Laguna Salada Uranium-Vanadium Deposit, Chubut Province, Argentina, Report Prepared for U3O8 Corp. (2014). [8] SALVARREDI, J.,Yacimiento Doctor Baulíes y otros depósitos del distrito uranífero Sierra Pintada, Mendoza,E. Zappettini (Ed.), Recursos Minerales de la República Argentina, Anales No. 35 SEGEMAR, pp. 895-906 (1999). [9] MINISTRY OF FOREIGN AFFAIRS AND WORSHIP OF THE ARGENTINE REPUBLIC, Press Released N°: 014/18. (2018) https://www.mrecic.gov.ar/en/argentina-russia-memorandum-understanding-uranium-exploration-and-mining [10] GORUSTOVICH, S.A., Metalogénesis del uranio en el noroeste de la República Argentina, PhD Thesis, University of Salta, unpublished (1988). [11] ROMANO, H.I., Distrito Uranífero Tonco Amblayo, Salta, E.O. Zappettini (Ed.), Recursos Minerales de la República Argentina, Anales No. 35 SEGEMAR, pp. 959-970 (1999). [12] LÓPEZ, L., SLEZAK, J., Technological transfer on in situ leaching (ISL) mining: A more Sustainable Alternative for Uranium Production in Argentina, Best Practices Dissemination Meeting INT/0/085, IAEA, Vienna(Austria), 3-4 February 2014 (2014). [13] FUENTE, A., GAYONE, M., Distrito uranífero Laguna Colorada, Chubut. (Zappettini, E., Ed.), Recursos Minerales de la República Argentina, Anales Nº 35 SEGEMAR 1253-1254 (1999). [14] UNITED NATIONS ECONOMIC COMMISSION FOR EUROPE, Application of the UNFC for Fossil Energy and Mineral Reserves and Resources 2009 to Nuclear Fuel Resources – Selected Case Studies. ECE ENERGY SERIES No. 46 UN New York and Geneva (2015). [15] INSTITUTO DE PESQUISAS ENERGÉTICAS E NUCLEARES, (2016) https://www.ipen.br /portal_por/portal/ interna.php?secao_id=40&campo=7531 [16] YANCEY, C., FERNÁNDEZ, V., TULSIDAS, H., LÓPEZ, L. ,Considerations related to the application of the United Nations Framework Classification for Fossil Energy and Mineral Reserves and Resources 2009 to uranium projects and associated resources in Paraguay, Economic and Social Council – United Nations, ECE/ENERGY/GE.3/2016/10 (2016).

Speaker: Mr Luis LOPEZ (CNEA (Argentina))

9 ESTIMATION OF URANIUM REQUIREMENTS FOR PLANNED NUCLEAR POWER PLANTS AND SUPPLY CAPACITY OF URANIUM RESOURCES IN TURKEY

INTRODUCTION The Turkish economy has a projected average annual growth rate of 7-8 % for the near future. Therefore, it has an increasing demand and consumption for electricity. According to the tenth five-year development plan, the primary energy demand of Turkey will increase by 25 %, while the total electricity demand will increase by 34 % during this period [1]. In an effort to achieve energy-supply reliability and diversity; Turkey has undertaken two nuclear power plant (NPP) projects: one with the Russian Federation in Akkuyu in the Mediterranean Region, the other with Japan in Sinop in the Black Sea Region. Additionally, Turkey has plans to initiate a third NPP project and increase the nuclear power capacity gradually. The ongoing NPP projects are based on the external supply of nuclear fuel. However, it is still important to evaluate the identified local resources of Uranium (U) in Turkey, explore U more widely and deeply, and determine the possible domestic contribution to the fuel need for the NPP projects. That is why U exploration and mining activities have been accelerated in recent years. This study aims to assess the fuel-supply capacity of the U resources in Turkey for the Akkuyu and Sinop NPP projects. First, the data related to the identified U resources in Turkey are reviewed. Then, lifetime U requirements for the planned NPPs are estimated and the domestic potential to meet the requirements is put forward. NATIONAL NUCLEAR POWER PROGRAM Turkey signed an agreement with the Russian Federation in 2010 for installation of four VVER-1200 units with a total capacity of 4800 MWe at the Akkuyu site. It is expected that first unit of Akkuyu NPP will be in operation in 2023. A second agreement was signed with Japan in 2013 to build four ATMEA-1 units with a total capacity of 4500 MWe at the Sinop site. Both projects are based on the Built-Own-Operate (BOO) model. In the Akkuyu site, Akkuyu Nuclear Power Plant Electricity Generation Joint-Stock Company (APC), which is a subsidiary of Russia's state-owned nuclear company Rosatom, will build, own and operate the plant. According to the intergovernmental agreement, APC will be responsible for fuel supply, radioactive waste and spent fuel management, and decommissioning of the facility. Provisions of the agreement related to fuel supply states that the nuclear fuel shall be sourced from suppliers based on the long-term agreements between APC and the fuel suppliers [2]. It can be foreseen that APC will deliver fuel from the Russian Fuel Company TVEL, which is the fuel supplier of almost all VVER reactors in operation. APC only recently obtained the Limited Construction Permit from the Turkish Atomic Energy Authority, and is expected to apply for a Construction License pretty soon. The Limited Permit allows some construction activities which do not have a direct bearing on the nuclear safety. The Sinop plant will be built, owned and operated by a consortium established by Mitsubishi Heavy Industries, Itochu Corporation, GDF Suez and the Turkish government-owned Electricity Generation Company (EÜAŞ). The fuel-supply issue is not detailed in the intergovernmental agreement and will be determined after the completion of the feasibility study. Currently, work related to the site and the environmental impact assessment is continuing. Most recently, the Environmental Impact Assessment (EIA) file for the Sinop project has been submitted to the Environment and Urban Planning Ministry. As a result of these developments, Turkey is expected to have at least 9300 MWe installed nuclear-electrical capacity in the next 15-20 years. Besides, the Chinese State Nuclear Power Technology Corporation, the US Westinghouse Electric Company and the Turkish EÜAŞ signed a memorandum of cooperation in 2014 to launch a negotiation in order to construct four NPP units, which apply the advanced-passive PWR CAP1400 and AP1000 technology. For the third project, site selection studies are going on. With respect to this, an agreement between China and Turkey for cooperation in the peaceful uses of nuclear energy was ratified by the Turkish Parliament in 2016 [3]. URANIUM EXPLORATION AND MINING STUDIES AND DOMESTIC RESOURCES In Turkey, radioactive raw material researches and U exploration work were initiated in the 1950s by the General Directorate of Mineral Research and Exploration (MTA). In early stages, the work was concentrated on the vein-type deposits in igneous and metamorphic rocks. Yet, after identification of some uneconomic uraninite mineral occurrences, efforts were directed toward sedimentary-type deposits. Until today, a total of 12614 tons of U resources has been identified in various regions of Turkey, most of them being the sedimentary type [4]. According to the MTA reports, Temrezli deposit in the Yozgat-Sorgun region is the largest and the highest-grade U resource, with 6700 t U at an average grade of 0.1 % U3O8. Other resources are located in Manisa-Köprübaşı, with 3487 t U at an average grade of 0.04-0.07 % U3O8; in Uşak-Eşme-Fakılı, with 3490 t U at an average grade of 0.05 % U3O8; in Aydın-Demirtepe, with 1729 t U at an average grade of 0.08 % U3O8; and in Aydın-Küçükçavdar with 208 t U at an average grade of 0.04 % U3O8 [4]. U exploration and mining activities have gained speed due to the recent developments in the national nuclear power program. In addition to the studies carried out by MTA, Adur, a private Turkish mining company which is a subsidiary of the US-based Uranium Resources Inc. (URI), is conducting drilling activities for resource evaluation in Temrezli and Sefaatli deposits located in the Yozgat-Sorgun region. A preliminary economic assessment of the Temrezli project was completed in 2015. At present, URI is planning to develop an in-situ leaching mine in the Temrezli site. Siting and EIA studies of the Temrezli project are ongoing. URANIUM REQUIREMENTS FOR THE PLANNED NPPs Annual fuel consumption of a nuclear power plant can be calculated by the following equation: M_fuel=(P_e*CF*365)/(η_th*BU)= (P_th*CF*365)/BU where P_e is the installed electrical capacity (MWe), P_th is the thermal power (MWth), CF is the capacity factor, η_th is the thermal efficiency, and BU is the average discharge burnup of the fuel (MWd/tU). The mass balances of the enrichment process yield the following expression for Natural Uranium (NU) requirement per unit of reactor fuel load. M_NU/M_fuel =(x_fuel-x_tails)/(x_NU-x_tails ) where x_fuel is the fuel enrichment, x_NU is the 235U content of NU [taken to be 0.711 weight percent (w/o)], and x_tails is the enrichment of tails (assumed to be 0.25 w/o here). Using the above expressions and the technical data for the Akkuyu and Sinop NPPs, lifetime NU requirements can easily be calculated. Each unit of the Akkuyu NPP (a VVER-1200 design) has a rated electrical power of 1200 MWe and a thermal power output of 3200 MWth. Total lifetime of each unit is 60 years. According to the EIA report, fuel enrichment is 4.79 w/o and the average discharge burnup is 55800 MWd/tU [5]. Using these numbers and an assumed capacity factor of 0.90 in the first equation, annual fuel load for each unit is calculated as 18.8 t U. M_NU/M_fuel is found to be 9.85 from the second equation. Then, lifetime NU requirement for four units is obtained to be 18.8 x 9.85 x 60 = 11110 tons. The Sinop NPP consists of four ATMEA-1 units with a total electrical power of 4500 MWe. The technical features of the plant will be detailed after the completion of the feasibility report. Therefore, the standard design properties of ATMEA-1 reactors are used to calculate NU requirement for the Sinop case. The ATMEA-1 design has a thermal power level of 3150 MWth (for each unit), a capacity factor of 0.90 and a service life of 60 years. The fuel load is 5 w/o enriched and the discharge burnup is 62000 MWd/tU [6]. With these data, annual fuel load for each unit is found to be 16.7 t U and M_NU/M_fuel to be 10.3. Then, lifetime NU requirement for four units is obtained to be 16.7 x 10.3 x 60 = 10320 tons. The total lifetime NU requirements for both Akkuyu and Sinop NPPs are 21430 tons. DOMESTIC SUPPLY CAPACITY For the time being, Turkey’s identified resources add up to 12614 t U. As estimated above, the lifetime NU need for the Akkuyu and Sinop NPPs is (11110+10320=) 21430 t NU. Then, it may be said that the domestic U supply can roughly meet the lifetime NU need for one of the projects (either Akkuyu or Sinop). Nevertheless, there are other issues to be taken into consideration: economy and losses. According to the preliminary economic assessment of the Temrezli project by URI, the deposit (6700 t U) is cost effective. As for the other identified resources in Turkey, the same cannot be said; further investigation is required. As noted above, the in-situ leaching is to be applied in the Temrezli mine. Recovery ratio in the in-situ leaching is less than that in the underground mining and may vary significantly from one site to another (recovery of about 70-90 % uranium ore) [7]. URI has not reported the expected recovery ratio for the Temrezli mine. Additionally, the losses in the other processes leading to the production of nuclear fuel assemblies should be taken into account. Noting that the Temrezli deposit is the only economic resource (that is, reserve under the cost-price conditions) for today in Turkey and presuming that 20 % of the reserve is lost during mining (and milling), refining, enrichment and fabrication; the domestic U supply can more or less meet the lifetime NU requirements for the two units of either Akkuyu or Sinop plants. CONCLUSION AND DISCUSSION At present, the U reserve in Turkey amounts to 6700 t U. Assuming a 20 % loss in all the processes in the front-end of the nuclear fuel cycle, this reserve can nearly feed two units of either Akkuyu or Sinop plants during 60 years. At first glance, this may seem to be insignificant. Yet, the total amount of electricity producible from the two units in 60 years is 1135x109 kWh for Akkuyu and 1064x109 kWh for Sinop. Turkey’s total electricity consumption was 278x109 kWh in 2016 [8]. Then, the possible contribution of nuclear electricity from this reserve is not insignificant. Duly, attempts to explore U resources all over the country and to convert the identified resources into reserves are likely to be fruitful. As well, it is reasonable to focus on research and development in mining (and milling), refining and fuel fabrication in concert with the planned NPP projects. REFERENCES [1] TURKISH REPUBLIC DEPARTMENT OF STATE PLANNING ORGANIZATION, 10th Five-year Development Plan (2014–2018), Ankara, Turkey (2013). [2] Agreement between the Government of the Russian Federation and the Government of the Republic of Turkey on Cooperation in relation to the Construction and Operation of a NPP at the Akkuyu site in the Republic of Turkey (2010). [3] Law on Ratification of Agreement between the Government of China and the Government of the Republic of Turkey for Cooperation in the Peaceful Uses of Nuclear Energy (2016). [4] REPUBLIC OF TURKEY MINERAL RESEARCH & EXPLORATION GENERAL DIRECTORATE, G. Eroğlu, M. Şahiner, Thorium and Uranium in the World and in Turkey, Ankara (2017). [5] EIA Report for Akkuyu NPP, Turkey (2014). [6] INTERNATIONAL ATOMIC ENERGY AGENCY, Interrigional Workshop on Advanced Nuclear Reactor Technology for Near Term Development; Presentation: ATMEA1 Reactor : A mid-sized Generation III+ PWR, Austuria (2011). [7] WORLD NUCLEAR ASSOCIATON, In situ leaching mining of uranium, http://www.world-nuclear.org [8] REPUBLIC OF TURKEY MINISTRY OF ENERGY AND RESOURCES, Electric Consumption data, http://www.enerji.gov.tr

Speaker: Dr Banu Bulut Acar (Hacettepe University Nuclear Engineerin Department)

10 CANADA’S URANIUM MINING INDUSTRY: 75 YEARS OF PRODUCTION AND FUTURE PROSPECTS

HISTORICAL BACKGROUND Pitchblende ore was mined at the Port Radium mine in the Northwest Territories from 1932 to 1940 to extract radium for medical use [1]. However, Canadian uranium production did not begin until 1942, when, at the request of the Government of Canada, the Port Radium mine was re-opened to supply uranium for the Manhattan Project [2]. With the onset of the Cold War, military demand for uranium soared, creating a uranium exploration boom in which thousands of uranium occurrences were discovered throughout Canada [1]. Canada’s second uranium mine opened in northern Saskatchewan in 1953, and by the late 1950s, there were 20 uranium production centres in Ontario, Saskatchewan and the Northwest Territories [1,3]. Annual production peaked in 1959 at 12 200 tonnes of uranium (tU), but declined rapidly as U.S. and U.K. military demand had been met and contracts were not extended. Only 8 mines remained in operation in 1961 [1], and by 1966, production had fallen to less than 3 000 tU with only 4 mines remaining in production [4]. In 1965, Canada made a policy decision that all future uranium sales would be for peaceful purposes only, and while the development of nuclear power was expanding, it was not until the 1970s that uranium demand had risen substantially and exploration and development activity increased [5]. By the late 1970s, new uranium mines were being developed in Ontario and Saskatchewan. Annual uranium production grew through the 1980s, with the focus of production shifting to the high-grade uranium deposits of the Athabasca Basin of northern Saskatchewan [6]. Uranium mining in Ontario ceased in 1996, leaving Saskatchewan as the sole producer of uranium in Canada. URANIUM PRODUCTION Canada is currently the world’s second largest producer and exporter of uranium, with 22% of world production in 2016 [7]. More than 85% of uranium production is exported, making it Canada’s largest clean energy export. Canadian uranium exported for use in nuclear power helps combat climate change by avoiding some 600 million tonnes of CO2 equivalent emissions annually. In addition to being a reliable supplier of uranium, Canada has also long been recognized as a responsible producer of uranium due to policies and practices than ensure protection of the environment, corporate social responsibility and nuclear-non-proliferation. The McArthur River Mine and the Cigar Lake Mine are the world’s largest and second largest uranium mines, respectively, in term of annual production [7]. These mines have ore grades of up 20% uranium, one-hundred times higher than the world average. Canada’s annual uranium production has risen substantially since the start-up of the Cigar Lake mine in 2014, increasing by 42% in 2015 and increasing a further 5% in 2016 to reach a record annual production level of 14,039 tU [7]. Low demand and low prices has resulted in a 8% decrease in Canada’s uranium production for 2017. Due to continued depressed market conditions, 2018 production is expected to decrease a further 40% as production at the McArthur River mine and Key Lake mill are suspended for ten months. This action will reduce operating costs, while uranium concentrates will continue to be supplied to customers from the excess inventory that is currently stored at the Key Lake mill [8]. While only the Cigar Lake mine and McClean Lake mill are currently in production, both the Cigar Lake mine the McArthur River mine have extremely high-grade uranium deposits with low production costs. As a result, the Canadian uranium industry is able to remain viable in a low uranium price market and could quickly ramp-up production to meet an increase in demand. In addition, the Rabbit Lake mine and mill, which has been in care in maintenance since mid-2016 due to low uranium prices, could be brought back into production should uranium prices increase substantially. URANIUM RESOURCES Canada has 9% of the world’s low-cost uranium resources (< US$130/KgU) and has the world’s highest-grade uranium deposits, ensuring that Canada will continue to be a major supplier of uranium well into the future [9]. Canada’s low-cost uranium resources have risen by 60% since 2009 due to increased exploration efforts. When uranium demand and prices increase, two advanced uranium projects in Saskatchewan, which have been put on hold due to low prices, could enter production and provide additional feed for the existing mills. Ore from the proposed Millennium mine would be processed at the Key Lake mill, while ore from the proposed Midwest mine would provide additional feed for the McClean Lake mill [9]. There are also additional undeveloped uranium deposits at McClean Lake that could be brought into production. The Athabasca Basin continues to be highly-prospective for discovering new deposits and several large high-grade uranium deposits have been identified that could be developed into mines in the future. Recent large discoveries in the eastern Athabasca Basin include the Roughrider deposit (Rio Tinto), the Phoenix and Griffon deposits (Denison Mines), and the Fox Lake deposit (Cameco) [9]. In the western Athabasca Basin, the Triple-R deposit (Fission Uranium) and the Arrow Deposit (Nex-Gen Energy) are currently the two largest undeveloped uranium deposits in Canada [9]. Through continued exploration, Canada’s uranium resources are expected to increase further. PUBLIC ACCEPTANCE The success of Canada’s uranium industry is not only the result of having a good resource base and the use of modern and sustainable mining methods, but also the result having an appropriate policy and regulatory regime which fosters a high degree of public acceptance. These policies and regulations address public concerns on health, safety and the environment, as well as nuclear non-proliferation and foreign ownership. The industry itself has adopted best practices through which it has earned a high degree of public support, especially among local Indigenous communities with which they have developed partnerships that provide much-needed local employment and business opportunities. SUMMARY This presentation will briefly outline Canada’s 75-year history in uranium mining as well as examine Canada’s current uranium production and the policy and regulatory regime that governs the Canadian uranium industry. Future prospects for uranium mining in Canada will be discussed, as well as the importance of developing community support. REFERENCES [1] J.W. Griffith, The Uranium Industry – Its History, Technology and Prospects, Mineral Report 12, Mineral Resources Division, Department of Energy, Mines and Resources, Ottawa, Ontario Canada, 1967, 335p. [2] R. Bothwell, Eldorado, Canada's National Uranium Company, University of Toronto Press, Toronto, Ontario, Canada, 1984, 515p. [3] O.J.C. Runnalls, Ontario’s Uranium Mining Industry – Past, Present and Future, Mineral Ontario Mineral Policy Background Paper No. 13, Ontario Ministry of Natural Resources, Toronto, Ontario Canada, 1981, 182p. [4] R. Bothwell, Eldorado, Canada's National Uranium Company, University of Toronto Press, Toronto, Ontario, Canada, 1984, 515p. [5] D.A. Cranstone and R.T. Whillans, An analysis of uranium discovery in Canada. 1930-1983, Uranium Resources and Geology of North America, Technical Document 500, International Atomic Energy Agency, Vienna, Austria, 1989, pp. 29-48 [6] Nuclear Energy Agency, Forty Years of Uranium Resources, Production and Demand in Perspective, Organisation for Economic Co-operation and Development, Paris, France, 2006, 276p. [7] World Nuclear Association, World Uranium Production (updated July 2017), http://www.world-nuclear.org/information-library/nuclear-fuel-cycle/mining-of-uranium/world-uranium-mining-production.aspx [8] Cameco Corporation, Cameco to Suspend Production from McArthur River and Key Lake Operations and Reduce its Dividend, November 8, 2017, News Release. [9] Nuclear Energy Agency, Uranium 2016: Resources, Production and Demand. Organisation for Economic Co-operation and Development, Paris. 2016.

Speaker: Dr Tom Calvert (Natural Resources Canada)

Uranium from Unconventional Resources

Conveners: Dr Brett Moldovan (IAEA), Mr Harikrishnan Tulsidas (UNECE)

11 Unconventional resources in IAEA Uranium DEPOsit Database (UDEPO)

INTRODUCTION Unconventional resources are defined in the 2016 version of the Red Book as “Resources from which uranium is only recoverable as a minor by-product, such as uranium associated with phosphate rocks, non-ferrous ores, carbonatite, black shale and lignite” [1]. Unconventional resources of uranium are recorded in UDEPO, the IAEA Uranium DEPOsit Database [2, 3]. They correspond to low to very low grade, generally very large geological resources where uranium can only be extracted as a co- or by-product of other mining production. In most cases, this cannot currently be done economically with existing technologies. In the IAEA geological classification of uranium deposits [4, 5], most unconventional resources are associated with the following deposits types and subtypes: intrusive plutonic, polymetallic iron-oxide breccias complexes (IOCG-U), volcanic-related, Au-rich paleo quartz-pebble conglomerate, placers, lignite-coal, phosphorite and black shale. The largest unconventional resources are in sea water with resources estimated at 4 billion tonnes at an average grade of 3.3 ppb (3.3 mg/m3). This resource is not included here. UNCONVENTIONAL URANIUM RESOURCES IN UDEPO In 2017, UDEPO total geological uranium resources stand at 62 674 137 tU hosted within 2755 deposits with known or estimated resources. There repartition is a follow: - Conventional uranium resources of 11 857 089 tU, hosted within 2475 deposits with known/estimated resources, - Unconventional resources of 50 817 048 tU, hosted within 280 deposits with known/estimated resources. Deposits such as Olympic Dam (IOCG-U) are included in the UDEPO unconventional resources category, which explains some of the differences in the figures when compared for example with Red Book data. UDEPO is firstly a geological database, thus there is no economic connotation taken into consideration. Unconventional resources or deposits are those that cannot be mined solely for uranium (co- and/or by-product). They include: - very large (generally > 1 Mt U), low grade (20-200 ppm) resources such as those in volcanic formations (Northern Latium province, Italy), lignite-coal (Northern Great Plains, USA), phosphorites (Morocco basins) and black shale formations (Baltoscandian district), - large (10 000–100 000 t U), low grade (50-250 ppm) resources located within peralkaline plutonic intrusions (Kvanefjeld, Greenland) and carbonatites (Palabora, South Africa), polymetallic iron-oxide breccia complexes (Olympic Dam, Australia) and Au-rich paleo quartz-pebble conglomerates (Witwatersrand Basin deposits, South Africa), - very low grade (“background”) uranium (10-30 ppm U) in porphyry copper deposits (Bingham Canyon, USA), volcano-sedimentary formations (El Boleo, Mexico) and base metal deposits (Talvivaara mine, Finland), - placer deposits. In UDEPO, 12 of these unconventional resources contain more than 1 million tonnes of uranium: - Phosphoria Formation (USA): 7 Mt, 0.005-0.015% (Phosphorite) - Tarfaya basin (Morocco): 6.4 Mt, 0.008% (Black shale) - Baltoscandian district (Estonia): 5.667 Mt, 0.0085% (Black shale) - Chattanooga Shale (USA): 5 Mt, 0.006% (Black shale) - Northern Great Plains (USA): 5 Mt, 0.006% (Coal-lignite) - Oulad Abdoum basin (Morocco): 3.2 Mt, 0.012% (Phosphorite) - Olympic Dam (Australia): 2.125 Mt, 0.023% (IOCG-U) - Timahdit (Morocco): 2.1 Mt, 0.005% (Black shale) - Meskala basin (Morocco): 2 Mt, 0.010% (Phosphorite) - Randstad Inlier (Sweden): 1.7 Mt, 0.021% (Black shale) - Gantour basin (Morocco): 3.2 Mt, 0.012% (Phosphorite) - Northern Latium province (Italy): 1 Mt, 0.005% (Volcanic-related, volcano sedimentary) Other than the Olympic Dam deposit which is an operating mine, precise estimation of these large geological resources is very difficult due to the size of the formations and the poorly characterized distribution of uranium grades. For example, the Phosphoria Formation (USA) covers an area of about 350 000 km2, with a thickness of 60-150 m for the mineralized phosphatic layers and uranium grades are estimated around 50-150 ppm. Thus, depending of the parameters used, the calculated content of uranium ranges between 5 and 60 Mt U (7 Mt in UDEPO from historical USA data). Historically, 184 tU was extracted from localized enriched areas with tenors reaching up to 1% U. REPARTITION OF THE UNCONVENTIONAL RESOURCES In detail, unconventional resources are associated with several deposit types and subtypes: - Type 1: Intrusive, plutonic subtype, with 3 classes (quartz monzonite, peralkaline complex and carbonatite). Resources: 1.907 Mt in 33 deposits; - Type 3: Polymetallic iron-oxide breccia complex (IOCG-U). Resources: 2.760 Mt in 18 deposits ; - Type 4: Volcanic-related, volcano-sedimentary subtype. Resources: 1.204 Mt in 2 deposits, - Type 10: Paleo quartz-pebble conglomerate, Au-rich subtype. Resources: 1.860 Mt in 100 deposits. Also, in South Africa, 16 areas with large tailings resources contain an estimated 175 500 tU; - Type 11: Surficial, placer subtype. Resources: 67 000 t in 13 deposits ; - Type 12: Lignite-coal, stratiform subtype. Resources: 7.223 Mt in 21 deposits; - Type 14: Phosphate, minerochemical phosphorite subtype. Resources: 14.148 Mt in 48 deposits ; - Type 15: Black shale, stratiform subtype. Resources: 21.473 Mt in 29 deposits. However, the types and subtypes listed above also contain deposits previously mined for uranium and those which could be mined in the future for uranium only owing to their grades (generally ˃ 0.05% U). In those instances the deposits are not considered unconventional in UDEPO. Examples include the coal-lignite deposits mined in the past in Germany (Freital district), the black shale deposits of Uzbekistan and the organic phosphorite deposits mined in Kazakhstan. - Type 1. Intrusive, subtype 1.2 plutonic: all quartz monzonite (porphyry copper), and most peralkaline complexes and carbonatites correspond to unconventional resources where low to very low (10-250 ppm) grade uranium is associated with Cu, Ag, Au, Mo, REE, Th, Nb, Ta, Zn and Zr. Some exceptions are Bokan Mountain (USA) and Poços de Caldas (Brazil) where uranium was mined in the past as a primary commodity. Uranium was produced in the past at Bingham Canyon (USA), Twin Buttes (USA) and Palabora (South Africa). Uranium production is planned in the near future at the Kvanefjeld project (Greenland) in association with REE and Zn. - Type 3. Polymetallic iron-oxide breccia complex (IOCG-U): deposits of this type, with grades of 30-250 ppm U, correspond to large to very large iron–copper–gold–silver deposits occurring on the Gawler Craton (Australia) and in the Carajas Province (Brazil). Uranium is extracted as a co-product along with copper–gold–silver at Olympic Dam, the largest world uranium deposit with resources of 2.2 Mt. Deposits from the Mount Painter area in South Australia which have grades of 0.05–0.20% U are considered conventional. Some of these deposits have already been mined in the past for radium or uranium alone. - Type 4. Volcanic-related, stratabound and volcano-sedimentary subtypes: Quaternary alkaline volcanics of northern Latium (Italy) contain in average 20-70 ppm U representing geological resources of more than 1 Mt. Sub-marginal resources in the volcano-sedimentary formations are in the range 5-10 000 t U at a grade of 300-600 ppm U. The El Boleo project (Mexico), a Cu-Co-Ni-Mn mine, is planning the extraction of very low grade (10 ppm) uranium. - Type 10. Paleo quartz-pebble conglomerate, Au-rich subtype: uranium is mined as a by-product of gold in the Witwatersrand Basin (South Africa). Average grade is around 250 ppm and uranium geological resources exceed 2 Mt. In addition, there are plans to extract uranium and gold from low to very low grade (35–75 ppm U) tailings which are a legacy of gold mining over the past 130 years. Total resources in 16 areas are estimated to be of the order of 175 500 tU. - Type 11. Surficial, placer subtype: placer deposits are accumulations of heavy minerals formed by gravity separation during sedimentary processes. The principal minerals containing thorium and uranium are zircon, monazite and xenotime. India has very large resources of monazite from which uranium could be extracted in addition to Th and REE. - Type 12: Lignite–coal: most coal and lignite deposits contain very low grades, of the order of U, on the order of 1–5 ppm. However, some coal deposits (such as those in South Africa, Kazakhstan, Kyrgyzstan, the Russian Federation and Ukraine) record unusually high uranium contents (0.05–0.15% U) and these are not classified as unconventional in UDEPO. In the past, uranium was extracted from fracture-controlled coal deposits in the former German Democratic Republic (Freital district). Very large quantities of tailings from coal processing around the world are enriched in uranium (5-20 ppm) representing significant unconventional resources. - Type 14: Phosphate: Phosphorites typically cover very large surface areas and represent large low grade (50-150 ppm) resources of uranium. Total world phosphate resources are estimated at 300 billion tones and assuming an average grade of 100 ppm U, would contain about 30 Mt U. Between 1978 and 2000, 17 225 t U were extracted from the phosphorite formations in Florida. Continental phosphate deposits (Central African Republic) and organic phosphorites (Kazakhstan, Russian Federation) are listed as conventional resources due to their grade (0.05-0.3%). Some of the Kazakhstan organic phosphorite deposits were historically mined for uranium as a major product, - Type 15: Black shale: in UDEPO, the uranium resources of black shales are currently estimated at 21.5 million tU, with stratiform black shale formations hosting the largest geological, low-grade (20–200 ppm U) uranium resources in the world. The uranium is associated with various other metals such as Ni, Co, Cu, Zn and V. Historically, uranium was mined as the primary product from this type of deposit in the Gera-Ronneburg district (former German Democratic Republic). PLANNED AND POTENTIAL MINING PROJECTS In 2018, several operating mines or new mining projects could produce uranium as a by- co-product: - Chuquicamata (Chile): Cu-Mo (porphyry-copper), potential production of 85 t U/year from ore containing 5-10 ppm U, - Kvanefjeld (Greenland): REE-Zn (peralkaline complex), planned production of 400 t U/year from ore containing 200-250 ppm U, - Round Top (USA): REE-Be (peralkaline complex), planned production of 115 t U/year from ore containing 20-50 ppm U, - El Boleo (Mexico): Cu-Ni-Co-Mn mine (volcanic-related), potential production of 60 t U/year from ore containing 10-20 ppm U, - Talvivaara (Finland): Cu-Ni-Co-Mn mine (black shale), potential production of 350 t U/year from ore containing 10-15 ppm U, - Haggan (Sweden): Mo-Ni-Zn-V (black shale), planned production of 385 t U/year from ore containing 120-150 ppm U, - MMS Vicken (Sweden): Zn-Ni-Cu (black shale). SUMMARY Currently 280 uranium deposits and resources listed in UDEPO are classified as unconventional resources associated with eight deposit types and containing geological resources in the order of 51 Mt U. Considering the number of analogous geological host rock examples worldwide, potential additions of unconventional deposits and resources to the UDEPO database can be estimated in the order of 5-6000: - Type 1. Intrusive plutonic deposits: 1660 occurrences worldwide (33 deposits in UDEPO); - Type 3. Polymetallic iron-oxide breccia complex (IOCG-U) deposits, 50 occurrences worldwide (18 deposits in UDEPO); - Type 11. Surficial placer deposits: 500-1000 occurrences worldwide (13 deposits in UDEPO) ; - Type 12. Lignite-coal deposits: about 1600 occurrences worldwide (21 deposits in UDEPO); - Type 14. Phosphate deposits: 1635 occurrences worldwide (48 deposits in UDEPO) ; - Type 15. Black shale deposits: around 1000 occurrences worldwide (29 deposits in UDEPO). This indicates that potential geological unconventional resources of uranium worldwide are enormous. Of course, most of these resources will never produce uranium due to their very low grades, their environmental impact and their economic conditions. However, unconventional uranium resources in conjunction with the concept of “comprehensive extraction” will probably play an important role in future world uranium production. REFERENCES [1] OECD NUCLEAR ENERGY AGENCY, INTERNATIONAL ATOMIC ENERGY AGENCY, Uranium 2016: Resources, Production and Demand, OECD, Paris (2017). [2] INTERNATIONAL ATOMIC ENERGY AGENCY, World Distribution of Uranium Deposits (UDEPO – 2016 Edition). IAEA-TECDOC (to be published in 2018). [3] BRUNETON, P., CUNEY, M., FAIRCLOUGH, M., JAIRETH, S., LIU, X., ZALUSKY, G., UDEPO – IAEA Uranium DEPOsits database, URAM 2018, to be published in Proc. Int. Symposium, Vienna, 2018, IAEA, Vienna, 4 p. [4] BRUNETON, P., CUNEY M., DAHLKAMP, F., ZALUSKI, G., “IAEA geological classification of uranium deposits”, Uranium Raw Material for the Nuclear Fuel Cycle: Exploration, Mining, Production, Supply and Demand, Economics and Environmental Issues, URAM 2014 (Proc. Int. Symposium, Vienna, 2014), IAEA, Vienna, 10 p. (to be published in 2018). [5] BRUNETON, P., CUNEY, M., “Geology of uranium deposits”, Uranium for Nuclear Power (HORE-LACY, I., Ed.), Woodhead Publishing Series in Energy No. 93, Elsevier, Amsterdam (2016) 11–52.

Speaker: Dr patrice bruneton (none)

12 Uranium: Waste or Potential Future Resource?

Abstract From the early days of the nuclear power industry, Australia witnessed a “Yellowcake Rush”, with prospectors scouring our countryside for uranium resources. Large resources of the metal were identified and a relatively buoyant market led to investment and a uranium export industry, despite a challenging political environment. A prevailing weak market for Uranium since the March 2011 Fukushima incident has slowed exploration, seen some resources change commercial operators and constrained investment in the sector. Drawing on mixed commodity resources which include uranium, a number of companies are developing large mines to extract copper, gold, phosphate and rare earth oxides. Rather than extract the uranium the operators plan to direct it to tailings repositories. While the resources in question may have been developed for uranium with vigour in the past, market conditions dictate an environment whereby several thousand tonnes of uranium resources will be stored in tailings dams. Should the uranium market improve in the future, it is possible that these resources will become readily extractable uranium resources. The expenses of mining, crushing and grinding of ore represent sunk costs. Future developments may be considered where uranium is extracted from the tails resources, by either: inexpensive digging and reprocessing or perhaps chemical extraction will be required. Case Study – Carrapateena The Carrapateena copper and precious metals mine is currently being developed by Oz Minerals. Located in South Australia, some 400 kilometres North North West of Adelaide, Carrapateena is a vertical breccia hosted, hematite dominant iron oxide copper gold (IOCG) deposit, covered by 470 metres of Neoproterozoic sediments extending 2,000 metres below the unconformity. Following geophysical targeting of gravity and magnetic anomalies in the Proterozoic basement of the eastern margin of the Gawler craton, drilling discovered the Carrapateena mineralization in 2005. Carrapateena is characterized by sulphides mineralization distributed a disseminated 0.1 to 4 millimeter grains of predominantly pyrite, chalcopyrite and bornite. Rare Earth Elements at Carrapateena are bound in monazite with uraninite bearing uranium. Both monazite and uraninite are closely associated with the bornite. The total reported resource of Carrapateena in November 2016 was 134 million tonnes, with a copper grade of 1.5 percent, gold at 0.6 grams per tonne, silver at 6.6 grams per tonne and an average orebody grade of 239 parts per million for uranium.¹ Milling and processing of Carrapateena ore will recovery primarily copper, gold and silver, but could result in the capture of some uranium which would present as a penalty constituent in the production streams. The project proponent, Oz Minerals estimates that the tailings radionuclide composition will be similar to that of the initial mineralized ore. For the purposes of calculating uranium remaining in the tailings stream a 10 percent recovery is estimated, resulting in 90 percent of the original uranium in processed ore being deposited in the Eliza Creek Tailings Storage Facility (TSF). Over the mine life an estimated 145 million dry tonnes of tailings will be transported to the TSF, resulting in over 31,000 tonnes of uranium being stored in the Eliza Creek TSF. ² Case Study – Nolans Bore The Nolans Bore project is currently being developed by Arafura Resources. Located in Australia’s Northern Territory, some 140 kilometres North North West of Alice Springs, the 1550-1510 Ma Nolans Bore pegmatite suite is situated in the 1860-1720 Ma metasedimentary rocks of the Aileron Province. First identified in 1995 following a thorium and uranium radiometric survey, the complex Nolans Bore primary mineralization is overprinted by hypogene mineralisation and subsequently supergene mineralisation. Coarse primary fluorapatite crystals (1-8 centimetres) occur within a microcrystalline fluorapatite matrix which dominates the vein texture and contains Rare Earth Elements (REE) and uranium. The second stage of mineralisation tends to exhibit lower grades of REEs and uranium in fluorapatite allanite breccias. The final stage of supergene mineralisation has variable distribution with extensive clay and kaolin alteration. The globally significant Nolans Bore REE deposit is open at depth and is characterized by comparatively high neodymium content. The total resource reported at Nolans Bore in December 2016 was 56 million tonnes, with a total REE oxide content of 2.6 percent, a phosphate (as P2O5) content of 12 percent and a uranium grade (as U₃O₈) of 200 parts per million.³ Project proposals by Arafura in 2010 included the extraction of the uranium and production of uranium oxide, however, later development application by the company excluded this option. Milling and other processing of the Nolans Bore ore to recovery primarily REEs and phosphate could result in the capture of the some uranium, possibly presenting a penalty constituent in the production streams. The project proponent, Arafura Resources estimates that the tailings radionuclide composition will be similar to that of the initial mineralized ore. For the purposes of calculating uranium remaining in the tailings stream a 10 percent recovery is estimated, resulting in 90 percent of the original uranium in processed ore being deposited in the above ground Tailings Storage Facility (TSF). Over the mine life an estimated 56 million dry tonnes of tailings will be transported to the TSF, resulting in over 10,000 tonnes of uranium being stored in the TSF. Case Study – Toongi The Toongi mine is operated by Alkane Resources to export rare earth and hafnium product streams from Australia. Located in New South Wales, about 300 kilometres North West of Sydney, the Jurassic age Toongi rare metal deposit is part of a 100 km2 Jurassic aged alkaline trachyte volcanic province intruding and overlying a folded Siluro-Devonian volcanic-sedimentary sequence. Weakly radioactivity in the area was identified in 1951 by the Bureau of Mineral Resources (Geoscience Australia) and fieldwork identified trachytic volcanics as the source the following year. Following up on the potential identified in regional exploration in1982 for a resource of zirconium, hafnium, niobium tantalum, yttrium, uranium and REE within the Toongi trachyte, commercial testing commenced in 2000. The Toongi orebody some shallow weathering and minor oxidation down to 40 metres, and some chill margins at the boundary of the trachyte. Mineralisation is generally fine grained with some crystal clusters, veinlets and vug fill. The total resource reported at Toongi is 73.2 million tonnes with 1.96 percent ZrO2, 0.04 percent HfO2 and 0.75 Rare Earth Oxides (REO).⁴ The project proponent at Toongi, Alkane Resources has indicated no interest in the recovery and production of uranium from the resource for a number of reasons, not least of which is current ban on mining and production of uranium in New South Wales and that the additional capital requirements and process flowsheet development costs are simply not economic. The company comprehensively addresses the risks of radioactivity at Toongi, but has not sought approval to produce uranium. Current mining of Toongi to recover primarily REEs and hafnium may result in the capture of the some uranium, possibly presenting penalty constituents in the production streams. The tailings radionuclide composition is estimated to similar to that of the initial mineralized ore. For the purposes of calculating uranium remaining in the tailings stream a 10 percent recovery is estimated, resulting in 90 percent of the original uranium in processed ore being deposited in the above ground Tailings Storage Facility (TSF). Over the mine life an estimated 60 million dry tonnes of tailings will be transported to the TSF, resulting in over 7,000 tonnes of uranium being stored in the TSF. Historical Case Study – Rosebery Mine Tasmania The reprocessing of old tailings can lead to increased product recovery and improved financial outcomes for some mining operations. For example, through the early 1990s the Rosebery mine was able to reprocess tailings produced from the 1880s to the 1930s in order to produce additional gold/silver dore. The older processing technology had recovered the majority of the zinc, lead and copper from the finely crystalline Rosebery ore. However, significant quantities of gold and silver remained in the crushed tailings. The tailings were readily dug from the old dams around the Rosebery mine site and transported to the mill for reprocessing. Utilising advance recovery technology not available to earlier generations, the Rosebery mill successfully treated the fine grained crystalline sulphides and recover additional saleable gold/silver dore. An additional benefit from the tailings reprocessing was environmental, as the tailings repositories that were reworked were readily rehabilitated with a rock then soil cover which facilitated the growth of vegetation, in particular, improving the visual impact of the older tailings dams. Other global examples of tailings reprocessing projects include; De Beers Consolidated Mines to extract overlooked diamonds from 360 million tons of old tailings surrounding the Kimberley mines in South Africa, DRD Gold’s South African Witwatersrand operations to extract gold from tailings utilising new recovery technology, South African projects to recover platinum group elements (PGEs) and chrome from Bushveld complex tailings, and Carbine Resources feasibility work on recovering gold and copper from tailings at Mount Morgan in Queensland. Conclusions The technology for reprocessing tailings left behind from old mining operations has proven profitable for a number of corporations globally. Advances in metallurgical technology, changing social, environmental or aesthetic considerations and changes in commodity prices could be the catalyst that initiates projects to recover value from old tailings. The Carrapateena, Nolans Bore and Toongi developments in Australia will each leave significant amounts of potentially valuable uranium in their respective tailings facilities. Each of the project proponents for economic and political reasons has chosen to not extract the uranium value at this stage. Should political or market conditions for uranium change in the future, the tailings repositories at Carrapateena, Nolans Bore and Toongi could represent significant potential commercial value for a project proponent. Geoscience Australia provides authoritative independent advice to the Australian Government supported by holdings of resources data over several decades. A record of potential resources including those with altered physical characteristics is maintained by Geoscience Australia, ensuring a complete picture of evolving circumstances is available to government and the public. ¹ Australian ore deposits, Phillips (ed.), Australasian Institute of Mining and Metallurgy (AusIMM) Publisher, September 2017. ² Carrapateena Project Environment Protection and Biodiversity Conservation Act 1999 Referral of Proposed Action, Oz Minerals March 2017 (EPBC Referral). ³ Australian ore deposits, Phillips (ed.), Australasian Institute of Mining and Metallurgy (AusIMM) Publisher, September 2017. ⁴ Australian ore deposits, Phillips (ed.), Australasian Institute of Mining and Metallurgy (AusIMM) Publisher, September 2017.

Speaker: Mr Paul Kay (Geoscience Australia)

13 Status of Uranium Activities on Unconventional Resources in the Philippines

While the initial search for uranium dates back as early as 1954, it was only in 1977 that the systematic exploration approach for uranium was started under the International Atomic Energy Agency (IAEA) Technical Cooperation (TC) project PHI/3/04 “Uranium Geochemical Prospection” [1]. This was tied up with the decision of the Philippine Government at that time to establish the Philippine Nuclear Power Program and build the first Philippine Nuclear Power Plant (PNPP) in the Country. Unfortunately, due to the Chernobyl accident that happened in April 26, 1986, the first PNPP was not allowed to operate and later on mothballed by the then government dispensation, although it was almost 100% complete. This led to the discontinuance of the quest for indigenous uranium mineral deposits. However, in May 1995, Executive Order No. 243 was issued, which created the Nuclear Power Steering Committee that provided the policies, direction, monitoring, evaluation, and other functions necessary and appropriate to attain the objectives of the overall Nuclear Power Program of the country. It states, in part, that, “the Philippine Nuclear Research Institute (PNRI) shall also conduct research and development programs on the various facets of the nuclear fuel cycle, including the resumption of activities on uranium exploration” [2]. A modest reconnaissance approach using the combined radiometric and geochemical exploration method was launched that resulted in covering, so far almost 70% of the entire Philippine archipelago. Results however were disappointing as no major uranium deposition have been delineated, except for a few minor mineralizations. Hence, the strategy was shifted to sourcing uranium from unconventional resources. This gave rise to the inclusion of PNRI in the IAEA Contract Research Project (CRP 18759) “Geochemical and Radiometric Characterization of the Cu-Mo-U Occurrences in the Larap-Paracale Mineralized District, Camarines Norte, Philippines” in 2015. It is in this mineralized district that the mineral uraninite was discovered by Frost [2] in 1959 and an indicated reserve of about 200 tons U3O8 contained in 500,000 tons of ore with a grade of 0.04% U3O8 at the Bessemer pit being operated by the Philippine Iron Mines was reported by Dr James Cameron, IAEA expert in 1965 [3]. Efforts at that time to locate other uranium mineralized areas were not encouraging, although a few copper (Cu) – molybdenum (Mo) with associated uranium (U) areas were noted. These areas are now the subject of investigation by the present IAEA CRP 18759. Surveys conducted delineated within the Nakalaya locality an area having field gamma-ray spectrometric measurements varying from 104 – 138ppm U with the use of RS230 gamma ray spectrometer. Fluorimetric analysis of rock and soil samples gave 39 – 193ppm U while Atomic Absorption Spectrometric analysis gave 209 – 588ppm Cu and 53 – 363ppm Mo. Interestingly, ICP-MS analysis showed 173 – 544ppm rare earth elements (REE). Recently, a more detailed gamma ray spectrometric survey pinpointed an area of about 100 meters south of the Nakalaya area having 76 – 236ppm U. Laboratory analyses of rock and soil samples are still pending. This anomalous area is underlain by the Tumbaga/Universal formation of Eocene age. It is part of a sedimentary rock sequence consisting of limestone, marl and shale that was subjected to thermal metamorphism resulting to skarns, hornfels and marble that acted as hosts to the iron deposits and minor base metal mineralization with associated uranium. It is therefore aimed that uranium will be produced as a by-product or co-product if this area is shown to be economically viable to mine with the combined production of Cu, Mo and REE, including U. Under the IAEA Technical Cooperation project PHI2010 entitled “Enhancing National Capacity for Extraction of Uranium, Rare Earth Elements and Other Useful Commodities from Phosphoric Acid”, a study on uranium recovery from phosphoric acid is being carried-out. This project is being undertaken in collaboration with the Philippine Phosphate Fertilizer Corporation (PHILPHOS) and with financial assistance from the National Research Council of the Philippines – Department of Science and Technology. PHILPHOS imports around 1.97 Mt of raw phosphate ores from different countries per year for the production of fertilizers. Samples of phosphate ores, phosphoric acid and fertilizer products were analyzed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) to determine elemental content. Analysis showed that the phosphate ores contain uranium as high as 139 ppm with 20.5 ppm thorium (Th), including REE’s up to 828 ppm. Analysis of phosphoric acid samples using ICP-MS gave values of uranium content varying from 66 – 189 ppm. Phosphatic fertilizer products, particularly Nitrogen-Phosphorus-Potassium (NPK) fertilizers, contain radionuclides and REEs having values reaching up to 223.8 ppm U, 0.8 ppm Th and 36.8 ppm REE and these fertilizers are contaminating the environment upon their application. Uranium in these fertilizers is well beyond the global average of uranium content in soils, which is 0.3 – 11 ppm [5]. A laboratory scale solvent extraction of uranium using a synergistic mixture of diethyl-hexyl phosphoric acid (D2EHPA) and trioctyl phosphine oxide (TOPO) from phosphoric acid was conducted. The static laboratory testing achieved a 92% recovery rate of uranium from phosphoric acid. This experiment thus led to the precipitation of the first yellowcake from phosphates in the Country. This study is projected to produce cleaner fertilizers mitigating the risk from environmental contamination, promote maximization of resources and the opportunity to utilize uranium if the Philippines will decide to go into the nuclear option. REFERENCES [1] Tauchid, M., Uranium Geochemical Prospection, report to the Government of the Philippines, IAEA TA Report No. 1511, International Atomic Energy Agency, Vienna, Austria, (1978). [2] Official Gazette of the Republic of the Philippines. Executive Order No. 243, s. 1995, “Creating a Nuclear Power Steering Committee”. Malacanang Palace, Manila, (1995), http://www.officialgazette.gov.ph/1995/05/12/executive-order-no-243-s-1995/ [3] Frost, J.E., Notes on the genesis of the ore-bearing structures of the Paracale District, Camarines Norte. The Philippine Geologist, 13(2): (1959), 31-43. [4] Cameron, J., Prospection and evaluation of nuclear raw Materials, report to the Government of the Philippines, IAEA TA Report No. 175, International Atomic Energy Agency, Vienna, Austria, (1965). [5] United States Environmental Protection Agency (USEPA). Potential uses of phosphogypsum and associated risks, (1992), https://www.epa.gov/sites/production/files/2015-07/documents/0000055v.pdf.

Speaker: Mr ROLANDO REYES (PHILIPPINE NUCLEAR RESEARCH INSTITUTE)

14 Conventional and unconventional uranium resources in the Carajás Mineral Province, Brazil: prospectivity criteria for IOCG and granite-related deposits

INTRODUCTION The Amazonian Craton (South America) hosts several favourable areas for uranium exploration that are still barely acknowledged. The most significant of the recognized resources are in the Carajás Province, the oldest known Archean crustal fragment in the craton. Identified uranium resources are unconventional, hosted by the world-class IOCG deposits from the Carajás Copper-Gold Belt [1, 2]. Nevertheless, the potential for granite-related resources is notable, as Paleoproterozoic A-type granitic plutons cover several thousands of square kilometres of the province’s surface and present very high uranium background values [3-4]. This work aims to present an overview of the uranium potential in the Carajás Mineral Province and regional prospectivity criteria for uranium-rich IOCG and granite-related uranium deposits, based on Airborne geophysics and regional- to deposit-scale structural and geological data. TECTONOSTRATIGRAPHIC FRAMEWORK There are three main rock-generation ages in the Carajás Province tectonostratigraphic evolution, namely in the Mesoarchean (3.02 to 2.83 Ga), Neoarchean (2.76 to 2.55 Ga) and in the Paleoproterozoic (1.88 Ga). The oldest rocks are gneisses, greenstone belts and granitoids developed under an accretionary-collisional system, reported as the Itacaiunas Belt [5-6]. Collisional peak metamorphism was dated at 2.85 Ga, and metamorphic fabrics are of medium to high amphibolite facies [6-7]. This rock association represents the basement of the Carajás Basin (2.76 to 2.70 Ga), a Neoarchean rift-related metavolcanossedimentary sequence [8-9] that hosts supergiant BIF-related iron ore deposits and other exhalative resources, such as Cu-Zn volcanogenic massive sulphides [9]. Coeval bimodal magmatism is represented by several A-type granites and mafic-ultramafic intrusions. Late stage granitic dykes persist to emplace until 2.55 Ga and are spatially and chronologically related to several magnetite-rich IOCG deposits [2, 10]. At about 1.88 Ga, the region experienced an anorogenic magmatic event, which also affected all the central-eastern side of the Amazonian Craton, known as the Uatumã magmatism. This event produced a second generation of A-type granites in the province [3], emplaced at shallower depths and related to widespread hydrothermal activity in a brittle, fluid-dominated extensional environment Neoarchean rocks were only deformed and metamorphosed in the Paleoproterozoic. There are two events of ductile to ductile-brittle deformation and metamorphism that can be recognized. The oldest one is the Transamazonian Orogenic Cycle (2.20 to 2.05 Ga), a collisional system that agglutinated several Archean nuclei and Rhyacian magmatic arcs and greenstone belts [6, 11], related in the province to low green schist (south) to high amphibolite (north) metamorphic fabrics and structures. To the north, the Archean units are limited by a collisional suture from Rhyacian plutonic assemblages that are imbricated over the province [6]. The youngest one is the Sereno Event, an intracontinental orogeny correlated to Orosirian accretionary-collisional belts that surrounded the Amazonian protocraton at 2.00 to 1.98 Ga [6]. Sereno fabrics are of very low grade, from sub-greenschist to greenschist facies. The Mesoarchean main structural trend is ductile in character and of an E-W direction, while the Transamazonian trend varies between ENE-WSW and NE-SW. The Sereno structures are widespread, although less penetrative and of a ductile-brittle style, in an X-shaped pair of oblique structures in WNW-ESE and ENE-WSW directions [6]. URANIUM RESOURCES IN CARAJÁS MINERAL PROVINCE The Carajás Mineral Province hosts some of the largest and oldest IOCG deposits in the world, known for their relatively high uranium contents in comparison to the majority of other deposits from the same class. Main orebodies are Archean (2.70 to 2.55 Ga), but several of them present a Paleoproterozoic (1.88 Ga) granite-related hydrothermal overprint, responsible for local remobilization, endowment in copper sulphides and, as a result, the formation of high grade oreshoots and/or spatially-related secondary orebodies, considered by some authors as a second IOCG-like event [2, 10, 12]. The deposits show a wide range of host rocks but share several characteristics, like an intense Fe metassomatism associated with the occurrence of low sulphidation sulphides, LREE enrichment, high yet variable amounts of Co, Ni, Pb, Zn, As, Bi, W and U, spatial and chronological correlation to A-type granitic plutons / dykes, and breccia-like textures [1-2, 10]. Archean and Paleoproterozoic orebodies differ from each other, however, in their hydrothermal assemblage and ore minerals, reflecting variations in the fluids oxidation stage, pH, fO2 and fS2 [10, 12]. Older deposits are magnetite-rich and thought to be formed in deeper crustal levels, while the secondary younger orebodies are hematite-rich, silica-saturated, and developed in shallower environments [2]. In addition, Archean deposits were deformed and metamorphosed by the Transamazonian and Sereno events, while Paleoproterozoic deposits are post-tectonic, preserving their original textures and mineralogy [13]. The most significant uranium-bearing minerals are uraninite, thorianite and thorite [10]. Allanite and monazite concentrations may also be relevant, although uranium grades are much smaller. All phases occur as inclusions or within massive sulphide and Fe-oxides masses in the ore mineral assemblage. Additionally, uraninite and allanite are common accessory minerals in the potassic alteration assemblage, usually occurring as inclusions in biotite and garnet. Known uranium resources are of 150,000 tU [14], but that value is highly underestimated, as it considers only four out of a dozen known IOCG deposits (Salobo, Sossego-Sequeirinho, Cristalino and Igarapé Bahia-Alemão). Grades are low, ranging from 60 to 130 ppm U [14] Paleoproterozoic granite-related (and metasomatic?) uranium deposits remain undiscovered in the province, but the exploration potential for that mineral system is remarkable, especially where plutons and dykes are affected by late to post-magmatic structures and alteration. Uranium background values are very high in comparison to other A-type granites, varying from 10 to 43 ppm U, while Th/U ratio is between 1.11 and 4.71. The A-type granites are subalkaline to alkaline, developed through fractional crystallization and presenting variable sources derived from Archean crust [3-4]. Hydrothermalism and brittle deformation also affect the granites, along NE-SW and NW-SE structures. Greisen zones are common within the granitic bodies, sometimes related to tin mineralizations [4]. DISCUSSION: PROSPECTIVITY CRITERIA FOR URANIUM RESOURCES Some authors suggest that high uranium grades in IOCG systems are dependent on higher background values of host rocks, as observed in Australian IOCG-U provinces [15-16]. In the Carajás Province, however, uranium (and gold) grades are usually higher at Paleoproterozoic oreshoots and orebodies, especially those that are close or crosscut by coeval granites. This indicate that uranium (and gold?) endowment is at least in part linked to granite-related hydrothermal input. The uranium source, in this case, would be mostly magmatic rather than leached from host rocks. The energy drive for Paleoproterozoic fluid circulation is thought to be related to the granitic magmatism, but the critical control for both magmatic and hydrothermal activities seems to be structural. Granitic plutons and dykes were emplaced in sites where structures are denser and their geometry roughly follows previous structural patterns. Besides this, the structural framework of the host rocks, reactivated under brittle conditions during granitic intrusion, coincides with the main granite-related and IOCG-like alteration zones. Structures that acted as primary fluid pathways usually present breccia textures and silicification, showing a singular prominent topography that is recognizable even in SRTM (Shuttle Radar Topography Mission) images. Regional alteration assemblage that indicates proximity to mineralized sites includes quartz, chlorite, epidote, albite, carbonate, actinolite, scapolite, greenish biotite, sericite, tourmaline and stilplomelane. The main oxide is hematite, but occasionally magnetite is also found, while sulphides include chalcopirite, bornite and chalcocite. This mineral assemblage can pervasively replace the host rocks or occur in zoned sintaxial veins, usually forming stockworks. Airborne radiometric data are a powerful tool to regional targeting for IOCG and granite-related deposits. The uranium concentrations normalized using thorium (Ud) strongly correlate with the extensional structures. Field relations also confirm that Ud anomalies are coincident with regional undeformed Paleoproterozoic alteration zones. Ud maps also highlight several potential sites for uranium research inside the granitic plutons, especially along crosscutting structures of NE-SW and NW-SE directions. CONCLUSIONS The development of prospectivity models for the Carajás Mineral Province is challenging, as three different mineralization ages are recognized. Isolating objective prospectivity criteria for each metallogenic epoch and mineral system is critical to the development of more precise exploration guidelines in the region. The main regional prospectivity criteria to target uraniferous IOCG deposits in the Carajás Province are: • Coincidence between high Ud values and fault zones; • Proximity to deep structures; • Proximity to 1.88 Ga granitic plutons and dykes; • Occurrence of silicified fault zones; • Occurrence of crosscutting structures and higher structural density; • Occurrence of undeformed, post-tectonic, hematite-bearing hydrothermal assemblages. Prospectivity criteria for granite-related deposits are still being investigated, but the most favourable sites seem to be those pointed out by Ud anomalies and that are coincident with post-magmatic alteration sites. REFERENCES [1] TALLARICO, F.H.B., “O Cinturão Cupro-Aurífero de Carajás, Brasil”. Unpublished PhD thesis, Universidade Estadual de Campinas, São Paulo, Brazil (2003), 12 pp. [2] XAVIER, R.P. et al. “The iron oxide copper‒gold deposits of the Carajás Mineral Province, Brazil: an updated and critical review”. In: Porter TM (ed) Hydrothermal Iron Oxide Copper-Gold & Related Deposits: A Global Perspective. Australian Miner. Fund, Adelaide (2010), Vol 3, pp. 285-306. [3] DALL’AGNOL, R. et al. “Petrogenesis of the Paleoproterozoic, rapakivi, A-type granites of the Archean Carajás Metallogenic Province, Brazil”. Lithos 80 (2005) 101-129 [4] TEIXEIRA, N.P. et al. “Geoquímica dos granitos paleoproterozóicos da Suíte Granítica Velho Guilherme, província estanífera do sul do Pará”. Rev Bras Geoc 35 (2005) 217-226. [5] ARAUJO, O.J.B. et al. “A megaestruturação da folha Serra dos Carajás”. Anais do 7º Congresso Latino Americano de Geologia (1988) 324-333. [6] TAVARES, F.M. “EVOLUÇÃO GEOTECTÔNICA DO NORDESTE DA PROVÍNCIA CARAJÁS”. Unpublished PhD thesis, Universidade Federal do Rio de Janeiro, Rio de Janeiro (2015) 115p. [7] MACHADO, N. et al. “U–Pb geochronology of Archean magmatism and basement reactivation in the Carajás Area, Amazon Shield, Brazil”. Precambrian Research 49 (2991) 1-26. [8] GIBBS, A.K. et al. “Age and composition of the Grão Pará Group volcanics, Serra dos Carajás”. Rev Bras Geoc 16 (1986) 201-211. [9] DOCEGEO. “Revisão litoestratigráfica da Província Mineral de Carajás - Litoestratigrafia e principais depósitos minerais”. Anais do 34º Congresso Brasileiro de Geologia, Belém (1988) 11-54. [10] GRAINGER, C.J. et al. “Metallogenesis of the Carajás Mineral Province, Southern Amazon Craton, Brazil: Varying styles of Archean through Paleoproterozoic to Neoproterozoic base- and precious-metal mineralisation” Ore Geology Reviews 33 (2007) 451-489. [11] CORDANI, U.G. et al. “A Serra dos Carajás como região limítrofe entre províncias tectônicas”. Ciências da Terra 9 (1984) 6-11. [12] MORETO, C.P.N. “Neoarchean and Paleoproterozoic iron oxide-copper-gold events at the Sossego deposit, Carajás Province, Brazil, Re-Os and U-Pb geochronological evidence”. Economic Geology 110 (2015) 809-835. [13] TAVARES, F.M. et al. “O Cinturão Norte do Cobre da Província Mineral de Carajás: épocas metalogenéticas e controles críticos das mineralizações”. Anais do 15º Simpósio de Geologia da Amazônia, Belém (2017), CD-ROM. [14] HEIDER, M. “Urânio”. In. Anuário Mineral Brasileiro: principais substâncias metálicas. Departamento Nacional de Produção Mineral, Brasília (2016) 70-92. [15] HITZMAN, M.W., VALENTA, R.K. “Uranium in iron oxide-coppergold (IOCG) systems”. Economic Geology 100 (2005) 1657-1661. [16] SKIRROW, R.G. “Controls on uranium in iron oxide copper-gold systems: insights from Proterozoic and Paleozoic deposits in southern Australia” 11th SGA Biennial Meeting abstracts, Antofagasta, Chile (2011) 482-484.

Speaker: Mr Felipe Tavares (Geological Survey of Brazil - CPRM)

15 Uranium Extraction Technology in the Philippines: The Next Step

The phosphate fertilizer industry is one of the key player in sustaining and the continuing development of the vastly agricultural Philippine economy. Since 2002, phosphate-based fertilizers have become one of the most important and consumed fertilizer next to nitrogen-based fertilizers [1]. About 60% of produced and imported fertilizers are consumed by major and staple food crops such as rice (38%) and corn (21%), fruits and vegetables (19%), sugar accounts (7%) and other crops (15%) (Mojica-Sevilla, cited in [1]). Currently, domestic fertilizer production is being sourced from five fertilizer companies. The Philippine Phosphate Fertilizer Corporation (PHILPHOS), located at the Leyte Industrial Development Estate, Isabel, Leyte, is the biggest and the leading fertilizer production company in the country, which has been in operation for the past 28 years. Phosphate rocks are potential sources of uranium (66 – 145 ppm), thorium (1 – 20 ppm), rare earth elements (108 - 1,085 ppm), and almost all elements in the periodic table [2]. Annually, more than 1.97M Mt of imported phosphate rocks are being used as raw materials and are being processed producing 1.17M Mt of diammonium phosphate (DAP) fertilizers at PHILPHOS. During the digestion of phosphate rocks with sulfuric acid, most of the uranium and other trace elements are being transferred into the phosphoric acid and ultimately producing uranium contaminated fertilizers. Around 44.97 Mt of uranium per year are lost into agricultural fields upon fertilizer application putting human and environmental safety at high risk [3]. The Philippine Nuclear Research Institute (PNRI) has pioneered the Uranium Extraction from Wet Phosphoric Acid (UxP) Technology in the country to recover uranium and critical elements from phosphate processing, thus, translating these problems into opportunities. URANIUM RECOVERY BY DEHPA-TOPO METHOD In 1987, the PNRI initiated the uranium recovery from phosphoric acid utilizing the liquid-liquid extraction method using the synergistic mixture of di-2-ethylhexyl phosphoric acid and trioctyl phosphine oxide (D2EHPA - TOPO). Although this method is already established and widely used, it has to be optimized to suit the Philippine phosphoric acid, which is a mixture of different phosphate rocks imported from several countries such as Israel, Egypt, Morocco, Jordan, etc. The team conducted only up to the first cycle solvent extraction and first cycle acid stripping, which had recovery ranging from 64% to 75% [4]. However, this initiative was discontinued due to downtrend of nuclear energy and there was a slump in the global price of uranium. Sometime in 2011, there was renewed interest to continue the UxP Project through the IAEA Technical Cooperation Project PHI/2/010 entitled “Enhancing National Capacity for Extraction of Uranium and other Valuable Elements from Phosphoric Acid”. The project was locally funded by the National Research Council of the Philippines (NRCP) through the project entitled “Comprehensive Extraction Of Uranium, REE and Other Valuable Resources From Wet Phosphoric Acid”. This time around, the PNRI has successfully developed and built its capacity to conduct static laboratory-scale extraction of uranium through trainings, fellowships and expert missions and the upgrade in laboratory infrastructure, which included the procurement of Wavelength Dispersive X-Ray Fluorescence Spectrometer (WDXRF), Fluorometer and portable gamma-ray spectrometer. The process parameters on uranium recovery by D2EHPA-TOPO method from pretreatment of raw phosphoric acid (absorbent materials, optical density, mixing time, and mixing intensity), to extraction (optical density, Organic/Aqueous ratio, P2O5 concentration, and contact time), to stripping (Aqueous/Organic ratio, amount of Fe, temperature) and to precipitation of uranium yellowcake were optimized during the three-year implementation of the project. The project ended on 2017 and demonstrated a feasible UxP technology in a laboratory-scale setup. THE NEXT STEP The UxP research and development undertakings, which started from basic research, will enhance indigenous capabilities and competence to execute the goal of building the first industrial scale UxP facility in the country. As a next step in this endeavor, a newly approved IAEA TC Project PHI/2/013 entitled “Enhancing Bench-scale Simulation for the Development of Continuous Extraction Technology of Uranium and Other Valuable Elements from Phosphates - Phase II” will be implemented for three years, 2018 – 2020, in cooperation with PHILPHOS. The project will develop the comprehensive and environmentally acceptable continuous uranium extraction process, which specifically aims to: (1) perform a scaled-up test, from static laboratory-scale into continuous recovery, for the extraction of uranium; (2) provide engineering design parameters for pilot-plant or commercial scale operations; and (3) determine waste minimization technologies. A bench-scale continuous laboratory-scale extraction system will be installed to validate the results from Phase I project and to obtain a more reliable and realistic process parameters that would better simulate conditions in an industrial/commercial setup. Financial assistance from local funding institution, Philippine Council for Industry Energy and Emerging Technology Research and Development (PCIEERD), through the project “Laboratory/micro-scale Continuous Extraction System for the Recovery of Uranium from Philippine Wet Phosphoric Acid: Phase I” is already in the pipeline. This will sustain other requirements of the project. With the deep dedication of the PNRI Team to develop a comprehensive extraction technology from phosphate resources, a Phosphogypsum Research entitled “Extraction of Radionuclides, Rare Earths and Other Valuable Industrial Elements from Philippine Phosphogypsum Tailings: Phase I” is conceived as a spin off project. The long-term goal of the project is to demonstrate and execute a technology of the recovery of radionuclides, rare earths and other valuable industrial elements in phosphogypsum resources from phosphate fertilizer plants. This project is also in the pipeline and will be financially supported by PCIEERD, as well. The growing capacity in this area in PNRI will have long-term impact in terms of a more sustainable and environmentally friendly methods of mining and extraction in the country. Uranium recovery from phosphates is a prime example of this safe and balanced sustainable management and use of natural resources promoting sustainable socio-economic and environmental development to address the country’s needs in regard to food, energy and water security. This will lead to (1) minimal environmental impacts and protection of human health by producing cleaner fertilizers with greatly reduced uranium content; (2) zero waste and maximized resource utilization; (3) additional revenue in the phosphate processing industry; and (4) an opportunity to utilize uranium in the nuclear fuel cycle if the Philippines decides on the nuclear option. REFERENCES [1] BRIONES, R.M., The Role of Mineral Fertilizers in Transforming Philippine Agriculture, Discussion Paper Series 2014-14, Philippine Institute for Development Studies, (2014), https://dirp4.pids.gov.ph/webportal/CDN/PUBLICATIONS/pidsdps1414.pdf [2] PALATTAO, B.L, RAMIREZ, J.D., TABORA, E.U., MARCELO, E.A., VARGAS, E.P., DIWA, R.R. AND REYES, R.Y. Recovery of Uranium from Philippine Wet Phosphoric Acid Using D2EHPA-TOPO Solvent Extraction, Philippine Journal of Science, 147 (2) (2018) 275-284. [3] HANEKLAUS, N., REYES, R. Y., LIM, W. G., TABORA, E. U., PALATTAO, B. L., PETRACHE, C., VARGAS, E. P., KUNITOMI, K., OHASHI, H., SAKABA, N., SATO, H., GOTO, M., YAN, X., NISHIHARA, T., TULSIDAS, H., REITSMA, F., TARJAN, S., SATHRUGNAN, K., JACIMOVIC, R., AL KHALEDI, N., BIRKY, B. K., AND SCHNUG, E., Energy neutral phosphate fertilizer production using High Temperature Reactors - a Philippine case study. Philippine Journal of Science, 44(1) (2015) 69-79. [4] PETRACHE C.A., MARCELO E.A., SANTOS JR G., Notes on the Extraction of Uranium from Phosphoric Acid. Philippine Technology Journal 12 (4) (1987) 95-99.

Speaker: Ms Jennyvi Ramirez (Philippine Nuclear Research Institute)

15:40 Break

Applied Geology and Geometallurgy of Uranium and Associated Metals

Conveners: Dr Susan Hall (U.S. Geological Survey), Dr Ziying Li (Beijing Research Institute of Uranium geology)

16 The ultimate origin of uranium provinces

INTRODUCTION The global distribution of mineral deposits on the Earth shows that some areas concentrate large resources (with high endowment), whereas others are almost devoid of any resource. This has led [1] to introduce for the first time the term "metallogenic province". The first definition of a uranium province was proposed by [2]: “Economic uranium deposits resulted from original inhomogeneity’s of uranium distribution in the Earth’s crust that commonly persisted through long periods of time, and through a combination of orogenic, metamorphic, and sedimentary processes produced rocks with enriched uranium contents. The initial enriched uranium domain was successively remobilized and concentrated into new enrichments of one or more magnitudes above normal background forming uranium ore deposits”. The nature, origin, evolution, and distribution of U provinces, and the characteristics of some of the major U provinces will be presented. The delineation of such provinces is of major importance for U exploration and the evaluation of the potential resources of such areas. IS AN ANOMALOUS METAL ENRICHMENT NECESSARY TO GENERATE ORE DEPOSITS ? A controversy exists about the necessity of an initial metal enrichment in the source rocks to generate ore deposits. Following [1], the term "metallogenic province" was defined by [3] simply, as a domain on the Earth with an unusual abundance of ores of a particular metal or type (e.g. Cu province of Chile. But, several authors, such as [4], [5], [6], similarly to [2] propose that metallogenic provinces are associated to a previous metal enrichment in the Earth's crust or even in the mantle, and this idea has led to the concept of geochemical provinces, regional geochemical specialization, or metal domain. This concept has been further precized by [7] with the introduction what he called the "basic theorem" of metallogeny: "The concentrations of a metal appear at the intersection of a metal domain (actually a volume capable of reaching down to the mantle), bearing during very long periods of time (permanency and heritage) a metal potential (that is the primordial metallotect), and of other metallotects, acting as revealers of this potential". The term "metallotect" was in fact introduced first by [8] and defined as "any geological feature or phenomenon associated with lithology, paleogeography, structure, geochemistry, etc. which has contributed to the formation of a mineral concentration". However, a metallogenic province cannot be simply assimilated to a geochemical province for which the definitions is highly variable [9] and ore forming processes are not considered. Conversely, other authors such as [10], propose that hydrothermal ore deposits of Cu, Pb, Zn or Ba, with crustal abundances higher than 10 ppm, do not require any pre-concentration in the crust for their formation. The main parameters controlling ore deposit formation would be the availability of a large volume of fluids able to extract and transport the metals and then to deposit them thanks to an efficient trapping mechanism. Similarly, [11] defends that Sn deposits result purely from a progressive concentration of the metal during magmatic processes from an inital average crustal Sn content. However, this model has been contradicted by [12] taking as example the Sn-W deposits of Western Europe, for which they propose their derivation from the partial melting of Sn-W enriched pelites. The source enrichment is related to intense chemical weathering of continents and to their fragmentation leading to the accumulation metal-rich sediments at the margin of fragments of those continents. The ore deposits within a single belt may be of different type and may be formed recurrently. More recently, a more quantitative estimation of the distribution of some metals in craton, terranes and districts, called metal endowment, is proposed with the use of cumulative frequency curves [13]. It is proposed that difference in the metal endowment of these domains is proportional to the intensity and duration of metal accumulation caused by a much larger system of energy and mass flux in a similar way as [10]. The role of possible initial metal enrichment of some crustal segments is not considered. SELECTIVE URANIUM ENRICHMENT OF SPECIFIC CONTINENTAL CRUST SEGMENTS After core segregation, U has been extracted from the mantle and transfered to the Earth’s crust through mantle partial melting, the strong incompatible behavior of U leading to its fractionation in the resulting silicate melts. Before the Mesoarchean (<3.2−3.1 Ga), these processes led to the formation of a relatively thin continental crust, dominantly of mafic composition, made essentially of komatiitic and tholeiitic basalts. Two opposite models of rate of U extraction from the mantle through time are proposed: either a rapid and early extraction of a large part of the U from the mantle corresponding to a generation of most of the continental before 4Ga or a progressive extraction through geologic time accompanying the progressive growth of the continents [14]. The Moon probably provides the state of the Earth at about 3.5 Ga, before subduction processes started on Earth, and illustrates how magmatic fractionation processes may have led, very early in the Earth’s history, to significant heterogeneities in Th and U enrichments over specific areas, up to 7 times their average concentration in the lunar crust, in the Procellarum KREEP Terrane (up to 2.1 ppm U and 7.3 ppm Th, [15]. From the Meso-Archean to Early Paleo-Proterozoic (3.2–2.4 Ga) U continued to be essentially fractionated by magmatic processes but another U enrichment mechanism was necessary, to generate the first granites/pegmatites able to crystallize uraninite. The major change leading to higher U content in magmatic rocks probably started when plate tectonics and subduction processes became significant [16]. The first granites sufficiently enriched in U and with sufficiently low Th/U ratios which permit the crystallization uraninite, have been discovered in the Barbeton Belt, as aplites and pegmatites derived from high-K calc-alkaline granites, and dated at about 3.1 Ga [17]. These uraninites are at the origin of the first U deposits on Earth associated with quartz pebble conglomerates, and also of the initial U endowment of one of the oldest U province on the Earth: the South African U Province. At about 2.3-2.2 Ga, the oxygen level in the atmosphere was high enough [18], for meteoric water, containing dissolved CO2, in contact with U, to pass it into solution as uranyl carbonate complexes. The U was dissolved from U-oxides having crystallized in highly fractionated U-rich granite, from metamict U-rich silicate minerals in plutonic or sedimentary rocks, from devitrified U-rich volcanic acidic glasses, and uraninite accumulated in the pre-2.2 Ga paleoplacers. Rise of oxygen in the atmosphere and oceans was sustained by high organic carbon burial, within the sediments (black shales), especially in marginal sea environments, and occurred during the so-called “Shunga event” [19], which have permitted the trapping of large quantities of U, mobilized by oxygenated meteoric water, in the reduced post-2.2 Ga epicontinental platform sediments. These Early Paleoproterozoic sedimentary units have represented a huge U reservoir for the formation of a variety of U deposits during the following tectono-thermal events. Typical examples are the FB Formation in the Franceville basin in Gabon, the upper Zaonezhskaya Formation, north of Onega Lake in Russia, and metamorphosed equivalents such as the Wollaston belt in northern Saskatchewan, Canada, and the Cahill Formation in the Northern Territory, Australia, all associated with significant U deposits. Then, between 2.1 and 1.8 Ga, most of these Early Paleoproterozoic U-enriched epicontinental platform sediments have been metamorphosed during a worldwide orogenic event that built the Nuna (also named Columbia), the first relatively well characterized supercontinent [20]. High grade metamorphism has led to the fractionation of U from these sediments to anatectic melts, which crystallized as uraninite-rich pegmatoids (also called alaskites) occurring worldwide. These pegmatoids may represent sub-economic U deposits as at Charlebois in northern Saskatchewan, and are a major U-source for later hydrothermal U deposits, such as the unconformity related deposits of the Athabasca U province. Similar episodes of extensive U trapping in epicontinental sediments has occurred at least at two other periods also corresponding the formation of supercontinents: at about 1.3 to 1.1 Ga with the Grenvillian-type orogens and the formation of the numerous U-enriched pegmatoids of the Grenvillian Belt in Canada (e.g. Bancroft, Mont Laurier, …), and at about 800 to 600 Ma with the Pan African orogeny and the formation of the alaskite-type deposits of the Damara Belt (Namibia) and the syn-metamorphic deposits of the Lufilian Belt (DRC-Zambia). A WELL CHARACTERIZED URANIUM PROVINCE: THE ATHABASCA U PROVINCE (AUP) Five to six steps of U enrichment have been characterized in the AUP. The Archean basement mainly consists of U-poor magnetite bearing tonalites, but locally potassic orthogneisses with high U contents are known. For example at Key Lake, high-K granitic gneisses have in average 6.8 ppm U with 4.1 ppm leachable [21]. Then, the decisive step of U enrichment in the AUP occurred during the Upper Paleoproterozoic with the U enrichment in the epicontinental platform sediments of the Wollaston-Mudjatik belt consisting of carbonaceous schist, metacarbonate and calc-silicate rocks, micaschist, feldspathic quartzite, para-amphibolite, and metaevaporites. The next important step of U reconcentration during the Paleoproterozoic has occurred in the Eastern part of the Athabasca Basin basement with the formation of abundant leucogranites and anatectic pegmatites during the Hudsonian Orogeny (ca 1.8 Ga). They occur as syn- to late-orogenic plutons, sheets, dykes, and stockworks deriving from the partial melting of the U-rich lithologies of the Wollaston- Mudjatik belt metasediments [22]. They are variably enriched in U, Th, Zr, and REE (e.g., Parslow and [23]; Mercadier et al., 2013) [1]. The U content of these pegmatites in generally in the order of some tens to hundreds of ppm but may reach several thousands of ppm. For example, the Charlebois Lake pegmatoids represent a sub-economic resource with 17,500 tU at about 600 ppm U. During Paleoproterozoic, a new input of U is represented by the emplacement of large amounts of high-K calc-alkaline granitoids in the western part of the Athabasca basement [24]. They belong to the southern extension of the Taltson Belt. In the eastern part of the Athabasca basement a U-rich potassic porphyritic granite, is reported in the Wheeler River district [22] and in the Eagle Point Mine [25]. A further Paleoproterozoic stage of U reconcentration, prior to Athabasca Basin deposition, led to the formation of the late Hudsonian (1.8 Ga) vein and episyenite type U-deposits (e.g. Beaverlodge) [26]. 25,939 tU were mined from the Beaverlodge area [27]. A last stage of U enrichment would have occurred during the deposition of the Athabasca sandstones (e.g. [28], [29]) and would have represented the major U-source for the unconformity deposits, with an initial U content of 70 ppm mainly hosted in detrital fluorapatite and zircon. It is rather believed that the initial U content of the Athabasca sandstone was low because of its low detrital accessory and clay mineral contents, the lack of efficient U traps such as organic matter and it is highly oxidized [30]. THE URANIUM PROVINCES OF THE WORLD Numerous U provinces are known in the world but the successive steps of U enrichment within these provinces are not always well characterized and their geographic extension is highly variable and sometime difficult to define. The history of many U provinces starts during the Archean (e.g. South Africa, or Athabasca U Provinces), whereas others are relatively young (e.g. the mid-European U Province and the Central Asian U Super-Province), some have a relatively small geographic extension (e.g. the Athabasca or the Central Ukrainian U Provinces, whereas others are very large (e.g. the Central Asian U and the Karoo Super-Provinces). A map of the most important U provinces is provided in the new edition of the World Uranium Map [31]. REFERENCES [1] LAUNAY, L., (de) Traité de métallogénie. Paris, 3 volumes (1913). [2] KEPPLER, M.R., WYANT, D.G., Uranium provinces, in Geology of uranium and thorium: Proceed. Internat. Conf. Peaceful Uses of Atomic Energy, Geneva, August 1955. 6 (1956) 217-223. [3] HAWKES, H.E., WEBB, J.S., Geochemistry in mineral exploration: Harper & Row, N.Y. (1962). [4] ROUTHIER, P., Les gisements métallifères : principes de recherche. Masson, Paris, 2vol. (1963). [5] SCHUILING, R.G., Tin belts on the continents around the Atlantic Ocean. Econ. Geol. 62 (1967) 540-560 [6] BRADSHAW et al. Exploration Geochemistry: A series of seven articles reprinted from Mining in Canada and Canadian Mining Journal. Barringer Research Ltd, Ont. (1972). [7] ROUTHIER, P., Où sont les métaux pour I'avenir? Les provinces métalliques. Essai de métallogénie globale. Masson, Paris (1980). [8] LAFFITTE et al., Cartographie mètallogénique, métallotecte et géochimie régionale. Bul. Soc. Fr. Minér. Crist, 88 (1965) 3-6. [9] REIMANN, C., MELEZHIK, V., Metallogenic provinces, geochemical provinces and regional geology - what causes large-scale patterns in low density geochemical maps of the C-horizon of podzols in Arctic Europe ? Appl. Geoch, 16 (2001) 963-983. [10] SKINNER, B.J., The many origins of hydrothermal mineral deposits. In: H.L. Barnes (Editor), Geochemistry of Hydrothermal Ore Deposits. John Wiley and Sons, New York (1979) 1-21. [11] LEHMAN, B. Tin granites, geochemical heritage, magmatic differentiation. Geol. Rdsch. 76 (1982) 177-185. [12] ROMER, R.L., KRONER, U., Phanerozoic tin and tungsten mineralization—Tectonic controls on the distribution of enriched protoliths and heat sources for crustal melting. Gond. Res. 31 (2016) 60-95 [13] JAIRETH, S., HUSTON, D. Metal endowment of cratons, terranes and districts: Insights from a quantitative analysis of regions with giant and super-giant deposits. Ore Geol. Rev. 38 (2010) 288-303 [14] WHITE W.M., Geochemistry, in: Geochemistry of Solid Earth. Chapter 11: The Mantle and Core. Wiley-Blackwell Edit. (2012). [15] YAMASHITA et al., U on the Moon: Global distribution and U/Th ratio. J.G.R.L. 37 (2010). [16] CUNEY, M., Evolution of uranium fractionation processes through time: driving the secular variation of uranium deposit types. Econ. Geol., 105 (2010) 449 – 465. [17] CARROUÉ et al., Uranium concentration processes in Archaean batholiths, sources of the oldest uranium deposits. Goldschmidt Conf. Abst., Montréal, Canada. Min. Mag. (2012) 1549. [18] LYONS et al., Rise of oxygen in Earth's early ocean and atmosphere. Nature 506 (2014) 307-315 [19] HANNAH et al., Re-Os geochronology of shungite: A 2.05 Ga fossil oil field in Karelia [abs.]: Goldschmidt Conference, 2008, Vancouver, B.C., Canada, Abstracts, A351. (2008) [20] ZHAO et al., Review of global 2.1–1.8 Ga orogens: implications for a pre-Rodinia supercontinent. Earth-Sci. Rev. 59 (2002) 125–162. [21] HÖHNDORF et al, Age determination of basement units in the Key Lake area, Saskatchewan, Canada. IAEA Tech. Com. Meeting on U Resources and Geology of North America. IAEA Tech. Doc. 500 (1989) 381-409. [22] ANNESLEY I., MADORE, C., Leucogranites and pegmatites of the sub-Athabasca basement, Saskatchewan: U protore? In Mineral Deposits: Processes to Processing (Stanley, C.J. et al., eds.), Balkema (1999) 297-300. [23] PARSLOW, G.R., THOMAS, D.J. Uranium occurrences in the Cree Lake Zone, Saskatchewan, Canada. Min. Mag. 46 (1982) 163-171. [24] BROUAND, M., et al., Eastern extension of the Taltson orogenic belt and eastern provenance of Athabasca sandstone: IMS 1270 ion microprobe U/Pb dating of zircon from basement plutonic rocks and from overlying sandstone (Canada). Proc Int. Conf. Uranium Geochemistry, Nancy (2003). [25] CLOUTIER et al., Geochemical, isotopic, and geochronologic constraints on the formation of the Eagle Point basement-hosted uranium deposit, Athabasca Basin, Saskatchewan, Canada and recent remobilization of primary uraninite in secondary structures. Mineral. Dep. 46 (2011) 35-56 [26] RUZICKA, V., Vein uranium; & Geology of Canadian Mineral Deposit Types, (ed.) O.R. Eckstrand, W.D. Sinclair, and R.I. Thorpe; Geol. Surv. Canada, Geology of Canada. 8 (1996). [27] JEFFERSON et al., Unconformity-associated uranium deposits of the Athabasca Basin, Saskatchewan and Alberta, in Goodfellow, W., ed., Min. Dep. Canada, Spec. Publ. 5 (2007) 273-305. [28] HOEVE, J., QUIRT, D., Mineralization and host-rock alteration in relation to clay mineral diagenesis and evolution of the middle-Proterozoic Athabasca Basin, northern Saskatchewan, Canada; Sask. Res. Counc., Tech. Rep. 187 (1984) 187p. [29] FAYEK, M., KYSER, T.K., Characterization of multiple fluid events and rare earth element mobility associated with formation of unconformity-type uranium mineralization from the Athabasca Basin, Saskatchewan, Canada. Can. Miner. 35 (1997) 627-658. [30] CUNEY, M., et al., What parameters control the high grade - large tonnage of Proterozoic unconformity related U deposits from the Athabasca? Proc Int. Conf. U. Geochemistry, Nancy (2003) [31] INTERNATIONAL ATOMIC ENERGY AGENCY, World Distribution of Uranium Deposits. IAEA-TECDOC (to be published in 2018).

Speaker: Dr Michel CUNEY (CNRS - GeoRessources - CREGU - Universite de Lorraine)

17 Uranium Provinces of the World

INTRODUCTION Uranium deposits in continental blocks of the Earth are distributed rather randomly and form uranium provinces and districts. Under the uranium ore province we mean crust block characterized by occurrence of uranium deposits of a certain type (or types), main features of which are resulted from specific ore-forming processes and peculiar geotectonic position. When systematizing uranium targets, great importance was attached to the ore-hosting environment and geotectonic conditions of ore formation at early stages of the crust evolution, and for particular areas, their relation to main typomorphic structures (arcogenic, taphrogenic, orogenic, epeirogenic) and derivatives of their activation of different age was considered to be the controlling factor. The analysis of extensive material is aimed at the identification of new patterns and prognostic criteria of commercial uranium mineralization location in various regions of the world. METHODOLOGY AND RESULTS The research is based on the historical-geological approach, which made it possible to systematize data on uranium geology, geochemistry, geophysics and metallogeny in various countries and continents and develop a unified research base. Most of known uranium and complex ore deposits and numerous (95) ore areas in the rank of provinces and regions on five continents were analyzed [1, 2, 3, 4]. Results of original paleotectonic and palinspastic reconstructions were used for analyzing uraniferous areas. It is shown that geological structures of arcogenic (dome) and taphrogenic (rift) origin played a leading role in the uranium metallogeny since the Early Precambrian. Two global generations of gigantic ore-bearing dome structures of different age have been identified: the Archean (3.2 to 2.5 Ma) generation of domes – nuclears and the Paleoproterozoic (2.5 to 1.6 Ma) generation of granite-gneiss domes. The identified generations of dome structures differ in internal structure and metallogeny mainly due to the structure and evolution of the granitized substrate. The metallogenic uranium zoning of the continents made it possible to identify transcontinental marginal and intracontinental ore-bearing megabelts and giant ore clusters in areas of megabelts’ telescoping [1]. Totally, 12 megabelts have been identified on the continents, including marginal continental: 1 – East Pacific with Cordilleran and Andean fragments, II – West Pacific; and inland: III – East African, IV – Damara-Katanga, V – Karpinsky, VI – Baltic-Carpathian, VII – West Siberian-Central Asian, VIII – East Siberian-Gobi, IX – Chara-Aldan, X – Central Australian, XI –Wollaston, XII – Grenvillian. In areas of megabelts’ telescoping (Middle European, Middle Asian, Mongolian-Transbaikalian), uranium resources reach 500,000-1,500,000 tons, but similar amounts are sometimes also typical of some provinces inside the megabelts (Athabasca, Colorado-Wyoming, Arnhemland, Olympic Dam). Two large groups, distinguished based on the degree of lithification of uranium-bearing rock complexes corresponding to main geological structures and genetic classes of uranium deposits are high-order elements in typification of uranium areas. The first group consists of ore provinces and regions with ore deposits in lithified rock complexes in the basement of old and young platforms, median massifs, fold areas, old epicraton depressions and in areas of continental volcanism and granitoid magmatism (endogenic and polygenic classes of deposits). Among them, ore provinces are distinguished in typomorphic proto-structures of nuclears and structures of activation of different age. Commercial uranium concentrations in the nuclears appear at the final orogenic stage of their formation and are often clastogenic formations resulted from the accumulation in placers of accessory uranium-bearing minerals from Late Archean potassium granite and pegmatite. Such metamorphosed placers in quartz-pebble conglomerate are typical of proto-orogenic depressions, occurring as spots along the periphery of the nuclears of mainly antiform (uninverted) type: Superior, East Brazilian, South African and other megaprovinces. With some epochs of activation of nuclears of different age, a number of provinces and regions with deposits of various types are associated: carbonatite (U-TR) in alkaline ring tubes of different ages (Ilimaussaq, Palabora, Khibiny, etc.); black shale type in superimposed foreland basins (South China, Carpathian and other provinces); leucogranite type in fault zones among the Mesozoic highly radioactive rocks in association with rare metal mineralization (Gan-Hang, Kerulen-Argun ore belts) [1, 2, 3]. Uranium mineralization accompanies all stages of the formation and transformation of dome structures of second generation (dome rise stages). The formation of typomorphic structures of domes of this generation started at the stage of compensatory destruction, subsidence, and collapse of the roof. Provinces in the fault-contact metasomatite (alaskite) (Rossing), albitite (Kirovograd) and glimmerite (Padma) types are associated with similar structures. Ore provinces in protostructures of Riphean granite-gneiss domes near zones of structural-stratigraphic unconformities at the base of epicratonic basins belong to polygenic ones (Canadian and Australian subtypes). In the Riphean-Phanerozoic, in some provinces (Franceville, Czech, Katanga), epigenetic regeneration of ore deposits occurred near the unconformity surfaces with a change in their morphology and scale of mineralization [4]. The second group includes ore provinces and areas with deposits in weakly lithified or unlithified rock complexes, in sedimentary basins of covers and young platforms (exogenous class of deposits). This group includes provinces with syngenetic concentrations of uranium of sorption nature (surficial, with carbonized residues, phosphate, black shale types) and provinces with epigenetic sandstone-type hydrogenous deposits represented by stratal, roll and paleovalley types. Ore provinces were formed in sedimentary basins in central (destroyed) parts of dome structures and in the inter-dome space within riftogenic structures. Syngenetic-type provinces are characterized by constant relationship between uranium and phosphorous and carbonaceous matter (Phosphoria, Chattanooga and other provinces) [3, 4]. For most of the epigenetic provinces with hydrogenous deposits in suborogenic depressions and platform covers, overlapping old dome structures, the role of linear, linear-arc faults in sedimentary basin deposits (cis-Tian Shan Province, Colorado Plateau, etc.) is emphasized. Faults play an important role in the localization of hydrogenous uranium mineralization near or in flanks of petroliferous areas, which are sources of gas-liquid reducing agents (South Texas, Central Kyzyl-Kum province) [1, 4]. The identified patterns and spatial position of ore districts and provinces allow drawing several conclusions concerning predicting the ore grade within their limits. The relation of uranium ore districts to similar geological structures does not always means a similar level of possible ore grade. The authors have established that the parameter called the “maturity” of the crust can serve as a regional criterion for predicting rich endogenous ores. The level of “maturity” clearly correlates with the level of medium uranium concentrations in granitoid formations of dome structures. Besides, there are ore formation types of uranium mineralization, which differ significantly in the ore grade. So, there is a group of ore formations characterized by low-grade ores but with huge reserves: Lower Proterozoic quartz-pebble conglomerate (Witwatersrand, South Africa), uranium-bearing black shale (southwestern Sweden), phosphorite (Morocco), pegmatite (Charlebois, Canada), nepheline syenite (Ilimaussaq, Greenland), anatectoid alaskite granite (Rossing, Namibia), carbonatite (Palabora, South Africa), calcrete (Yeelirrie, Western Australia), uranium-coal deposits (Nizhneiliyskoe, Kazakhstan). However, the formation type of mineralization also does not guarantee that the ore grade will be similar. Features of ore-hosting rocks do not always affect significantly the degree of concentration of uranium mineralization. The role of lithological factors as well as structural factors in the localization of rich mineralization cannot be considered separately from the nature of metasomatic transformations. Extensive areas of pre-ore metasomatism testifies to relative openness of hydrodynamic systems and is evidence of the dilution of ore-forming solutions. Closed hydrodynamic systems that ensure the presence of high metal concentrations in the solution and local, contrast zones of wall-rock alterations are more favorable for the formation of rich ores. Probably, the alkaline solution containing H2, H2S, S-2, CH4, hydrocarbons, Fe+2, and other reducing agents is initially most suitable for the formation of a large volume of rich ores. Highly concentrated brine of salt complexes is one of the sources of heated subalkaline waters. The ore grade of hydrogen deposits is also controlled by several ways of ore deposition. If the reduction barrier contains only syngenetic reducing agents (primary grey color), the ores are usually poor and lean. The epigenetic preparation of the barrier to ore deposition can be a result of the action of ascending reducing thermal waters and lateral migration of hydrocarbons from neighboring oil and gas basins. CONCLUSIONS When analyzing the huge factual material, a number of important planetary factors of uranium geology and metallogeny were discovered: linear-geoblock divisibility of the continental crust as the basis of metallogenic zoning on global and regional scales; factor of irreversible geological time in ore genesis; factor of tectonophysical correspondence of global and local geotectonic settings in the forecast of giant deposits; important conditions for the formation of rich ores are shown. Many of the discussed problems are beyond the scope uranium metallogeny and allow the discussion of a number of basic factors of the metallogenic school as a whole from a new viewpoint. REFERENCES [1] Afanasiev G.V., Mironov Yu.B. Uranium in Crust Dome Structures. Experience of paleoreconstructions in metallogeny. – St. Petersburg: VSEGEI Publishing House, 2010. 360 p. [2] Uranium Deposits in Russia/ Edited by G.A. Mashkovtsev. – Moscow, 2010. 850 p. [3] Dahlkamp F.J. Uranium Deposits of the World – Asia. – Berlin-Heidelberg: Springer Verlag, 2009. 508 p. [4] Dahlkamp F.J. Uranium Deposits of the World – USA and Latin America – Berlin-Heidelberg: Springer Verlag, 2010. 518 p.

Speaker: Ms Elena Afanasyeva (Leading Researcher)

18 Sr-Nd-Pb isotope systematics of U-bearing albitites of the Central Ukrainian Uranium Province: implication for the source of metasomatizing fluids

INTRODUCTION Sodium metasomatites are relatively widely distributed in the world and often contain uranium mineralization that occasionally may reach industrial scale [4]. Uranium concentrations in deposits of this type are rather low but resources can be quite large especially in the areas where sodium metasomatites achieve wide distribution. As was pointed out by [4], deposits of this type are significantly underexplored and may represent a promising target for further exploration. This is especially true as sodium metasomatites often contain complex mineralization that, besides U, includes Th, Sc, V, Nb, HREE, and Ag. The Central Ukrainian Uranium Province (CUUP) hosts several large deposits and numerous subeconomic deposits and occurrences. The production started in 1951 and since that time two deposits were completely exhausted. The remaining U resources of the CUUP exceed 300 000 t U with grade varying between 0.05 to 0.20 wt. % U [4]. In spite of the long history of exploration and exploitation of Na-metasomatite type of U deposits in Ukraine, many questions regarding their origin still remain unanswered. The main questions that were debated during decades are related to the source of the metasomatic fluids and the source of ore components. A lot of studies were focused on the geological structure of U deposits in the CUUP, on their mineralogical and chemical compositions, and on stable isotope systematics. Results of these studies were summarized in [1, 4, 13]. However, high-quality geochemical data regarding these deposits were absent until recently [4, 5], whereas radiogenic isotope data is still absent that hampers a reasonable discussion about origin and evolution of the Na metasomatites and about the source of ore components. The present ideas regarding the origin of metasomatic fluids and their ore load are controversial. The main problems are: (1) a source of huge volumes of high-temperature hydrothermal solutions (with meteoritic waters, basin waters and magmatic fluids being the main alternatives; complex sources evolving in time were also invoked [4]); (2) a source of U and Na, as large volumes of these elements cannot be derived from low-crustal and mantle lithologies, and middle- to upper-crustal sources were considered. However, simple calculations indicate that hydrothermal leaching of the host upper-crustal rocks cannot produce such enrichment as these rocks are relatively poor in both U and Na, and huge volumes of leached rocks are unknown in the area; (3) the association of elements typical for this type of deposits includes elements that are more typical for mafic alkaline igneous complexes rather than for felsic crustal rocks. In our contribution, we present new Sr-Nd-Pb isotope data obtained for Na-metasomatites of the CUUP and for a large variety of host rocks and discuss possible contribution of different sources to the origin of this type of U deposits. GEOLOGICAL SETTING The CUUP is located in the central part of the Ukrainian Shield, within the predominantly Palaeoproterozoic Inhul mobile belt, and partly within the Mesoarchaean Middle Dnieper domain. Most of the deposits and occurrences are located near the southern contact of the Korsun-Novomyrhorod anorthosite-mangerite-charnockite-granite (AMCG) complex (1757-1744 Ma, [7]) where they are hosted by the Novoukrainka gabbro-monzonite-granite massif (2038-2028 Ma, [3, 10]) and granites and migmatites of the Inhul Complex (2022-2062 Ma, [8, 11, 12]). Several deposits are located within in the Kryvyi Rih synform structure which is filled mainly with siliciclastic sediments and banded iron formation. The age of this structure remains poorly constrained and commonly regarded as Palaeoproterozoic to Neoarchaean. Na-metasomatites being confined to the major fault zones closely associate with numerous mafic dykes widely distributed in the same area. Some of the mafic dykes are older than metasomatites and can be affected by sodium metasomatism whereas other dykes clearly cut metasomatic bodies. Available geochronological data [6] indicate the formation of the mafic dykes at ca. 1800 Ma. Depending on the lithology of the host rocks, Na-metasomatites are represented by two main mineralogical types. The first type develops after felsic igneous rocks and represented by albitite. The second type includes aegerine-riebeckite metasomatites that develop after iron-rich rocks of the banded iron formation. In all cases, metasomatic bodies are confined to the major fault zones and occur as irregular elongated zoned bodies that were traced along strike for several km whereas the widths of metasomatic bodies may reach several hundred meters and over. The largest bodies were traced by drillings down to 1200 meters and over. In the further description, we shall focus on the first type of the Na-metasomatites, i.e. on U-bearing albitites. In a generalized form, zoning in these rocks can be described as a gradual transition from unaltered host rock (granite, migmatites, gneiss etc.) to quartz-free (desilicified) microcline-albite metasomatite (“syenite”) and then to albitite. This rock succession formed during the progressive (albititic) stage of the alkaline sodic metasomatic process. The late mineral assemblage that includes phlogopite (or late chlorite), carbonate and hematite are often superimposed on the internal parts of albitites. Besides this, secondary quartz, epidote, and microcline are often superimposed on intermediate and external parts of the metasomatic bodies. These minerals are regarded as developed during removal of silica, calcium, and potassium from central (albititic) parts of metasomatic bodies [1, 4, 13]. MINERAL COMPOSITION Albite occurs as the main (up to 90 %) rock-forming mineral, whereas the amount of mafic minerals usually does not exceed 10 %. The typical mafic minerals are alkaline amphibole, alkaline pyroxene, epidote, chlorite, diopside, actinolite, and garnet. The proportion of albite and mafic minerals is generally defined by the composition of the initial rock. The amount of pyroxene varies from almost 0 to 10 %. Pyroxenes belong to aegirine (amount of the Ca component varies from 0 to 45 mol. %) and diopside-sahlite (amount of the Na component varies from 0 to 20 mol. %). Pyroxenes that contain over 10 % Sc2O3 occur as well-defined inclusions within the aegirine-pyroxene matrix. Amphibole usually associates with pyroxene and varies in composition from riebeckite to slightly alkaline actinolite. Garnets belong to the andradite-grossular series and occur mainly in deposits located in the Novoukrainka granite massif where the amount of garnet may reach 50 %. Garnets occur in association with diopside, actinolite, and epidote; sometimes it may be found in association with aegirine. Epidote is a rock-forming mineral in so-called “syenites” and certain types of albitites. It often replaces garnet in the garnet-diopside metasomatites. Epidote in albitites of the Partizanske ore field contains a large amount of Sr. Accessory minerals in albitites are apatite, zircon, titanite, monazite, uranothorite, allanite, which present in all types of U-bearing sodic metasomatites. Phenakite, thortveitite, and schorlomite are rare minerals. The origin of accessory minerals is not clear as they may represent relict phases left from the initial (pre-metasomatic) rocks. Albitites contain also various opaque minerals, including hematite, magnetite, titanomagnetite, rutile, ilmenite, galena, pyrite, chalcopyrite, sphalerite etc. Native silver in concentration reaching up to 1 % in Na-metasomatites of the Kryvyi Rih – Kremenchuk zone was known for a long time. In the northern part of the Vatutinske deposit concentration of silver reaches 300 ppm. The accompanying minerals are galena, pyrite, marcasite, chalcopyrite, sphalerite, minerals of U, Ti, and Ba. Main U minerals are uraninite (U4+, U6+ Pb, Ca, RЕЕ, Zr)O2-x and brannerite (U4+, Ca, Th, Y)[(Ti, Fe)2O6]·nH2O. Uraninite is unevenly distributed and absent in some deposits. Electron microprobe analyses have revealed the presence of up to 20.51 % PbO, 6.20 % СаО, 0.78 % Y2O3, 3.90 % Ce2O3, and 1.72 % ZrO2. Brannerite occurs as the main ore mineral in many of the deposits of the CUUP. It often develops after Ti and Ti-bearing minerals; there is a persistent association of brannerite with rutile, anatase, carbonate minerals, quartz, and sericite. GEOCHEMISTRY Our data demonstrate regular variations of the chemical composition in the vertical profile across the albitite bodies. Being compared to the host granite, albitites demonstrate a sharp decrease in the abundances of SiO2 and K2O. Al2O3 slightly increases near contacts against host granites and then decreases in the central part of the metasomatic body. Most other major oxides show significant enrichment in albitites. Fe2O3, CaO, TiO2, and MgO demonstrate pronounced enrichment in the U-rich central (axial) parts of the albitite body. Na2O is sharply increased in metasomatites, but demonstrate a moderate decrease in the axial part of the body. According to [4], distribution of REE in barren albitites is very close to that in the host granite. In general, barren albitites are slightly enriched with respect to LREE, and depleted in HREE, being compared to the host granite, but these differences are not significant. Our new data indicate that albitite samples rich in U are highly enriched in HREE. We suppose that metasomatic fluids responsible for U enrichment were also rich in HREE. This feature is not typical for felsic rocks that may be considered as the main source of U (and Na). SR-ND-PB ISOTOPE SYSTEMATICS A set of whole-rock samples was collected at the Novokostyantynivka and Novooleksiivka deposits. These rocks were analyzed for Sr, Nd, and Pb isotopes. As can be seen from Sr isotope data, metasomatic rocks have isotope signature typical for the crustal rocks. Specifically, rocks of the Novokostyantynivka deposit have 87Sr/86Sr(1800) in the range 0.7087 to 0.7105, whereas in the rocks of the Novooleksiivka deposit 87Sr/86Sr(1800) varies from 0.7172 to 0.7207. There is no strict correlation between 87Rb/86Sr and 87Sr/86Sr ratios that makes impossible the construction of isochrons and production of reasonable Rb-Sr isotope ages. This indicates inhomogeneity of the Sr isotope composition that could result from the variable host rock/metasomatic rock ratio in our samples. In the Novooleksiivka deposits samples were collected systematically across the vertical section of the metasomatic body. As follows from our results, there is a tendency for albitite samples in the axial part of the body to have less evolved initial Sr isotope composition. This tendency may indicate that the metasomatic fluids were derived from a source that had a lower Rb/Sr ratio than the upper crustal granites. However, this question requires further confirmation on other deposits. Neodymium isotope composition, in contrast to Sr, is much more consistent in both studied deposits and allows construction of a rather good isochron. The age yielded by the isochron (1728 ± 110 Ma) corresponds within error to the U-Pb age previously obtained for the U deposits of the CUUP. εNd value according to the isochron is -4.8 and indicates the crustal source of albitites, in accordance with Sr isotope data. There is, however, a small systematic difference between the Novokostyantynivka and the Novooleksiivka deposits: the average εNd(1800) value for the Novokostyantynivka albitites is -3.7, and for the Novooleksiivka albitites is -4.5. These results are consistent with Sr isotope data, according to which the Novooleksiivka deposit reveal more “evolved” crustal source. Lead isotope compositions indicate the great prevalence of radiogenic Pb, whereas “common” Pb is virtually absent. This allows calculation of the Pb-Pb age of the deposits formation. There is no sufficient difference in the age of the Novokostyantynivka and Novooleksiivka deposits, both deposits were formed at 1810 ± 17 Ma. This age is in good agreement with the previously obtained U-Pb ages and with Sm-Nd isochron age (sees above). The obtained isotope results can be compared with data available for the main lithologies present in the area. Albitites of the Novokostyantynivka deposit plot between fields of the Novoukrainka massif and Korsun-Novomyrhorod AMCG Complex, closer to the Novoukrainka field. In contrast, albitites of the Novooleksiivka deposit plot entirely within the field defined by the Inhul granitoid Complex. It has Nd isotope characteristics similar to the Novoukrainka massif but differs by their much higher Sr isotope values. DISCUSSION AND CONCLUSIONS Many features of the U-bearing Na-metasomatites of the Central Ukrainian Uranium Province have received a due attention of the researchers. These features include the geological structure of the deposits, their mineral composition and some aspects of the isotope geochemistry (O, C, and H isotopes, see [4] for an overview). However, some features, very important for the understanding of the origin of Na-metasomatites and related mineralization still remain underexplored. For instance, high-quality geochemical data regarding metasomatic rocks are still very limited in number. This is especially true with respect to U ores geochemistry of which is still poorly studied. The same can be said about isotope geochemistry of Sr, Nd, and Pb. In the author`s opinion, following features are very important for the understanding of the origin of Na-metasomatites and related mineralization: (1) close spatial relation of the Na-metasomatites with the Korsun-Novomyrhorod AMCG plutonic complex. Most of the deposits and occurrences are located within 30 km away from the contact of the complex. In addition, Na-metasomatites closely associate with numerous mafic and ultramafic dykes of tholeiitic affinity; (2) close temporal relationships with mafic dykes which according to the available geochronological and geological data intruded simultaneously with the formation of Na-metasomatites at c. 1815-1800 Ma. The Korsun-Novomyrhorod AMCG Complex is 50-60 M.y. younger, but its formation may have started at c. 1800 Ma, as evident from findings of older xenolith of anorthositic rocks; (3) “Mixed” geochemical characteristics of the Na-metasomatites: these rocks are rich in Na, U, Th, Sc, V, Nb, HREE, and Ag. This combination of elements is not typical for felsic rocks and can be rather related to mafic alkaline sources; (4) newly obtained Sr and Nd isotope data indicate crustal sources of the main volume of Na-metasomatites. Formation of the mafic dykes and Korsun-Novomyrhorod AMCG Complex was linked to a long-lived mantle plume [6, 7], although relation of the mafic magmatism to the rotation-caused crustal extension and mantle melting was also proposed [2, 9]. In any case, emplacement of numerous mafic dykes and formation of the huge Korsun-Novomyrhorod AMCG Complex implies the presence of the large-scale thermal anomaly in the mantle and low crust. Metasomatizing fluids were probably generated in the upper mantle and on the way through the crust they have achieved crustal isotope signature. However, their useful load was probably derived from the mantle as crustal felsic rocks can hardly be considered as a source of such elements as Sc, V, Nb, HREE. We assume that metasomatizing fluids may be related to mafic alkaline melts which were responsible for the formation of various alkaline (syenites, aegerine-riebeckite syenites) and subalkaline (monzonites) rocks that are present in the Korsun-Novomyrhorod plutonic complex. It is interesting that available isotope geochemical data indicate the significant dependence of the isotope composition of the Na-metasomatites on low-crustal (?) rocks. Both studied deposits occur within the Novoukrainka gabbro-monzonite-granite massif and there is no reason to assume that host rocks for these two deposits are very different in terms of their isotope composition. However, one of the deposits (Novokostyantynivka deposit) has Sr-Nd isotope composition more typical for the Novoukrainka rocks, whereas another deposit (Novooleksiivka deposit) reveals Sr-Nd isotope composition more typical for the Inhul granites. Some differences in their mineralogy and geochemistry may also occur, but this question requires further detailed investigation. According to our model, metasomatizing fluids were derived from the hot upper mantle melts from which they have inherited their useful load. On the way through the low crust they achieved their crustal isotope signature which apparently was not significantly modified during the interaction with the upper-crustal rocks. 1. BELEVTSEV, Ya., et al., Genetic types and regularities of the location of uranium deposits in Ukraine, Naukova Dumka, Kyiv (1995) (In Russian). 2. BOGDANOVA, S., et al. Late Palaeoproterozoic mafic dyking in the Ukrainian Shield (Volgo-Sarmatia) caused by rotations during the assembly of supercontinent Columbia, Lithos, 174 (2013), 196–216. 3. CUNEY, M., et al. Petrological and geochronological peculiarities of the Novoukrainka massif rocks and age problem of uranium mineralization of the Kirovograd megablock of the Ukrainian shield, Mineral. J. (Ukraine), 30(2) (2008) 5-16. 4. CUNEY, M., et al., Uranium deposits associated with Na-metasomatism from central Ukraine: a review of some of the major deposits and genetic constraints, Ore Geol. Rev. 44 (2012) 82–106. 5. MYKHALCHENKO, I., et al. A. Rare earth elements in Th-U-bearing albitites of the Novooleksiivka occurrence, the Ukrainian shield, Kryvyi Rih University (2016), pp. 34-39. 6. SHUMLYANSKYY, L., et al. The ca. 1.8 Ga mantle plume related magmatism of the central part of the Ukrainian shield, GFF, 138 (2016), 86-101. 7. SHUMLYANSKYY, L., et al. The origin of the Palaeoproterozoic AMCG complexes in the Ukrainian Shield: new U-Pb ages and Hf isotopes in zircon, Precam. Res. 292 (2017) 216-239. 8. SHUMLYANSKYY, L., et al. The Palaeoproterozoic granitoid magmatism of the Inhul region of the Ukrainian Shield, Geol.-mineral. Proceed. Kryvyi Rih Nation. Uni., 33(1) (2015), 80-87. (In Ukrainian). 9. SHUMLYANSKYY, L., et al. U-Pb age and Hf isotope compositions of zircons from the north-western region of the Ukrainian shield: mantle melting in response to post-collision extension, Terra Nova, 24 (2012), 373-379. 10. STEPANYUK, L., et al. Age of the Novoukrainka massif, Mineral. J. (Ukraine), 27(1) (2005) 44-50. (In Ukrainian). 11. STEPANYUK, L., et al. Geochronology of granitoids of the eastern part of the Inhul region (the Ukrainian Shield), Geochemistry Ore Formation, 38 (2017), 3-13. 12. STEPANYUK, L., et al. U-Pb geochronology of the rocks of the K-U formation of the Inhul region of the Ukrainian Shield, Mineral. J. (Ukraine), 34(3) (2012) 55-63. (In Ukrainian). 13. VERKHOVTSEV, V., et al., Prospects for the development of uranium resource base of nuclear power of Ukraine, Naukova Dumka, Kyiv (2014) (In Russian).

Speaker: Dr Leonid Shumlyanskyy (M.P. Semenenko Institute of geochemistry, mineralogy and ore formation)

19 DEVELOPMENT OF HANDHELD X-RAY FLUORESCENCE (hXRF) SPECTROMETRY FOR MAJOR AND MINOR ELEMENTS ANALYSIS IN GEOLOGICAL SAMPLES FROM PHUKET PROVINCE, THAILAND

INTRODUCTION Soils and rocks have a complex matrix composition and their contained-element chemical analysis is interested in geochemical and environmental studies. A well-established and commonly technique to obtain chemical composition in geological sample is X-ray fluorescence (XRF) spectroscopy [1]. The XRF technique has been used to eliminate matrix effects and sample heterogeneity but analytical precision and the ultimate accuracy of the results depend on several factors. These factors includes instrumental setting and stability, the calibration procedure, mineralogical and matrix effects, the reference materials used to calibrate the instrument, sample preparation and the strategy adopted to maintain the results within accepted limits [2]. For providing the higher quality data possible, the measurements can be costly, require intensive sample preparation and analysis time [1]. Field handheld instruments can be a new application for in and out of standard laboratory setting [1]. The hXRF has precisions comparable to benchtop models. Moreover, it allows for direct substrate measurements without the need to collect samples or the use of special containers for the analyses. The hXRF is less expensive than benchtop model [3,4]. In recent years, the hXRF has been used to analyze major and minor elements in different materials (rocks, soil, sediment, wood and archeological [5]. However, the hXRF analysis has some limitations in the efficient application which constrain its reliable uses for optimal element analysis of different types of materials. The hXRF limitations are: (1) calibration of a small number of element analyses; (2) measurement based on the instrument’s internal calibration; (3) a priori measuring-time determination based on the relative deviation as a determinant factor and (4) absence of criteria to establish the minimum amount of sample that can be measured and its container material [3]. In this study, handheld XRF (hXRF) was developed to determine major and minor elements in soil and rock samples at the different horizontal soil profiles. Effect of film type on chemical compositions of samples was investigated. The accuracy of the methods was done by using geological reference materials. MATERIALS AND METHODS **Sample preparation** Ten samples were taken per horizon which varied in thickness according to the profile characteristics, O horizon (0-0.1 m), A horizon (0.1-0.3 m), B1 horizon (0.3-1.0 m), B2 horizon (1.0-2.0 m), C1 (2.0-3.0), C2A (3.0-5.0), C2B (5.0-8.0), C3 (8.0-12.0), D (12.0-20.0) and RK (> 20.0 m).The sample location was Tambon Chalong, Amphoe Meuang, Phuket province, Thailand (Latitude 7°51'24.22"N, longitude 98°19'19.49"E). Each sample was manually homogenized and passed through a 250 µm sieve. The sample was dried to constant weight at 110˚C before the element analyses. **Wavelength dispersive X-ray fluorescence spectrometry (WD-XRF) analysis** The sample was prepared by 2 methods following; Fused bead method: The dried sample and flux were weighed in an exact ratio into the platinum crucible (0.62 g of sample, 1.24 g of lithium metaborate, 4.96 g of lithium tetraborate and 0.08 g of ammonium iodide). The fusion was performed at 1000˚C for 2.30 min in a furnace. Loose powder method: Two types of film were used in this study including (1) 4 µm Prolene® thin film and (2) 6 µm Mylar® polyester film. Each cup was covered with thin film. The fine powder sample was then filled into the cup. **Handheld X-ray fluorescence spectrometry (hXRF) analysis** The sample was prepared by the loose powder method with two film types. A Delta Professional hXRF Analyzer, DPO 2000 (Olympus Scientific Solutions Americas, Inc.) equipped with an instrument’s prolene window of 8 mm2, a 4W miniature X-ray tube (200 μA maximum current), and silicon drift detector (SDD) was used to measure all samples using Geochem mode with two beams. The first beam (40 kV) measured the elements V, Cr, Fe, Co, Ni, Cu, Zn, W, Hg, As, Se, Pb, Bi, Rb, U, Sr, Y, Zr, Th, Nb, Mo, Ag, Cd, Sn and Sb, also Ti and Mn. The second (10 kV) was used to determine the light elements Mg, Al, Si, P, S, Cl, K, Ca, Ti and Mn. The measuring time for an individual beam was set at 120 s. The internal hXRF stability was monitored by measuring Fe K-α count on a 316-stainless steel coin every day of use. Each sample was analyzed three times. The hXRF was calibrated after measuring intensities in the following seven geological reference materials: JA-1, JG-1a, JG-2, JSy-1 (andesite, granodiorite, granite, syenite, GSJ, Japan); BCR-2, COQ-1, GSP-2 (basalt, carbonatite, granodiorite, USGS, rseton). Each reference material was analysed ten times. RESULTS AND DISCUSSION **Calibration curves** The collected data of the reference materials were constructed linear calibration curve for each element. It was found that the calibration curves of Ag, As, Cd, Cr, Hg, Mg, Mo, Ni, S, Sb, Se, Sn, U, V and W measured using hXRF were poor because of their restricted rang in the standard materials for both film types. Whereas those of Al, Ca, Fe, K, Si, Ti, Mn, Nb, Pb, Sr, Th and Zn were acceptable with R2 ≥ 0.95except for Cu, P and Y. The calibration curves of Nb and Rb analyzed using 4 µm Prolene® thin film (R2 ≥ 0.95). The slopes of the regression line for each element was inputted into the hXRF analyser software for automatic correction of sample data, if the difference between the hXRF analysed value and the CRM recommend value was more than 10%. When 4 µm Prolene® thin film was used for the analysis, the recalibration factors for Al, Fe, K, Si, Ti, Rb and Th were 1.0649, 0.8487, 0.9140, 0.9615, 0.9810, 0.9892 and 0.9167, respectively. In the case of 6 µm Mylar® polyester film, these elements including Al, Fe, K, Si, Ti and Th were recalibrated with 1.8805, 0.8969, 1.0251, 1.4803, 1.1013 and 0.8689, respectively. P and Na could not be detected by hXRF spectrometer. For P, it is due to its concentration found in the geological reference materials were very low. In case of Na, it was too light to be detected by the hXRF model [1]. Hunt and Speakman [6] suggested that Na-X rays were extremely low energy, Kα line at 1.041 keV, and re-absorbed into the sample matrix and scattered as Bremsstrahlung radiation. There was a much higher degree of scatter between the hXRF analysis and the results at low concentration [7]. **Measurement of major and minor elements in soil and rock samples by hXRF and WD-XRF techniques** The major elements including Si (20-27 wt%), Al (13-17 wt%), Fe (1-4 wt%) and K (1-3 wt%) could be detected. The minor elements were composed of Mn (135-793 g/kg), Th (128-188 g/kg), Zr (65-89 g/kg) and Sr (25-63 g/kg). It can be also noted that the concentrations of Th found in the studied samples were very high and over the calibrated range (> 105 ppm). There was variation of each element in difference soil and rock horizon. For the hXRF analysis using the 6 µm Mylar® polyester film without recalibration, Al and Si concentrations were lowest values but these values could be improved by the recalibration method. However, the recalibration was not required for the hXRF analysis using the 4 µm Prolene® thin film. Therefore, efficiency of element analysis by the hXRF depended on film type and film thickness. Some elements i.e. Al, Fe, Ti, Pb, Sr, Th and Zr were reliable when compared to WD-XRF results (fused bead and loose powder techniques) but other elements (such as K, Si and Mn) differenced from the laboratory values (> 20%). The concentrations of K, Si and Mn obtained using the hXRF tend to be significantly underestimated. The variance in Pb, Sr, Th and Zr related directly to small concentrations contained in these samples. Though the hXRF was able to dependable measure some geologically important elements (such as Al, Fe, Ti, Pb, Sr, Th and Zr) but the instrument was unable to detect other important elements reliably (i.e. Ca and Mg). This was due to the particle size, mineralogical, the coexisting component effects (matrix effect) when hXRF spectrometer was used for these geological samples even using the recalibration method. These effects were increased when the sample contains abundant sheet silicate minerals, quartz and accessory minerals [8]. CONCLUSION The results demonstrated that the hXRF could provide data consistent with laboratory reported values. The hXRF measurement of geological reference material by both film types were in satisfactory agreement with certified values for all elements except for Cu, Nb, Ni, P, U, V, W, Y, Zn. The recalibration was required for 6 µm Mylar film analysis. The accuracy and precision of the elements in geological reference materials by hXRF after recalibration were acceptable. The elements such as Al, Ca, Fe, K, Mn, Si, Sr, Th, Zn in geological samples were detected by pXRF technique. Good agreement between the result values obtained by pXRF and by WD-XRF was found for some elements including Al, Fe, Ti, Pb, Sr Th and Zn. The study showed that the hXRF had significant potential as a geochemical tool. For the future work, the effect of particle size, sample preparation and moisture content will be investigated for reliable quantitative analysis. REFERENCES [1] YOUN, K.E., et al., A review of the handheld X-ray fluorescence spectrometer asa tool for field geologic investigations on Earth and in planetary surface exploration, Appl Geochem 72 (2016) 77-87. [2] KRISHNA, A.K., et al., Rapid quantitative determination of major and trace elements in silicate rocks and soils employing fused glass discs using wavelength dispersive X-ray fluorescence spectrometry, Spectrochim Acta Part B At Spectrosc 122 (2016) 165-71. [3] MEJIA-PINA, K.G., et al., Calibration of handheld X-ray fluorescence (XRF) equipment for optimum determination of elemental concentrations in sediment samples, Talanta 161 (2016) 359-367. [4] ROUILLON, M., TAYLOR, M.P., Can field portable X-ray fluorescence (pXRF) produce high quality data for application in application in environmental contamination research?, Environ. Pollut. 214 (2016) 255-264. [5] BLOCK, C.N., et al., Use of handheld X-ray fluorescence spectrometry units for identification of arsenic in treated wood, Environ. Pollut. 148 (2007) 627-633. [6] HUNT, A.M.W., SPEAKMAN, R.J., Portable XRF analysis of archaeological sediments and ceramics, J. Archaeol. Sci. 53 (2015) 626-638. [7] FAJBER, R., SIMANDL, G.J., Evaluation of rare earth element-enriched sedimantary phosphate deposits using portable x-ray fluorescence (XRF) instruments, Geological Fieldwork (2012) 199-209. [8] TANAKA, R., ORIHASHI, Y., XRF analysis of major and trace elements for silicate rocks using low dilution ratio fused glass, HUEPS Technical Report 2 (1997) 20.

Speaker: Ms Sasikarn Nuchdang (Thailand Institute of Nuclear Technology)

20 GEOCHEMICAL PROSPECTING STUDY OF THE VANADIUM–URANIUM MINERALIZATION OF PUYANGO, ECUADOR

INTRODUCTION A geochemical prospecting study has been carried out in the Puyango sector, Loja province, Ecuador to determine uranium and vanadium anomalies and identify the main mineral phases that make up the mineralized rocks, through chemical analysis using portable X-ray fluorescence (pXRF), gamma spectrometry, petrographic analysis and X-ray diffraction (XRD). Maximum eU values of 136 ppm were detected by gamma spectrometry in situ and maximum values of V2O5 of 1.60%. The mineralization is hosted mainly in black bituminous limestones of Cretaceous age belonging to the Ciano and Puyango Formations of the Alamor - Lancones marine basin [1]. These rocks are composed mainly of calcite, quartz, illite, apatite, uranospathite and minor amounts of phyllosilicates and vanadium minerals such as sherwoodite, rossite and ronneburgite. The hypothesis of the formation of this mineralization is that both vanadium and uranium were deposited in a reducing environment, in marine waters under euxinic, anoxic to sub-oxic conditions, this is evidenced by V/Cr - V/V + Ni ratios and by the presence of organic matter in the samples, in which these elements can be linked in compounds such as porphyrins, where V can complex. METHODS AND RESULTS Mineralogical analysis. Petrographic and mineralogical analyzes by X Ray Diffraction (XRD) it was obtained that the main minerals that make are calcite (CaCO3) (61 – 88%), quartz (SiO2) (6 – 22%), fluorapatite (Ca5(PO4)3(F), uranospathite (Al1-xx[(UO2)(PO4)]2(H2O)20+3xF1-3x) (1-3%), sherwoodite (Ca9Al2V5+4V5+24O80•56(H2O)) and, smaller amounts of rossite (CaV2O6), ronneburgite (K2MnV4O12), illite ((K,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)]), biotite (K(Mg,Fe)3[AlSi3O10(OH,F)2), kaolinite (Al2Si2O5(OH)4), chloritoid ((Fe,Mg,Mn)2Al4Si2O10(OH)4), chamosite ((Fe,Mg,Fe)5Al(Si3Al)O10(OH,O)8) and, glauconite ((K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2). Chemical analysis. Chemical analysis was done by portable X Ray Fluorescence (pXRF), according to this the background of the concentration of U is 49 ppm, reaching a maximum value of 153 ppm in black bituminous limestones. In relation to vanadium, the background value was statically determined in the area of 1500 ppm of V2O5, with a maximum value of 23100 ppm. Anomalous values were determined statistically P2O5 (4.52%), Zn (3340 ppm), Mo (219 ppm), Cu (165 ppm), Cd (131 ppm) and, Se (21 ppm). High concentrations of other uranium pathfinder elements and geochemically associated to this and to vanadium are detected: sub-anomalous values As (95 ppm), Bi (68 ppm), Ni (337 ppm) and, Pb (72 ppm). In situ Gamma Spectrometry. Gamma spectrometry analysis in situ was made with a portable gamma spectrometer, according to which anomalous values of eU (86 ppm) were detected, with a maximum value of eU (136 ppm). This evidence U mineralization associated with the in black bituminous Cretaceous limestones, since this technique is useful to delimit radioactive elements mineralization [2]. DISCUSSION AND CONCLUSION Mineralogy analysis. According to the geochemical prospecting carried out, the majority of the rocks correspond to bituminous limestones, of Cretaceous age of the Puyango Formation, since most of the samples are composed of calcite (CaCO3) (61 - 88%) and to a lesser extent quartz, phosphates and phyllosilicates (clays and micas). The petrographic analysis showed that the majority of the samples correspond to micritic limestones and sparritic limestones with foraminiferous fossils. The mineralogical studies show the uranium and vanadium to be present in the following forms: • Fluorapatite (28-75%). • Uranospathite (2-3%). • Sherwoodite (1-2%). • Rosiite and ronneburgite (<1%). Urannospatite may have been formed by weathering and chemical alteration of the primary phosphate (uranipherous apatite) [3]. The minerals that contain vanadium (sherwoodite, rossite and ronneburgite), are vanadates with V5+ and V4+ in their crystalline structures, in addition there may be V3+ in clay minerals such as illite, since it can replace Al3+ during diagenesis [4]. This occurs similarly in vanadium deposits in black shales and, vanadium accumulations in carbonaceous rocks in general [5-6]. The samples contain organic material of marine origin according to the sedimentation environment, so it is likely that vanadium is also linked to organic matter, in compounds such as porphyrins [7-8]. Chemical analysis and statistics. The chemical analyzes it was obtained that the U and Ca correlates with the P, indicating that the minerals that host are the apatite and uranospathite. There are strong correlations between V-Ni, V-U, V-Mo, V-Zn probably associated with organic matter, which may be geochemically associated with porphyrins [7-8]. By calculating elementary relationships V/Cr - V/V + Ni ratios, the sediments were deposited under under euxinic, anoxic to sub-oxic conditions [9], thus the hypothesis of the formation of this mineralization is that both vanadium and uranium were deposited in a reducing environment, in marine waters and by the presence of organic matter in the samples, in which these elements can be linked in compounds such as porphyrins, where V can complex [7-8]. Several authors [10] have indicated that the sediments of the Puyango Fm. were deposited in a marginal marine basin, formed between the Celica arc volcanic to east and Amotape - Tahuin Massif in the west, which corroborates the results obtained through elementary relations. Gamma analysis interpretation. According to the analysis of in situ gamma spectrometry, anomalous values of eU (86 ppm) and a maximum value of eU (136 ppm) were detected in bituminous limestones. The values of eTh reached a maximum of 31 ppm detected in shales, with a background value of 5 ppm, which evidences the low mobility of Th in the conditions of formation of the mineralization, due to its geochemical properties. The eU / eTh ratio was calculated for the samples analyzed and the values fluctuated between 0.06 - 18.80, which shows the mineralized areas with high values of the ratio. Conclusions. The geochemical prospection study of the Puyango sector using chemical, mineralogical and gamma spectrometry analysis, determined that there is a V-U mineralization associated with black bituminous limestones, which are part of Fm. Puyango of Cretaceous age. There are anomalous values of P2O5 (4.52%), Zn (3340 ppm), Mo (219 ppm), Cu (165 ppm), Cd (131 ppm) and, Se (21 ppm), in addition sub anomalous values of uranium pathfinders elements: As (95 ppm), Bi (68 ppm), Ni (337 ppm) and, Pb (72 ppm). The host minerals of uranium are apatite and uranospathite, that is (the last) formed by the weathering and chemical alteration of the primary phosphate. The minerals that contain vanadium are the sherwoodite and in a smaller proportion rossite and ronneburgite, which are vanadates with V5+ and V4+ in their structures, in addition there may be V3+ in clay minerals such as the illite, since this can replace Al3+ during diagenesis. Mineralogical and geochemical analysis should be done through SEM to identify with greater precision the mineral phases that contain vanadium, as well as its association with organic matter. According to the calculation of the eU/eTh ratio for the samples analyzed by in situ gamma spectrometry, the values fluctuated between 0.06 - 18.80, which shows the mineralized areas with high values of the ratio. REFERENCES [1] JAILLARD, H., et al., Stratigraphy and evolution of the Cretaceous fore arc Celica-Lancones basin of southwestern Ecuador, Journal of South American Earth Sciences 12 (1999) 51. [2] INTERNATIONAL ATOMIC ENERGY AGENCY, Radioelements Mapping, IAEA Energy Nuclear Series No. N-FT-1.3, IAEA, Vienna (2010). [3] LOCOCK, A., KINMAN, W., BURNS, P., The structure and composition of uranospathite, Al1–x_x[(UO2)(PO4)]2(H2O)20+3xF1–3x, 0 < x < 0.33, a non-centrosymmetric fluorine-bearing mineral of the autunite group, and of a related synthetic lower hydrate, Al0.67_0.33[(UO2)(PO4)]2(H2O)15.5, The Canadian Mineralogist 43 (2005) 989. [4] ZHANG, Y., et al., The occurrence state of vanadium in the black shale-hosted vanadium deposits in Shangling of Guangxi Province, China, Chi. J. Geochem. 34 4 (2015) 484. [5] LEHMANNS, B., Metals in Black Shales, Acta Geologica Sinica 88 2 (2014) 258. [6] BREIT, G, N., WANTY, R, B., Vanadium accumulation in carbonaceous rocks: A review of geochemical controls during deposition and diagenesis, Chemical Geology 91 (1991) 83. [7] GAO, Y, Y., et al., Vanadium: Global (bio) geochemistry, Chemical Geology (2014) 417 68. [8] HUANG, J, H., et al., Distribution of Nickel and Vanadium in Venezuelan Crude Oil, Petroleum Science and Technology (2013) 31 509 [9] JONES, B., MANNING, D., Comparison of geochemical indices used for the interpretation of paleoredox conditions in ancient mudstones, Chemical Geology 111 (1994) 111. [10] JAILLARD, H., et al., Stratigraphy of the western Celica basin (SW Ecuador), Third ISAG, St. Malo, France (1996) 17.

Speaker: Mr John Manrique (Universidad Técnica Particular de Loja)

Nuclear Power and Associated Modern Energy Markets

Conveners: Dr Luminita Grancea (OECD NEA), Mr Richard Schodde

21 The emerging uranium industry landscape: Push or Pull resource recovery?

The simultaneous idling of the world’s richest and one of the largest uranium deposits and cutbacks in production against a background of low prices, has brought to a head the strategic question of what future path the troubled global uranium industry should tread? If there is a positive way forward, the practical consequence is to define in detail how uranium recovery and production pathways should be redesigned for a more predictable and sustainable future. This paper will discuss the inevitable impact of these change drivers as causing the uranium sector to pivot from a “push” to a “pull” business model, one based on uranium as a critical material for climate action not as a traded commodity. This paper will detail the necessary interactions of policy and technology innovation from which this new "push" model can be developed, taking into account the demand for mineral resource recovery of any kind as a low- or zero-waste generating activity. This means rethinking uranium as a new economic resource, placing innovative uranium extraction technologies and flow sheets at the centre of process design and operation, with particular emphasis on uranium as a co- or by-product.

Speaker: Mr Harikrishnan Tulsidas (UNECE)

22 Uranium Mining Towards Sustainable Clean Energy: Indian Scenario

INTRODUCTION Energy plays a key role in the development and functioning of the world’s economy. However, increased energy use and mechanization to support ever growing industrialization brings with it the burdens of environmental pollution adversely affecting health, safety, lifestyle, etc. Ideally, a matured society should find ways to keep a balance between socially desirable, economically workable and ecologically sustainable measures through an adaptive process of integration. Sustainable clean energy supply to the mankind is an essential factor for sustainable development. Global energy sector is characterised by definite sources of energy like coal, oil & gas, atomic minerals, hydro power, solar etc. However, the challenge lies in finding ways to reconcile the necessity and demand for energy resource with acceptable impact on the environment within available natural resource base. India, with a population of more than one billion has been facing formidable challenges in addressing its energy needs. Though fossil fuels and hydro power dominate the country’s energy production scenario, recognition of nuclear power as a clean, reliable and abundant source of energy with no greenhouse gas emissions in the country is a giant step towards sustainable development process. It has a great potential to protect the earth from irreversible environmental damage. URANIUM MINING IN INDIA AND SUSTAINABILITY India's nuclear programme adopts a unique three-stage strategy based on a closed fuel cycle, where the spent fuel of one stage is reprocessed to produce fuel for the next stage. The objective is to utilize both fertile and fissile components of uranium, and utilisation of thorium. This scheme also takes into account the country’s unique atomic mineral resource base (modest uranium and abundant thorium) with a goal for clean energy security. India’s PHWR programme (First stage of three-stage strategy) has reached a state of commercial maturity over the years with indigenous capability and the county is now entering into second stage of U-Pu based fuel reactors. The third stage of reactors with thorium as fuel has been developed in pilot scale and development of commercial technology is underway. Indian uranium deposits are of low grade and moderate size. Most part of the country’s uranium resources are in carbonate host rock that calls for adoption of alkaline leaching which is acknowledged as a complex and costly process. These resources do not lend themselves for development on plain commercial considerations. However, the integrated economic model of nuclear power production programme (exploration, uranium mining, fuel fabrication, power production, waste management) of the country facilitates not only to absorb the commercial disadvantage of indigenous uranium production, but also provides fiscal latitude for adoption of new technology with higher level of safety standards and environmental measures. With successful commissioning of first alkali leaching based plant at Tummalapalle, more such projects are planned to be set-up soon to extract uranium from carbonate host rock. Uranium mining technology in India are appropriately chosen with an aim to achieve minimum generation of waste rock, use of waste rock in underground mines as fill, minimum disturbance to surface topography through continuous filling of voids created by underground mining, reuse and recycle of the liquid waste etc. Adoption of decline entry, ramps as entry into stopes, use of electro-hydraulic underground equipment replacing diesel powered etc in underground mining help in maintaining the operations within the absorptive capacity of local sinks for wastes. Uranium mining in India is gradually absorbing globally acceptable technology of trackless mining with improved efficiency and safety features. Recently commissioned Tummalapalle underground uranium mine with three declines as entry and conveyor transport of ore from mine through central decline to the plant is a landmark development in Indian mining industry. Uranium ore processing through acid leaching though dominate in the uranium production scenario of the country, continuous efforts are made for up-gradation with utmost consideration on maximising recovery, reduction in discharge of effluents and maximising the recovery of by-products. Recovery of by-products ensures optimum utilization of all useful materials from the ore in an integrated sequence (single flowsheet). This helps in minimising waste streams and mine-site disorders demonstrating comprehensive extraction of resources. Extraction of magnetite from ores of Singhbhum and proposed extraction of sulphides from ore of Rohil uranium deposit in the country illustrate recovering values from the waste. Adopting a shorter processing route, implementing measures to maximize the re-use of water, producing environmentally benign product like uranium peroxide etc. are some of the distinctive features which exemplify the values of sustainability. Management and eco-restoration of uranium tailings impoundment (solid and liquid waste) facilities are the crucial part of uranium mining all over the world. In India, the technology for management of tailings has been constantly upgraded in line with the international practices. Tailing ponds have been designed with improved floor lining to prevent downward movement of effluent and robust monitoring mechanism to maintain the permissible discharge quality of water. Eco-restoration of the filled tailings pond with appropriate thick layer of soil for arresting radon emanation, planting specific varieties of non-edible grass to control soil erosion and prevent radioactive incursion into the food chain through grazing animals etc. are well acknowledged in the society. Presently, a new innovative method of tailings management – called Near Surface Trench Disposal is being developed which aims at effective utilization of land within mining area available away from public domain and ease of handling and monitoring of tailings. Avoiding the transfer of large financial burden through time to future generations is a part of “future-proofed” sustainable development goals. Future financial liabilities and costs associated with closure of uranium mines, decommissioning of process plants and reclamation of tailings impoundment facilities are adequately set aside to ensure funds availability when needed in the future. Displacement and disruption of settlements around mining sites is generally seen as a major cause of resentment in the communities. Hand holding for skill development and education to students in the area around uranium projects in India at early stage of project development helps creating a skilled society in the area, thus avoiding large scale influx of trained manpower from other parts of the country. It also helps in the growth of secondary industries in the neighbourhood. Local industries are encouraged to progressively develop the competency to support the need of the mining sector thereby brining in sustainability of new technologies and developing the competency to support need of critical components enhancing the skill base of the community. The uranium production facilities in the country have helped in creating self-sustainable skilled society for mining and processing industries thereby supporting other similar industries. CONCLUSION With limited uranium resource base, India marches ahead in its goal of multi-fold increase in uranium production and nuclear power generation by delicately balancing the sustainability of the community around the production facilities through appropriate mix of technology, environmental measures, social harmony, finance and governance. Apart from strengthening the operations in its eight mines and three process plants, efforts are on for setting up new units in different parts of the country. Sharing of knowledge on past practices and collective wisdom of good systems is essential for sustainable uranium industry particularly to engage the countries with little or no experiences in such fields. Indian experience, assimilated over time of working with low grade small to medium size deposits and organisational structure of nuclear power sector may become a model for new practitioners in the field of uranium production and nuclear power in the world. BIBLIOGRAPHY ACHARYA, D., “Overview of Uranium Production in India”, Special ASSET Bulletin/Souvenir during 6th DAE-BRNS Symposium on Emerging Trends in Separation Science and Technology (SESTEC- 2014) ACHARYA, D. and SARANGI, A. K., “Development of carbonate hosted uranium mineralisation in India”, International Symposium on “Uranium Raw Material for the nuclear Fuel cycle: Exploration, Mining, Production, Supply and Demand, Economics and Environment issues (URAM 2014)”, organized by International Atomic Energy Agency (IAEA) during June 23 – 28, 2014 BHARDWAJ, S. A., “Indian nuclear power programme – Past, present and future”, Indian Academy of Sciences- Sadhan, Vol. 38(2013) GUPTA, R., “Uranium Mining and Environmental Management-The Indian Scenario”, 13th National Symposium on Environment, Shillong, India, (2004) GUPTA, R. and SARANGI, A. K., “Overview of Indian uranium production scenario in coming decades”, Energy Procedia, Volume 7, pp. 146-152 (2010). http://www.sciencedirect.com/science/article/pii/S1876610211015281 INTERNATIONAL ATOMIC ENERGY AGENCY, New 'Comprehensive' Approaches to Uranium Mining and Extraction (2011), https://www.iaea.org/OurWork/ST/NE/NEFW/News/2011/repository/New-Comprehensive-Approaches-to-Uranium-Mining-and-Extraction.html SARANGI, A. K., “Uranium exploration, resources and production in India” in the book “Geo-resources”, published by Scientific Publishers (India), Vol. II-25, 2014, pp.253-263 (2014). SARANGI, A. K., “Geological characteristics of Indian uranium deposits influencing mining and processing techniques”, Proceedings International Symposium on Uranium Raw Material for Nuclear Fuel Cycle: Exploration, Mining, Production, Supply and Demand, Economics and Environmental Issues (URAM-2009), Vienna, pp. 143 (2009). http://www.pub.iaea.org/MTCD/Meetings/PDFplus/2009/cn175/cn175_BookOfAbstracts.pdf SARANGI, A. K., "Uranium Resource Development and Sustainability—Indian Case Study" in the book "Modelling Trends in Solid and Hazardous Waste Management", published by Springer, ISBN 978-981-10-2409-2, pp 105 – 126 (2016). SURI, A.K., PADMANABHAN, N.P.H., SREENIVAS, T., ET AL., “Process development studies for low grade uranium deposit in alkaline host rocks of Tummalapalle”, IAEA Technical Meeting on Low Grade Uranium Deposits, Vienna, March 29-31, 2010

Speaker: Dr Akshaya Kumar Sarangi (Uranium Corporation of India Ltd)

23 History of nuclear fuel cycle development, facility decommissioning and site restoration at IPEN — CNEN/SP, Brazil

INTRODUCTION With the decommissioning of the pilot plants of the nuclear fuel cycle at the Nuclear and Energetic Research Institute - IPEN-CNEN / SP an important period of the Institution is being concluded. From its foundation until the 1990s, the technological domain of the various stages of the fuel cycle was perhaps the most important activity of IPEN, in terms of the number of researchers and technicians involved, as well as the financial resources used. IPEN was founded in 1956 and its growth was centered in the IEA-R1 Reactor, a pool type reactor in operation since 1957. IPEN is located at the west of Sao Paulo city, inside the Campus of the University of Sao Paulo – USP. IPEN occupies an area of nearly 500.000 m2 (20 % buildings). It is associated to the University of Sao Paulo for teaching purposes. Through a partnership with USP, IPEN conducts a post-graduation program. The IPEN research centers have been engaged in multidisciplinary areas such as nuclear radiation applications, radioisotope production, nuclear reactors, nuclear fuel cycle, radiological safety, dosimetry, laser applications, biotechnology, materials science, chemical processes and environment. An example of a large national impact IPEN activity has been the production and supply of radiopharmaceuticals. About 2 million diagnostic and therapeutic nuclear medicine procedures per year have been performed in 2004 with products supplied by IPEN. Nowadays, the main IPEN’s facilities include: the nuclear research reactor IEA-R1m that reached criticality in 1957 (built with United States support under the Atoms for Peace Program) and has been upgraded recently to operate at 5 MWth; a Zero Power Reactor IPEN/MB-01 (critical assembly); two Cyclotrons (CV-28 and Cyclone 30 MeV – for radioisotope production); two electron beam accelerators of 1.5 MeV for irradiation applications in the industry and engineering; two Cobalt-60 Irradiators (11,000 and 5,000 Ci); dispersed fuel fabrication facilities (for research reactors); laboratories for chemical and isotope characterization, micro structural and mechanical tests [1]. IPEN had an important role in the development of uranium and thorium fuel cycles in Brazil. Since its foundation, IPEN has played a decisive role in the development of the nuclear science and technology in Brazil. It was created with the main purpose of performing research and development of nuclear energy peaceful applications. The Institute recent history has shown a major participation in the technological development of all steps of the nuclear fuel cycle. Nuclear fuel cycle R&D activities in the IPEN, from uranium purification to hexafluoride conversion and fuel fabrication for research reactors, besides thorium and zirconium purification, were accomplished in pilot plant scale and most facilities were built in the 70-80 years, destined to the technological domain of the several stages of the fuel cycle. The facilities were used to promote human resources, scientific research and better understanding of fuel cycle technologies. The pursuit of autonomous technological development was emphasized in the Institution for several decades, having experienced a considerable impact when the Brazil-Germany agreement was signed in 1975. Initially, the IPEN’s researchers felt unmotivated by the option of acquiring technology. However, the agreement was beneficial in terms of training and qualification opportunities for technical teams. IPEN had a new stimulating period when cooperation with the Brazilian Navy began in the early 1980s. Autonomous technological development had once again become important and mobilized a large contingent of people at the Institute. One example of the important engagement of IPEN in the technological development in the nuclear fuel cycle area is the isotopic enrichment of uranium by ultra centrifugation, nowadays in process of industrial implantation. This significant achievement was performed in cooperation with the Brazilian Navy. Another important achievement was the IPEN-MB 01, a research reactor built in IPEN also in cooperation with Brazilian Navy, using UO2 pellets produced at the IPEN’s pilot plant. Nevertheless, in the nineties, radical changes in the Brazilian nuclear policy determined the interruption of the fuel cycle research activities and the plant-pilot's shut-down. Unfortunately, those changes interrupted decades of autonomous research and development efforts in the area of the nuclear fuel cycle at IPEN, with significant losses for the country. Despite the existence of a nuclear industry currently consolidated in Brazil, it is necessary to distinguish clearly between autonomous development and acquisition of technology. Since then, IPEN has faced the problem of the dismantling and/or decommissioning its Nuclear Fuel Cycle old pilot plants. Most Nuclear Fuel Cycle Facilities had the activities interrupted until 1992-1993. Those facilities already played their roles of technological development and personnel's training, with transfer of the technology for institutions entrusted of the “scale up" of the units. Most of the pilot plants interrupted the activities more than twenty five years ago, due to the lack of resources for the continuity of the research [2]. HISTORY OF URANIUM DEVELOPMENTS AT IPEN This section summarizes the progress of research concerning the uranium fuel cycle set up at the IPEN from the raw yellow-cake to the uranium hexafluoride, besides the reconversion of the hexafluoride to ammonium diuranate (ADU) and, at a later period, to ammonium uranyl carbonate (AUC). Also it is presented the progress in the obtainment of thorium compounds from concentrates produced by the monazite processing. About sixty years ago, IPEN began a systematic R&D program on establishing of the uranium and thorium technology as part of the Brazilian program for developing nuclear energy for peaceful uses. The main activities were focused on the recovery of uranium from ores of domestic resources, purification of uranium and thorium raw concentrates and their transformation in compounds with purity and properties suitable for further fabrication of fuel elements for research reactors. The strategy adopted to dominate the uranium cycle was, like other countries, to develop processes on a laboratory scale, bench and pilot, to finally start industrial production. The first studies for the installation and operation of a pilot unit for uranium purification at IPEN were initiated in the Division of Radiochemistry (DRQ) of the IEA (by that time IPEN was named IEA – Atomic Energy Institute), under the guidance of Prof. Dr. Fausto W. Lima, in 1959[3,4]. After preliminary laboratory-scale studies, a pilot plant was installed and operated, which went into operation in 1960 and continued until 1963, when its first stage was closed. The starting product was sodium diuranate (SDU), and then produced by the industrial processing of the monazite in São Paulo, by a private company (Orquima). The final product should be a high purity ammonium diuranate (ADU) with characteristics appropriate for conversion to uranium oxides and these in uranium tetrafluoride. It was also envisaged in a long-term program to obtain uranium hexafluoride. This first facility for uranium purification was based on an ion-exchange process. During its operation, the pilot plant produced approximately 4 tons of ammonium diuranate (ADU). This ammonium diuranate was converted into uranium dioxide (UO2) and used in the manufacture of fuel elements by the Division of Nuclear Metallurgy (DMN) of the IEA [5], founded in1962 under leading of Prof. Dr. Tharcísio D. Souza Santos. Those fuel elements were destined to the construction of a sub-critical unit, named RESUCO, to be installed in the Nuclear Energy Institute of the Federal University of Pernambuco, in Recife. At that time a sodium diuranate (SDU) obtained by the industrial processing of the monazite and containing, among others, sodium, thorium, rare earths (RE), iron, phosphorus and silicon as main impurities was used as uranium concentrate. It should be noted that this uranium concentrate obtained from monazite is different from most concentrates obtained from other ores. The presence of thorium, RE and phosphate demands special considerations about the decontamination that depends on the chemistry process employed [4]. The sodium diuranate was dissolved with nitric acid for the preparation of a uranyl nitrate solution. The main concern was the removal of Th and RE. The loaded strong cationic resin was washed with water and then with diluted HNO3 and eluted with ammonium sulfate. ADU was precipitated by flowing the elution into ammonium hydroxide and keeping the reaction medium at a pH not less than 6.5 to maintain the co precipitated sulfate at a minimum level (< 0,5% U3O8) [6]. Following completion of the first stage of its existence, this pilot plant was dismantled [3]. With the completion of construction of the building of the Chemical Engineering Division - DEQ, in December 1966, under guidance of Prof. Dr. Alcídio Abrão, the installation of new laboratories was initiated as well as the construction of a new purification pilot plant by solvent extraction [7, 8]. This unit was based on the conventional liquid-liquid extraction technique. The facility comprised a section for yellow cake dissolution and three pulsed columns with perforated plates for the extraction of uranyl nitrate – UN - with TBP-varsol, scrubbing and stripping of pure U. The development of U purification by pulsed columns was carried some years before the assembling of the pilot plant [9]. Besides the development of purification processes related to monazite concentrates, some alternative techniques were evaluated for the extraction of U, Mo and V from sulfuric acid liquors since, by that time, it was being developed an acid leaching process for the uranium ore from Poços de Caldas, State of Minas Gerais [10]. The dissolution of the impure yellow cake was accomplished with 2M HNO3 at ~100°C and the concentration was adjusted to 300 gU/L. The extraction was done in countercurrent with org/aq ratio of 2.2. The loaded organic phase (TBP-varsol) with 135 gU/L was scrubbed with HNO3. The organic phase was stripped with water, resulting a purified uranyl nitrate solution. A pilot plant was built to perform the precipitation of DUA by bubbling anhydrous NH3(g) into uranyl nitrate with 100 gU/L, at 60°C. The unit could be operated in a batch as well as a continuous way. The process pH was an important parameter to be controlled depending on the use of the ADU. For production of UF4, it was important to keep the pH between 4.0-4.5, to avoid oxide agglomeration. However, for obtaining of UO2 with better ceramic reactivity it was important to keep the pH at 7.0-7.5 [10]. The calcination of ADU to UO3 (for UF4 conversion) was accomplished in a belt furnace, with the ADU loaded in trays of stainless steel, at 500°C. After some preliminary studies, a pilot plant facility for UF4 production was set up. The establishment of this unit had the collaboration and technical assistance from the International Atomic Energy Agency – IAEA. The UF4 pilot plant operated using the moving bed process. The starting material was UO3, reduced to UO2 by cracked NH3, and anhydrous hydrogen fluoride for the conversion to UF4 [11-13]. A laboratory scale development work was also carried out to obtain UF4 by alternative method via uranium dioxide reaction with hydrofluoric acid (wet method). A semi-pilot unit for this technology was also installed, with the construction of a reactor in polyethylene with mechanical agitation with a capacity of 100 kg UF4/batch. An alternative method to ADU route for UO3 obtainment was reached with the construction of a denitration pilot plant. This facility used a fluidized bed process for conversion of uranyl nitrate solution to uranium trioxide and recovery of nitric acid. The bed of UO3 was fluidized by upward flowing of air in a 3” Φ tube (reaction chamber) heated by external electric heaters. Uranyl nitrate solution is injected at the bed level by a nozzle. UO3 seeds were previously placed to form the bed and the decomposition of uranyl nitrate occurred around the seeds. The spherical form of UO3 was preserved. Obtaining of UO3 directly by denitration of uranyl nitrate avoids precipitation, filtration and drying ADU which occurred in the conventional process. The next step was the construction of an electrolytic fluorine generator and a pilot plant for UF6 production, having the UF4 produced in the moving bed reactors as starting material. During its operational life, the unit produced tens of metric t of UF6, used in developments of ammonium uranyl carbonate – AUC precipitation process. The development of the AUC process was of fundamental importance in the production of the UO2 fuel pellets for the IPEN-MB 01 research reactor that was totally design and constructed by Brazilians in a cooperation of IPEN and Brazilian Navy. In parallel with the uranium related developments, a program for thorium purification and production was conducted at IPEN. The alkaline process for breaking up the monazite had been practiced since 1948, in São Paulo city by the private company Orquima. The processing of the monazite sands aiming the export of rare earths and other materials gave origin to thorium concentrates suitable for purification by solvent extraction. A pilot plant was built. The production and purification of thorium compounds was carried out at IPEN for about 18 years. During this period, the main product sold was the thorium nitrate with high purity (nuclear grade), having been produced over 170 metric tons of this material in the period, obtained through solvent extraction. The raw materials used were some thorium concentrates obtained from the industrialization of monazite sands. The thorium nitrate was supplied to the domestic industry and particularly used for gas portable lamps (Welsbach mantle). The thorium compounds produced permitted to accomplish several studies with a view to conversion of nitrate nuclear-grade thorium oxide suitable for the manufacture of fuel pellets, manufacture of mixed oxide pellets (U,Th)O2, obtaining of thorium tetrafluoride and its reduction to metallic thorium and studies of some properties of the UO2-ThO2 solid solutions [14, 15]. The process developments, besides construction and operation of pilot plants, gave rises to several additional related developments such as treatment of effluents, construction of a fuel reprocessing laboratory, production of Sol-Gel microspheres, analytical procedures for quality control, as well as, the development of further metallurgic processing of uranium and thorium compounds and studies for strategic materials like Zr and RE. DISCUSSION AND CONCLUSION Immediately after the nuclear R&D program interruption, in the nineties, the uncertainties related to an eventual retaking of the Program created some political hesitation about the facilities dismantling decision. As the retaking of the R&D Nuclear Program had been discarded, the decommissioning seemed to be the obvious choice. The appropriate facilities maintenance had been also harmed by the lack of resources, with evident signs of deterioration in structures and equipments. The existence of these facilities also implicates in the need of constant surveillance, representing additional obligations, costs and problems. With the decommissioning of nuclear fuel cycle facilities at IPEN [2, 16], not yet concluded, an important cycle of the institution’s life is being closed. The first years of a new research center like IPEN in the sixties were full of problems and challenges. This work is a modest record and a tribute to the achievements of those pioneers who began their studies on the nuclear fuel cycle and related materials in Brazil. REFERENCES [1] INSTITUTO DE PESQUISAS ENERGÉTICAS E NUCLEARES, IPEN’S webpage https://www.ipen.br/portal_por/portal/default.php, (2018) [2] LAINETTI, P.E.O. Decommissionig of Nuclear Fuel Cycle Faciilities in the IPEN-CNEN/SP, Proceedings’ European Nuclear Conference, Brussels (2007). [3] LIMA, F. W. , ABRÃO, A. Produção de Compostos de Urânio Atomicamente Puros no Instituto de Energia Atômica - IEA Publication nº 42, (1961) (in portuguese). [4] ABRÃO, A., FRANÇA JR, J. M. Usina Piloto de Purificação de Urânio por Troca Iônica em Funcionamento no Instituto de Energia Atômica - IEA Publication n° 219 (1970) (in portuguese). [5] SANTOS, T.D.S., HAYDT, H.M. , FREITAS, C.T. Fabricação dos elementos combustíveis de UO2 para o conjunto sub-crítico "Re-Suco" – Metalurgia, Revista da Ass. Bras. Met. v. 21, n? 88, p. 217-222, IEA Publication nº 92, (1965) (in portuguese). [6] ABRÃO, A. et alii Precipitação Reversa de Diuranato de Amônio a Partir de Soluções de Sulfato de Uranilo: Descontaminação do Íon Sulfato - IEA Publication n° 278 (1972) (in portuguese). [7] FRANÇA JR, J. M. Usina Piloto de Purificação de Urânio pelo Processo de Colunas Pulsadas em Operação no Instituto de Energia Atômica - IEA Publication n°277, (1972) (in portuguese). [8] FRANÇA JR, J. M., Tecnologia da Purificação do Urânio por Extração com Solvente - IEA Publication n°309 (1973) (in portuguese). [9] BRIL, K.J. and KRUMHOLZ, P. Um Processo Industrial de Produção de Urânio Nuclearmente Puro, Report LPO-9, Lab. de Pesquisas / ORQUIMA (1960) (in portuguese). [10] ABRÃO, A., “O Ciclo do Urânio no IPEN”, IPEN Publication n°398 (1994) (in portuguese). [11] RIBAS,A.G.S. and ABRÃO, A. Preparação de UO2 Apropriado para Obtenção de UF4- IEA Publication n°318 (1973) (in portuguese). [12] CUSSIOL FILHO, A. and ABRÃO, A. Tecnologia para a Preparação de Tetrafluoreto de Urânio por Fluoridretação de UO2 Obtido de Diuranato de Amôni - IEA Publication n°379 (1975) (in portuguese). [13] FRANÇA JR, J. M. Unidade Piloto de Tetrafluoreto de Urânio pelo Processo de “Leito Móvel” em Operação no IEA - IEA Publication n°381 (1975) (in portuguese). [14] BRIL, K. J. and KRUMHOLZ, P., Produção de Óxido de Tório Nuclearmente Puro - IEA Publication n°115 (1964) (in portuguese). [15] LAINETTI, P.E.O., FREITAS, A.A. and MINDRISZ, A.C., Review of Brazilian Activities Related to the Thorium Fuel Cycle and Production of Thorium Compounds at IPEN-CNEN/SP, Journal of Energy and Power Engineering 8 (2014). [16] INTERNATIONAL ATOMIC ENERGY AGENCY, Innovative and Adaptive Technologies in Decommissioning of Nuclear Facilities - IAEA-TECDOC-1602, IAEA, Vienna (2008).

Speaker: Dr Paulo Ernesto Oliveira Lainetti (Nuclear and Energetic Research Institute - IPEN-CNEN/SP Brazilian Nuclear Energy Commission)

17:40 Welcome Reception

Untill 20:00

Tuesday, 26 June

Advances in Exploration

Conveners: Dr Igor Pechenkin (All-Russian Scientific-Research Institute of Mineral Resources, Moscow, Russia), Dr Mark Mihalasky (U.S. Geological Survey)

24 INVESTIGATION OF THE GEOLOGICAL PROCESSES WHICH CONTROL THE GENESIS OF UNCONFORMITY-TYPE URANIUM DEPOSITS USING PARALLELIZED NUMERICAL SIMULATION ON A SUPERCOMPUTER

Uranium deposits of the Athabasca Basin, Canada and Alligator Rivers region, Australia are located near subhorizontal unconformities between polydeformed/metamorphosed Archean/Paleoproterozoic rocks and overlying essentially undeformed Proterozoic sedimentary rocks. Most deposits are associated with basement-rooted faults; however the location of uranium mineralization to the unconformity is quite variable. Athabasca Basin deposits occur at/above/below the unconformity. Conversely, all discovered deposits in the Alligator Rivers region occur below the unconformity. Conceptual models for these deposits invoke sandstone-sourced oxidised fluids moving down into the basement (basement mineralisation), or basement-sourced reduced fluids moving up into the sandstone (sandstone mineralisation); driven by topography, deformation or thermal buoyancy. This study focuses on deformation-driven flow, using numerical simulations to explore fluid flow controls. The model is subjected to horizontal shortening, and fluid flow directions are explored by varying fault dip, shortening direction, strain rate, basement rock strength, or permeability. Over 300 finite-element simulations were performed using MOOSE simulation framework. The results indicate that shallow fault dip, high strain, and fault-perpendicular shortening favour downward flow, whereas steep fault dip, low strain, and low-angle-to-fault shortening favour upward flow. These results are used to predict new mineralization targets.

Speaker: Dr Irvine R. ANNESLEY (ENSG, Universite de Lorraine and Department of Geological Sciences, University of Saskatchewan)

25 The Midwest Project, East Athabasca Basin, Northern Canada: Reviving old deposits to prepare for the future

INTRODUCTION The Midwest property, which hosts the Midwest Main and Midwest A deposits, is located within the eastern part of the Athabasca Basin in northern Saskatchewan. The Midwest Project is a joint venture between Orano Canada Inc. (Orano; 69.16%), Denison Mines Corp. (25.17%), and OURD (Canada) Co., Ltd. (5.67%) with Orano as the active project operator. The Midwest Main uranium deposit was initially discovered in 1977 by Esso Resources with the initial discovery of sandstone mineralization immediately above the sub-Athabasca unconformity drilled from the follow-up of initial airborne and ground geophysical surveys, ground geochemical sampling, and boulder surveys. The Midwest A uranium deposit was later discovered along trend in 2005 by Orano following up on historical mineralized intercepts from the Esso Resources’ property wide drill program between 1977 and 1981 [1, 2]. DESCRIPTION Located 840 km northeast of Saskatoon in northern Saskatchewan on the east margin of the prolific Athabasca Basin, the Midwest Project was recently updated with new mineral resource estimates as of November 2017. The project is estimated to comprise 1.060 Mt of Indicated mineralization at an average grade of 2.19% U3O8 (1.85% U) with a contained uranium metal content of 51.1 Mlbs U3O8 (19,650 tU) as well as 0.830 Mt of Inferred mineralization at an average grade of 0.99% U3O8 (0.84% U) with a contained uranium metal content of 18.2 Mlbs U3O8 (6,980 tU) [1, 2]. The Midwest Project contains two separate deposits, Midwest Main and Midwest A, which feature high grade uranium mineralization mainly situated along the regional unconformity between the Athabasca Group sandstones and basement rocks of the Wollaston-Mudjatik Transition Zone comprising Paleoproterozoic Wollaston Group metasediments and Archean orthogneisses [3]. Midwest Main is interpreted to consist of a large unconformity lens with a basement mineralized root and 19 perched sandstone lenses. Midwest A consists of a large unconformity low grade lens that encompasses an interior high grade lens with a small basement root. PURPOSE OF THE WORK In response to the envisaged forecast of increased growth in electricity demand, and in turn the growth of nuclear power worldwide, medium to long term uranium prices are expected to reflect this increase in uranium demand [4]. In an effort to prepare and better plan for the next phase of the uranium market, mineral resources will need to be brought up to modern resource estimation standards to be readily available when their need arises. The Midwest Main and Midwest A deposits have seen several resource estimations since their discoveries, however none were considered readily available to be used for the next levels of assessment prior to mining. Over the course of 2017, intensive work was completed to bring the dataset and estimates up to a more modern and rigorous standard. This resulted in the completion of separate resource estimates for both deposits in accordance with CIM Definition Standards (2014) in National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”), which not only represented an increase in contained resources, but also an upgrade in the confidence level. METHODS AND RESULTS To modernize the mineral resource estimates at both deposits a comprehensive review of project data was undertaken prior to resource estimation. Concerns were identified at both deposits that needed to be addressed to increase both the confidence and the accuracy of the final estimate. Given the historic nature of the data at Midwest Main a limited amount of data was readily available digitally; downhole gamma probe (“probe”) data existed only as paper logs making it previously unavailable to be used, no comprehensive 3D geological model was available, perched mineralization was not fully modeled, as well as further data QAQC was needed. Midwest A has a much more modern data set, however no dry bulk density measurements were available, the latest drilling was not taken into account in the previous estimate, and the High Grade Zone was assigned an average uranium grade rather than performing grade estimation. Additionally, both deposits required new probe to chemical uranium assay grade (“grade”) correlations for the calculation of equivalent uranium (eU), combination of probe and grade data based on core recovery and probing/drilling parameters to be available for estimation, updated lithology and structural models (geological model), and updated resource model. Work began with verifying the grade data against assay certificates and a historical nine track database from ESSO. Some discrepancies were noted in the sample locations as well as some of the grades due to typographical errors. After comparison to the original drill logs and probe logs, these were rectified. The Midwest deposits often have core loss associated with the mineralization, due to the high amount of clay alteration and quartz dissolution which makes core recovery while drilling difficult. This results in gaps in the grade dataset that are typically addressed by using probe equivalent uranium (eU) data. Digital probe data was available for Midwest A, however for Midwest Main most of probe data was never digitized and remained only available on paper logs. The paper logs for 218 holes were digitized and added to the Midwest data set. This was followed up by ensuring the probe data was depth matched with grade data, as well as the creation of grade correlations for both deposits. Midwest Main had a robust density to grade correlation however, Midwest A did not have any dry bulk density measurements taken. The only density data at Midwest A was in the form of specific gravity measurements which do not take into account porosity and therefore tend to overestimate the density. Due to the high density of uranium, density is a vital reference for the expected tonnage of high-grade uranium deposits which has a direct effect on the amount of uranium estimated. Given this uncertainty at Midwest A, previous resource estimations were forced to use a very conservative grade to density regression formula to avoid overestimation of resources. During a 2017 site visit 25 dry bulk density measurements were taken from the remaining Midwest A drill core and sent for dry bulk density and geochemical analyses. A new grade to density regression formula was established showing an increase to the correlation by approximately 10%. This corresponded to a similar increase in mineral resources. At Midwest Main, uncertainty of basement lithologies’ foliation trends existed, which have a control on the basement and unconformity mineralization. More data is needed to improve the understanding of the structural setting, as few oriented structural measurements are available leaving some uncertainty on fault orientations. A geological model, which provided additional information on the controls and constraints on the mineralization, was created. For Midwest Main, this included digitization and generalization of drill log descriptions to make them available for cross-sectional 2D and 3D interpretation. To aid in this interpretation, the geophysical surveys (electromagnetic, magnetic, and resistivity) were re-interpreted to confirm orientation of some structures and basement lithologies. Based on this work, a complex structural setting appears to control the mineralization location at Midwest Main. Several reactivation stages occurred within the north-northeast-trending belt of graphitic metasediments which was a key-element for Egress-style hydrothermal fluid circulation along the unconformity and into the Athabasca sandstone. These NNE faults are interpreted extending into the sandstone, off-setting certain lithological markers. A series of N80° “EW” small-scale structural features (probable faults) appear to cross-cut the unconformity mineralization, locally off-setting and extending the mineralization. Additionally, these “EW” structures appear to be limiting the extensions of certain perched mineralized lenses. North-south trending “Tabbernor”-style faults cross-cut the deposit and appear to control some extents of the high-grade mineralization at the unconformity. Additionally, the main mineralized basement root seems to follow this fault in the northern part of the deposit. High-grade mineralization at Midwest Main is interpreted to be located in certain triple-point zones where the reactivated northeast-trending graphitic belt is intersected by cross-cutting EW and NS trending fault systems. The dominant control for perched mineralization in the sandstone appears to be the stratigraphic bedding planes. Mineralizing fluids are believed to have circulated through localized fault zones precipitating uraninite/pitchblende along bedding planes. The updated geological model at Midwest A showed that the uranium mineralization follows the northeast-southwest structures with some broader areas where interpreted north-south structures cross-cut the mineralization. These north-south structures also appear to limit the extent of the high-grade mineralization along strike, with the unconformity limiting its down-dip extents. Mineralization was also modelled to reflect the control by the basement graphitic lithologies, and the unconformity on the mineralization. The higher-grade material is generally interpreted to be associated with the graphitic packages and NE-SW structures. Some mineralization control is also provided by the unconformity. A relatively minor basement mineralized root was modelled and is interpreted to follow the steeply-dipping graphitic packages. At Midwest Main the mineralization is interpreted to consist of a larger Unconformity Zone, a small Basement Zone, and 19 Perched Zones. The Unconformity Zone is relatively flat lying and approximately 920 metres long, 10 to 140 metres wide, and up to 33 metres in thickness, not including the basement roots which have been modeled to extend approximately an additional 90 metres into the basement. The bulk of the mineralization occurs in the Unconformity Zone at depths ranging between 170 and 205 metres below surface. Perched mineralization was interpreted to be flat-lying, occurring along stratigraphic bedding planes in the sandstone. Midwest A mineralization is interpreted to consist of a larger Low Grade Zone encompassing an interior High Grade Zone. The deposit is approximately 450 metres long, 10 to 60 metres wide, and ranges up to 70 metres in thickness. It occurs at depths ranging between 150 and 235 metres below surface. Based on the geological model, the interior High Grade Zone was interpreted to reflect the orientation of the steeply dipping basement graphitic lithologies while being limited down dip by the unconformity and along strike by the cross-cutting north-south structures. The relatively minor basement mineralized root was modelled and is interpreted to follow the steeply-dipping graphitic packages. Block models were created for both deposits, constrained by the re-interpreted mineralization models which utilized the geological models. A two to three-run ordinary kriging analysis was conducted for the unconformity mineralization at both deposits estimating DG (density x grade in %U) and density. The majority of the blocks were estimated with the first run. The remaining run(s) were used to fill in any un-estimated blocks. Hard boundaries were used to prevent the use of composites between the unconformity, perched, and basement zones. A single run inverse distance estimate was completed for the Basement and Perched lenses. In order to manage the influence of high grades within the unconformity zones, the influence of high grade samples were restricted to prevent smearing into lower grade areas. No restrictions were placed on the High Grade Zone at Midwest A, as it was able to be domained and estimated separate from the surrounding lower grade mineralization. CONCLUSION Data mining and QAQC as well as a detailed evaluation of lithology and structures that control the mineralization are vital to the construction of a robust resource model. Many of the previous outstanding issues were addressed, readying the Midwest Project deposits to become a new source of uranium supply to help meet global uranium market demands when the price recovers. The authors would like to thank Orano Canada Inc., ORANO (formerly AREVA), Denison Mines Corporation, and OURD (Canada) Ltd. for giving permission to publish this abstract. REFERENCES [1] ALLEN, QUIRT, MASSET, Midwest A Uranium Deposit, Midwest Property, Northern Mining District, Saskatchewan, NTS Map Area 74I/8: 2017 Mineral Resource Technical Report. AREVA Resources Canada Inc., internal report, no. 17-CND-33-01, (2017). [2] ALLEN, T., QUIRT D. H., MASSET, O., Midwest Main Uranium Deposit, Midwest Property, Northern Mining District, Saskatchewan, NTS Map Area 74I/8: 2017 Mineral Resource Technical Report. AREVA Resources Canada Inc., internal report, no. 17-CND-33-02, (2017). [3] ANNESLEY, I. R.; MADORE, C.; PORTELLA, P., Geology and thermotectonic evolution of the western margin of the Trans-Hudson Orogen: evidence from the eastern sub-Athabasca basement, Saskatchewan, Canadian Journal of Earth Science, v. 42, (2005). [4] NUCLEAR ENERGY AGENCY, INTERNATIONAL ATOMIC ENERGY AGENCY ANNESLEY, Uranium 2016: Resources, Production, and Demand, (2016).

Speaker: Mr Trevor Allen (Orano Group Canada)

26 POTENTIAL FOR UNCONFORMITY-RELATED URANIUM DEPOSITS IN THE NORTHERN PART OF THE CUDDAPAH BASIN, TELANGANA AND ANDHRA PRADESH, INDIA

INTRODUCTION The intra-cratonic, Mesoproterozoic Cuddapah Basin in the Dharwar Craton of India hosts several types of uranium deposits in its various stratigraphic levels. Signatures of uranium mineralisation are recorded in the Gulcheru and Vempalle Formations in the lower part and along the unconformity between the basement granite and the overlying sediments of Srisailam / Banganapalle Formation in the upper part of the Cuddapah sequence. The Srisailam and Palnad sub-basins lying in the northern part of the Cuddapah basin hosts Proterozoic unconformity related uranium mineralisation. Uranium mineralisation in these sub-basins occurs close to the unconformity between the basement complex containing basement granitoid, basic dykes of Paleoproterozoic age and greenstone belt of Achaean age and arenaceous, argillaceous and calcareous sediments of Meso-Neoproterozoic age. Concerted sub-surface exploration over two decades has established three small to medium tonnage uranium deposits at Lambapur (~1,200tU), Peddagattu (~6,400tU) and Chitrial (~8,000tU) along the unconformity between the basement Mahabubnagar granite and overlying Srisailam Formation in Srisailam sub-basin; and one small tonnage deposit at Koppunuru (~2,300tU) close to the unconformity contact between basement granite and Banganapalle Formation of the Kurnool Group in the Palnad sub-basin. In all these deposits, uranium mineralisation is concealed and lies below the cover rocks at a depth of <5-150m. Uranium mineralization located in these sub-basins show dissimilarity with that of unconformity-type uranium deposits in Canada and Australia, especially in respect of basement and marked absence of palaeosol. GEOLOGICAL SETTING AND URANIUM MINERALISATION The Cuddapah basin, having a spread over 44,000 sq km, is the second largest Proterozoic basin in India, with a thick pile of sediments and subordinate volcanics and hosts Proterozoic unconformity related uranium deposits in its Northern part in the states of Telangana and Andhra Pradesh [1]. The Cuddapah basin comprises Papaghni, Srisailam, Palnad and Nallamalai sub-basins. The Srisailam and Palnad sub-basins lie in the northern parts of Cuddapah basin and exposes sediments of Srisailam Formation and Kurnool Group respectively [2]. The Srisailam, Palnad and part of Nallamalai sub-basins, developed over the basement granitoid of Paleoproterozoic, covers an area of ~ 10,000 sq km. The basement complex for the Srisailam and Palnad sub-basins comprises Archaean schist (Peddavoora Schist belt), Paleoproterozoic granite, basic dykes, pegmatites and quartz veins of Paleoproterozoic (2268±32 Ma to 2482±70 Ma) age [3]. Well-developed fracture systems (N-S, NE-SW, NW-SE) along with basic dykes traversing both cover rocks and basement cross cut the nonconformity surface. The N-S to NE-SW trending dykes in the basement have played vital role to increase thermal gradient to release uranyl ions into the solutions and remobilsation along fractures and to the unconformity plane. Grit to pebbly horizon immediately above the unconformity surface act as conducting system for uranium mineralisation. The Srisailam sub-basin, covering an area of around 3000 sq km forms a prominent plateau, exposing Neoproterozoic sediments of Srisailam Formation, the youngest unit of Cuddapah Supergroup. The sediments show sub-horizontal dips due southeast, and attains a maximum thickness of 300m. The Srisailam Formation comprises a sequence of feldspathic to sub-feldspathic quartzite with intercalated shale, siltstone and grit. The sediments directly overlie the basement rocks in its northern margins, whereas in the southeastern margin the sediments are underlain by Nallamalai Group metasediments with an angular unconformity. The northern fringes the Srisailam sub-basin has a highly dissected topography with several flat topped outliers occurring within the basement and rising 100 to 150m above the ground level. The Lambapur, Peddagattu and Chitrial uranium deposits are located in three such separate outliers [4]. The outliers of Srisailam Formation is characterised by a sequence of pebbly gritty arenite horizon successively overlain by shale, shale/quartzite intercalations and massive quartzite having thickness of 5-70m with a gentle dip of 3 to 5o towards southeast. The basement granitoids are sodic in nature, with moderate to high Na2O/K2O ratio (0.09 - 1.62). Compositionally, they vary from granite to granodiorite and are strongly peraluminous with A/CNK ratio > 1.1 [4]. The granitoids, mineralogically characterised as biotite-granite, consists of an assemblage of albite-oligocalse, quartz, K-feldspar with accessory hornblende, biotite, apatite, sphene, zircon, allanite and epidote. These are equivalents of Closepet granite of Eastern Dharwad Craton (EDC). Alterations such as chloritisation, sericitisation, calcitisation and epdotisation are pronounced in the basement especially close to the unconformity. Pyrite, chalcopyrite, galena, ilmenite, anatase and hydrated iron oxides are the opaque minerals. Study of granitiod core samples shows two to three sets of foliations, traversed by dolerite dykes and quartz veins. Radiometric analysis of granite reveals fertile nature (~20ppm of U) with U/Th ratio of 6.68 [5]. In all the three deposits in the Srisailam sub-basin viz. Lambapur, Peddagattu and Chitrial, uranium mineralization occurs close to the unconformity, both in the granites, basic dykes and vein quartz within the basement along with and the overlying pebbly arenite, with most part (>85%) in the basement [6]. Though, the ore body appears to be a blanket along the unconformity, scout drilling in various spacings in the entire outliers has indicated that the rich grade pods and ore shoots are confined to definite trends viz., NNE–SSW and NW–SE (Lambapur), WNW-ESE and N–S (Chitrial) and N-S in Peddagattu. The intensity of fractures within the granite and their intersections with the unconformity, thus apparently controls the grade of mineralization [7]. The ore bodies show gentle dips towards southeast and follow the basement slopes. Mineralisation is manifested in the form of radioactive phases viz. pitchblende, uraninite and coffinite as primary minerals and uranophane and autunite as secondary minerals. These are well exposed on the outcrops of granitoids at Lambapur and road cuttings of Peddagattu and Chitrial plateaus. Botryoidal and massive pitchblende occurs as thin veins sub-parallel to non-conformity surface, massive pods, in fracture planes of feldspar, as irregular segregations and also as adsorbed in globular organic matter. The massive pitchblende is replaced by coffinite at places. Extensive hydrothermal activity, both in the basement and overlying sediments is evidenced by high amounts of sulphides such as pyrite, chalcopyrite and galena. Petrographically, the pitchblende veins are found to cut across the basement granitoid and enter into the covers rocks. EPMA studies of radioactive core samples of granitiod of Chitrial area have indicated that UO2 content in pitchblende and coffinite range from 71.37 to 88.14% and 59.97 to 73.91% and also has confirmed the presence complexes such as U-Si, U-Si-Ti and U-Si-Al. X-ray diffraction studies of uraninite indicate unit cell dimension of Lambapur area in the range of 5.3973Ao – 5.4285 Ao and for uraninite of Chitrial area is 5.3959Ao. The oxygen content in the formula unit (UO2) is in the range of UO2.30 to UO2.69 in uraninite of deposits in Srisailam sub-basin. Evidences of remobilsation have been observed in the samples. Radiogenic lead of Lambapur reveals 480–500 Ma while the Sm–Nd data of uraninite yield an isochron age of 1,327±170 Ma as two phases of mineralizing events. The Palnad sub-basin, having an extent of around 4,500 sq km, hosts the Koppunuru uranium deposit in its western part [8]. The sub-basin exposes Neoproterozoic Kurnool Group comprising a thick sequence of clastic and calcareous sediments. In the northern part of the basin, basement granite and gneisses are unconformably overlain by the sub-horizontal sediments. Banganapalle Formation, the lowermost sequence of Kurnool Group, comprises gritty arenite successively overlain by shale/siltstone intercalations and quartzites of high mineralogical maturity [9]. The fertile nature of the basement granite is indicated by higher intrinsic uranium (Av. 32 ppm; n=16) and high U/Th ratio (Av. 4.41; n=16) as compared to the average uranium and U/Th ratio of normal granite (U/Th =0.25). An inlier of the granite is exposed to the east of Koppunuru, along the upthrown block of the Kandlagunta fault trending WNW- ESE. Both the basement and the sediments are fractured and traversed by quartz veins trending N-S, NNE- SSW and WNW- ESE. Uranium mineralisation in Koppunuru deposit occurs both in the sediments and in the basement manifested by three sub-horizontal ore lodes, two in the arenite of Banganapalle Formation and one in the basal polymictic grit/conglomerate of Banganapalle Formation, transgressing into basement granite, at places [10]. Pitchblende and coffinite are identified as primary uranium ore minerals in Koppunuru deposit. Traces of carbonaceous matter are associated with uranium mineralization along with sulphide minerals. EPMA analysis has indicated that pitchblende and coffinite contain 73.47 to 78.58% UO2 and 63.45– 71.53% UO2 respectively, while mixed phases contain lesser uranium oxide (42.14 – 47.90% UO2). In addition, uranophane, phosphuranylite, metazeunerite and U-Ti complex occur as secondary uranium minerals. The radioactive minerals are epigenetic in nature and occur as fine veins, fracture/cavity and grain boundary fillings. Other ore minerals are galena, pyrite, chalcopyrite, pyrrohotite, marcasite and traces of pentalandite. X-ray diffraction studies uraninite indicated unit cell dimension for Koppunuru deposit in the range of 5.4382Ao – 5.4534Ao. The oxygen content in the formula unit (UO2) is in the range of UO2.15 to UO2.29 in uraninite in Palnad sub-basin. Radiometric age of mineralized granite samples is 1,545 ± 140 Ma. In addition, dating of uraniferous quartzite samples by Pb-Pb step leaching method has indicated 576±180 Ma, 891±160 Ma and 936±60 Ma as mineralisation ages. This suggests multi-episodic nature of mineralization where uranium concentration/enrichment took place in different phases. DISCUSSION AND CONCLUSION The northern margins of Cuddapah basin is established as potential for hosting Proterozoic unconformity related uranium mineralisation. Litho-structural and metllogenic characters are well established for Lambapur, Peddagattu, Chitrial and Koppunuru uranium deposits. In Srisailam and Palnad sub-basins two major mineralization events are envisaged. Primary mineralization event took place during 1300-1500 Ma with a major mobilization / rejuvenation event around 450-950 Ma in Srisailam and Palnad Sub-basins in northeastern part of Cuddapah Basin. Concerted exploration efforts in the northern margin of Srisailam sub-basin has established ~ 20,000 tonnes of uranium oxide resources at a shallow depth of 75-120m. Large area of Srisailam sub-basin with considerable thickness of cover rocks is still unexplored and likely to multiply the resources with increase in tenor at a vertical depth of 200-250m. Extensive surficial exploration in other outliers and also in the main Srisailam sub-basin, viz. Amrabad, Akkavaram, Udimilla, etc. has resulted in establishing several surface uranium shows, thereby indicating the prevalence of metallogenetic factors observed in Lambapur, Peddagattu and Chitrial deposits which lie in the marginal portions, in the entire Srisailam sub-basin. Similarly in Palnad sub-basin, the Koppunuru uranium deposit is unique in respect of the mineralisation pattern in the sediments, proximal to the unconformity contact with the basement granitoids. Structures have played a major role in controlling the mineralisation. Nearly, 150km stretch of the northern margin of Palnad sub-basin with similar litho-structural setup as that of Koppunuru is available for exploration. Ground radiometric and heliborne geophysical surveys in the entire stretch of the northern margin of Palnad sub-basin has delineated several surface uranium shows viz. R.V.Tanda, Mathamapalle, etc. and geophysical anomalies viz. Durgi, Daida, Gurajala, etc. Intensive sub-surface exploration is envisaged in several sectors of Srisailam and Palnad sub-basins. REFERENCES 1. RAMESH BABU, P.V., RAHUL BANERJEE, ACHAR, K.K., Srisaialm and Palnad sub-basins: potential geological domains for unconformity related uranium mineralisation in India. Exploration and Research for Atomic Minerals, 22 (2012) 21-42. 2. NAGARAJA RAO, B., RAJURKAR, S., RAMAILINGASWAMY, G., RAVINDRA BABU, Stratigraphy, structure and evolution of the Cuddapah basin. In: Purana basins of Peninsular India. Geological Society of India Memoir, 6 (1987) 33-86. 3. PANDEY, B.K., PRASAD, R.N., SASTRY, D.V.L.N., KUMAR, B.R.M, SURYANARAYANA RAO, S., GUPTA, J.N., Rb-Sr whole rock ages for the granites from parts of Andhra Pradesh and Karnataka, In: Fourth national symposium on mass spectrometry, Indian Institute of Science, Bangalore, India. (1988) EPS-3/1. 4. SINHA, R.M., PARTHASARATHY, T.N., DWIVEDI, K.K., On the possibility of identifying low cost, medium grade uranium deposits close to the Proterozoic unconformity in the Cuddapah basin, Andhra Pradesh, India, IAEA Tecdoc-868 (1996) 35-55. 5. VERMA, M.B., SOM, A., LATHA, A., UMAMAHESWAR, K., MAITHANI, P.B., Geochemistry of host granitoids of uranium deposit at Chitrial area, Srisailam subbasin, Nalgonda District, Andhra Pradesh, Geological Society of India Memoir, 73 (2008) 37-54. 6. VERMA, M.B., MAITHANI, P.B., CHAKI, A., NAGESWARA RAO,P., KUMAR PRAKHAR. Srisailam Sub-basin, an uranium province for unconformity –related uranium deposits in Andhra Pradesh – case study of Chitrial uranium exploration. Current Science, 96 4 (2009) 588-591. 7. UMAMAHESWAR, K., ACHAR, K. K., MAITHANI,P.B. Proterozoic unconformity related uranium mineralisation in the Srisailam and Palnad Sub-basins of Cuddapah basin, Andhra Pradesh, India. IAEA-CN-175/28 (2009) 93. 8. JEYAGOPAL, A.V., PRAKHAR KUMAR, SINHA,R.M., Uranium mineralization in the Palnad Sub-basin, Cuddapah basin, Andhra Pradesh, India., Current science,71 12 (1996) 957-959. 9. GUPTA SHEKHAR, BANERJEE RAHUL, RAMESH BABU, P.V., MAITHANI, P.B. Sedimentation pattern and depositional environment of Banganapalle Formation in southwestern part of Palnad Sub-basin, Guntur district, Andhra Pradesh. Gondwana Geological Magazine Special Publication 12 59-70. 10. VERMA, M.B., GUPTA SHEKHAR, SINGH, R.V., LATHA, A., MAITHANI, P.B., CHAKI,A. Ore body characterisation of Koppunuru uranium deposit in Palnad sub-basin, Guntur district, Andhra Pradesh. Indian Mineral, 45 1 (2011) 51-61.

Speaker: Mr M. B. VERMA (GOVERNMENT OF INDIA, DEPARTMENT OF ATOMIC ENERGY, ATOMIC MINERALS DIRECTORATE FOR EXPLORATION AND RESEARCH)

27 The challenges to explore and discover an unconformity deposit at depth

INTRODUCTION Proterozoic unconformity uranium deposits are considered the highest grade deposits in the world. The most recognized deposits occur in the Athabasca basin in Canada [1]. As indicated in the 2016 “Red Book”, Proterozoic unconformity deposits account for about one-third of the world’s uranium resources based upon reasonably assured resources [2]. In 2017, the only two producing uranium mines in Canada allowed for over 20% of the world supply utilizing underground mining methods [3]. One matrix using current research of active mining operations with publicly disclosed data involving ore reserves, calculated according to an international standard, has outlined Cameco’s Cigar Lake and McArthur River operations as having the most valuable ore [4]. Expenditure spending in the search for deposits has diminished since a peak spot price of uranium in 2007 [5]. There are a number of well documented factors related to a decline in uranium prices that has led to a weak demand for the product. A few of the reasons for the lack of demand, but not limited to, include the events in Fukushima, Japan in 2011, economic challenges from fuel sources with cheaper capital costs for start-up, secondary supplies from government inventories as well as re-enrichment sales has also provided excess inventory. Even with the previous described “headwinds” in the nuclear power industry there are reasons for optimism due to the new builds and forecasted growth in central and eastern Asia. The IAEA’s high case projection has the global nuclear generating capacity increasing from 2016 levels by 42% in 2030, by 83% in 2040 and by 123% in 2050 [6]. Current statistics obtained from the Saskatchewan Mining Association indicate that exploration expenditures in the Athabasca Basin were $CAD 44.8 million in 2016 [7]. Major uranium companies such as Orano Canada (previously AREVA Resources Canada Inc.) and Cameco Corporation have committed the majority of their annual exploration dollars to the Athabasca Basin. Other known uranium companies with publicly announced discoveries such as NexGen Energy Ltd (NexGen), Denison Mines (Denison) and Fission Uranium Corp. (Fission) continue to release promising results in defining new discoveries and provide optimism to investors with their exploration expenditures. CURRENT LAND STATUS IN THE ATHABASCA BASIN An internal review of the current land disposition in the Athabasca Basin (includes the provinces of Alberta and Saskatchewan) involving uranium exploration was conducted in February, 2018. Upon review, it is estimated that 40% of the claims deemed for uranium exploration are located on the edge or outside of the sandstone cover of the Athabasca Basin. In terms of actual surface area within the confines of the basin itself, 53% of the land mass has been staked between the depths of 0 to 500 metres with the majority of the southern, central and eastern edges of the basin being claimed. The rational for the land disposition has to do with current and past mining operations in the eastern Athabasca; the Wollaston-Mudjatik transition zone hosts the Cigar Lake and McArthur River operations and the majority of economical and non-economical deposits. The staking along the southern and central edges of the basin has been driven in part by the discoveries by NexGen and Fission. As the unconformity becomes deeper there is less staked land and at a known unconformity depth between 500 and 1000 metres only 25% of the land mass has been claimed. The acquired land at this depth is associated with the lateral extension of known fertile trends related to conductive corridors or regional fault systems. Within the deepest portions of the basin, greater than 1000 metres depth to the unconformity, less than 4% of the land mass is acquired. There are numerous factors, mainly conjectural, that can be implied to interpret the current land status in the Athabasca Basin including a company’s available funding for exploration, current exploration portfolio, company strategies, availability of favourable geological trends and access to a project area. RATIONAL FOR LOOKING AND DISCOVERING NEW ECONOMIC DEPOSITS AT GREATER DEPTHS Potential for discovering new economic deposits can be evaluated by ranking different projects according to multiple parameters among which the depth of the targets at the unconformity or in the basement can be considered as of most importance. Exploration maturity can be also judged on the basis of potential based on available conductor strike length following the traditional unconformity-type model [8]. Thus, the probability to find a new economic deposit at depth lower than 250m with the minimal footprint such as the Cigar Lake deposit is limited taking into account the existing spacing of drill holes along the main conductive trends. However exploring high grade pods at shallow depth remains a short to medium term objective as these targets may be economic by small open pit means or if the possibilities of surface access borehole extraction methodology becomes cost effective. In a long term vision, the critical depth of exploration within the Athabasca Basin will likely evolve and it is probable that the deepest portions of the basin, will be considered for greenfield exploration. However, several economical and technical challenges will have to be faced. What type of mineral deposit and which size will have to be targeted to become economic? Can we expect some technical and scientific breakthrough that would improve significantly the resolution of the geophysical methods, the drilling technologies and our ability to vector our geological exploration? This new frontier and challenges are discussed in relation to the present state of art and in reference to the Cigar Lake deposit. As a hypothesis, one considers that other world class deposits exist at the unconformity at depths greater than 500 metres. Although the geological conditions under which such a deposit can be formed are not fully understood [8], it is unlikely that these conditions were only met in a single locality over the whole extent of the Athabasca Basin. As a support to this hypothesis, other deposits like Shea Creek [9, 10] or Phoenix [11, 12] are formed under near identical mineral systems: association with long lived deeply penetrating and steeply dipping structures, enhanced permeability fault system within a compressive tectonic context, leaching of huge volume of sedimentary and metamorphic lithologies by oxidized basin and reduced basement fluids, formation of uranium deposits from highly concentrated uranium-bearing acidic brines [13]. An economic scenario for deep unconformity deposits is presently very difficult to define. Kerr and Wallis [14] consider that, if low grade deposits can be economically mined at depth lower than 200m, only purely basement hosted deposits and unconformity hosted giant deposits will possibly be qualified as reserves below 200 metres. A high level study can be completed to determine the economics of a hypothetical mining and milling operation located in the centre portion of the basin. However, such calculation is very sensitive to the uranium price and capital cost and a detailed scenario is out of the scope of this discussion. To follow up the discussion, one considers that the footprint of the targeted deposit should be an unconformity type deposit, comparable if not larger than the Cigar Lake deposit to be effectively economic at an uranium price of $US 40/lbs U3O8 [15]. This deposit style is selected due to the alteration halo that reaches up to 200 metres in width and 250 metres in height and that is associated with mineralizing processes [15, 16]; likely to be identifiable under deep cover. Other styles such as basement mineralization were considered, NexGen’s Arrow deposit and Denison’s Gryphon deposit, but ultimately rejected due to the potential limiting size of an alteration halo in the sandstone for a basement deposit with greater than 500 metres of sandstone cover. THE CHALLENGE TO EXPLORE AND DISCOVER A GIANT UNCONFORMITY DEPOSIT AT DEPTH There is no direct uranium detection for deposits buried at depth. Our present exploration technologies for depth greater than 500 metres are limited by several factors as the cost of drilling, in particular in remote sectors, and the decreasing resolution of geophysical modelling at increasing depth. However, some technical and scientific breakthrough in the coming years may improve our ability to vector our geological exploration. Junior and major companies are investing millions of dollars every year for geophysical surveys, downhole geophysical probing and acquisition of complete petrophysical datasets including density, magnetic susceptibility and resistivity. Numerous case studies of ground and airborne electromagnetics (EM) and magnetics surveys, resistivity ground campaign, downhole geophysics are regularly presented and should enable the definition of best practices according to the different geological context if a complete return of experience could be achieved. Moreover, such analysis should guide the developments for the acquisition, processing and modelling. Thus, the principle of combined acquisition and joined inversion of EM, magnetotellurics (MT) and resistivity surveys is the current inherited way to explore at depth and to improve the resolution of the geophysical 2D and 3D models. The main budget of exploration is oriented to drilling. One of the main problems faced today by the companies is the cost of drilling in purely greenfield terrain, the high risk of lost holes in zones of sandstone dissolution (that induces high cost and then limitation of the meterage to be drilled) and the low recovery of cores in fault zones that hampers the structural reconstruction of the architecture of the explored domains and a careful study of the mineralizations. Innovations should be deployed to use or test equipment in order to limit the risk of hole lost because of difficult geological environment, improve the drilling practices and for example generalize the use of directional drilling to explore large zones at depth from a pilot hole. The monitoring of the drilling parameters should also help to control the progress of the drilling in these zones and enhance the quality of coring. High resolution imagery of the structures of the hole and recording of the physical properties while drilling should also be an objective to be elaborated and tested by the drilling and exploration companies. Exploring Cigar Lake analogs at the base of the unconformity can benefit of the geological knowledge that has been acquired since exploration and exploitation started. The Cigar Lake deposit is located 420-445 metres below the surface within the Athabasca Group’s Manitou Falls Formation. The mineralization has a flat to tubular shaped lens approximately 2000 metres in length, ranges between 20 and 100 metres in width and with an average thickness of about 6 metres [17-19]. The mineralization has a crescent-shaped cross-sectional outline that closely reflects the topography of the unconformity. The alteration halo surrounding the Cigar Lake deposit is extensive and affects both sandstone and basement rocks, characterized by extensive development of Mg-Al rich clay minerals (illite and chlorite). It is presently possible to build a 3D earth model reconciling geological and geophysical data, based on extensive datasets including geological, geochemical and physical properties centered on the deposit but also extending along trend and other underexplored conductive trends. This type of modelling of the Cigar Lake domain could use recent developments performed on the application of Artificial Intelligence and learning machine [20, 21] to update the footprint of the deposit. It will also provide an excellent return of experience for defining appropriate acquisition parameters, processing and modelling of geophysical methods considered above as a first step to be accomplished for exploring at greater depth. An earth model resulting of the updated footprint of Cigar Lake domain could be used to simulate the geological, geochemical and geophysical footprint that could be created by such a deposit in different localities at the base of the basin. Reprocessing and acquisition of complementary geological and geophysical datasets, linked to the measured, estimated or interpolated petrophysical datasets, should then provide a set of unconstrained and constrained inversions that will be compared with the simulated footprint. This modelling, both data and knowledge driven, could lead to a virtual exploration of Cigar lake analogs at the base of the Athabasca Basin. Finally, as the exploration will provide new datasets from drilling, the new information could be used to refine constrained inversion and to evaluate the possibility to vector exploration towards new deposits. In conclusion, this long term vision can be put in perspective with the challenges that were faced by the oil and gas industry when exploration targeted deeper, more structured and remote reservoirs. Although the geology is much more complex than oil and gas reservoir, pre competitive research and development programs could be set up in order to be on time when greenfield exploration will become open for defining a new critical depth for unconformity related uranium deposits. REFERENCES [1] INTERNATIONAL ATOMIC ENERGY AGENCY, World Distribution of Uranium Deposits (UDEPO) with Uranium Deposit Classification, IAEA-TECDOC-1629, Vienna (2009). [2] URANIUM 2016: RESOURCES, PRODUCTION AND DEMAND, Organization For Economic Co-Operation And Development - Nuclear Energy Agency and the International Atomic Energy Agency, NEA No. 7301 (26th edition of the “Red Book”), Paris, France, p. 546. [3] WORLD NUCLEAR ASSOCIATION, World Uranium Mining Production (Updated July 2017), http://www.world-nuclear.org/information-library/nuclear-fuel-cycle/mining-of-uranium/world-uranium-mining-production.aspx. [4] BASOV, V., These 10 mines have the world's most valuable ore (2017), http://www.mining.com/top-10-mines-digging-out-most-expensive-ores. [5] The Ux Consulting Company, LLC, http://www.uxc.com/. [6] INTERNATIONAL ATOMIC ENERGY AGENCY, Board of Governors General Conference - International Status and Prospects for Nuclear Power 2017, GOV/INF/2017/12-GC(61)/INF/8, dated 28 July, 2017. [7] Saskatchewan Mining Association (2016), http://saskmining.ca/ckfinder/userfiles/files/EmergencyResponseCompetitionPhotos/SMA%20-%20Uranium%20Fact%20Sheets%202016ti.pdf [8] Jefferson, C.W., et al., 2007b, Unconformity-associated uranium deposits of the Athabasca Basin, Saskatchewan and Alberta, in Goodfellow, W.D., ed., Mineral deposits of Canada: A synthesis of major deposit-types, district metallogeny, the evolution of geological provinces, and exploration methods, Geological Association of Canada Mineral Deposits Division, Special Publication no. 5, p. 273-305. [9] Carroll, J., Robbins, J., Koning, E., The Shea Creek deposits, west Athabasca Basin, Saskatchewan, in Uranium: Athabasca deposits & analogues, 2006 CIM Field Conference, CIM Geological Society, Saskatoon Section, Saskatoon, Saskatchewan, September 13-14, 2006, Field Trip 3 “Cluff Lake and Shea Creek deposits” guidebook, p. 33-48. [10] Kister, P., Cuney, M., Golubev, V.N., Royer, J.J., Le Carlier De Veslud, C., Rippert, J-C., Radiogenic lead mobility in the Shea Creek unconformity-related uranium deposit (Saskatchewan, Canada): migration pathways and Pb loss quantification. C. R. Geoscience, 2004, 336, p.205–215. [11] Kerr, W.C., The discovery of the Phoenix deposit, a new high-grade, Athabasca Basin unconformity-type uranium deposit, Saskatchewan, Canada. Society Economic Geologist, 2010, Sp. Publi. 15, Chapter 34, p. 703-728. [12] Roscoe, W.E., Technical Report on a mineral resource estimate update for the Phoenix uranium deposit, Wheeler River Project, eastern Athabasca Basin, Northern Saskatchewan, Canada: National Instrument 43-101 Technical Report, 2014, RPA Inc., p.134. [13] Richard, A., Rozsypal, C., Mercadier, J., Banks, D.A., Cuney, M., Boiron, M-C., Cathelineau, C, Giant uranium deposits formed from exceptionally uranium-rich acidic brines. Nature Geoscience, 2012, vol 5, p. 142-146. [14] Kerr, W.C., Wallis, R., “Real-World” economics of the Uranium deposits of the Athabasca Basin, North Saskatchewan: Why grade is not always king! Society Economic Geologists, Newsletter, 2014, 19, p. 10-15. [15] The Ux Consulting Company, LLC, UXC special report, Uranium Production Cost Study, September, 2017, p. 120. [16] Exploration ’17, http://www.exploration17.com/, October 22-25, 2017, Proceedings. [17] Andrade, N., Geology of the Cigar Lake uranium deposit; in The Eastern Athabasca Basin and its Uranium Deposits, Field Trip A-1 Guidebook (ed.) N. Andrade, G. Breton, C. W. Jefferson, D.J. Thomas, G. Tourigny, W. Wilson and G.M. Yeo; Geological Association of Canada-Mineralogical Association of Canada, Saskatoon, Saskatchewan, May24-26, 2002, p.53-72. [18] Bruneton, P., Geological environment of the Cigar Lake uranium deposit; Canadian Journal of Earth Sciences, v. 30 (1993), p. 653-673. [19] Bishop, C., S., et al., Cigar Lake Project Northern Saskatchewan, Canada: National Instrument 43-101 Technical Report. 2010, Cameco Corporation, p. 213. [20]Bishop, C., S., et al., Cigar Lake Project Northern Saskatchewan, Canada: National Instrument 43-101 Technical Report. 2012, Cameco Corporation, p. 196. [21] Bishop, C., S., et al., Cigar Lake Project Northern Saskatchewan, Canada: National Instrument 43-101 Technical Report. 2016, Cameco Corporation, p. 164. [22] Lescher et al., 2017, Disseminated Au, McArthur River-Millennium nconformity U, and Highland Valley Porphyry Cu Deposits: Preliminary Results from the NSERC-CMIC Footprints Research Network. Exploration 17, 23p. [23] Feltrin et al., 2016, HYPERCUBE: mining exploration data, a case study using the Millennium uranium deposit, Athabasca basin. GAC MA

Speaker: Mr Patrick Ledru (AREVA Resources Canada)

28 Integration and Cost Saving Utilization of the Seismic Reflection Technique in the Athabasca Basin, Canada

The Seismic Laboratory (UofS) through industrial partnerships has conducted many seismic reflection experiments within the western and eastern Athabasca Basin. Results to date illustrate that the seismic investigations deliver high-quality primary structural images of the subsurface, with resolution not matched by other geophysical techniques. Correlation of similar seismic signatures from section to section has defined the mineralization fault systems and allowed spatial extension of previously unrecognized exploration target zones. Extended analysis of seismic signal attributes and full-wave data offer detailed lithological characterization, including anomalous alteration zones and petrophysical attributes. Although seismically detected anomalies are primary indicators of mineralization, the seismic method is still not a “standard basin” exploration tool because of its negative attribute. Unquestionably, locally, drilling of boreholes provides the most explicit reliable information to a certain depth. Comparing the costs of all geophysical techniques to the cost of a single logged drill-hole illustrates that the results of a properly designed seismic data acquisition program not only leads to more effective drilling programs, but also to much quicker recognition of the major mineralized zones and their fingerprints. This integrated approach to exploration would translate into significant reduction of required exploratory boreholes and the total exploration expenditure.

Speakers: Dr Irvine R. ANNESLEY (ENSG, Universite de Lorraine and Department of Geological Sciences, University of Saskatchewan), Dr Zoltan HAJNAL (Department of Geological Sciences, University of Saskatchewan)

Applied Geology and Geometallurgy of Uranium and Associated Metals

Conveners: Mr C.K. ASNANI (HINDU), Dr Michel CUNEY (CNRS - GeoRessources - CREGU - Universite de Lorraine)

29 Structural Characteristics and Its Control on Uranium Mineralization in Xiangshan Uranium Ore-Field

Xiangshan uranium ore-field is the largest volcanic-related hydrothermal uranium deposit in China. Based on high precision deep geophysical survey, 3D geologic modeling and scientific drilling projects, EW-trending faults in basement were rejuvenated by strong shearing of Suichuan-Dexing fault during later Jurassic to Early Cretaceous, the tectonic-stress field changed from compression to extension at the beginning of Early-Cretaceous, and it is advantageous to the ascension of deep-derived materials, with ore-bearing hydrothermal fluid transiting, precipitating and enriching. The favorable position for uranium mineralization include the junctions of faults with different directions, the junctions between main faults and subsidiary fractures, the junctions between branch fractures of main faults and derived fractures of subsidiary faults. EW-trending faults in basement is the main channel-way in which substance can transmit to surface, the linear, ringlike and radial pattern structures which are connect with faults in basement controlled the shape, occurrence, scale and spatial locations of uranium ore bodies, these faults are main ore-hosting structures. Therefore, we hold fault structures are still the emphasis of ore-finding, especially, the belts where deep E-W faults and surface faults intersected are favorable areas to explore uranium resources.

Speakers: Mr Jiangtao Nie (Beijing Research Institute of Uranium Geology), Dr Ziying Li (Beijing Research Institute of Uranium geology)

30 VOLCANIC TYPE URANIUM DEPOSITS IN NORTH CHINA

INTRODUCTION Volcanic type uranium deposit is one of the four largest kind of uranium deposits in China (volcanic type, granite type, sandstone-hosted type and Carbonaceous-Siliceous-Argillaceous Rock Type), and is play an important role in uranium resources. In 90s of last century, before the large-scale application of In-situ Leaching technology (ISL) in sandstone-hosted type uranium deposits, volcanic type uranium deposit was one of the main targets for exploration and exploitation in China. Uranium reserves in volcanic and granite type deposits account for 61% of China's total reserves[1]. As far as 2015, the volcanic type uranium still occupied 35.48% of the annual output[2]. It is different from granite type uranium deposits are mainly developed in southern China and sandstone type uranium deposits are mainly developed in northern China, volcanic type uranium deposits have been found in both southern and northern China. Southern China represented by Gan-hang uranium metallogenic belt, Northern Chinese represented by Guyuan-Hongshanzi uranium metallogenic belt and Qinglong-Xingcheng uranium metallogenic belt. In the two metallogenic belts of northern, there are 17 volcanic type uranium deposits and more than 100 mineralized points have been found, which are the important uranium-mining and production area in China. TYPICAL URANIUM DEPOSITES Guyuan-Hongshanzi uranium metallogenic belt and Qinglong-Xingcheng uranium metallogenic belt are located in northern margin of the North China Craton (NCC) uranium polymetallic metallogenic province of the circum-Pacific metallogenic zone[3]. The former is located in the middle section of northern margin of NCC, and the latter is located in the eastern section of the northern margin of NCC. According to the characteristics of ore-bearing rock and ore-controlling structures, volcanic type uranium deposits can be divided into 5 subtype[4], namely volcanic breccia subtype, sub volcanic subtype, dense fracture zone subtype, interlayer fracture zone subtype and pyroclastic rocks subtype. The volcanic type uranium deposit in north China is mainly composed of sub volcanic subtype and pyroclastic rocks subtype, Zhangmajing deposit, Daguanchang deposit and Hongshanzi deposit in Guyuan - Hongshanzi uranium metallogenic belt as the representative for sub volcanic subtype, and Gangou deposit and Dayingchang deposit in Qinglong- Xingcheng uranium metallogenic belt as the representative for pyroclastic rocks subtype. The geological characteristics of the typical uranium deposits are briefly introduced as follows: Zhangmajing uranium deposit is located in the north edge of Zhangmajing volcanic collapse depression in Guyuan volcanic basin, the southern part of Zhangmajing - Hongshanzi uranium metallogenic belt, and controlled by Sub volcanic type crater. The ore bearing rock is potassium rhyolite, the fifth layer in the third lithology of Zhangjiakou group upper Jurassic and rhyolitic porphyry (main ore host rock). Zhangmajing uranium deposit is a typical sub rhyolite porphyry uranium-molybdenum deposit. It is the product of multi-phases of volcanic magmatic hydrothermal geological events that happened in late Jurassic, early Cretaceous and Paleogene-Neogene, the mineralization age are 122Ma, 89Ma and 23.7Ma. Daguanchang uranium deposit is located in the south edge of Daguangchang volcanic collapse depression in Guyuan volcanic basin, the southern part of Zhangmajing - Hongshanzi uranium metallogenic belt, and controlled by Subvolcanic type crater. The ore bearing rock is potassium rhyolite of volcanic effusive facies (main ore host rock), Zhangjiakou group upper Jurassic and rhyolitic porphyry of volcanic intrusive facies. Daguanchang uranium deposit is a typical cryptoexplosion potassic rhyolite type uranium-molybdenum deposit. It is a product from multi-phase of volcanic magmatic hydrothermal geological events happened in early Cretaceous and Paleogene, and the mineralization age is 67Ma and 30Ma. Hongshanzi uranium deposit is located in the west and east edge of Hongshanzi volcanic collapse depression where rhyolitic porphyry and granite porphyry distribution as ring, the northern part of Zhangmajing - Hongshanzi uranium metallogenic belt, controlled by the contact zone of Subvolcanic type crater. The ore bearing rock is trachyte in middle Manketouebo group upper Jurassic and rhyolite porphyry. Hongshanzi uranium deposit is a typical contact zone of subvolcano controlled - volcanic hydrothermal type uranium deposit. It is the product of multi-phases of Volcanic magmatic hydrothermal geological events that happened in late Jurassic, and early Cretaceous, and the main metallogenic age is 156Ma, 120 ~ 130Ma. Gangou uranium deposit is located in the south edge of Gangou middle Jurassic volcanic fault basin, eastern of Qinglong-Xingcheng uranium metallogenic belt. The ore bearing rock is Sedimentary pyroclastic rock formation of Middle Jurassic Haifanggou group, there were strong mafic and alkaline volcanic magmatic activities in the stage of mineralization. Gangou deposit is a typical volcanic hydrothermal fluid and meteoric water mixed type uranium deposit, it is the product of of multiple geological evolution with syndepositional pre enrichment and multi-stage volcanic hydrothermal fluid superimposed meteoric water mineralization, main metallogenic age is 121Ma and 76Ma. Dayingchang uranium deposit is located in the magmatic active belt of the intersection area of the NE-trending Hongluoshan-Wuzhishan regioanl fault and EW-trending Qinglong-Jinxi regional fault, in the western part of Qinglong-Xingcheng uranium metallogenic belt. The ore bearing rock is medium-coarse grained quartzite in Middle Proterozoic Changzhougou group, Jurassic acid granitic and basic magmatic activities are the main causes of mineralization. Dayingchang uranium deposit is a typical multiple volcanic magmatic hydrothermal superimposed uranium deposit. The uranium mineralization is characterized by contemporaneous sedimentary preconcentration and volcanic magmatic hydrothermal overlap. The main metallogenic epoch is late Jurassic to early Cretaceous (142Ma ~ 123Ma). DISCUSSION AND CONCLUSION Through comprehensive study of geological and mineralized characteristics of several typical uranium deposits, the volcanic type uranium deposits in North China are characterized by the following: (1) Metallogenic geological background: in general, the volcanic uranium deposits occur on the paleo-landmass, especially on the edge of the paleo-landmass. The continental volcanic eruption belt dominated by acidic (or partial alkaline) volcanic rocks is the main production environment. Volcanic type uranium deposits often occur in the composite parts of regional faults and volcanic basins formed by multi-stage volcanic activities. (2) Metallogenic epoch: all uranium deposits have the characteristics of multistage superposition and mineralization. Paleoproterozoic, large-scale potassic migmatization in north margin of NCC caused preliminary enrichment of uranium, formed the mainly uranium source layer in North China. Multi stage volcanic hydrothermal activity in late Jurassic to early Cretaceous is the main heat source and power for activation and migration of uranium mineralization. The intermediate-mafic volcanic magmatic activity in Paleogene Neogene is important to superposition activities for mineralization. The age of main ore mineralization is concentrated in 156~120Ma, 89~67Ma, 30~23.7Ma. (3) Mineralizing characteristics: Coexisting and associated minerals is commonly existed in volcanic uranium deposits in North China. Guyuan - Hongshanzi Uranium metallogenic belt is mainly characterized by uranium - molybdenum mineralization, even the intensity and range of molybdenum mineralization were greater than uranium, such as Zhangmajing deposit, the reserves of molybdenum are more than 100 000 tons, far greater than uranium reserves (8000 tU). From the southern section of Zhangmajing uranium deposit, Daguanchang uranium deposit to the northern section of the Hongshanzi uranium deposit, Guangxingyuan uranium deposits, uranium minerals are mainly pitchblende and coffinite, but molybdenum-bearing mineral changed from jordisite into molybdenite. The temperature from fluid inclusions show that the main metallogenic temperature of Guyuan area concentrated in the 137.7 ~ 217.7℃, and metallogenic temperature of Hongshanzi area concentrated in 218 ~ 275℃, Ore forming temperature increased obviously from south to north. Qinglong - Xingcheng uranium metallogenic belt is mainly single uranium mineralization type, but it is also associated with a small amount of Mo, Pb, Zn, Cu, Ag and other metallic minerals[5]. Uranium is dominated by dispersed as adsorption states, uranium bearing minerals are secondary, are mainly pitchblende, with a small amount of uraninite and secondary uranium minerals. (4) Ore controlling factor: Neoproterozoic - paleoproterozoic potassic migmatitic granite basement; Mesozoic uranium rich volcanoclastic rock, volcanic rock and sub volcanic rock; late Jurassic volcanic-sedimentary basin, volcanic collapse basin and volcanic apparatus, such as caldera structure, volcanic dome structure, volcanic collapse. This entire three are the major controlling factors of volcanic type uranium deposits in North China, and with regional faults together to control the location and scale of uranium deposits. The uranium deposits in Qinglong-Xingcheng uranium metallogenic belt is controlled by layer in general and the uranium ore bodies are stratified and lenticular, the occurrence of ore bodies is in accordance with the formation of the strata. The uranium deposits in Guyuan-Hongshanzi uranium metallogenic belt are controlled by volcanic or sub volcanic rock and tectonic obviously, the ore bodies mainly as disseminated or veins. The host rock in both of two belts, is not given but is diversify, such as volcanoclastic rock, rhyolites, trachyte and rhyolite porphyry. (5) The ore-forming fluid mainly originated from mantle: Isotope research indicate that the ore-forming fluid of Guyuan - Hongshanzi uranium metallogenic belt consists of little change of Pb isotope, 206Pb/204Pb = 16.857 ~ 19.934, 207Pb/204Pb = 15.413 ~ 15.726, 208Pb/204Pb = 37.596 ~ 38.904, it is mainly between the mantle and lower crust or orogenic belt, more closely to mantle. Sr isotopic ratios (87Sr/86Sr)i = 0.707 ~ 0.727, Between the depleted mantle (0.7022 ~ 0.7035) and the upper crust of North China (0.7120 ~ 0.7200), it has a very low Sr content (14.7×10-6 ~ 19.8×10-6), which is close to the content of Sr in depleted mantle, indicating that ore-forming fluid has the characteristics of mantle source. δ34S of pyrite in Gangou deposit varied from 1.2% to 5.7%, close to the sulfur isotopic composition of meteorite. La/Yb - ∑REE diagram shown the lithology belong to continental alkali basalt series, suggesting that the sulfide (also metallogenic material) mainly derived from the upper mantle. (6) Metallogenic regularity: Since Mesozoic, volcanic activity was frequent in North China, and as a regularity of basic ~ intermediate acid ~ basis, intrusion ~ eruption and multi cycle activities in general. Uranium polymetallic deposits are mostly produced in transition zone of gravity high field and low field. The deposits are characterized by structure (include faults and volcanic structures) and sub volcanic rock controlled, reducing ore-forming fluids with high temperature and high pressure derived from mantle, superimposed alteration are development and associated with Mo, Pb, Zn, Ag and other elements. Uranium is enriched in late melts or fluids, and the age of mineralization is later than the intrusive age of the related rock masses[6]. All of above reflect the typical characteristics of hotspot uranium metallogenesis[7], the uranium mineralization may be related to the mantle plume activities in North China. In conclusion, the volcanic type uranium deposits in North China have similar metallogenic epoch, metallogenic regularities, genesis and characteristics, which may be related to the same tectonic settings, indicating that the northern margin of NCC has undergone concerted and relatively large-scale volcanic uranium mineralization activities since Mesozoic era. REFERENCES [1] Shen Feng. Characteristics of Uranium Resources and Prospecting Direction in China. Uranium Geology, 3(1989):129-133 (in Chinese) [2] NUCLEAR ENERGY AGENCY and INTERNATIONAL ATOMIC ENERGY AGENCY, 2016. Uranium 2016: Resources, Production and Demand. [3] Huang ZX, Li ZY and Cai YQ, Metallogenic model of the Uranium deposits in Guyuan area, China. 1146. Abstract 35th International Geological Congress, Cape Town, South Africa (2016). [4] BEIJING RESEARCH INSTITUTE OF URANIUM GEOLOGY. Evaluation of the potential for volcanic uranium deposits in China. 2011. [5] Li Haidong, Zhong Fujun, Zhang Zhiyong, et al. Characteristics and significance of uranium polymetallic combination in volcanic uranium deposits in China. Mineral Resources and Geology 293 (2015):283-289. (in Chinese) [6] Zhixin Huang, Ziying Li and Zhaoqiang Wang. Hotspot uranium metallogenesis in North Heibei province, China. Acta Geologica Sinica, 88 S2 (2014):1360-1361. [7] Li Ziying. Hostspot uranium metallogenesis in South China. Uranium Geology, 222 (2006): 65-69. (in Chinese)

Speaker: Dr Zhixin Huang (Beijing Research Institution of Uranium Geology)

31 Geological and geochemical characteristics of the Huayangchuan U-Nb-Pb deposit, Shan'xi China

INTRODUCTION Huayangchuan U-Nb-Pb deposit is located in the west part of Xiao Qinling area at the southern margin of the North China Block. It is proved to be a super-larger U-Nb-Pb polymetallic deposit in China in recent years [1-9]. The Huayangchuan deposit is located at a junction between Huashan Granites (92-142 Ma) [10] on the north and Laoniushan Granites (146 and 228 Ma) [11] on the south. Archeozoic gneissic suite is the wall rock in the area. The NW trending (290°-310°) Huayangchuan fault runs through the area, controlling the distribution of the ore bodies and vein rocks. The fractures are well developed in the deposit with mainly NNW and NW trending. Various vein rocks filled in the fractures includes biotite amphibole, biotite granite porphyry, pegmatite, calcite veins, lamprophyre, fine-grained granite veins and so on. Calcite veins are the main ore-bearing vein rocks. Based on the collection and analysis of regional geological data and the exploration and investigation work in recent years, we made clear about the ore-forming background, the characteristics of ore-bearing pegmatite and carbonate rock and the characteristics of U-Nb-Pb mineralization. The ore-controlling mechanism and genesis of ore deposit are preliminarily discussed under this paper. DESCRIPTION Characteristics of vein rocks Various vein rocks outcroping in the Huayangchuan deposit includes biotite amphibole, biotite granite porphyry, pegmatite, calcite veins, lamprophyre, Fine-grained granite veins and so on. These vein rocks have been divided into three groups (Pre-mineralization group, Mineralization group and Post-mineralization group) based on their rock types, relationship with mineralization and cross-cutting relationship. Biotite granite porphyry veins, located on the south of fault zone, are NNW trending, 4km in length and 10 to 200m in width. They were cut by the ore-bearing quartz-calcite veins. Hui (2014) suggested two episodes of intrusions of biotite granite porphyry veins (225.5±4.2Ma and 207±2.3Ma). Qiu (1993) obtained the K-Ar age of 204-206Ma in the ore-bearing carbonate veins，which is younger than the age of biotite granite porphyry confirmed that they are prior to the mineralization. Lamprophyre amazonite pegmatite and fine-grained granite veins cut the ore-forming quartz and calcite vein rocks, and they are not cut by other veins indicated that they are post to the mineralization. The mineralization epoch is divided into two stages: Pegmatitic stage and Carbonate stage. Veins in the Pegmatitic stage includes Pegmatite veins and migmatic pegmatite veins. The Pegmatite has the porphyritic and graphic texture and lumpy structure. Migmatic pegmatite veins mainly consists of k-metasomatism pegmatite， biotitization- actinolitization pegmatite and the biotite-feldspar -quartz veins. Uneven U-Nb mineralization developed during this stage. Veins in the Carbonate stage include quartz – calcite veins, feldspar- aegirine-augite veins, barite-quartz - calcite veins with aegirinite and sodium amphibolite veins, barite – quartz-calcite veins with biotite and a small number of aetolite and barite-quartz calcite veins with zeolite. (1) Quartz – calcite veins are the most widely distributed ore bearing veins in the region, consisting of quartz (> 50 %), calcite (30-40%,), barite and a small amount of plagioclase. Quartz is mostly “breccia”. The calcite is xenomorphic granular breccia. Pb mineralization was found in this type of veins. There is no obvious uranium mineralization. (2) Feldspar- aegirine-augite veins have strong Pb-U mineralization. The dark minerals in this type of veins are dominated by aegirinite and light-colored minerals are mainly microcline, followed by quartz, calcite and barite. Pb minerals are often disseminated in the aegirine-augite and are irregular clumps and become thin veins between feldspar and calcite granules. (3) Barite-quartz - calcite veins with aegirinite and sodium amphibolite have obvious banding phenomenon. The main mineral is calcite follow by aegiran, microcline, quartz, barite and so on. (4) The barite – quartz-calcite vein with biotite and a small number of aetolite veins are not large and are generally 0.5-1m wide, with the characteristics of collection of biotite. Calcite is mainly gray and white. The gelenite and blomstrandite are disseminated and star point distributed. The mineralization is weak. The mineral distribution in the veins is disorder. (5) Barite-quartz calcite veins with zeolite veins are not large and is generally 1-2mm in width and they are reticular and fine veins filled in the early-formed fractures. It is seen that the galena is granular living with barite, calcite and quartz. The mineralization is weak, we do not find the U mineralization, mainly Pb mineralization. These veins are the last phase of ore-bearing veins, and cut the early mineralized veins. The second and third type of veins are the most important U-Nb-Pb mineralized veins. The ore bearing rocks are mainly pegmatite and carbonate veins. The single vein is not large (tens cm wide), but dense. Veins of different types and scales penetrated in different directions and different types of fractures. The veins of different stages are interlaced and interwoven, so we saw branches and meshes on the wall. The overall trending is NW, especially for those with mineralization. Characteristics of mineralization The Huayanchuan deposit is mainly a U-Nb-Pb deposit, with a combination of precious metals and rare earth elements. The U mineralization minerals are mainly blomstrandite and uraninite, followed by the uranium contained changbaiite and fergusonite. The Nb mineralization minerals are mainly blomstrandite followed by a small amount of fergusonite and niobium rutile. The Pb mineralization minerals are mainly galena and a small amount of oxidized cerussite. Precious metal Ag and scattered elements Bi, Cd, Se and Te are mainly dispersed in galena. Rare earth elements here are mainly about La, Ce and Y, and the minerals mainly include xenotime, allanite , monazite, bastnasite and fergusonite and so on. The biotitization, actinolitization and potassic alteration are typical characteristic of the uranium mineralization during the pegmatite stage. In the pegmatite with biotitization, we found the uranium grade is normally over one-in-one-thousand. Blomstrandite was found in the area where biotitization and actinolitization developed The mineral assemblages of biotite-aegirine-augite-sphene-zoisite-amphibole-apatite is closely related to U mineralization. The more these minerals develop the more obvious uranium mineralization found. Among these assemblages, the biotite-aegirine-augite- sphene is especially closely correlated with the U mineralization. The galena is mainly produced on the boundary, and in general where pyritization developed, where there is strong lead mineralization. Assemblage of aegirine-augite and pyrite is the main metallogenic character of galena. DISCUSSION AND CONCLUSION The wall rock of Huayangchuan deposit is Archeozoic gneissic suite. The boundary between ore-bearing veins and wall rocks is clear. And the wall rock alteration is not obvious. There are no specific wall rocks that are closely related to the mineralization. However, there are differences of the development degree of the fractures among different types of wall rocks. For example, it is easier to form more dense fracture and fissure system among the biotite-plagioclase gneiss than hornblende gneiss and granite gneiss. The development degree of fractures and fissures in the region directly affected the density and mineralization of ore-bearing veins. We divide the metallogenic process into two stages: pegmatite stage and carbonate stage. Qiu (1993) date the feldspar within the carbonate using the K-Ar dating and got 204~206Ma. Yu (1992) date the flogopite in carbonate using the K-Ar dating and got 181Ma. He et al. (2016) obtained the age (39Ar-40Ar）of 133.01±0.74Ma from biotite in the carbonatite, and the age（39Ar-40Ar）of 91.49±1.97Ma biotite in pegmatite. The ages, 204~206Ma and 181Ma can be compared with that of the intrusion of Laoniushan granites (146 and 228 Ma) [11] and the ages, 91.49Ma and 133.01Ma were basically in line with the time of the intrusion of Huashan Granites (92-142Ma) [10]. There is a high degree of consistency and affinity in time and spatial distribution between the formation of pegmatite and carbonate veins and the Huashan and Laoniushan Granites. In different stages, symbols of hydrothermal metasomatism was found. We suggested that the Huayangchuan U-Nb-Pb deposit is the result of the co-action of the carbonate rocks and the Huashan, Laoniushan plutons. And the deposit is magmatic-hydrothermal genetic type. In summary, we found that: (1) The Huayangchuan U-Nb-Pb deposit occurred in the Archean gneiss. The main ore-hosted rocks are pegmatite and various veins of carbonate rocks. (2) U-Nb mineralization occurred during the pegmatite stage within granitic pegmatites and migmatic pegmatite veins. U-Nb-Pb mineralization mainly developed in the carbonate rock stage within quartz- carbonatite veins. (3) Ore bodies extended NW and are mainly controlled by the NW-trending Huayangchuan fault followed by NNW-trending secondary fractures. (4) The characteristic symbols for the uranium mineralization within the pegmatite stage are the biotite-actinolite assemblages, and that in the carbonate rock stage are the biotite-aegirine-kaolinite-kaolinite-amphibole-apatite assemblages. In contrast, characteristics of Pb mineralization are marked by breccia aegirineaugite -metal sulfide combinations. (5) We proposed that the Huayangchuan deposit is the magmatic-hydrothermal superposition type. REFERENCES [1] WANG, L.，XU, C.，WU, M., SONG, W., A Study of Fluid Inclusion from Huayangchuan Carbonatite, ACTA MINERALOGICA SINICA 31 (2011) 372-379 [2] GAO, C., KANG, Q., ZHANG, X., CHEN, X., and HU, J., Uranium occurrences and carbonatite petrology in Huayangchuan, Geology of Shanxi 33 (2015) 10-13 [3] HUI, X., HE, S., Mineralization Characteristic of Carbonatite Veins in Huanyangchuan U-polymetal Deposit, Shanxi Province, Uranium Geology32 (2016) 93-98 [4] HE, S., LI, Z., HUI, X., GUO, J., 40Ar/ 39Ar Geochrononlogy of biotite in Huayangchuan uranium-polymetallic deposit in Shanxi Province and its Geiological significance, Uranium Geology 32 (2016) 159-164 [5] HUI, X., LI, Z., FENG, Z., CHENG, D., Research on the Occurrence State of U in the Huayangchuan U-Polymetallic Deposit, Shanxi Province, ACTA MIERALOGICA SINICA 34 (2014) 573-580. [6] HE, S., LI, Z., HUI, X., GUO, J., Characteristics of mineralization alteration from Huayangchuan U-Nb deposit in Shanxi province, World Nuclear Geoscience 33 (2016) 8-32. [7] WU, C., LIU, Z., MA, J., TANG, B., Occurrence state of uranium in Huayang Chuan polymetallic deposit. Uranium Mining and Metallurgy 34 (2015) 30-34. [8] XU, C.，CAMPBELL, I .H.，ALLEN, C. M.，HUANG, Z. L，Qi, L.，ZHANG, H，ZHANG, G. S., Flat rare-earth element patterns as an indicator of cumulateprocesses in the Lesser Qinling carbonatites，China, Lithos 95(2007) 267-278. [9] XU, C.，WANG, L.，SONG, W., Carbonatites in China: A review for genesis and mineralization, Geoscience Frontiers 1 (2010) 1-10. [10] GUO, B., ZHU, L., LI, B., GONG, H., WANG, J., Zircon U-Pb age and Hf isotope composition of the Huashan and Heyu granite plutons at the southern margin of North China Carton: Implication for geodynamic setting. Acta Petrologica Sinica 25 (2009) 265-281. [11] QI, Q., WANG, X.，KE, C. and LI, J., Geochronology and origin of the Laoniushan complex in the southern margin of North China Block and their implications: New evidences from zircon dating, Hf isotopes and geochemistry, Acta Petrologica Sinica 28 (2012) 279 -301 [12] YU, X., Geological，petrol-mineralogical characteristics and origin 0f the carbonatites from Huayangchuan, Shaanxi province, Earth Science-Journal of China University of Geosciences 17(1992) 151-158. [13] QIU, J., ZHEN, G., LI, C., Qinba alkaline rock, BEIJING:GEOLOGY PRESS, 1993.

Speaker: Dr Jie Yan (East China University of Technology)

32 Alteration fingerprint of the early Yanshanian granite-related high-temperature hydrothermal uranium mineralization in the Nanling Metallogenic Belt, Southeast China

ABSTRACT In the Xiazhuang and Zhuguang uranium ore fields of the Nanling Metallogenic Belt, southeast China, granite-related hydrothermal uranium deposits formed in two major mineralisation stages: (i) an early Yanshanian high-temperature stage (175–145 Ma) concomitant with the early Yanshanian magmatic event; and (ii) a late Yanshanian low-temperature stage (110–50 Ma) that occurred during the Cretaceous-early Cenozoic crustal extension in eastern Asia. To date, the Baishuizhai occurrence (175±16 Ma) and the Shituling and Zhushanxia deposits (162±27 and 165–146 Ma, respectively) represent the early Yanshanian uranium mineralisation in the belt. The Zr-Th-Ta-bearing disseminated-to vein-type uranium mineralisation is cogenetic with a hydrothermal alteration assemblage of epidote, chlorite, muscovite, adularia, illite, calcite, apatite, APS and titanite. The ore trace element signature and the propylitic and potassic alteration are both in agreement with relatively high temperatures (>250°C), corroborated by temperatures of 316–455 °C estimated from chlorite. This early mineralisation stage appears to be related to the intrusion of the early Yanshanian granites where the mineralising fluids could partly to totally derive from the granites in a high-temperature hydrothermal system. This would be to date, the first description and known occurrences for a new type of hydrothermal uranium deposit associated with granites worldwide. INTRODUCTION AND GEOLOGICAL SETTING The South China Uranium Province accounts for the largest amount of explored uranium deposits and resources in China (∼50% of identified uranium resources; [1-4]). It includes three major types of uranium deposits, from the most to the least economic: (i) granite-related vein-type deposits, (ii) volcanic-related vein-type deposits and (iii) black shale-related deposits (i.e., C-Si-pelite type; [1, 5, 6]). Some small sandstone-type uranium deposits are also hosted in several Mesozoic-Cenozoic basins of the province. In addition to uranium, the province is also renowned for W, Sn, Bi, Sb, Mo, Au, Ag, Cu, Pb and Zn deposits [2, 3, 6], some of which belonging to the world-class category in terms of grade and tonnage. Granite-related hydrothermal uranium deposits from the Xiazhuang (eastern part of the Guidong batholith) and Zhuguang ore fields (OF) within the Nanling Metallogenic Belt (NMB) formed in two major mineralisation stages [5]: (i) an early Yanshanian high-temperature stage (175–145 Ma) concomitant with the early Yanshanian magmatic event that occurred in South China during the Jurassic; and (ii) a late Yanshanian low-temperature stage (110–50 Ma) that occurred during the Cretaceous-early Cenozoic crustal extension in eastern Asia. To date, the early Yanshanian stage is only represented by the Baishuizhai occurrence (175±16 Ma) and the Shituling (162±27 Ma) and Zhushanxia (165–146 Ma; [7]) deposits located in the Xiazhuang OF [5]. These early Yanshanian deposits are mainly hosted in Triassic granites (e.g., Baishuizhai and Maofeng plutons) emplaced during the Indosinian orogeny, among which peraluminous S-and L-type leucogranites and highly fractionated high-K calc-alkaline A2-type granite constitute the most favourable U sources [5]. The primary uranium mineralisation mainly occurs as Zr-Th-Ta-bearing uraninite and pitchblende disseminated in the host-granite or as vein filling fractures. Large amounts of secondary uranium mineralisation are also characteristics of these deposits. Preliminary description of the alteration mineral assemblage including hydrothermal epidote, chlorite, muscovite, K-feldspar, apatite etc. presented in [5] and ore-forming fluid temperatures ranging from 290 to 338 °C at the Shituling deposit [8] were strong evidence for a high-temperature hydrothermal system. Now, this work aims to better characterise the genetic conditions of the early Yanshanian uranium stage through detailed petrographic and mineralogical studies carried on the alteration minerals associated with the uranium mineralisation. **MATERIAL AND METHODS** Six mineralised samples were collected from the Baishuizhai occurrence (XB1) and the Shituling (XS1, XS2) and Zhushanxia (ZSX1, ZSX2, ZSX3) deposits in the Xiazhuang OF. The textural and paragenetic relationships of the alteration minerals associated with the early Yanshanian uranium mineralisation were determined through detailed petrographic studies by optical reflected light microscope and scanning electron microscope (SEM). The chemical composition of the alteration minerals was analysed by electron microprobe (EMP) and their trace element concentrations were measured by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). RESULTS 1. PETROGRAPHY AND MINERAL ASSEMBLAGE OF THE ALTERATION The hydrothermal alteration of the host granites associated with the early Yanshanian uranium mineralisation can be pervasive (e.g., Baishuizhai) or confined in the vicinity of fractures (e.g., Shituling and Zhushanxia). The alteration mineral assemblage identified in the studied deposits includes epidote, chlorite, calcite, adularia, muscovite, illite, quartz, apatite, titanite, aluminium phosphate-sulphate (APS) minerals, albite and Fe-oxide. Sulphide minerals such as pyrite, chalcopyrite, galena, molybdenite, sphalerite, bismuthinite and greenockite are also frequently observed. These alteration minerals either occur disseminated in the altered host-granite (e.g., Baishuizhai) or along the mineralised veins (e.g., Shituling). This typical mineralogy characterise extensive propylitic (epidote-chlorite-calcite±albite) and potassic (adularia-muscovite-illite) alterations and silicification (quartz). In the Baishuizhai occurrence, the magmatic feldspars are completely replaced by muscovite, illite and quartz, which is characteristic of greisenisation. 2. CHEMICAL SIGNATURES OF THE ALTERATION MINERALS Among the alteration minerals that were identified, epidote, chlorite and muscovite occur in the three studied deposits and show specific major, minor and trace element compositions, although chlorite is rare in samples from the Shituling deposit. Epidote from Baishuizhai is characterised by its Mn content (16.3–17.5 wt%) whereas epidote from Shituling and Zhushanxia presents similar compositions ranging from 22.9–36.4 wt% CaO, 11.4–25.9 wt% Al2O3 and 5.7–13.4 wt% FeO. All epidotes are characterised by variable concentrations of Ti (27–1215 ppm), V (10–819 ppm), Zn (6–309 ppm), Y (0.1–99 ppm), Sn (5–89 ppm) and Zr (limit of determination (LOD)–8 ppm). It can be noted that only epidote from Baishuizhai returned heavy REE concentrations up to 7 ppm Lu, 11 ppm Er and 33 ppm Yb. Epidote from Shituling and Zhushanxia also has additional concentrations of Sr (5–287 ppm), W (3–56 ppm) and Nb (9–42 ppm). Chlorite from Baishuizhai and Zhushanxia is Fe-dominant (18.9–31.4 wt% FeO; 9.0–16.9 wt% MgO) giving a chamosite composition. Trace elements of petrogenetic interest are Ti (70–1559 ppm), Zn (473–1450 ppm), Li (441–1024 ppm), V (25–425 ppm), Rb (4–170 ppm), Sn (2–58 ppm), Cs (9–51 ppm), Nb (LOD–31 ppm) and Zr (LOD–12 ppm). The calculated temperatures from the chlorite compositions (Al IV thermometer, after [9]) range from 316 to 455 °C (n= 19). Muscovite from the three studied deposits shows relatively homogeneous composition with 46.2–53.2 wt% SiO2, 27.4–33.8 wt% Al2O3 and 3.1–11.5 wt% K2O contents. It has variable Rb (120–2856 ppm), Ti (37–2319 ppm), Cs (29–1667 ppm), Li (43–1084 ppm), Sn (LOD–628 ppm), Sr (LOD–252 ppm), Nb (LOD–451 ppm), W (LOD–111 ppm), Zr (LOD–57 ppm) and Ta (LOD–31 ppm) concentrations. Titanite from the Zhushanxia deposit (average of 34.4 wt% TiO2, 30.9 wt% SiO2 and 29.4 wt% CaO) shows minor Al2O3 (0.9–1.4 wt%) and FeO (0.1–0.8 wt%) contents and has variable W (160–2010 ppm), Zr (42–878 ppm), Y (81–352 ppm), Sn (47–248 ppm), Nb (100–190 ppm) and Ta (4–12 ppm) concentrations. Finally, apatite from the Shituling and Zhushanxia deposits presents a fluorapatite composition with 52.2–58.5 CaO wt%, 38.0–43.3 wt% P2O5 wt% and 1.6–2.2 F wt% contents. Trace elements with significant concentrations are Sr (615–3640 ppm), Y (69–777 ppm), Rb (2–151 ppm), Th (1–130 ppm), W (3–70 ppm) and Sn (2-19 ppm). DISCUSSION AND CONCLUSIONS The alteration mineral assemblage from Baishuizhai, Shituling and Zhushanxia including epidote, chlorite, K-bearing silicate, titanite and apatite associated with Zr-Th-Ta-bearing uranium oxides characterise an extensive propylitic and potassic alteration strongly suggesting high temperature conditions. The high temperature of the hydrothermal system was thus confirmed by temperature estimates ranging from 316 to 455 °C calculated with the Al IV thermometer in chlorite [9], which is also corroborated by temperatures of 290–338 °C determined from fluid inclusions for the ore-forming fluid of the Shituling deposit [8]. The chemical signatures of the alteration minerals showing characteristic concentrations of incompatible elements (K, Cs, Li, Rb, Sr, Y, Zr), rare metals (Sn, W, Nb, Ta) and occasionally heavy REE indicate highly differentiated crustal source-rocks [10, 11] such as peraluminous leucogranite or highly fractionated high-K calc-alkaline granite [5], widely represented in the NMB, and also suggest the contribution of magmatic-derived fluids. For instance, hydrothermal titanite largely occurs in alteration zones associated with the intrusion of igneous rocks. It is a common alteration product highlighting late magmatic to post-crystallisation hydrothermal alteration in porphyry Cu and Fe-Cu-Au-W-Mo skarn mineralising systems [12, 13]. Moreover, the Zr content in titanite, up to 878 ppm in titanite from Zhushanxia, also reflects the magmatic contribution as a source of fluid for the hydrothermal system [13]. The greisenisation characterised in Baishuizhai constitutes another strong evidence for the contribution of magmatic-derived fluids to the hydrothermal system. It is indicative of late magmatic alteration of the host-granite that most likely occurred during the cooling stage of emplacement of the early Yanshanian granite in the district. As they are generated during the final stage of granite crystallisation, the late magmatic fluids responsible for the greisenisation tend to be enriched in incompatible elements [10, 11], and also known to be at the origin of W-Sn-Mo-(U) etc. mineralisation in the province [2, 3, 6, 14]. Then the significant and systematic record of this suite of elements in the studied alteration minerals would be the marker of the contribution of such fluids. In the Xiazhuang OF, the early Yanshanian uranium mineralisation is also associated with minor tungsten occurrences such as wolframite in the Shituling deposit [15] and sheelite in the Zhushanxia deposit (up to 0.3% W; [7]), indicating possible genetic relations between uranium and tungsten mineralisation. Finally, the occurrence of fluorapatite (up to 2.2 wt% F) in the Shituling and Zhushanxia deposits together with calcite in the three studied deposits suggest that the hydrothermal solutions were enriched in fluoride and carbonate ions that can form complexes able to transport metals including uranium [5]. Therefore, the early Yanshanian uranium stage appears to be strongly related to the intrusion of the early Yanshanian granites providing: (i) the heat source for the high temperature hydrothermal system, (ii) magmatic-derived fluids that can mix with hydrothermal fluids already present in the basement and (iii) major sources for incompatible elements and rare metals that are concentrated in the alteration minerals and the uranium mineralisation. This model is new for hydrothermal uranium deposits related to granites and seems to represent the only occurrence of this type in the world. At the scale of the NMB, the alteration fingerprint that was characterised in this study for the early Yanshanian uranium event presents numerous similarities with the genetic model proposed for the giant W-Sn event in South China [5, 6, 14], also related to the intrusion of the early Yanshanian granites (peak at 160–150 Ma). Further studies will be conducted in order to characterise the spatial-temporal relations between the U and W-Sn mineralising systems in the NMB. ACKNOWLEDGMENTS The study was supported by the East China University of Technology in Nanchang, Jiangxi Province, and the Research Institute No. 290 from the Bureau of Geology of the Chinese Nuclear National Corporation (CNNC) in Shaoguan, Guangdong Province. REFERENCES [1] DAHLKAMP, F.J., Uranium Deposits of the World. Springer Ed., Asia (2009) pp. 493. [2] MAO, J.W., et al., “Mesozoic metallogeny in East China and corresponding geodynamic settings – an introduction to the special issue”, Ore Geology Reviews 43 (2011) pp. 1–7. [3] MAO, J.W., et al., “Major types and time-space distribution of Mesozoic ore deposits in South China and their geodynamic settings”, Mineralium Deposita 48 (2013) pp. 267–294. [4] OECD-NEA/IAEA, Uranium 2016: Resources, Production and Demand (2016). [5] BONNETTI, C., et al., “The genesis of granite-related hydrothermal uranium deposits in the Xiazhuang and Zhuguang ore fields, North Guangdong Province, SE China: Insights from mineralogical, trace elements and U-Pb isotopes signatures of the U mineralisation”, Ore Geology Reviews 92 (2018) pp. 588–612. [6] PIRAJNO, F., Yangtze craton, Cathaysia and the South China block, In: Pirajno, F. (Ed.), The Geology and Tectonic Settings of China's Mineral Deposits, Springer Ed, (2013) pp. 127–247. [7] HU, B.Q., et al., “The early high-temperature uranium mineralization in Zhushanxia deposit”, Journal of East China Geological Institute (2003), in Chinese with English abstract. [8] WU, L.Q., et al., “Discussion on uranium ore-formation age in Xiazhuang ore-field, northern Guangdong”, Uranium Geology 19-1 (2003) pp. 28–33. [9] CATHELINEAU, M., “Cation site occupancy in chlorites and illites as a function of temperature”, Clay Minerals 23 (1988) pp. 471–485. [10] LEHMANN, B., “Metallogeny of granite-related rare-metal mineralization: a general geochemical framework”, Resource Geology Special Issue 15 (1993) pp. 385–392. [11] CERNY, P., et al., “Granite-related ore deposits”, Economic Geology 100 (2005) pp. 337–370. [12] CAO, M.J., et al., “In situ LA-(MC)-ICP-MS trace element and Nd isotopic compositions and genesis of polygenetic titanite from the Baogutu reduced porphyry Cu deposit, Western Junggar, NW China”, Ore Geology Reviews 65 (2015) pp. 940–954. [13] CHE, X.D., et al., “Distribution of trace and rare earth elements in titanite from tungsten and molybdenum deposits in Yukon and British Columbia, Canada”, The Canadian Mineralogist 51 (2013) pp. 415–438. [14] LEGROS, H., et al., “Detailed paragenesis and Li-mica compositions as recorders of the magmatic-hydrothermal evolution of the Maoping W-Sn deposit (Jiangxi, China)”, Lithos 264 (2016) pp. 108-124. [15] ZHU, B.Q., et al., “Isotopic geochemistry of Shituling uranium deposit, northern Guangdong Province, China”, Mineral Deposits 25–1 (2006) pp. 71–82, in Chinese with English abstract.

Speaker: Dr Christophe Bonnetti (State key laboratory breeding base of nuclear resources and environment, East China University of Technology)

33 RARE EARTH ELEMENTS IN URANINITE: BRECCIA PIPE URANIUM DISTRICT, NORTHERN ARIZONA, USA

INRODUCTION Interest in rare earth minerals (REE) originated in 1883 with the development of incandescent gas mantles containing rare earth and zirconium oxides. The knowledge that the supply of REE will not be able to keep up with new and ever-growing demands has been no secret in the geological community for years. However, it was not until it was presented to congress as a “potential shortage that could impact US renewable energy sources, communications and defense industries” that politicians and the public tumbled to how critical these metals are and just how vulnerable the US currently is to supply disruption. In 2008, China produced 97% of the worlds REE (primarily from Bayan Obo), India 2.2%, Brazil 0.5%, and Malaysia 0.3%. Up until 2002, the Mountain Pass REE Mine in California produced about 5% of the world’s REE supply. China’s lock on the world’s supply will be difficult to break. Starting in 2005, China put export taxes on REE of 15-20% and put on export restrictions. Forecasts predicted a critical shortage for the rest of the world outside of China by as early as 2012. So, REE prices went up. Just as the Mountain Pass Mine was getting ready to go into production in 2012, China eased their export restrictions and the price of most of the REE plummeted downward. Three years later in 2015, Mountain Pass mine went into bankruptcy. REE were extracted as a by-product of uranium mining in Canada during 1966-1970 and 1973-1977 at the Blind River and Elliott Lake deposits. The ore mineral uraninite contained sufficient REE to make extraction of REE profitable from the raffinate fluids. From 1966 to 1970, uranium mines in the Elliot Lake district were the world’s major source of yttrium concentrate. All rare earths except promethium have been detected in these ores. The Elliot Lake ores also contain about 0.11% uranium oxide (U3O8), and 0.028% rare-earth oxides [1]. The economic appeal of this occurrence is that the REE are concentrated in the uraninite, which was already being concentrated from the ore, so the REE are a bonus. “For a short period of time, HREE were extracted from the raffinate fluids that emanated from the chemical processing of uraninite at Blind River, Ontario.” [2]. Since REE are significantly concentrated within the uraninite from breccia pipes in northern Arizona, they likewise could be extracted from northern Arizona uraninite. POLYMETALLIC NORTHERN ARIZONA BRECCIA PIPE DISTRICT A unique polymetallic-rich uranium, solution-collapse breccia-pipe district lies beneath the plateaus and in the canyons of northwestern Arizona. It is known for its large reserves of high-grade uranium (average grade of 0.65% U3O8 [3]) that were estimated by the US Geological Survey to comprise over 40% of the US’s domestic uranium resources [4]. The breccia-pipe uraninite contains REE enrichment similar to that of the Canadian Athabasca Basin’s uranium deposits. From late1980’s until about 2004, the price of most metals had been sufficiently depressed such that little was done to explore or study these polymetallic ores, particularly the REE, that are rich in the district’s uranium deposits. Since 2008, the price of most REE has increased over 10-fold. This is true of all energy critical elements, including Co and Cu, also heavily enriched in the breccia pipe ore. These important elements commonly comprise over 1% of the breccia pipe ore. The northern Arizona metallic district can be thought of as a paleo-karst terrain pock-marked with sink holes, where in this case most “holes” represent a collapse feature that has bottomed out over 3000 ft below the surface in the underlying Mississippian Redwall Limestone. These breccia pipes are vertical pipes of breccia formed when the Paleozoic layers of sandstone, shale, and limestone collapsed downward into underlying caverns. A typical pipe is only approximately 300 ft (91 m) in diameter and extends upward as high in the section as the Triassic Chinle Formation. Although each breccia pipe in itself is not a huge ore deposit – up to 10 million pounds (lbs) (4500 tU) of uranium per pipe – in total the resources in the district are enormous. Many of the various small, mineralized pipes are clustered together providing somewhat contiguous mineralization, which reduces the mining costs. The water table is deep below the orebodies, which lie 500-1600 ft below the surface, sufficiently above the water table to minimize potential contamination of the aquifer. Mining activity in the Grand Canyon breccia pipes began during the nineteenth century, although at that time mining was primarily for copper, with minor production of silver, lead, and zinc. It was not until 1951 that uranium was first recognized in the breccia pipes. The intrinsic geology of these pipes, together with growing understanding of the nature of telethermal ores, (a classification category to which the base-metal deposits of the pipes belong), are important components of the model of their genesis. The metallized pipes are base-metal bearing and, regionally, bear a slightly later metal overprint of uraninite. A model was proposed for genesis of these ores as members of the class of Mississippi Valley Type (MVT) deposits, but with late-stage uranium mineralization [3]. U-Pb ages on uraninite of 200 and 260 Ma [5] link the mineralization with Pangean time, events, and mid-continent MVT ores; chemistry and fluid-inclusion temperatures on sphalerite and dolomite of 80°-173° also link them with MVT deposits [3]. Mixing of oxidizing groundwaters from overlying sandstones with reducing brines that had entered the pipes due to dewatering of the Mississippian limestone created the uranium deposits. Proximity to the west of the Cordilleran miogeocline and various uplifts to the east allow consideration of a basin-dewatering mechanism as the genetic mechanism [3]. RARE-EARTH ELEMENTS IN BRECCIA PIPE URANINITE REE are significantly enriched in much of the breccia pipe ore. Whole-rock analyses of uranium ore-bearing rock from across the district show REE enrichment that is not uncommonly 20 times average crustal abundance. A study of REE within uraninite was undertaken at the facilities of CREGU-GeoRessources, Nancy, France, using Laser Ablation ICP-MS in conjunction with electron microprobe analyses of the uraninite [6]. This research has confirmed that a significant percentage of the bulk rock REE content is tied up in the uraninite crystal structure. Although the breccia-pipe bulk-rock REE content is not as enriched as in the carbonatites at Mountain Pass, California (CA), the breccia-pipe uraninite contains concentrations of Nd, for example, that are between 15-20% of the Nd concentrations in the bastnaesite of Mountain Pass. Considering that at Mountain Pass the bastnaesite (REE ore mineral) has to be mined strictly for REE, the uraninite in the breccia pipes is already processed for the uranium. Hence, the Nd and other REE collected from the raffinate fluids are an added value to the profit. Additionally, the more valuable heavy REE (HREE) are enriched in the uraninite, whereas the Mountain Pass, CA and Bayan Obo, China ore deposits contain essentially little significant HREE. REE PRIMARY & REMOBILIZED ORE-DEPOSIT SIGNATURES Distinctive REE signature in uranium oxides is directly related to the variability of the mineralizing processes and geological setting between uranium deposit types [9]. All the uranium oxides from unconformity related deposits, such as from the Eastern Alligator district in Australia and Athabasca Basin district in Canada, are characterized by a bell-shaped REE pattern centered on dysprosium. This type of pattern seems to be characteristic of uranium oxide primary ore deposited from high-salinity basinal brines. The Sage and Pinenut breccia pipes of northern Arizona have bell-shaped chondrite-normalized distributions that are remarkably similar to the Athabasca Basin’s McArthur River (currently produces 25% of the world’s uranium) and Shea Creek uraninites [8], with a normalized maximum centered on Sm-Eu-Gd. Interestingly, the Pinenut breccia pipe, with its bell-shaped REE pattern, has the oldest age, 260 Ma [5] of those that were part of this study, suggesting it is primary ore (no age determination was completed on the Sage orebody by Ludwig & Simmons). The REE element patterns of uraninite samples from three of the breccia-pipe uranium mines (Pigeon, Kanab N, and Hack 2) have chondrite-normalized distributions that show some fractionation and a negative Eu anomaly. They distinctly resemble chondrite-normalized plots of uraninite samples [7] from the Athabasca Basin Eagle Point deposit, but with overall lower REE content. The rocks from both the three breccia pipe orebodies and Eagle Point show striking oxidation-reduction fronts within some of the ore. Such samples correspond to uranium oxides that are remobilized by oxidized meteoric fluids. These fluids mobilized the LREE preferentially over the HREE. Therefore, the uranium oxides from the redox front are characterized by LREE enrichment, which differs from the primary ores, and clearly demonstrate their distinct conditions of formation from the primary ore [9]. The HREE part of the chondrite-normalized distribution is preserved. The negative Eu anomaly of these samples could possibly be a result of oxidizing meteoric fluids albitizing the detrital feldspars in the clastic host rocks, permitting preferential incorporation of Eu over the other REE into the albite structure (similar to magmatic plagioclase creating a negative Eu anomaly). The three more-fractionated uraninite orebodies (Pigeon, Kanab N, and Hack 2) have younger ages of 200 Ma [5] as contrasted with the Pinenut 260Ma ore with a bell-shaped REE pattern. All of the breccia-pipe orebodies are believed to have formed due to a mixing of high-salinity basinal brines (based on fluid inclusion results) and oxidizing groundwaters [3]. Hence, the primary ore, breccia pipe uraninite samples fit the same REE chondrite-normalized pattern as do uraninites from the primary uranium deposits of McArthur River and Shea Creek. Interestingly, the Pigeon, Kanab N, and Hack 2 mines all lie along a N45°E trend that is parallel to one of the two major fracture directions in northern Arizona. So, they may have been more open to oxidizing groundwaters than the Pinenut and Sage orebodies. More samples from each mine and from other uraninite deposits within the district will provide insight into the fluids containing the REE. However, the pipe in pipe structure in many breccia pipes proves secondary dissolution. It is quite possible that all of the breccia-pipe orebodies have an older primary ore preserved and a later secondary oxidation/reduction front ore. The primary ore would be a higher U and REE grade. BRECCIA PIPE URANIUM & REE RESOURCE ESTIMATES The northern Arizona breccia-pipe district contains the highest-grade uranium in the U.S., with the potential for reserves that greatly exceed any other province in the U.S. With an average grade of 0.65% U3O8, and an environment conducive to relatively low cost conventional mining, these deposits are still economic in the $45/lb price range [10]. Unfortunately, in 2011, President Obama chose to issue an executive order withdrawing the million acres of northern Arizona land that encompassed most of the mineralized breccia pipes in the district. With the current emphasis by President Trump enabling exploration for strategic metals, these lands may soon be reopened to mineral exploration. Multiple approaches to uranium-resource calculations on these lands by separate researchers have shown remarkably similar results: 1. A uranium-resource estimate (referred to as resource endowment [11]) based on industry drilling for the 1050 mi2 (2719 km2) “mineralized corridor” of the breccia-pipe district have been made by [11]. Spiering and Hillard defined a “mineralized corridor” within the Breccia Pipe uranium district where they believe most of the mineralized pipes lie. It provides a smaller focused area to work with where more data are available. However, these authors still believe that considerable mineralized rock abounds beyond this corridor on private and public lands (the NE quadrant of the Hualapai Reservation is an example). Spiering & Hillard calculated the uranium resources [11] by (a) using VTEM Airborne Geophysics results and concluded that the mineralized corridor had 270 million lbs (122,500 tU) of U3O8 and (b) using known pipe density they concluded the corridor has 269 million lbs (122,000 tU) U3O8. 2. In 1987, the USGS [4] calculated the uranium endowment of the entire breccia pipe district. Spiering and Hillard [11] show that these calculations when applied to the “mineralized corridor” result in 375 million lbs (170,000 tU) of U3O8. 3. Using a control area of detailed surface mapping of solution-collapse features and mineralized rock [12] on the NE portion of the Hualapai Reservation, the current authors calculated that the “mineralized corridor” contains 260 million lbs (118,000 tU) of U3O8 (table 2) and the entire withdrawal area contains 385 million lbs (175,000 tU) U3O8.(table 2) These 3 independent resource estimates average to 302 million lbs (137,000 tU) of U3O8. The estimate by Spiering and Hillard and that by Wenrich et al. using completely different types of data within different geographic parts of the district (industry drilling vs. detailed surface mapping) have come to remarkably similar resource endowment estimates—270 vs. 260 million lbs (122,000 vs. 122,500 tU) of U3O8. Yetin 2011, the USGS, within the Final Environmental Impact Statement (EIS) for the breccia-pipe land withdrawal, arrived at a paltry 79 million lbs (36,000 tU) for their resource estimate. To arrive at this number, they did not use industry drilling [11], or previous USGS maps [12] or extensive resource calculations [4], but rather a non-peer reviewed elementary article written for the general public by Wenrich in 1988 where a simple statement was made that about 8% of collapse features and breccia pipes were mineralized. There were no data provided for this statement. To formulate such a low resource estimate based on such unsubstantiated data may have been an effort to support an administration political agenda. The three resource calculations above are in amazing agreement, so for the USGS in 2011 to arrive at such low numbers, ignoring industry drilling and other resource calculations indicates an incomplete and biased analysis. 4. A 4th approach is also applicable, which results in an estimate closer to the IAEA reasonably assured resources (RAR) 4 rather than a resource endowment. Prior to 1989 over 110 breccia pipes were drilled; 71 of these were identified to have ore-grade mineralization [13]. At an average of 2.9 million lbs (1300 tU) of uranium/pipe, the RAR (IAEA) or “indicated reserves” (USGS definition) total 206 million lbs (93,400 tU) of resources in the part of the district covered by Sutphin and Wenrich’s map [13]. Of these 71 mineralized pipes, 9 became uranium mines, 27 are known to contain an orebody, and 46 were mineralized, but with insufficient drilling to identify an orebody. Because the district is known to have very little low grade mineralization, if a pipe is mineralized with ore-grade mineralization, the odds are great that it contains an orebody. Since 1989, there has been significant exploration for uranium in the northern Arizona breccia-pipe district and more pipes have been located that are known to be mineralized. Hence, this Reasonably Assured Resource number of 206 million lbs (93,400 tU) is probably not an unreasonable estimate based on the historic drilling in the district. U.S. Energy Information Administration (EIA, U.S. Uranium Reserves Estimates, 2008) estimates that at $50/lb uranium, the US reserves are 539 million lbs (244,000 tU) of U3O8. They state that the definition of “’reserves’ for these estimates “…corresponds, in general, to the category of ‘Reasonably Assured Resources’ often used in international summaries of uranium reserves and resources…” Comparing the US RAR of 539 million lbs (244,000 tU) of U3O8 .and the RAR calculated above in item 4 to be 206 million lbs (93,400 tU), the breccia-pipe district contains 38% of the US uranium reserves. Using the minimum reserve calculation of 206 million lbs (93,400 tU) of U3O8 and the maximum endowment of 375 million lbs (170,000 tU), the “mineralized corridor” contains between 10 and 18 billion dollars at $50/lb uranium price and 21 and 38 billion dollars at $100/lb uranium price. REE analyses of breccia-pipe uraninite ore (this study) in France showed the total REE content of the uraninite to be around 0.43%. Hence, between 471,000 and 860,000 lbs (214 and 390 tU) of LREE and 405,000 and 737,000 lbs (184 and 334 tU) of HREE could be produced from the breccia-pipe district. The more valuable HREE have a greater presence in uraninite ores than in bastnaesite ores from the Bayan Obo and Mountain Pass Districts. The value added by REE to the uranium ore at $3.10/lb of U3O8 would be between 639 million dollars and 1.2 billion dollars (based on 2011 REE prices). The REE, badly needed for energy and industrial technology, coupled with the 10 to 38 billion dollars of uranium is a significant amount of money and energy reserves to lose from the US economy due to a land withdrawal that has essentially no significant scientific or environmental basis, as shown in the final EIS analysis. These estimates do not include value for other metals that are significantly enriched (many reaching and exceeding 1%) in the breccia-pipe polymetallic ore. These metals include Ag, Co, Cu, Mo, Ni, Pb, V, and Zn [3]4 CONCLUSIONS Rare earth elements are significantly enriched in much of the breccia-pipe ores. A study of REE within uraninite has confirmed that a significant percentage of the whole rock REE content is tied up in the uraninite crystal structure. All the uranium oxides from unconformity related primary ore deposits from the Eastern Alligator district in Australia and the Athabasca Basin district in Canada are characterized by a bell-shaped pattern centered on dysprosium. The Sage and Pinenut breccia pipes have bell-shaped chondrite-normalized plots that are remarkably similar to the Athabasca Basin’s McArthur River and Shea Creek uraninites). The Pinenut breccia pipe, with its bell-shaped REE pattern, has the oldest age, 260 Ma [5] in the district, suggesting it is primary ore. The REE patterns of uraninite from Pigeon, Kanab N, and Hack 2 breccia pipes (age of 200 Ma) have chondrite-normalized distributions that show some fractionation and a negative Eu anomaly, similar to the Athabasca Basin’s Eagle Point uranium deposit. The rocks from both these 3 breccia pipe orebodies and Eagle Point show oxidation-reduction fronts within some of the ore suggesting remobilization by oxidized meteoric fluids. Multiple approaches to uranium resource calculations have been made by separate scientists: (1) Uranium resource estimates based on industry drilling for the 1050 mi2 (2720 km2) “mineralized corridor” have been made by Spiering and Hillard [11], to be 270 million lbs (122,000 tU) of U3O8. (2) In 1987, the USGS [4] calculated the uranium endowment of the entire breccia pipe district. Spiering and Hillard [11], show that these calculations, when applied to the “mineralized corridor,” result in 375 million lbs (170,000 tU) of U3O8. (3) A resource estimate (part of this study) using detailed surface mapping of breccia pipes and mineralized rock [12], on the NE portion of the Hualapai Indian Reservation, showed that the “mineralized corridor” contains 260 million lbs (118,000 tU) of U3O8 and the entire withdrawal area contains 385 million lbs (175,000 tU). Uraninite analyses (this study) show the total REE content of the uraninite to be 0.43%. Hence, using the average 302 million lbs (137,000 tU) of the above three estimates, 1.3 million lbs (590 tU) of REE could be produced from the breccia pipe district “mineralized corridor”, adding REE value to the uraninite of $936 million. Between 28 and 48% of the REE production would be the more valuable HREE. REFERENCES CITED [1] CRANSTONE, D.A. 1981, Rare earths. Can. Miner. Yearb., 1979, pp. 365–371. [2] MARIANO, A.N., Hedrick, J., and Cox, C., 2010, REE deposits on a world level – real and potential: Part I: SME Technical Program Abstracts, March 2010, p. 87. [3] WENRICH, K.J. and Titley, S.R., 2008, Uranium exploration in Northern Arizona breccia pipes in the 21st century and consideration of genetic models, in: Titley, S.R. and Spencer, J., Ores & Orogenesis: Circum-Pacific Tectonics, Geologic Evolution, and Ore Deposits: Arizona Geological Society Digest 22, pp. 295-309. [4] FINCH, W.I., Sutphin, H.B., Pierson, C.T., McCammon, R.B., and Wenrich, K.J., 1990, The 1987 estimate of undiscovered uranium endowment in solution-collapse breccia pipes in the Grand Canyon region of northern Arizona and adjacent Utah: U.S. Geological Survey Circular 1051, 19 pp. [5] LUDWIG, K.R., and Simmons, K.R., 1992, U-Pb dating of uranium deposits in collapse breccia pipes of the Grand Canyon region: Economic Geology, v. 87, pp. 1747-1765. [6] LACH, P., Mercadier, J., Dubessy, J., Cuney, M., Boiron, M.C. 2013. Improved in-situ quantitative measurements of rare earth elements in uranium oxides by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry. Geostandards and Geoanalytical Research, accessed on line. [7] MERCADIER, J., Cuney, M., Lach, P., Boiron, M.C., Bonhoure, J., Richard, A., Leisen, L., Kister, P. 2011. Origin of uranium deposits revealed by their rare earth element signature. Terra Nova, v. 23, p. 264–269. [8] BONHOURE, J., Kister, P., Cuney, M., and Deloule, E., 2007, Methodology for Rare Earth Element Determinations of Uranium Oxides by Ion Microprobe: International Association of Geoanalysts, Geostandards, and Geoanalytical Research, v. 31, n. 3, pp. 209-225. [9] MERCADIER, J., Cuney, M., Cathelineu, L. Mathieu, 2011, U redox fronts and kaolinisation in basement-hosted unconformity-related U ores of the Athabasca Basin (Canada): Late U Remobilization by Meteoric Fluids: Mineral Deposita, v. 46, pp.105-135. [10] PILLMORE, Donn, 2013, oral communication. [11] SPIERING, E.D. and Hillard, P.D., 2013, Estimates of the withdrawn uranium endowment of the Arizona Strip District, Northern Arizona: Society of Mining Engineers, 2013 Annual Meeting, Feb 25, 2013. [12] WENRICH, K.J., Billingsley, G.H., and Huntoon, P.W., 1997, Breccia-pipe and geologic map of the northeastern part of the Hualapai Indian Reservation and vicinity northwestern Arizona: U.S. Geological Survey Miscellaneous Investigations Map I-2440, 19 p., 2 plates (includes fifteen 7-1/2 minute quadrangles), scale 1:48,000. [13] SUTPHIN, H.B., and Wenrich, K.J., 1989, Map of locations of collapse-breccia pipes in the Grand Canyon region of Arizona: U.S. Geological Survey Open-File Report 89-550, 1 plate with text, 1:250,000. [14] EIA US Uranium Reserves Estimates 2008.

Speaker: Dr Karen Wenrich (Wenrich Consulting 4 U)

10:40 Break

Applied Geology and Geometallurgy of Uranium and Associated Metals

Conveners: Dr Alexander Boytsov (Uranium One Group), Mr Christian Polak (AREVA MINES)

34 GENETIC DEPOSIT MODEL FOR CALCRETE URANIUM IN THE SOUTHERN HIGH PLAINS REGION, UNITED STATES OF AMERICA

The semiarid Southern High Plains (SHP) physiographic region hosts calcrete uranium deposits in Pliocene and Pleistocene sediments. This region was identified by the U.S. Geological Survey (USGS) as prospective for calcrete uranium deposits, although no deposits of this type had been identified in the US. The existence of deposits in the area was confirmed through historic exploration reports that identified two drilled deposits and additional prospects in the region. Outcropping mineralization adjacent to a known deposit was sampled and analyzed and combined with analysis of regional geology to develop a genetic deposit model. USGS dating of uranyl vanadates, and volcanic ash found in the host rock indicates periodic mineralization occurred between about 631,000 and 4,000 years before present. The entire SHP is characterized by elevated dissolved uranium in groundwater, likely derived from the Triassic Dockum Group or volcanic ash in host sediments. Elevated dissolved vanadium in groundwater, coupled with areas of higher hydraulic conductivity define areas most highly prospective for the formation of carnotite, the major ore mineral for this deposit type. Mineral-solution equilibrium modeling indicates that evaporative concentration of local groundwater could produce saturation with carnotite, which suggests that the mineralizing systems may remain active.

Speaker: Dr Susan Hall (U.S. Geological Survey)

35 UDEPO: THE IAEA URANIUM DEPOSITS DATABASE

HISTORICAL BACKGROUND In 1995, the International Atomic Energy Agency published a map, World Distribution of Uranium Deposits followed in 1996 with a World Guidebook [1] to accompany the map. The guidebook contained information for 582 uranium deposits (≥ 500 tU, ≥ 0.03% U), describing 13 parameters that included location, status, resource range, average grade range, age, host rock and tectonic setting. However, at that time, for many deposits this knowledge was very limited. In the late 1990s a considerable amount of information on uranium deposits, particularly from the former Eastern Block countries became available. Then, a sharp increase in the price of uranium in 2005, led to greatly increased exploration and the discovery of many new deposits. The guidebook and the database on which it is based are known as UDEPO (Uranium DEPOsits). The database has been published on the IAEA web site since 2004 and was continuously updated to include new deposits and provide more information on uranium geology and technical characteristics of the deposits. In 2009, a technical document World Distribution of Uranium Deposits (UDEPO) with Uranium Deposit Classification [2] was published by the Agency with data for 874 uranium deposits (≥ 500 tU, ≥ 0.03% U, 37 parameters described). A new report to be published in 2018, World Distribution of Uranium Deposits (UDEPO) – 2016 Edition [3], contains information on 1807 uranium deposits (≥ 300 tU, no grade restriction), and uses the new classification of uranium deposits adopted in 2013 by the Agency [4-6]. It contains summary tables, diagrams and figures illustrating the diversity of the uranium deposits. The database is continually updated and improved and despite not publishing exact values of resources and grades, is hopefully an interesting and useful tool for geologists and researchers. In addition, a world map of uranium deposits will be published by the Agency in the near future to accompany the database. THE UDEPO DATABASE As of December 2017, 2939 deposits and resources are listed in the database. All deposits with resources greater than 1 tU are included, regardless of their grade or status. The economic value of a resource is not taken into consideration for its inclusion. In the latest 2016 version of the Red Book, a uranium deposit is defined as “a mass of naturally occurring mineral assemblage from which uranium has been or could be exploited at present or in the future” [7]. For the IAEA UDEPO database, which is primarily a geological database, the definition has been broadened to include any identified geological concentration of uranium resource regardless of the tonnage and grade. Thus, UDEPO lists conventional deposits/resources and also large to very large low grade unconventional resources [3, 8]. The database contains four main types of data with a total of 49 parameters: I) general data, II) geological data, (III) resource data and IV) mine data. Entered parameters in the database are as follows: I - General data: 1) Deposit ID, 2) Country Name, 3) Deposit Name, 4) Synonym Names, 5) Political Province, 6) Latitude, 7) Longitude, 8) Deposit Status and 9) References. II - Geological data: 10) Uranium Province Name, 11) Geological Province Name, 12) Deposit Type, 13) Deposit Subtype, 14) Deposit Class, 15) Historical Background, 16) Regional and Local Geological Setting, 17) Deposit Description, 18) Depth to the Top of Mineralization, 19) Mineralization Description, 20) Elemental Association, 21) Stratigraphic Host Rock Age, 22) Radiometric Host Rock Age, 23) Mineralization Stratigraphic Age, 24) Mineralization Radiometric Age and 25) Metallogenic Aspects. III - Resource Data: 26) Resource (tU), 27) Resource Range (tU), 28) Ore Tonnage, 29) Grade (U%), 30) Grade Range (U%), 31) Date of Estimate, 32) Type of Estimate, 33) Source of Data and 34) Description of Resources. IV - Mine Data: 35) Cumulative Production (tU), 36) Production Grade (U %), 37) Mined Ore Tonnage, 38) Remaining Ore Tonnage, 39) Mining Methods, 40) Production Centre, 41) Milling Process, 42) Commodities Recovered, 43) Production Period, 44) Remaining Resources, 45) Grade of Remaining Resources, 45) Grade of Remaining Resources, 46) Production Cost, 47) Technical Remarks, 48) Operator and 49) Owners and Shares. Currently, deposits coordinates (6, 7), discrete grades and resources (26, 29) and production costs (46) are not published by the Agency even where some of these data are available on the web. Only ranges of grade and resource are listed on the UDEPO public site (http://www-nfcis.iaea.org/). UDEPO is organized in a relational database format comprising one main table and several associated tables. The structure of the database allows filtering and systematic querying of the database. UDEPO is designed to facilitate the retrieval of data sets on various deposit related topics ranging from specific information on individual deposits to statistical information on deposits worldwide. Data can be searched according to deposit type, status and country, using the filter tools provided [3]. RESOURCES IN UDEPO In UDEPO, resources include all current resource categories and where available, past production. For some historical districts (Canada, Czech Republic, France, Germany, USA, etc.), in many cases, only the production data are available. Where resources for a deposit have been estimated (NI 43-101, JORC, etc.) at several cut-off grades (which is generally the case in company reports and press releases), resources at the lowest cut-off grade are adopted. All data are given in metric tonnes of uranium (tU). As of the end of 2017, the database includes 2939 deposits distributed among the 15 types, 38 subtypes and 14 classes of deposits defined in the IAEA geological classification of uranium deposits [4-6]. The 15 types with their numbers of deposits and their aggregate geological resources are listed below: Type 1. Intrusive 129 deposits 2 847 000 t U Type 2. Granite-related 586 deposits 527 000 t U Type 3. Polymetallic iron-oxide breccia complex 21 deposits 2 562 500 t U Type 4. Volcanic-related 204 deposits 1 908 500 t U Type 5. Metasomatite 152 deposits 1 070 000 t U Type 6. Metamorphite 225 deposits 663 000 t U Type 7. Proterozoic unconformity 114 deposits 1 547 500 t U Type 8. Collapse breccia pipe 18 deposits 19 500 t U Type 9. Sandstone 951 deposits 4 827 000 t U Type 10. Paleo quartz-pebble conglomerate 144 deposits 2 504 000 t U Type 11. Surficial 123 deposits 532 000 t U Type 12. Lignite-coal 75 deposits 7 406 500 t U Type 13. Carbonate 34 deposits 184 000 t U Type 14 Phosphate 73 deposits 14 326 000 t U Type 15. Black shale 75 deposits 21 749 000 t U Unknown 15 deposits In 2017, total geological resources of uranium in UDEPO stand at 62 674 137 tU, within the 2755 deposits with known/estimated resources. The largest resources are contained in unconventional resource deposit types such as those associated with polymetallic iron-oxide breccia complex (IOCG-U), phosphate, lignite–coal and black shale. It should be noted that for the polymetallic iron-oxide breccia complex deposits, 80% of the resources are contained within a single deposit, Olympic Dam. The most important conventional resource deposit types are the sandstone-hosted type followed by the Proterozoic unconformity type and the volcanic-related type. Eighty three countries have uranium deposits/resources listed in UDEPO. Geological resources within UDEPO can be compared to the “economic” Red Book data: - World historical uranium production to 2016: 2 802 230 t U, - Red Book 2016 conventional resources (< USD 260/KgU): 7 641 600 t U, - UDEPO conventional resources (including Olympic Dam): 14 034 700 tU. The sum of world historical production and Red Book resources is 10 443 830 t U, thus UDEPO identifies an additional 3.5 Mt. VALUE OF UDEPO The various data contained in the database, even if not currently complete enable one to produce compilations for deposit types, subtypes and classes, country resources, uranium provinces resources, statistical diagrams using various parameters, cumulative frequency diagrams, grade-resource-tonnage scatter plots for each types and subtypes, etc. With the addition of new data, it will be possible to derive statistical geological information on parameters such as tectonic setting, age of mineralization, associated elements, and also on various mining parameters, etc. The number of deposits for each resource range and their total geological resources is presented below: - >1 000 000 t U 11 deposits 41 013 600 t U - 100 001-1 000 000 39 deposits 8 081 000 t - 50 001- 100 000 52 deposits 3 016 000 t - 25 001- 50 000 89 deposits 3 200 000 t - 10 001-25 000 218 deposits 3 342 500 t - 5 001-10 000 250 deposits 1 795 300 t - 2 501-5 000 300 deposits 1 098 000 t - 1 001-2 500 428 deposits 721 000 t - 300-1 000 580 deposits 355 700 t - 1-300 786 deposits 87 000 t General information such as the uranium endowment (tU/km2 x 100) for each continent can be calculated using conventional resources numbers: - North America: 12 - South America: 2 - Asia: 7 - Europe: 13 - Africa: 13 - Australasia: 12 This may indicate that South America as well as Asia, are probably underexplored in comparison to other continents. PRESENT AND FUTURE OF THE DATABASE In term of data presented, the UDEPO database is unique as it provides freely accessible information on global uranium deposits. However, it must be emphasized that: - Data entry of 49 parameters for each deposit/resource is time consuming as for most databases. Large portions have not yet been completed, - Coordinates are collected, but are not published. Collected data will permit the publication of a world map of uranium deposits in 2018, - Exact numbers for resources and grades are not published owing to the loose definition of resources in an economical sense, and the aggregation of different categories of resources. However, the Agency will allow the publication of these data in the near future if the official references to the numbers are presented in the database, - None, little or incomplete deposit information has been compiled for some countries like China, Kyrgyzstan, Pakistan, Uzbekistan, - The recent inclusion of small deposits within the range 1-300 t U has drastically increased the number of deposits which were previously aggregated in historical mining districts or ignored (Czech Republic, France, Germany, USA, etc.). For example, today, USA has 406 deposits/resources listed in UDEPO, but a recent compilation indicates that the number of deposits/resources is in the order of 4000 ! - In the future, new additions will most likely come from unconventional resources/deposits associated with intrusive plutonic, phosphates, black shale and coal-lignite deposit types. It is inferred that most of these host rock formations contain at least some uranium concentrations in the range of 10-200 ppm, but no information is available concerning their specific grades. Estimates of the number of such geological formations suggest there could be in the range of 5-6000 additional unconventional deposits [8]. REFERENCES [1] INTERNATIONAL ATOMIC ENERGY AGENCY, Guidebook to accompany IAEA map: World Distribution of Uranium Deposits, IAEA, Vienna (1996). [2] INTERNATIONAL ATOMIC ENERGY AGENCY, World Distribution of Uranium Deposits (UDEPO) with Uranium Deposit Classification, IAEA-TECDOC-1629, IAEA, Vienna (2009). [3] INTERNATIONAL ATOMIC ENERGY AGENCY, World Distribution of Uranium Deposits (UDEPO) – 2016 Edition. IAEA-TECDOC to be published in 2018, IAEA, Vienna. [4] BRUNETON, P., CUNEY, M., “Geology of uranium deposits”, Uranium for Nuclear Power (HORE-LACY, I., Ed.), Woodhead Publishing Series in Energy No. 93, Elsevier, Amsterdam (2016), 11–52. [5] BRUNETON, P., CUNEY M., DAHLKAMP, F., ZALUSKI, G., “IAEA geological classification of uranium deposits”, Uranium Raw Material for the Nuclear Fuel Cycle: Exploration, Mining, Production, Supply and Demand, Economics and Environmental Issues, URAM 2014, Proc. Int. Symposium, Vienna, 2014), IAEA, Vienna, 10 p. (to be published in 2018). [6] INTERNATIONAL ATOMIC ENERGY AGENCY, Geological Classification of Uranium Deposits and Description of Selected Examples, IAEA-TECDOC (to be published in 2018). [7] OECD NUCLEAR ENERGY AGENCY, INTERNATIONAL ATOMIC ENERGY AGENCY, Uranium 2016: Resources, Production and Demand, OECD, Paris (2017). [8] BRUNETON, P., CUNEY, M., FAIRCLOUGH, M., JAIRETH, S., LIU, X., ZALUSKY, G., Unconventional uranium resources in IAEA Uranium DEPOsit Database (UDEPO), URAM 2018, to be published in Proc. Int. Symposium, Vienna, 2018, IAEA, Vienna, 4 p.

Speaker: Dr Patrice Bruneton (Private Consultant)

36 URANIUM DEPOSITS OF THE KARELIAN-KOLA PROVINCE (RUSSIAN FEDERATION)

INTRODUCTION The Karelian-Kola uranium ore province is situated within the East European Platform and covers its fragments: the eastern Baltic Shield and the northern Russian Plate. The area of studies includes Kola-Belomorian, Laplandian-Karelian, Svecofennian megablocks and dividing suture fold-overthrust zones: East Karelian and Raakhe-Ladoga. These long-living structures are composed of Archean and Proterozoic volcanogenic and sedimentary-volcanogenic formations of various compositions subject to repeated structural transformations under the impact of tectonic, hydrothermal-metasomatic and exogenic processes of various ages. It is reflected in geochemistry of geological formations and the specifics of ore genesis. In the Precambrian geology of the Baltic Shield, several tectonomagmatic cycles (TMC) and corresponding metallogenic epochs can be distinguished: the Early Archean (older then 3.15 Ga), the Late Archean (3.15-2.6 Ga), the Early Karelian (2.6-2.4 Ga), the Late Karelian (2.4-1.95 Ga), the Svecofennian (1.95-1.65 Ga), the Riphean (1.65-0.65 Ga), and the Vendian-Paleozoic (0.65-0.34 Ga). Each of them is characterized by specific type of sedimentation, vоlcanism, metasomatosis and the emergence and concentration of ore. Of all the above-described uranium-ore epochs, the Svecofennian TMC epoch is most productive for uranium and complex uranium mineralization as regards the variety of ore types. It is caused by the complication of ore-forming systems in time and the superposition of later ore associations on the earlier ones. URANIUM TARGETS OF VARIOUS ORE-FORMATION TYPES Intense and purposeful predictive metallogenic and prospecting studies conducted in the Russian part of the Baltic Shield led to the discovery of uranium and complex uranium deposits of different ore types: unconformities, sandstone, quartz-pebble conglomerates, veins, metasomatic, etc [1, 2, 5, 8]. Their resource potential is more than 2 MT U [5]. Zones of structural-stratigraphic unconformity (SSU) are widespread in the Baltic Shield. Uranium mineralization within the uranium-bearing SSU zones are of different grades: high-grade ore in Pre-Riphian zones, low-grade ore but with significant reserves in the Pre-Vendian SSU zones, low-grade ore in Pre-Early Proterozoic SSU zones. The Pre-Riphean SSU zone is characterized by greatest potential because the Pasha-Ladoga through hosts the Karku unconformity-type uranium deposit. The structural-stratigraphic unconformity is caused by the gentle occurrence of Riphean sedimentary deposits on intensively dislocated Archean and Proterozoic rocks. Riphean sediments and basement rocks are intensively kaolinized, carbonatized. Sulphide and bitumen are abundant. The uranium mineralization is confined to the sandstone cement; it is represented by pitchblende and coffinite. Elevated grades of Zn, Ag, Pb are recorded. The uranium mineralization is also recorded in the basement rocks. Uranium grade ranges from 0.03% to 0.2-0.5% U, up to 19% U. The age of the mineralization varies from 1400 Ma to 200-190 Ma. Prognosticated resources of the Karku deposit are 6, 7 t.t. U (category Р1) and 50 t.t. U (category Р1 + P2) [7]. Riphean troughs also occur in the Belomorian block. Here there are the Tersky Bereg potentially uranium ore district. Speculative resources of the district are 63, 9 t.t. U (category Р3) and 9, 387 t.t. U (category Р2) [5]. The position of the targets of the pre-Vendian unconformity ore type is regionally related to the joint of the plate complex of the Russian plate with the structures of the Baltic Shield and the Baltic-Mezen fault-block zone. The sandstone and gritstone of the Vendian basal horizon overlie Early Proterozoic schist and gneiss intruded by uranium-specialized leucogranite. Anomalous uranium concentrations have been recorded both in the sandstone and gritstone of the basal horizon and in the rocks of the weathering crust. The uranium occurs as pitchblende and uranium oxide; coffinite sometimes appears. The uranium mineralization is accompanied by pyrite, galena, molybdenite. Uranium grade ranges from 0.03% U to 0.1% U for a thickness of 0.5 to 3.5 m. The age of the formation of main uranium concentrates is 350-420 Ma. Younger ages (from 300 to 5 Ma) evidence uranium redistribution till the recent time. This ore type is represented by the Ratnitskoe, Ryabinovskoe, Slavyanka deposits. The metasomatic in black shale ore type is recorded in the Onega depression (Onega uranium ore district). Carbon-bearing terrigenous rocks host the ore. The location of the complex uranium-gold-platinum-palladium-vanadium deposits in space are controlled by linear fold-fault zones (FFZ). Eleven zones were recognized within the Onega depression. These are systems of narrow anticline of NW strike having the length of 30 to 100 km and the width of 2 to 4 km. The ore-bearing intervals that host complex deposits are 2 to 2.5 km long and 500 to 600 m wide. In the fold-fault zones the rocks are intensively albitized, carbonatized, biotitized. By the present, several significant deposits (Srednyaya Padma, Kosmozero, Tsarevka and other deposits) and nine ore-showings of this type were discovered in the Onega depression. The uranium mineralization is represented by brannerite, coffinite, pitchblende. Average uranium grade is 0.15 to 0.25% U (up to several percent for 1-3 m), that of vanadium oxide is 2.5-3.5%. Speculative resources (category P3) are 110 t.t. U [5]. Metasomatic pegmatite ore type (metasomatic) unites numerous group of ore targets located in the rocks of the Archaean basement complex, mainly in the Ladoga-Barents Sea longitudinal fault-block zone; small showings were also identified in granite-gneiss domes of the Svecofennian Megablock. The fault-block zones are characterized by processes of granite formation, silico-alkali and siliceous metasomatosis. Ore-hosting metasomatite is dominated by quartz-microcline, quartz-albitite, and quartz-microcline-albitite metasomatite, microclinite, albitite, pegmatite that form vein bodies concordant with hosting gneiss. They are from several tens of meters to several hundreds of meters long and from several meters to 30 m wide. Ore minerals are dominated by uraninite, thorite, uranothorite. The age of the mineralization ranges from 2700-2200 to 1800-1700 Ma. In the Karelian Megablock, this ore type is represented by the the Gimoly, Khukkaly and other ore showings; speculative resources (category Р2) of the Khukkaly uranium clusters are 60, 0 t.t. U [7]. In the Svecofennian Megablock, this ore type is represented by Khirsimyaki, Khotinoya, Mursula ore showings. The initiation and evolution of Early Proterozoic protoriftogenic and protoplatform depressions was accompanied by the formation of basal horizons represented by conglomerate-gritstone strata with the weathering crust in the base. The quartz-pebble conglomerate ore type is closely associated with these rocks. The location of ore targets is controlled by deep fault zones, where basement rocks are chloritized and carbonatized; gritstone and conglomerate are carbonatized, sericitized, and silicified. The ore mineralization is represented by uraninite, uranium titanite. Gold occurs as nuggets. Uranium grades vary from 0.017% to 0.05% U. Examples of ore targets of this type are the Rigovaraka, Pjajavara, Jangozero and other ore showings. The metasomatic (vein) type unites uranium targets located in micaceous and aluminous gneiss, in the influence zone of leucocratic granite, granodiorite of the Litsa-Araguba Complex. Chloritization, hydromicatization, albitization of host rocks were intensive in the contact zone of the granite with host rocks complicated by NE faults. The uranium mineralization is represented by pitchblende, coffinite, uraninite. Uranium grades range from 0.073-0.0138 to 1.74% U. The absolute age of the uranium mineralization is 400 - 1750-1650 Ma. The Litsevskoe, Beregovoe, Koshkajavr and other ore showings belong to this ore type. The ore targets of the phosphorous-uranium (phosphorous) type are concentrated in the fold-fault Raahe-Ladoga zone of the Svecofennian Megablock. Skarned and intensively brecciated Jatulian dolomite and dolomitized limestone host the ore. They are characterized by elevated phosphorus and organic matter grades. The ore mineralization is represented by uraninite, fluorine-apatite; abundant sulphide and carbonaceous matter are also recorded. Average uranium grade ranges from 0.02-0.05% to 0.044% U (maximum grade is 0.098% U); phosphorous grade is 6% P. The age of the mineralization is 2300±50, 1720-1960 Ma. This ore type is represented by the Mramornaya Gora, Ruskeala, and Kharlu ore showings. An interest in gold-uranium mineralization located in Early Proterozoic structures has increased with the discovery of the Rompas group deposits in Finland. Gold-uranium deposits are located in the Perapohja schist belt with widespread mafic volcanic rocks, black and mica schists, manifestation of intrusive magmatism in the form of late orogenic (1.84-1.80 Ga) and postorogenic (1.79 -1.76 Ga) granitoids, occurrence of abundant quartz-carbonate veins with anomalous gold grades (up to 617 ppm for 6 m Au) [3]. Gold mineralization has clear relationship with uranium mineralization. Gold minerals (native gold, hunchunite, maldonite) fill in cracks in uraninite and form fine disseminations in carbonates in the immediate vicinity of uraninite [3]. Gold mineralization, identified in the Ozernoe ore occurrence (Pana-Kuolayarvi structure, North Karelian), is similar to the Rompas group deposits as concerns its location. Uraninite grains identified in albite-carbonate metasomatite in ore zones of the Ozernoe ore occurrence have a dense system of fine fractures. Veinlets consisting of intergrowths of native gold and altaite occur in the fractures in uraninite [6]. The intrusive carbonatite (uranium-thorium-rare-metallic in carbonatite) type is related to the Kovdor, Vuorijarvi, Sokli and other carbonatite massifs. The mineralization is represented by tantalum-niobium and thorium-uranium ores. Main uranium concentrators are baddeleyite, perovskite, uranothorite. Uranium grades vary from 0.025 to 0.31% U. The age of the deposit is determined at 360 to 420 Ma. The Kovdor deposit, Afrikanda, Vuorijarvi and some other ore showings are among the ore targets of this type. The lignite (black shale) type is related to the Cambrian-Ordovician black dictyonema oil shale widespread in the southern slope of the Baltic Shield. The ore bodies here are stratal. The uranium mineralization is represented by pitchblende, uranium oxide. Uranium grade varies from 0.02 to 0.046 % U. The ore targets of this type are the Krasnoe Selo, Kotlovskoe, Kingiseppskoe deposits. Of the variety of the ore types, the uranium in the pre-Riphean SSU (unconformity) ore type (Karku) and the metasomatic in black shale ore type (Srednyaya Padma and others) are of economic significance. Main distinctive geological, petrographic-lithological, epigenetic, radiogeochemical, geophysical, and other features typical of the ore-bearing areas have been identified based on the pattern analysis of the location of uranium deposits and ore showings. Structural evidence controls the location of ore targets in space. These are deep faults, zones of schistosity, fissuring, brecciation, which are characterized by elevated permeability and promote migration of ore-bearing fluids, including from deep crustal zones into upper horizons. Zones of regional structural-stratigraphic unconformities (SSU) are the most important of them in this region. Petrographic-lithological criteria are uranium-specialized sedimentary and magmatic rocks: leucogranite, alkaline intrusive rocks, carbonatite, carbon-bearing shale, phosphate-bearing sand, bauxite-bearing rocks, etc. These rocks provide to a great degree the geochemical resource during the epigenetic ore formation. Epigenetic evidence includes ore-preparation, ore-accompanying, and ore-hosting epigenetic rock transformations. Hydrothermal-metasomatic conditions favourable for the ore formation are quartz-feldspathic pegmatite and metasomatite accumulating uranium, thorium, and other elements in ore concentrations; greisens which promote uranium transformation into migration state; albite-carbonate-micaceous metasomatite creating environment favourable for ore formation; chlorite-carbonate, albite-hydromicaceous and other metasomatites, which form near-ore and ore-hosting zones. A group of indicators evidencing the processes of ore matter concentration separated from the bedrock occurrence of the ore, is assigned to indirect features. Indicators showing immediately an occurrence of a mineral of prognostic type are direct features. Uranium metallogenic zoning of the Karelian-Kola Area was made based on analysis of manifestation of geological evidence and prospecting indicators of uranium mineralization. Following metallogenic taxa were identified depending on the degree of ore enrichment and manifestation of ore-controlling factors: uranium and potentially uranium structural-metallogenic zones (SMZ) or regions that correspond to structural zones or their parts; uranium and potentially uranium districts corresponding to local structures; uranium clusters and potentially uranium clusters– areas characterized by high ore enrichment and the most intensive manifestation of all controlling factors. The most industrially significant of them are the following. Onega uranium ore district, which covers the Onega depression and the Preonega depression; speculative resources of the Onega district are 100 t.t. U [5]. North - Ladoga SMZ covers the Raahe-Ladoga structural-formational zone and activated margin of the Karelian megablock. Karkulampi uranium ore cluster is established in the northern part of the North - Ladoga SMZ. Karkulampi uranium ore cluster hosts the Karku uranium deposit and a group of ore-showings confined to the pre-Middle Riphean unconformity surface in the NE Pasha-Ladoga graben. Speculative resources (category Р1+P2) of the Karkulampi uranium cluster are 50, 0 t.t. U; prognosticated resources (category Р1) – 6,7 t.t. U [7]. South-Ladoga SMZ is situated in the zone of joint of the East European platform basement and the Vendian-Paleozoic plate complex. Uranium potential of the zone consists of deposits and ore-showings in the basal layers of the Gdov horizon and enormous uranium reserves in the Ordovician dictionemous shale. Neva-Volkhov and Baltic uranium ore districts are established in the South-Ladoga SMZ. Neva-Volkhov district hosts the Slavyanka, Ryabinovskoe and Ratnitskoe uranium deposits. Speculative resources of the Neva-Volkhov uranium district are 520, 5 t.t. U [4, 5]. Dictionemous shale of the Lower Ordovician Pakeror horizon is host rock in the Baltic uranium ore district. The ores are low-grade – 0.01-0.03 % U (up to – 0,07 % U); in addition to uranium, the shale is enriched in molybdenum, vanadium, and other elements. Speculative resources (category Р3) are 600 t.t U [5]. CONCLUSIONS The zones of stractural-stratigraphic unconformities and fold-fault zones have the highest potential for uranium and complex with uranium deposits. The Pasha-Ladoga graben (pre-Riphean unconformity type deposits), Onega trough (fold-fault zones) show considerable promise for uranium mineralization. Areas, hosting the uranium deposits located in the Archean-Early Proterozoic basement and controlled by the superimposed low-temperature alterations also have great potential (Litsa and other areas). The Early Proterozoic structures are promising for the gold and uranium deposits. REFERENCES [1] AFANASIEVA E.N, MIRONOV Yu.B. Uranium metallogeny of the Baltic Shield. Mineral Exploration and Protection. No. 10. 2015, pp. 82-88. [2] AFANASIEVA E.N, MIKHAILOV V.A., KHARLAMOV M.G., Caillat C et al. Uranium in the Baltic Shield: spatial and temporal mineralization emplacement. International conference “Uranium Geochemistry”. Nancy-France, 2003. pp. 27-29 [3] Ferenc Molnar, Harry Oduro, Nick D.J.Cook, Esa Pohjojainen. Association of gold with uraninite and pyrobitumen in the metavulcanic rock hosted hydrothermal Au-U mineralization at Rompas, Perapohia Schist Belt. Miner Deposita, 2016, pp. 681-702. [4] GRUSHEVOY G.V., MIRONOV Yu.B., IVANOVA, T. A. Uranium potential of the Russian platform cover. Regional Geology and Metallogeny. No. 3, 2007, pp. 28-39 [5] KUSHNERENKO V.K. The prospects of North-West region uranium mineralization. The Scientific-Practical Seminar “Problems of supplying Atomic Energy with raw materials”. St. Petersburg, 2004, pp. 32-41. [6] MIRONOV Yu.B., AFANASIEVA E.N. Gold-uranium mineralization in the Kuusamo-Pannajarvi Ore District (Fennoscandian Shield). 13th SCA Biennial Meeting, Proceedings, Volume 5, Nancy-France, 2015, pp. 1843-1845. [7] MIKHAILOV V.A., KLYUEV N.K., TIKHOMIROV L.I. Uranium metallogeny of the Onega-Ladoga uranium province. Regional Geology and Metallogeny. No. 8, 1999, pp. 65-82 [8] MIKHAILOV V.A., AFANASIEVA E.N, MIRONOV Yu.B, KUSHNERENKO V.K. Metallogenic uranium potential of the Northwest region of the Russian Federation. Regional Geology and Metallogeny. No.32, 2007, pp. 20-27.

Speaker: Ms Elena Afanasyeva (Russian Geological Research Institute)

37 Free thermal convection model for formation of the largest uranium field in the Streltsovka caldera (Transbaikalia, Russia)

INTRODUCTION The Streltsovka collapse caldera hosts the largest U ore field associated with volcanism in the world. Its total ore resource of more than 250,000 tU is distributed in 19 deposits. The dominant hypotheses of the origin of these Mo-U deposits, as proposed by exploration geologists, suggest that uranium was transported to the sites of ore deposition by ascending flow of magmatic fluids separated from the deep-seated intracrustal or subcrustal magmatic source [1]. According to this concept, the origin of deposits is only paragenetically related to the volcanic process of caldera formation, since such a distinctive feature of volcanic collapse calderas as the shallow source magma chamber was not taken into consideration in the deep source hypotheses. However, from the standpoint of general ideas about the relationship of uranium ore deposits with continental volcanism, an alternative hypothesis suggesting genetic relationship between caldera volcanism and Mo-U ore formation has been proposed in the Russian scientific literature already more than 40 years ago: “magmatic chambers, at an early stage of their development supplying volcanic material, at the consolidation stage were a source of uranium, fluorine, molybdenum and other associated components of molybdenum-uranium deposits" [2]. The authors of this early caldera- related genetic concept envisaged as paleohydrodynamic conditions of ore formation “thermo-artesian systems of volcanic depressions that determined the conditions for mobilization of dispersed ore components, their migration and position of the sites for discharge of productive hydrotherms" (page 17). In a more modern formulation, the caldera-related concept of the uranium deposits formation implies “the existence of the relatively shallow magmatic chamber inducing convective hydrothermal fluid circulation lasting over a long period of time allowing an important alteration of rocks and thus remobilization of the U from the volcanic rocks” [3, page 136]. In this article we present the summary of preliminary results of numerical simulation of the process of free thermal convection of fluids specifying this hypothesis with reference to the formation conditions of the deposits Streltsovka and Antei. The short information about the simulation results obtained is published in [4]. PROBLEM FORMULATION The Streltsovska deposit is localized in the volcanic-sedimentary cover of the caldera. The Antei deposit is the lower continuation of the central section of the Streltsovka deposit in granitoid rocks of the caldera basement. Thus, structurally conjugate deposits Streltsovka and Antei with the unique total uranium reserves of about 90,000 tons, can be regarded as a product of a single Antei–Streltsovska ore-forming system. According to the geochronological data given in [5] and the results of the thermophysical calculation given in [6], the magma chamber under the caldera must have been fully crystallized by the beginning of ore formation process, but a residual locally elevated geothermal gradient should still be preserved. We developed a 2-D computer simulation model for the Antei–Streltsovska ore-forming system with the geothermal gradient of 60oC/km. The total thickness of the volcanic-sedimentary sequence of the Streltsovka caldera filling is up to 1200 m. The ore bodies of the Streltsovka deposit are localized within it mainly in the depth interval above the caldera bottom to 150-300 m beneath the present-day surface. The morphology of the "blind" ore deposits, the mineral and geochemical zoning of the hydrothermal rock alteration haloes [7] permit to suggest that the upper horizons of the caldera rock section played the role of a hydraulic screen that prevented the outflow of ascending ore-bearing fluids to the caldera paleosurface. With this assumption, we adopted in the simulation model a two-layer structure of the caldera filling with the thickness of the top screening horizon, including its eroded part, equal to 500 m, the thickness of the lower ore-bearing horizon of 1000 m, and the total thickness of the two-horizon volcanic-sedimentary rock sequence equal to 1.5 km. The Streltsovka collapse caldera is borded by a system of ring faults with the vertical displacement of up to 700 m. Based on the results of tectonophysical (thermomechanical) modeling of the collapse caldera structure [8], the caldera ring faults are specified in the model as vertical zones extending from the magma chamber roof to the caldera paleosurface or to the bottom of the screening horizon of the caldera filling. The fault zone of the Antei deposit is represented as a vertical fault extending from the magma chamber roof to the caldera base in the middle between the ring faults. The zone of the Antei fault traces the vertical line of the model symmetry what permits to consider in simulation as a modeling domain only a half of the caldera cross section with the one ring fault and the half width of the Antei fault zone. The distance between the faults in the modeling domain is 5 km, the width of the ring fault zone and the half width of the Antei fault zone are taken to be 100 m, as in the Antei deposit [1]. The boundaries of the consolidated magma chamber are traced by the caldera ring faults. The critical value of the dimensions of the magma chamber at which the caldera ring faults are formed is D/d > 5, where D is the chamber diameter and d is the depth of the chamber roof [8]. Taking the value D ~ 12 km for the Streltsovka caldera, we obtain as an estimate of the depth of the magma chamber under the caldera bottom, d ~ 2.5 km. Taking into account these data and the 1.5 km of the caldera volcanogenic-sedimentary filling, the depth of the magmatic chamber under the paleosurface of the caldera can be estimated approximately equal to 4 km. This estimate corresponds to the results of gravimetric studies, according to which the magmatic chamber was located at a depth of about 5 km [1]. The diameter and vertical thickness of the caldera magma chamber were assumed to be 12 km and 4 km, respectively, what gives for its volume about 450 km3. This estimate is consistent with the extruded volume of rhyolitic ignimbriete estimated to be not less than 50 km3 [9]. According to the estimate obtained in the analysis of US geothermal resources, from 3 km3 to 9 km3 of molten rocks remain in the feeding center for each cubic kilometer of erupted volcanic material in the process of caldera formation [10]. Taking this estimate into account, the volume of 50 km3 of the erupted ignimbrite corresponds to the residual volume of rhyolitic magma in the caldera chamber from 150 km3 to 450 km3, the last value corresponding to the adopted magma chamber vertical thickness of 4 km. The structural scheme with the above geometric parameters of the modeling domain is given in [4, Fig. 1]. RESULTS In the numerical simulation, the structure of the fluid flow and the distribution of temperature in the modeling domain were determined. In addition, the velocity value of the fluid upward flow along the Antei fault at the depth of its top termination in contact with the volcanic-sedimentary rocks of the caldera filling was calculated. To determine the main features of thermoconvective fluid heat and mass transfer, the following simplifying approach was implemented. Based on the results of test calculations, the basic model was identified, after which we examined what influence exert variations in permeability values of the main structural elements of the model on calculation results. In the basic model, the following permeability values were adopted: for the caldera basement rocks 10-15 m2, for the ore-bearing lower horizon of the caldera filling 10-14 m2, for the top screening horizon 10-16 m2, for the ring fault 10-14 m2, for the Antei fault 10-13 m2. The simulated fluid flow self-organizes into a convective cell with a descending branch along the ring fault and an ascending branch along the Antei fault. The heat input by fluids of the ascending branch leads to an increase in temperature in the range of 400-340°C in the zone of the Antei fault and in the range of 340-200°C in the caldera filling rocks. The calculated value of the fluid flow velocity along the Antei fault is 7.5 m/year. The descending branch of the fluid convection cell penetrates deeply into the caldera basement rocks, thus providing the conditions for mobilization of uranium from both the host granitoids in the caldera basement and the consolidated magma chamber rocks. The representative pattern of the fluid flow configuration in the basic model is given in [4, Fig. 2]. The numerical simulation experiments with variation in the permeability values of the structural elements of the basic model were carried out for checking what influence exert permeability contrast between the caldera ore-bearing and screening horizons and the changes in permeability values of the ring fault zone and of the Antei fault zone on fluid circulation. The results obtained permit to conclude that the favorable conditions for ore formation in the Antei–Streltsovka thermoconvective system could be realized only under certain and narrow range of permeability values of its main structural elements. This limiting factor, as the authors believe, is one of the distinctive paleohydrodynamic conditions that predetermined the uniqueness, among the volcanic-related uranium deposits, of the exceptional uranium reserves of the Streltsovka ore field. DISCUSSION AND CONCLUSIONS The potential ore-producing capacity of the Antei–Streltsovka thermoconvective system can be estimated from data on rate of ore-forming solutions discharge from the Antey fault zone into the volcanic-sedimentary sequence of the caldera filling. With the calculated value of fluids flow velocity along the Antei fault 7.5 m/year, its along-strike extent of about 1000 m [11] and the fault zone thickness of 100 m, the rate of fluids discharge from the fault zone to the caldera filling is 7.5 105 m3/year. The equilibrium concentration of the ore-forming fluids, as estimated by the results of thermodynamic modeling, in the process of the medium-temperature leaching of uranium from leucocratic rocks is within the range between 1·10-6 and 2·10-5 mol U [12]. With this range of uranium concentration, the time period needed for the formation of total uranium reserves about 90,000 t U of the Streltsovska and Antei deposits is from 500,000 to 25,000 years, respectively. At exceptionally high uranium concentration of 1·10-4 mol U [13], established in the fluid inclusions of Canadian unconformity-related uranium deposits, the assessment of the duration of the ore deposition process is reduced to 5000 years. A distinctive feature of thermoconvective systems with a closed circuit of convective circulation is the absence of restrictions on the amount of fluids. However, since ore loading of fluids should be extracted from the enclosing rocks, the limitation on the resources of the ore material within the contour of the convective cell is maintained. As noted above, the convective circulation of fluids penetrates deeply into the rocks of the Streltsovka caldera basement, thus providing the conditions for mobilization of uranium from the both available sources: the host granitoids and the anomalously enriched rocks of the consolidated magma chamber. According to the data on differences in the uranium content between the rhyolite magma [14] and in the geochemically similar granite massifs in the Southern Transbaikal Region [15], the possible scale of uranium extraction from the rocks of the consolidated magma chamber by the thermoconvective circulation of postmagmatic fluids can be estimated at U content of ~ 13-14 g/t or, at a granite density of 2.6 t/m3, as ~ 35,000 t/km3. Assuming that the volume of the magma chamber under the caldera was 450 km3, an estimate of the total amount of uranium mobilization from the consolidated magma chamber will be ~ 16 million tons of uranium, which is approximately 60 times greater than the total reserves of uranium deposits of the Streltsovka ore field. This huge uranium source can be summed with uranium leached from the caldera basement the potential amount of which, as evaluted in [14], can also exceed several times the uranium resources of the Streltsovka ore field. Thus, the proposed thermoconvective model of the Antei-Streltsovka ore-forming system ensures the formation of the uniquely large uranium reserves without restrictions both on the required amount of the ore-transporting fluids and on the amount of the accessible source of uranium for its leaching, transport and deposition by fluids convection. According to the general geological-genetic classification, such a model of the ore-forming system is close to the conceptual models of ore-forming systems of epithermal deposits. This work was supported by the Federal Agency for Scientific Organizations of Russia under project 0136-2018-0017 of IGEM RAS. REFERENCES [1] ISHUKOVA L.P., et al., Uranium Deposits of Strel’tsovska Ore Field in Transbaikal Region, (NAUMOV S.S., ed.), Geologorazvedka, Irkutsk, (2007) (in Russian). [2] LAVEROV N.P., CHERNYSHEV I.V., “Temporal connection of uranium deposits with continental volcanism”. In: Geochronology and Problems of Ore Formation, Nauka, Moscow (1977), pp. 5-18 (in Russian). [3] CUNEY M., KYSER T.K., “Hydrothermal Uranium Deposits Related to Igneous Rocks”, In: Recent and Not-So-Recent Developments in Uranium Deposits and Implications for Exploration. Mineralogical Association of Canada Short Course Series 39, (2008), pp. 117-160. [4 ] PEK A.A., et al., “Possible Role of Fluids Free Thermal Convection Process in Formation of Uranium Deposits in the Streltsovka Ore Field”, Doklady Earth Sciences, vol. 474, Part 1, (2017), pp. 583-586. [5] CHERNYSHEV I.V., GOLUBEV V.N., “The Streltsovskoe Deposit, Eastern Transbaikalia: Isotope Dating of Mineralization in Russia’s Largest Uranium Deposit”, Geochimiya, nu. 10, (1996), pp. 924-937 (in Russian). [6] MALKOVSKY V.I., et al., “Estimation of the time of magma chamber solidification beneath the Streltsovka caldera and its effect on the nonstationary temperature distribution in the upper crust, the Eastern Transbaikal region, Russia”, Geology of Ore Deposits. vol. 50, nu. 3 (2008), pp. 192-198. [7] ANDREEVA O.V., GOLOVIN V.A., “Metasomatic processes at uranium deposists of Tulukuev caldera, Eastern Transbaikal region, Russia”, Geology of Ore Deposits, vol. 40, nu. 3 (1998), pp. 184-196. [8] GUILLOU-FROTTIER L., et al., “Genetic links between ash-flow calderas and associated ore deposits as revealed by large-scale thermo-mechanical modeling “, Journal of Volcanology and Geothermal Research, vol. 102, issues 3-4 (2000), pp. 339-361. [9] SHATKOV G.A., “Krasnokamensky type of uranium deposits as the most important reserve of industrial mineralization of the Streltsovka ore cluster”, Regional geology and metallogeny, nu. 67 (2017), pp. 88-95. [10] WOHLETZ K., HEIKEN G. Volcanology and Geothermal Energy. Berkeley: University of California Press, (1992), 415 p. [11] PETROV V.A., et al., “Tectonophysics of hydrothermal ore formation: An example of the Antei Mo-U deposit, Transbaikalia”, Geology of Ore Deposits, vol. 57, nu. 4 (2015), pp. 292-312. [12] BORISOV M.V., Geochemical and thermodynamic models of the vein hydrothermal ore formation, Nauchny Mir, Moscow (2000), 360 p. (in Russian). [13] RICHARD A., et al., “Giant uranium deposits formed from exceptionally uranium-rich acidic brines”, Nature Geoscience, vol. 5 (2012), pp.142-146. [14] CHABIRON F., et al., “Possible uranium sources for the largest uranium district associated with volcanism: the Streltsovka caldera (Transbaikalia, Russia)”, Mineralium Deposita, vol. 38 (2003), pp. 127–140. [15] PETROV V.A., et al., “Tectono-Magmatic Cycles and Geodynamic Settings of Ore-bearing System Formation in the Southern Cis-Argun Region”, Geology of Ore Deposits”, vol. 59, nu. 6 (2017), pp. 445-469.

Speaker: Prof. Vladislav Petrov (IGEM Russian Academy of Sciences)

38 EXPLORATION AND RESOURCE DEVELOPMENT OF URANIUM MINERALIZATION IN CENTRAL JORDAN

INTRODUCTION Uranium mineralisation has been known within the central areas of the Hashemite Kingdom of Jordan for a long time [1], however uranium resources were only estimated in 2014 [2]. The exploration success has become possible because of detailed geological studies that has allowed to better understand the geological control of uranium mineralisation in central Jordan. Based on these studies the exploration model was revised and implemented by Jordanian Uranium Mining Company (JUMCO) for delineating mineralisation and estimated resources. REGIONAL GEOLOGICAL CONTROL Most of Jordan’s territory is covered by platform sedimentary rocks of Cretaceous and Paleogene age. Uranium mineralisation was discovered within the platform cover where it is confined mainly to the Upper Cretaceous rocks, in particular the MCM (Muwaqqar Chalk Marl) formation. Uranium minerals, found in the weakly lithified friable sediments of the MCM formation are represented mainly by uranium vanadates colloquially termed carnotite [2]. Uranium mineralisation is distributed as fine-grained disseminations forming areas of variable size and shape that have impregnated the host sedimentary rocks and also coating the surfaces of the joints and fractures. The faults possibly also played a role in distribution of the uranium mineralisation in central Jordan where higher grade mineralisation and associated gamma anomalies are broadly coincident with the location of regional faults, mainly the East-West and North West–South East striking splays of the Dead Sea Transform fault. PYROMETAMORPHISM Unique feature of the surficial uranium mineralisation in central Jordan is its close spatial relationship with pyrometamorphic marbles that are hosted by unmetamorphosed marls, chalks and limestones. The marbles are varicoloured, commonly brown, greenish, reddish, white and locally black. They are cut by hydrothermal veins and have experienced different degrees of low temperature alterations. A unique feature of these rocks is the widespread distribution of high- and ultra-high temperature (up to 1500°C) low-pressure metamorphic mineral assemblages including spurrite, wollastonite, ellastadite, diopside and garnet [3-5]. The contacts of marble with the unmetamorphosed host sequence are sharp, although contact outlines are often irregular. The formation of marbles in central Jordan is commonly explained by pyrometamorphism, either caused by the burning of bituminous marls [5] or alternatively by the combustion of deep reservoirs of hydrocarbon gases relating to mud volcanoes [3-4]. Another unique geological feature of the uranium deposits in Jordan is occurrences of the exotic paramagmatic dykes that cut pyrometamorphic marbles. These dykes were identified in exploration trenches and marble quarries in central Jordan. These are similar to the dykes found in the in Israel and Palestine, where they also associate with high-temperature metamorphic rocks [3]. The dykes are interpreted as paralavas that have been formed as a result of the host rocks melting during high-temperature combustion metamorphism [2-4]. Dating of these pyrometamorphic rocks has identified several episodes of combustion metamorphism that have occurred in Miocene (~16 Ma), Pliocene (~ 3 Ma) and Pleistocene (1.7 – 1.0 Ma) [6]. These ages broadly coincide with the age of mafic magmatism that occurred in Jordan during the Miocene (23.8 - 21.1 and 12.05 - 8.08 Ma) and Pleistocene (3.2 - 1.5 Ma) [7-8], suggesting that this basaltic magmatism could have triggered the rapid combustion of hydrocarbons, or at least that these processes are part of the same tectono-magmatic event. SUPERGENE PROCESSES Within the MCM formation the uranium mineralisation is hosted by near-surface weathered chalks and marls and concentrated in a narrow layer, approximately 4.5m thick, distributed close to the topographic surface. Vertical profile of uranium distribution in central Jordan was studied in high details using 2188 trenches and 5691 drill holes [2]. It was noted [2] that the degree of weathering varies from complete alteration, when rocks have been converted to saprolite, to mildly weathered sedimentary rocks and the highest uranium concentrations were found located along the contact between saprolite and mildly weathered/fresh rocks. Near surface distribution of uranium mineralisation which was characterized by highly variable degree of isotopic disequilibrium has required using of exploration trenches for obtaining representative samples and estimating uranium resources [9]. Mapping of the trench walls have shown that uranium mineralisation is not controlled by phosphorite layers. SUMMARY AND CONCLUSIONS In general, the uranium mineralisation that is hosted by the weathered chalk and marl of the MCM formation in central Jordan has many common characteristics with the conventional surficial-type uranium mineralisation [10]. However, a close spatial relationship of uranium in central Jordan with the pyrometamorphic rocks suggests that this is a special type of surficial uranium mineralisation which has resulted from the interplay of the different processes, where combustion metamorphism has played a very important role in facilitating leaching of uranium from the host rocks. The liberated uranium was eventually redistributed by supergene processes towards the surface, where uranium minerals were precipitated along the contact between saprolite and fresh to weakly weathered rocks. This mineralization should not be confused with synsedimentary accumulations of uranium in the phosphorite beds which also present in Jordan [2]. REFERENCES [1] BENDER, F. (1975) Geology of the Arabian Peninsula, Jordan: US Geological Survey, Professional Paper 560-1, p.1-36. [2] ABZALOV, M.Z., et al. (2015) Geology and metallogeny of Jordanian uranium deposits: Applied Earth Science, 124, p.63-77. [3] VAPNIK, Ye. et al. (2007) Paralavas in a combustion metamorphic complex, Hatrurim basin, Israel, in Geology of coal fires: Case studies from around the world (ed. G.B.Stracher): Geological Society of America, GSA Reviews in Engineering Geology, XVIII, p.133–153. [4] SOKOL, E., et al. (2010) Combustion metamorphism in the Nabi Musa dome: new implications for a mud volcanic origin of the Mottled Zone, Dead Sea area: Basin Research, 22, p.414–438. [5] KHOURY et al. (2014) Mineralogy and origin of surficial uranium deposits hosted in travertine and calcrete from central Jordan: Applied Geochemistry, 43, p.49–65 [6] GUR, D., et al. (1995) Ar40/Ar39 dating of combustion metamorphism: Chem. Geol., 122, p.171–184. [7] STEINZ, G., and BARTOV, Y. (1991) The Miocene – Pleistocene history of Dead Sea segment of the rift in light of K-Ar ages basalts: Isr. Journal of Earth Sciences, 40, p.199-208. [8] IBRAHIM, K.M., et al (2003) Phases of activity and geochemistry of basaltic dike systems in northeast Jordan parallel to the Red Sea: Journal of Asian Sciences, 21, p. 467-472. [9] ABZALOV, M. (2016) Applied Mining Geology. Modern Approaches in Solid Earth Sciences, 12, Springer, Berlin, 448p. [10] DAHLKAMP, F.J. (1993) Geology of the uranium deposits, Springer, Berlin, 460p.

Speaker: Dr Marat Abzalov (MASSA geoservices)

Health, Safety, Environment and Social Responsibility

Conveners: Mr Harikrishnan Tulsidas (UNECE), Prof. Jim Hendry (University of Saskatchewan)

39 AN INTERNATIONALLY STANDARDIZED REPORTING TOOL TO UNDERSTAND THE SUSTAINABLE DEVELOPMENT PERFORMANCE OF URANIUM MINING AND PROCESSING SITES

The World Nuclear Association has developed an internationally standardized reporting tool to understand the sustainable development performance of uranium mining and processing sites (referred to as the ‘Checklist’). The goal is to achieve widespread agreement on a list of topics and indicators (for example, environment, health and safety, corporate social responsibility) for common use in demonstrating producers’ adherence to sustainable development performance. Accompanying guidelines have also been prepared to support its use and completion. The Checklist is designed to draw on producers’ existing reporting, supplemented by additional information required to achieve comprehensive supply chain risk management. The Checklist has been developed to align with the Association’s policy document ‘Sustaining Global Best Practices in Uranium Mining and Processing: Principles for Managing Radiation, Health and Safety, and Waste and the Environment’. It has been prepared in cooperation with experts from some of the Association’s member organizations. It is anticipated that the Checklist will be reviewed over the next year to ensure that it accounts for any recent developments and feedback from user testing.

Speaker: Mr Frank Harris (Rio Tinto Uranium)

40 URANIUM, THE ENVIRONMENT AND SUSTAINABLE DEVELOPMENT: LESSONS FROM NAMIBIA

INTRODUCTION Namibia has a well-established uranium exploration and mining sector, and proudly looks back onto four decades of uranium mining at the Rössing Uranium Mine. The Langer Heinrich Mine has produced uranium for a decade, and another milestone was reached in 2016 with the opening up of the Husab Mine, set to become one of the largest uranium mines in the world. Namibia also has a number of known deposits at an advanced exploration or early development stage, just awaiting an improvement in the uranium market to become active contributors to the Namibian economy. Furthermore, active exploration is ongoing, and received a boost when a moratorium on nuclear fuel licenses was lifted by the Ministry of Mines and Energy last year. The Namibian uranium sector has an excellent record of cooperation with government, including active collaboration on environmental issues. The Ministry of Mines and Energy’s Strategic Environmental Management Plan, which is assessing the environmental performance of uranium exploration and mining activities, is implemented with active participation of the industry. This is an important aspect, as the industry is operating in a sensitive arid environment. BACKGROUND Uranium Mining in Namibia is carried out in the Erongo Region in the central western part of the country. This region is characterized by its aridity, vast desert landscapes, scenic beauty, high biodiversity and endemism and heritage resources. It has the second largest economy of all the Namibian regions, and mining plays a very important part in this economy. Walvis Bay and Swakopmund are amongst Namibia’s five largest towns, at the same time, large parts of the Erongo Region, especially along the coast, are under active conservation in the form of national parks [1]. The Namibian uranium deposits belong to two main types, namely primary uranium mineralisation in light-coloured granite (alaskite) (Rössing, Husab), and secondary uranium mineralisation in calcrete (Langer Heinrich). Secondary mineralisation is the result of weathering of rocks with primary mineralisation. The predominant uranium mineral in alaskite is uraninite [UO2], but betafite [U(Nb,Ti)2O6(OH)] can be a major mineral phase in some places. Secondary uranium deposits are found in calcrete which formed in paleo-valleys of ancient rivers flowing westwards from the Great Escarpment some 88 to 25 million years ago. The main uranium mineral in calcrete is carnotite [K2(UO2)2(VO4)2 x 3H2O]. It occurs in cracks and as a coating on sediment grains in the calcretised fluvial channels. Both mineralisation types are amenable to open cast mining methods [2]. The Namibian uranium exploration and mining activities occur in the ecologically sensitive central Namib Desert, and in an area partly belonging to the Namib-Naukluft and Dorob National Parks. Mining is vital for the growth of the Namibian economy, and the country must therefore reconcile development objectives and mineral exploitation with environmental protection for its long-term socio-economic growth and stability. An integrated approach is required so that development of one resource will not jeopardize the potential of another. In order to support and facilitate such an integrated approach, the Namibian Uranium Association was formed by the industry in 2013. THE NAMIBIAN URANIUM ASSOCIATION (NUA) Members of the NUA include all Namibian uranium mining operations, Namibia’s leading uranium exploration companies, and associated contractors. NUA is the leading point of contact for government, media, stakeholders, the general public and anybody interested in the position and policies of the Namibian uranium industry. Members of NUA accept product stewardship as a pillar that supports the overarching concept of Sustainable Development. In this way the Association makes a lasting contribution to the socio-economic development of Namibia while at the same time minimizing the environmental footprint and promoting the Namibian uranium brand [2]. Product stewardship ensures that the industry focus on economic development, environmental impact management and social responsibilities by building partnerships throughout the uranium life cycle to ensure that production, use and disposal are consistent with the global sustainable development goals and global best practices. Cumulative socio-economic and biophysical impacts of mining cannot be successfully addressed by one company only, and unsustainable practices by one company can impact negatively on the entire industry. Proactive cooperation in health, environment, radiation safety and security and community issues companies is therefore a necessity. THE NAMIBIAN URANIUM INSTITUTE (NUI) As part of its stewardship mission, NUA has established the NUI. NUI is guided by respected independent scientists who serve on NUA’s Scientific Committee. The main purpose of NUI is to act as a hub for the uranium industry in Namibia, and promote knowledge and capacity building in specialized skills in environmental management, radiation safety and health. NUI therefore provides an opportunity for NUA members to work together to improve safety and health performance through the implementation of world-class leading best practices an. As such, NUI is working closely with the Namibian Government and with the Namibian University of Science and Technology. NUI’s activities are guided by a Sustainable Development (SD) Committee, which was formed to assist the uranium industry in safeguarding its reputation as a safe and responsible commerce. The committee was also established to assist NUI in promoting best practices with regard to health, environment, and radiation safety and security; and in its oversight responsibilities by reviewing, monitoring, and advising NUI and NUA from a uranium industry-wide perspective. At policy level, the SD Committee reviews and guides NUA policy formulation to ensure that it incorporates principles of sustainable development early in the process. These principles include public participation, inter-generational equity, sustainable use of natural resources and public access to information. The SD Committee’s duties include the assessment and monitoring of all risks associated with health, environment and radiation safety and security matters of the uranium industry; assistance with the development and implementation of internal compliance and control systems and procedures to manage risks; coordination of assessment and monitoring of the effectiveness of controls instituted; and the review and making of recommendations to NUI and NUA in relation to risk management. In order to achieve this, the SD Committee has also appointed four working groups, namely the Services Working Group, the Radiation Safety Working Group, the Water and Air Quality Working Group, and the Swakop River Farmer’s Working Group. NUI’s Communication Technical Advisory Committee (C-TAC) was established in order to recommend to NUI the overall strategic direction of the institute’s communications. It is an advisory committee tasked to advise and assist NUA through NUI in carrying out its mission and strategic plan by developing and monitoring communication protocols, initiatives and policies, and formulating and implementing a stakeholder engagement and communication strategy for the uranium mining industry in Namibia. TRAINING An integral part of NUI’s activities is teaching in order to improve knowledge, safety and the implementation of best practises in the field of occupational health, environmental management and radiation safety. As part of its stewardship mission, NUI has developed partnerships with various scientists to develop standards, guidelines and training courses to cater for the needs of the uranium industry. NUI is officially registered with the Ministry of Labour and Social Welfare as an Approved Inspection Authority in terms of the Regulations made under Schedule 1(2) of the Labour Act, 2007 (Act 11 of 2007), with competencies in the fields of health, environment and radiation safety and security [2]. THE STRATEGIC ENVIRONMENTAL MANAGEMENT PLAN Some 10 years ago, when prices for fuel for civil nuclear reactors were rising fast, resulting in a worldwide boom in uranium exploration and mining, the Namibian uranium industry recommended to the Namibian government to undertake a Strategic Environmental Assessment (SEA) of the Namibian uranium province, where exploration for uranium was also expanding rapidly. Subsequently, such an assessment was carried out by the Geological Survey of Namibia (GSN), Ministry of Mines and Energy (MME), and provided vision and generated a culture of cooperation between the uranium mining industry, government and the public. A Strategic Environmental Management Plan (SEMP) was developed as a result of the SEA, and has been implemented by the Geological Survey of Namibia in cooperation with the Namibian uranium industry since 2011. It is an over-arching framework and roadmap addressing the cumulative impacts of existing and potential developments and the extent to which uranium mining is impacting the central Namib. The SEMP has 12 themes, the so-called Environmental Quality Objectives (EQOs), each articulating a specific goal, providing context, setting standards and having a number of key indicators that are monitored. These themes include socio-economic development, employment, infrastructure, water, air quality, health, effect on tourism, ecological integrity, education, governance, heritage and future, and mine closure and future land use [3]. Implementation of the SEMP is guided by a steering committee that is chaired by GSN (MME). Members include the Department of Water Affairs in the Ministry of Agriculture, Water and Forestry, the Ministry of Health and Social Services, which includes the National Radiation Protection Authority, the Ministry of Environment and Tourism, the Gobabeb Research and Training Centre’s Namibia Ecological Restoration and Monitoring Unit, the Namibian Coast Conservation and Management Project and NUA. NUI is actively contributing to the compilation of the Annual SEMP Reports. A great achievement of the SEMP to date is the fact that the Annual SEMP Reports have established a long-term monitoring and decision-making tool through which potential impacts are highlighted so that measures can be developed to avoid unnecessary impacts or to mitigate unavoidable impacts. The aim of the SEMP process is to increase the commitment of key government institutions, the uranium industry and NGOs to undertaken whatever actions will take the region towards its desired future state of the SEMP. SUSTAINABLE DEVELOPMENT In Namibia, sustainable development is a constitutional imperative. In Article 95, the Namibian Constitution obliges the state to actively promote and maintain the welfare of the people by adopting policies that are aimed at the maintenance of ecosystems, essential ecological processes and biological diversity of Namibia and utilisation of living natural resources on a sustainable basis for the benefits of all Namibians both present and future. Hence there is a duty to ensure that Namibia’s environment remains healthy and productive and that Namibians use their natural resources in sustainable and productive ways to combat poverty and improve people’s quality of life. Through the implementation of its stewardship principles, which ensure a focus on economic development, environmental best practice and social responsibility, NUA is actively involved in the sustainable development of Namibia. In September 2015, 17 Global Sustainable Development Goals (SDGs) were adopted in New York by world leaders under the United Nations 2030 Agenda for Sustainable Development. Even before this event, the African Union has formulated a Consolidated African Position (CAP) in support of the United Nations 2030 Agenda for Sustainable Development. In addition, the African Union Agenda 2063 is a global strategy to optimize the use of Africa’s resources for the benefit of all Africans. The domestication of the African Union Agenda 2063 and the SDGs was launched in Windhoek in June 2016 by the Hon Deputy Prime Minister and the Director General of the National Planning Commission. The Namibian National Development Plan 5 has Sustainable Development as the overarching theme, and alignment of the AU Agenda 2063 and the SDGs with NDP 5 is under way. NUA’s contributions towards Sustainable Development and the work of NUI’s Sustainable Development Committee are therefore fully in line with Government policies. NUI was actively involved in the drafting of NDP5 at National Planning Commission level and is also represented on the Namibian government’s Sustainable Development Advisory Council. The mining industry has the potential to contribute positively to all 17 SDGs. The SDGs have 90 indicators, and an analysis showed that 53 are already met by the uranium industry in Namibia. These fall under SDG 1 (No poverty), SDG 2 (No Hunger), SDG 3 (Good Health), SDG 4 (Quality Education), SDG 5 (Gender Equality), SDG 6 (Clean Water and Sanitation), SDG 7 (Good Jobs and Economic Growth), SDG 8 (Renewable, Affordable, Clean Energy), SDG 9 (Innovation and Infrastructure), SDG 10 (Reduced Inequalities), SDG 11 (Sustainable Cities and Communities), SDG 12 (Responsible Consumption), SDG 13 (Climate Action), SDG 15 (Life on Land), SDG 16 (Peace and Justice), and SDG 17 (Partnerships for the Goals). REFERENCES [1] SCHNEIDER, G.I.C., The Namibian Uranium Association, the environment, and sustainable development, SAIMM Uranium 2017 International Conference, Symposium Series 195. [2] Namibian Uranium Association, Annual Review 2017. [3] Ministry of Mines and Energy, Strategic Environmental Assessment for the central Namib Uranium Rush, Southern African Institute for Environmental Assessment.

Speaker: Dr Gabi Schneider (Namibian Uranium Institute)

41 PERSPECTIVES ON SOCIAL COMMUNICATION IN THE BRAZILIAN NUCLEAR LICENSING PROCESS AND CHALLENGES ON STAKEHOLDER ENGAGEMENT: CAETITÉ URANIUM MINING CASE

INTRODUCTION According to the Brazilian system of laws and regulations, uranium and thorium mining and milling facilities are considered as nuclear installations, being subject to both licensing process: (i) a Nuclear Licensing Process performed by the Brazilian Nuclear Energy Commission – CNEN and (ii) an Environmental Licensing Process performed by the Brazilian Institute for the Environment and Renewable Natural Resources – IBAMA, with the participation of state and local environmental agencies. The nuclear licensing process is individualized in steps (starting with siting up to the decommissioning phase), encompassing the submission of reports/documents and, in case of subsequent approval, the emission of specific authorizations for each step. Proactive stakeholder’s engagement activities are taking into account, such as the performance of Public Hearings, foreseen by law just within the environmental licensing. In the nuclear licensing process, the main activities of the regulatory body are the safety assessments of the applicant documentation and regulatory inspections. It is worth mentioning that the nuclear regulation establishes that no nuclear installation shall operate without a license, as well the necessary review and assessment process including the specification of the documentation to be submitted to nuclear regulatory body at each phase of licensing. Additionally, there is a system of regulatory inspections and the corresponding enforcement mechanisms that include the authority to modify, suspend or revoke the license. Nuclear installations shall also have an authorized Radiation Protection Supervisor certified by the nuclear regulatory body. In the town of Caetité (State of Bahia) is located the only uranium mine in operation in Brazil named Uranium Concentrate Unit (URA), which activities are developed by the Brazilian state-owned company named Brazilian Nuclear Industries (INB), including the development of environmental and radiological protection monitoring programs [1]. During the uranium mining and milling operations some events had occurred and their impacts on social media reflect the concerns, demands and challenges surrounding the perspectives on social communication and accountability. Also, in the event presented in this paper, is possible to perceive that despite the environmental monitoring programme conducted by the operator did not demonstrate any contamination, the local community did not yet feel confident about the operation of the uranium mining facility. DESCRIPTION NUCLEAR REGULATORY BODY ACTIONS ON COMMUNICATION AND TRANSPARENCY In the last decades, Brazil has been developing initial actions in terms of opening and transparency of information, using as framework the 1988 Constitution, however, even before a legal mechanism concerning Access Information, some measures were taken in the way to facilitate the citizen access to public data: [2] • Files Law (nº 8.159, 1991); • Habeas Data Law (nº 9.504, 1997); • Fiscal Responsibility Law (Complementary Law nº 101, 2000) – financial data; • Transparency Portal - activated in 2004 – made available on the internet the budget and expenditure data of the Executive • Transparency Portal for the States and Towns (2006); • Agreements System of the Federal Government (SINCOV – 2007); • Providers Registration System (SICAF – 2008). In 2003, was enacted in Brazil the Law nº 10.650 [3], concerning, specifically, the public access to environmental information data that are available in public and member institutions of the National System of the Environment (SISNAMA) [4], however, the nuclear licensing information data was not included. A significant progress has been made in recent years with the enactment of the “Information Access Law” nº 12.527/11 [5] and its regulation by the Decree 7.724 [6], where all the public institutions must provide specific information in their websites and, also, must create the “Information Service to Citizens” (ISC), in order to answer any questions proposed by the general public, promoting a significant change in the conception of public information and in the transparency culture [2]. Similarly, legal advances were also made in relation to the rights to information and the availability and publishing of open data, establishing a new concept of open data policy for governmental institutions (Normative Instruction nº 4/2012, Decrees nº 8.638/2016 and nº 8.777/2016) [7]. Despite the majority of the documentation related to the nuclear licensing process are considered as “classified” [8], the nuclear regulatory body provides information concerning environmental, effluent and waste monitoring, inspections, reports, denouncements, among others, when requested by the “Information Service to Citizens” and “Talk to Us, officially or by “Courts”. CAETITÉ URANIUM MINE CASE Some events occurred in Caetité uranium mining and milling site, and their impacts on social media reflect the concerns and challenges surrounding the perspectives on social communication and accountability. The historical occurrence of denouncements by non-governmental organizations (NGOs) and the population, and their publication in regional and national media, allows the development of factors that may lead to stigmatization of the inhabitants that live close to the uranium mining facility, public manifestations, increasing of denouncements and rejection of mining activities. The last event occurred in August of 2015 and was related to a denouncement published in a national newspaper whose the headline was “Uranium contaminates water in Bahia” [9], which reported a finding of uranium, iron and manganese contents above the limit of Potability Level (Resolution nº 396 CONAMA/2008 and Order MS nº 2914/2011) in groundwater samples. On that specific event, a local farmer requested for INB/URA to sample and carry out chemical analysis of a groundwater well that was located inside of his own property. A first sample was collected by the operator in October of 2014 and a second one in March of 2015, however, the results exhibiting uranium, iron and manganese contents above the limit of Potability Level were just officially informed to the local farmer and the Mayor in May of 2015, seven months after the first sampling. In the case of that specific event, despite the environmental monitoring program conducted by the operator did not demonstrate any contamination related with the mining operation in the locality, the location of the well is outside of the mining watershed and the information by the operator that the uranium concentration were linked to natural processes (region with 38 uranium anomalies) [10, 11], the environmental regulatory body determined the immediate suspension of water consumption in the wells of the region [12], and, specially, the local community did not feel confident about the operation of this uranium mining facility. DISCUSSION AND CONCLUSION The regulatory licensing process comprises a formal authorization related to specific legislative and regulatory requirements and procedural conditions that are usually clearly defined in scope and received at a specific time by a recognized government authority, although, requires sustained investment by proponents to acquire and maintain social capital within the context of trust-based relationships. In view of past events, the concerns and demands in terms of stakeholder engagement and social communication, some aspects shall be included in further discussions, mainly about: • credibility (as a social license perspective) is a continuous process of engagement and effort; • a “License” does not mean an “universal” acceptance by the community thus the opposition and questioning shall be used as experiences of improvement and new considerations inside a licensing process management; • despite the mining activities are implementing their Social Responsibility and Communication Programs, it is necessary a continuous evaluation of the community engagement, a real consideration of the stakeholder’s concerns, as well the appreciation of using approaches of social cartography to define local groups of stakeholders; • consider that public perception of radiation risks has shown that scientific arguments are not enough to address social and political concerns; • consider a social licensing perspective in all of the mining life cycle – from exploration to exploitation and decommissioning; • development of strategies to avoid lack in communication of activities and events in the operation unit by the operator – improvement of transparency; • applying effective communication in term of providing timely and complete information, as well, presenting information, also, by the stakeholder’s point of view and interest; Although the nuclear regulatory body has advanced in the communication and transparency culture, in searching of social legitimacy, it still presents a reactive behavior, often in response to judicial demands. Therefore, it is necessary the development and/or improvement of: • proactive policy, improving the communication in terms of availability of information; • coordination of programmes among the different regulatory authorities, including, also, the development of a forum for critical situations. Coordination among regulators is important to avoid duplication of efforts, omission and gaps or overlaps of competences; • implementation of effective communication pathways among regulatory agencies and community; • development of legal basis as well programs ensuring stakeholder engagement, transparency and communication, including: o Planning (objective & strategy); o Implementing; o Evaluation and adjusting Even though the development of actions in terms of information opening, it is essential the continuous evaluation and promotion of further efforts that address discussions about the development of transparency culture, enhancing of credibility and public confidence, timely and effective engagement and communication, among other aspects that will allow the construction of social participation practices as regular part of the decision-making process and effective stakeholder engagement and social communication approaches. REFERENCES [1] NUCLEAR INDUSTRIES OF BRAZIL (INB), official website. Available in: http://www.inb.gov.br/en-us/INB/Where-we-are/Caetit%C3%A9>. Access in: 26 February of 2018. [2] LIMA, C. H. P. et al. “Do sigilo à transparência: avaliação do primeiro ano da lei de acesso à informação em uma autarquia federal”, X Congresso Nacional de Excelência em Gestão, 2014. [3] LAW Nº 10.650 - Public access to data and information in the organisms and entities that are members of SISNAMA. Presidência da República, Casa Civil, Subchefia para Assuntos Jurídicos, 16 April of 2003. Available in: http://www.planalto.gov.br/ccivil_03/Leis/2003/L10.650.htm>. Access in: 26 February of 2018. [4] NATIONAL SYSTEM OF THE ENVIRONMENT (SISNAMA), official website. Available in: http://www.mma.gov.br/port/conama//estr1.cfm>. Access in: 26 February of 2018. [5] LAW Nº 12.527 - Regulates the access to information provided in item XXXIII of art. 5, item II of § 3 of art. 37 and in § 2 of art. 216 of the Federal Constitution; amends Law Nº. 8,112 of December 11, 1990; revokes Law No. 11,111, of May 5, 2005, and provisions of Law No. 8.159, of January 8, 1991; and makes other arrangements. Presidência da República, Casa Civil, Subchefia para Assuntos Jurídicos, 18 November of 2011. Available in: http://www.planalto.gov.br/ccivil_03/_ato2011-2014/2011/lei/l12527.htm>. Access in: 26 February of 2018. [6] DECREE Nº 7724 - Regulates the Law nº 12.527/11. Presidência da República, Casa Civil, Subchefia para Assuntos Jurídicos, 16 May of 2012. Available in: http://www.planalto.gov.br/ccivil_03/_ato2011-2014/2012/decreto/d7724.htm>. Access in: 26 February of 2018. [7] NATIONAL SCHOOL OF PUBLIC MANAGEMENT FOUNDATION (ENAP), Módulo 3, “Classificação de Informações e Dados Abertos”, Curso “Acesso à Informação”, 2017. [8] BRAZILIAN NUCLEAR ENERGY COMMISSION (CNEN), official website. Available in: http://www.cnen.gov.br/informacoes-classificadas>. Access in: 26 February of 2018. [9] ESTADÃO, “Urânio contamina água na Bahia”, 22 August of 2015, official website. Available in: http://brasil.estadao.com.br/noticias/geral,uranio-contamina-agua-na-bahia,1748686>. Access in: 26 February of 2018. [10] ASSOCIAÇÃO BRASILEIRA DE ENERGIA NUCLEAR (ABEN), “INB: atividades de mineração de urânio em Caetité não contaminam águas da região”, 29 April of 2015, official website. Available in: http://www.aben.com.br/noticias/inb-atividades-de-mineracao-de-uranio-em-caetite-nao-contaminam-aguas-da-regiao>. Access in: 26 February of 2018. [11] BOLETIM INFORMATIVO PARA CAETITÉ E ARREDORES (DAQUI CAETITÉ), Indústrias Nucleares do Brasil (INB), nº 18, December of 2015. [12] ESTADÃO, “Após denúncia, água contaminada por urânio é vetada”, official website. Available in: http://brasil.estadao.com.br/noticias/geral,apos-denuncia--agua-contaminada-por-uranio-e-vetada,1748976>. Access in: 26 February of 2018.

Speaker: Mr Alexandro Rocha Scislewski (Brazilian Nuclear Energy Commission (CNEN) / District of Caetité (DICAE/BA))

42 Uranium deposit types, exploration methods and Corporate Social Responsibility (CSR) Programs: Case of LERE (Chad)

INTRODUCTION The Lere Uranium deposit was one of numerous uranium showings in Chad. It was highlighted in the Mayo-Kebbi West, close to the border with Cameroon. This deposit is best known because it has been the subject of previous studies by UNDP (United Nations Development Program) and the IAEA (International Atomic Energy Agency) between 1970 and 1980. Recently, these studies were supplemented by exploration Signet Mining Services Ltd (SMS), a European-based mining company called in Chad by Chad Mining Service (CMS). Furthermore, SRK was requested by Signet to generate a mineral resource estimate of the lere deposit as part of the initial exploration program. DESCRIPTION: METHODS AND RESULTS Located in southwestern of Chad, the Lere deposit has uranium hosted near vertical shear zones and secondary foliation in albitised and silicified granite in a mixed terrain of Precambrian units. It occurs within the Zabili granitoids, proximal to the contact with the schist and amphibolites of the Mayo kebbi series. The ore-body is a weathered, iron-stained (hematised), fractured and sheared, feldspar-rich (albite), low-quartz granite. Within the orebody; de-silicified as well as silica impregnated zones, are recognized. Signet Mining Services Ltd had (6) concessions comprising (841 kilometer-square km2) that include the Lere Project in south-western Chad near the towns of Lere and Pala. Exploration activities have included an airborne geophysical survey, a geological survey and a surface radiometric survey. Uranium anomalies and potentially significant structures have been identified. Anomaly A and B have been drilled by percussion drilling (18 541 meter) and core drilling (2 676 meter), enabling the development of a geological model and providing sufficient data for resource estimation. Chad Mining Services Company has completed over 170 vertical wells, 22 trenches and a dozen drilling inclined concentrations vary from one well to another the greatest value is in the order of (4000 ppm) in wells and is (50 to 100 ppm) in surface during the mapping. The deposit is estimated at (8,000,000 t) [2]. Resources compliant with the South African code for the reporting of exploration results, mineral resources and minerals reserves (The South African Mineral Resource Committee [SAMREC] Code) have been evaluated to amount to (3 190 tU), at an average grade of (200 ppm U) or (0.020% U). At a uranium price of less than USD 50/lb U3O8, the identified deposit is considered uneconomic. Further structures will need to be identified to increase the resources in order to move the project to a development stage [1]. CSR initiatives of CMS included various aspects namely: Employment, Infrastructure, Supplies, Compensation, Transfer of competences, Safety, Environmental protection, Information and communication, other community programs. DISCUSSION AND CONCLUSION In general, the subsoil of Chad has an abundance of important mining resource particularly an important potential in uranium’s ore that it exploitation will contribute to the national economy. It is important to note that Chad is still very under explored compared with other African countries. For that reason, as prospecting or mining research is the first step in the development of the mining sector, Chad Mining Services (CMS) made uranium exploration in the Mayo Kebbi Province (LERE). Studies conducted by CMS have outlined several areas that are highly prospective for uranium. However, exploration, mining and/or processing operations can have both positive and negative environmental, economic and social impacts on communities. They can provide employment and business opportunities to local communities such as exploration activities of CMS. In addition, a rational exploitation coupled with the modernization of techniques for extracting and processing minerals will increase employment nationally and regionally. REFERENCES [1] CHAD MINING SERVICE, report (2011). [2] NAYGOTIMTI BAMBE, Exploration of Uranium in Chad, State of places, (2010).

Speaker: Mr Abdallah Hassan Abakar (Ministry of Petroleum and Energy)

43 SOCIETAL BARRIERS TO URANIUM MINING: A CASE STUDY FROM BRAZIL

INTRODUCTION Attitudes of different communities against uranium mining can cause severe constraints in uranium mining operations, eventually leading to insuperable barriers to project implementation and development. Some studies have investigated the public opinion on uranium mining in different countries. One of these studies in Australia revealed that just under half of the public support the mining of uranium, while 36% opposes it [1]. The study also informed that over the previous decades, public support for nuclear energy in Australia has declined, while support for uranium mining has remained relatively stable. In Canada a study prepared by Areva Resources [2] indicated that “the uranium mining and uranium mining companies continue to hold a place of importance in the minds of Saskatchewan residents. Support remains high among survey respondents, both province-wide and in the North… “as the result of the perception…that the primary companies operating in the industry operate safely and responsibly, and contribute positively to the province”. A study developed by the University of Eastern Finland, Joensuu [3] indicates that public opinion was more critical of uranium mining operations in comparison to other types of mining activities e.g. metals and industrial minerals. Only 1 to 4% of the interviewed individuals considered these activities not acceptable while in the case of uranium mining this level was determined as being between 38 to 51%. Six variables were examined in the study: Environmental attitudes, Perceptions of the disadvantages and benefits, knowledge of the mining, Trust, Trust in officialdom and Acceptability of foreign mining companies. Familiarity with operations correlated strongly with the acceptance. Drawbacks have a stronger impact in the acceptability than have the benefits. Trust in the authorities and legislation is strongly and positively correlated with acceptance. Finally, it was seen that the people that are more willing to accept foreign mining companies were also those more inclined to accept uranium mining. Regarding Africa’s situation the place of the continent in the global nuclear market was examined [4]. The paper considers international and African tools that either exist or are being set up to improve the governance of uranium mining in Africa. It concludes that improvement requires attention to strengthening government capacity and ensuring wider consultative processes. PERSPECTIVES FROM THIS WORK In the scope of this work over one hundred entries in the internet that captured individual views on uranium mining all over the world were examined. This strategy did not follow any strict scientific-based methodology. The intention was to achieve a preliminary assessment of the hypothesis that basic perception towards uranium mining was the same all over the world and if so, what would be the main aspects to drive people’s views and positions. Because of this investigation, it was found that attitudes were affected by four main issues: i) Misuse of scientific evidence that ends up propagating fear; ii) Influence of historical (legacy) sites - that in many cases were developed outside proper regulatory framework - that are associated with practices that are no longer accepted or even seen as good practices, iii) Long term issues i.e. mining sites remain dangerous even after their closure, iv) the perception that these operations bring considerable burden to indigenous people (this because mining operations in many circumstances take place in remote areas). These points above seem to be fully consubstantiated by a wide diverse publications/reports available in the literature. Some examples are provided below. The Quebec Mineral Exploration Association (AEMQ) and Quebec Mining Association (QMA) wrote an open letter protesting the “attempts to manipulate public opinion against the mining and industry and the uranium industry in particular” [5]. The manifesto refers to the announcement made by a group of doctors that would be leaving the area of a future mining operation. The open letter indicates that the group of doctors were claiming that the principles of precaution and prevention should be considered in any decision regarding the implementation of a new uranium mining project and led to a more extreme claim for a “moratorium on uranium mining and exploration in Quebec. The letter signatories indicated that the overall manoeuvre against uranium mining was intended to “to instil doubt and fear in the largest possible number of citizens of good faith, including doctors”. A report released by NEA/OECD in 2014 [6]. The publication reveals that public perception of uranium mining is largely based on the adverse health and environmental impacts resulting from past practices i.e. those that took place during an essentially unregulated early phase of the industry. The work from Brugge and Goble (2002) [7] points out that federal government in the USA “deliberately avoided dealing with a health disaster among Navajo uranium miners”. The authors indicate that even after two decades after the harmful effects of uranium mining were known, the implementation of protective measures have not been implemented. No doubt that what makes uranium mining even more sensitive to public scrutiny than other mining activities or industrial operations is the radioactive properties of uranium and its daughters. In addition one cannot ignore the obvious link of mining operations to atomic bombs (in the past) and nuclear power (nowadays). It is also a critical aspect that the legacy sites created with the operations that were initiated during the 1940’s/1950’s up to the 1980’s now need governmental funding to finance the remediation required to render the sites safe and stable. Funding to be allocated for the remediation of these sites will compete – specially in countries with less advantaged economies - with other demands, particularly those of social nature (e.g. education, health, etc.) and that will not be well perceived by the public. An obvious reaction is that societies with that perception will stand against future operations based on the experience accumulated from past operations. THE CONTEXT IN BRAZIL In Brazil the only ongoing uranium mining and processing operation was started in 2000 and is located at Caetité (Lagoa Real province) a semi-arid region at the central-southwest of Bahia state. The extraction of uranium from the ore is achieved by means of a Heap-Leach process. Due to scarcity of water, local population rely, to a considerable extent, on the abstraction of groundwater for living purposes. Enhanced concentrations of uranium in those waters come to be an issue for the local population as it is not seen because of natural processes but rather because of the uranium mining operations. Since the beginning of the mining operations in Caetité, accusations involving workplace accidents, tailing spills, potential soil and water contamination, and uncertain risks (e.g. cancer) to the health of the workers and the population which lives in the surrounded area of the mine have taken place In April 2008, a team of Greenpeace collected eight samples of groundwater (allegedly used for human consumption) in an area within a circle of 20 km diameter centred in the uranium facility. It has been reported that two of these samples presented uranium concentration “far above” the guideline proposed by the World Health Organization (WHO). The report, entitled “Ciclo do Perigo – Impactos da produção de Combustível Nuclear no Brasil - Denuncia: Contaminação da Água por Urânio em Caetité Bahia”. (Cycle of Danger: Impacts of Nuclear Fuel Production in Brazil. Complaint: Contamination of Water by Uranium in Caetité, Bahia), was then released. The report refers to some publications that are intended to support the hypothesis that undesired health effects allegedly caused by the uranium operations in the region are being observed. The Greenpeace report in page 17 states that in one of studies the uranium incorporation rates by inhabitants of Caetité were 25 times higher than those presented in a control region. The referenced study was indeed a M.Sc. Dissertation that was subsequently published in a peer review journal [8]. In the journal the information is presented in a different way i.e. “uranium concentrations in teeth from residents of Caetité are about 8 times higher than those from the control region”. The article also reveals that from a total of 41 tooth samples collected in the Bahia state, 17 came from the city of Caetité and only 2 from the city of Lagoa Real area where the mine is located. The results are not depicted in tables, rather in graphics. It can be seen thought that the two samples came from an individual of around 17 and another one of 31 years old. While the first sample presented uranium concentration of something around 5 ηg.g-1 the other one showed a value 10 times higher. Based on these results the authors infer that higher values could correspond to overexposure cases potentially due to food and water ingestion. As a conclusion and based on the data set mentioned above the article suggests that “uranium body levels in residents of Caetité are also much higher than the worldwide average and because of that daily ingestion of uranium in Caetité, from food and water, is equally high. Finally, it is proposed that “The populations of the studied localities, and Caetité´ in particular, are subject to radiobiological risks much higher than those for populations living in other regions of Brazil or abroad”. It is recognised that few data are available that adequately describe the dose-response toxicity of uranium after an oral exposure in humans but in case of high levels of exposure transient renal dysfunction would be expected. The point to be made here is that if any health effects would be expected due to chronic ingestion of uranium these would have been kidney disfunctions instead of radiation induced effects. Along the same lines a great deal of fear is caused by the potential effects of radon gas associated with the mining operations. In this regard an oncologist suggested that the number of lung cancers in Caetité was twice the average for the state of Bahia and three times higher than the number observed in the southwest region of the state. It is also suggested that the increased number of lung cancers is due to the radon concentration in the air that is said to be “10 times higher than the value recommended by the World Health Organisation”. Association between neoplasm increase and mining operations in Caetité is also proposed by another study [9] particularly thyroid cancer and leukaemia. Reference levels for radon in dwellings set out in the IAEA international safety standards is of the order of 300 Bq.m-3 [10]. Radon concentrations in open air of a uranium mining area is reported to vary in the range of 1.75 to 25.6 Bq.m-3 [11]. The Canadian Nuclear Safety Commission states in its home page addressing the question - “Do uranium mines and mills increase radon levels in the environment? “– states that studies have shown that uranium mining and milling activities do not increase radon levels above background levels in the environment away from the mine site [12]. In addition, it is said that “Radon exposure to members of the public from CNSC-regulated activities is virtually zero”. With those pieces of information in mind and considering that: i) the main health effects of uranium are not related to its radiological properties, ii) the main health effect of radon is lung cancer not leukaemia neither thyroid cancer and iii) with the typical environmental concentrations of radon – even in areas close to uranium mining – no increase in adverse health effects would be expected, it can be stated that all the issues raised so far in NGO’s report, blogs, social media and other sites in the internet are not consistent and constitute perfect examples of how (pseudo/inconsistent) scientific information can be used to propagate fear as indicated above. They cause huge negative psychological impact in the populations that are exposed to these pieces of information. IAEA RELATED ACTIVITIES IN CAETITE The IAEA organised – in 2010 – one mission of the Uranium Production Site Appraisal Team (UPSAT) to review the uranium production site of Caetité under the request of INB [13] . It was found that the operations at Caetité were run with no evidence of adverse environmental impact outside the mining licence area. The UPSAT team also noted that within the mining production area some environmental impacts in ground water have been noted and these should be further studied. Between 2012 and 2015 the IAEA supported Brazil – under the Agency’s Technical Cooperation Programme – in implementing a project entitled “Sustainable Water Resources Management in a Uranium Production Site” (BRA 7010). This project was intended to contribute to the formulation of proposals that could lead to the sustainable management of water resources in INB operations in Caetité, considering the environmental aspects of water management in addition to social issues. The main counterpart of the project was the Institute of Radiation Protection and Dosimetry (IRD) from the Brazilian Nuclear Energy Commission (CNEN). Taking into consideration the many concerns of the population related to the contamination of the environment an expert mission to Brazil, to advise the project team on the best approaches to be used in the communication of the project results to the relevant audiences, was implemented under the auspices of BRA 7010 project. To support a wider understanding of the overall perception in relation to mining operations a wide survey, that included analysis of information provided in local blogs, electronic newspapers and materials available texts available in NGO’s sites as well as interviews with residents available in the YouTube, was conducted. The acquisition of information by means of the above survey did not follow any science-based method of information acquisition. DISCUSSION AND CONCLUSION The survey confirmed that the dissemination of inaccurate information is very intensive. While public opinion (local community) is constructed based on information of questionable scientific consistency results provided by more robust technical/scientific work is not made available to local stakeholders and/or simply disregarded by those interested in promoting unjustified fear. That was accompanied by an expressed and considerable sense of lack of transparency by INB regarding its operations. Opinions formed based on what is perceived as reliable scientific investigations indicate that cases of cancer in the region have risen after the operations of the mining company began. The study on the concentration of uranium in teeth of the population of Caetité mentioned above has been widely used to sustain the idea that people are getting exposed to uranium isotopes. It is also suggested that some of observed cancer cases are related to high radon concentrations in air. It was also seen that complaints about the mining and milling operations go beyond the radiological impacts. On the social dimension it is argued, among other things, that the company did not absorb a significant number of workers from the region. It was also indicated that selling the agricultural products cultivated in the region became rather difficult because of the belief that these produces are contaminated with radioactive elements. In addition to the radiological impacts, complaints of the dust coming from mining operations (due to explosions to remove the ore) do also exist. There are also complaints on the scarcity of water springs that – in the past – would allow the irrigation of soil in which different agricultural products were cultivated. Finally, the collected information indicates that complaints also extend to the nuclear regulatory body. The notion of lack of transparency, lack of information and eventually lack of independency is present. The attitude though seems not to be the same regarding other regulatory bodies (e.g. the environmental regulator IBAMA). As a conclusion the perception that the official organizations and local authorities are not “protecting” the local population gives room for NGO’s from outside the region to fill this gap. By adopting an anti-nuclear discourse and emphasizing the risks related to the mining operations, these organizations end up aligning side by side with the population. They get the trust of residents and, by providing concerted information suggesting the inappropriateness of the operations, lead the population to stand against the development of INB operations in the region. In this regard it can be clearly seen that the arguments put forward by the NGO’s in the different channels of communication end-up being reproduced by members of the community in their interviews. The analysis of this situation suggests that INB does not have or does not sustain a consistent communication/engagement plan. As it happens in many occasions, operators tend to be reactive and not proactive. That means, by not having in place a continued mechanism of interaction with the population, INB leaves room for the action of groups and individuals that clearly demonstrate an attitude against nuclear energy and related activities. Some of the statements made go far beyond the issues that directly affect the local population and bring to the local discussions an agenda that is far broader and belongs to an international conversation THE PATHFORWARD Due to the many concerns expressed by the population of Caetite about environmental contamination (more specific contamination of groundwater) it is of utmost importance that all information acquired with the IAEA supported Technical Cooperation Project is communicated to the relevant stakeholders. The expert mission to Caetité served as the first step in a process to help improving a situation that is currently hindered not only by the lack of trust amongst the actors but also because of the lack of proper understanding of the potential environmental impacts associated with uranium mining and the operations in Caetité. The expert mission was complemented with additional work of investigation of information contained in different web sites in the internet as mentioned before in the text. With these considerations in mining the proposed course of actions include: INB should have a more proactive attitude in terms of communication with the different stakeholders, not only with the different regulatory bodies and other relevant organizations, but also, and perhaps mainly, with the local communities. It must be recognized that the lack of engagement allows that other organizations continue filling the existing gap and aligning with these communities. Therefore, they will be perceived as those who really care about their lives and wellbeing. Under these circumstances it is not a surprise, as this study revealed, that members of the local communities will adopt the discourse and ideas presented to them by these organizations. IRD on its part should hold joint public meetings including INB, CNEN, IBAMA, and other relevant organizations and people from local communities, especially those living in areas where water samples were collected. The meetings would then start with information on the project (why? how? what?). Then explanations on natural radiation should be provided (making comparisons with exposures to radiation in our daily lives). Project results should then be presented. In support to these meetings, press releases should be prepared. They should be short with easily understandable information and photos. An important issue to be considered will be how to involve NGO’s in these meetings. They should also be participating in the discussions and their arguments should be carefully listened to and discussed but not in a confrontational way. It must be ensured that that the aims/ethics of science are cleared understood, and the consequences, lessons learned, and future steps in the project are explained. Connected to this point, a specific part of the IRD website should be devoted to the project and an online information channel should be opened with as many relevant summaries and scientific abstracts as possible, but in language suitable for a layperson. Scientific articles on the project results should be prepared and published. Beyond the project scope, educational material on environmental and natural background radiation for different levels of students and children and community groups could be developed. The initiative can be proposed to INB and/or to the local municipality (responsible for education). A last point to be carefully considered refers to the expectations of the local communities on the social role to be played by INB in the region. Taking into consideration that many of these communities need basic assistance (to be provided by the State) a natural expectation is that some of the needed actions could be provided by INB. It is not expected that a company will replace the role of the State in addressing the basic needs of a population. However, in the scope of the so called “social responsibility” it might be the case that the mining company can address – to a certain extent – some of these needs. In this regard the notion of social responsibility goes beyond the concept of “justifying the company existence and documenting its performance through the disclosure of social and environmental information” [14] ACKNOWLEDGMENT The authors would like to acknowledge the work done by Phil Richardson; Nadja Zeleznik; Eeva Salminen during the expert mission to Brazil in the scope of TC Project BRA7010. REFERENCES [1] McAllister, I. Public Opinion Towards the Environment. Results from the ANU Poll., The Australian National University (2008). [2] AREVA RESOURCES, Public Support for the Uranium Mining Industry in Saskatchewan. http://mining.areva.com/canada/liblocal/docs/Information/Publications/More-Publications/2017_Public_Opinion_Survey_Situation_Summary_web.pdf (2017) [3] LITMANEN, T, JARTTI, T & RANTALA, E., Citizens’ attitudes toward mining in Finland http://www.uef.fi/documents/547540/0/Citizens%E2%80%99+attitudes+toward+mining+in+Finland+10.2.2016+UEF.pdf/1777f53e-a079-4056-97a8-d87f77dbcd55 (2016). [4] SOUTH AFRICAN INSTITUTE OF INTERNATIONAL AFFAIRS. Uranium Mining in Africa: A Continent at the Centre of a Global Nuclear Renaissance. SAIIA Occasional Paper No 122 (2012). [5] MARKET WIRED. Uranium and the Manipulation of Public Opinion (2010), http://www.marketwired.com/printer_friendly?id=1134761 [6] NUCLEAR ENERGY AGENCY, Perceptions and Realities in Modern Uranium Mining. Extended Summary. NEA No. 7063, Organisation for Economic Co-Operation And Development (2014). [7] Brugge, D and Goble, R. The History of Uranium Mining and the Navajo People. Am. J. Public Health 92(9) 1410 – 1419. (2002). [8] Prado, G. et all. Evaluation of uranium incorporation from contaminated areas using teeth as bioindicators—a case study. Scientific Note. Radiation Protection Dosimetry, 130, 2, 249–252 (2008). [9] INTERNATIONAL ATOMIC ENERGY AGENCY. Radiation Protection and Safety of Radiation Sources: International basic Safety Standards. General Safety Requirements Part 3 No. GSR Part 3. International Atomic Energy Agency. Vienna (2014). [10] RAGHAVENDRA T., RAMAKRISHNA S.U.B., VIJAYALAKSHMI T., HIMABINDU V., ARUNACHALAM J., Assessment of radon concentration and external gamma radiation level in the environs of the proposed uranium mine at Peddagattu and Seripally regions, Andhra Pradesh, India. Journal of Radiation Research and Applied Sciences, 7, 3, 269-273, (2014). [11] CANADIAN NUCLEAR SAFETY COMMISSION, Radon in Canada’s Uranium Industry. http://nuclearsafety.gc.ca/eng/resources/fact-sheets/radon-fact-sheet.cfm#levels (2012). [12] New Uranium Production Cycle Assessment Service Makes its Debut (2010). https://www.iaea.org/newscenter/news/new-uranium-production-cycle-assessment-service-makes-its-debut [13] CRUZ, J.A. & RIBEIRO, F.S., Association between the neoplasm increase and uranium exploration in the municipalities of Caetité and Lagoa Real, Bahia, Brazil. European Journal of Cancer. 60, 1, 15. (2016). [14] JENKINS, H. & YAKOVLEVA, N., Corporate social responsibility in the mining industry: Exploring trends in social and environmental disclosure. Journal of Cleaner Production Volume 14, Issues 3–4, 271-284 (2006).

Speaker: Dr Mariza Franklin (Brazilian Nuclear Energy Commission (CNEN) - Institute of Radiation Protection and Dosimetry (IRD))

12:40 Lunch Break

Advances in Exploration

Conveners: Dr Igor Pechenkin (All-Russian Scientific-Research Institute of Mineral Resources, Moscow, Russia), Dr Susan Hall (U.S. Geological Survey)

44 DASA: AFRICA’S NEWEST WORLD CLASS URANIUM DEPOSIT IN NIGER, WEST AFRICA — A GLOBAL ATOMIC CORPORATION PROJECT

SYNOPSIS The DASA deposit is located in the north central part of the Republic of Niger, West Africa. It is 100 km north of the city of Agadez, 80 km south of the uranium mining areas of Arlit and 1000 km east of the capital Niamey. The project area is found within the sedimentary Tim Mersoi basin; one of the world’s foremost uranium producing areas. The area is accessible using an all weather road connecting Agadez, Niger’s second largest city with the town of Arlit. Global Atomic Corporation (GAC), a Canadian junior exploration company has six exploration permits in Niger. The DASA deposit is positioned within the Adrar Emoles 3 permit. The GAC head office is based in Toronto, Canada and a subsidiary office operates in Niamey, Niger. The initial uranium mineralization was observed on surface in 1956 near Azelik, just west of the GAC property. An intensive geological exploration program was implemented between 1957-1967 by CEA (French Nuclear Energy Commission) and this resulted in the discovery of the uranium deposits of Azelik (1960), Madaouela (1964), and finally Arlit-Akouta (1966-1967). The CEA eventually became Cogema and is now known as Orano (formerly AREVA). Global Atomic Corporation signed exploration agreements with the Government of Niger on six permits during 2007 totalling approximately 3500 km². The DASA deposit was discovered in 2010 through surface prospection which led to a high grade (>30%U³O⁸) outcrop. Since 2010 GAC has conducted significant drilling programs (> 120,000 meters to date) in conjunction with other exploration surveys leading to the definition of the DASA deposit. The GAC Adrar Emoles 3 permit, on which DASA is located presently, comprises an area of 121.3 km². Exploration and drilling programs are ongoing. Geology and Stratigraphy The GAC permits are located predominantly over continental sediments of the Tim Mersoi basin which is bordered to the east by the metamorphic Pre Cambrian terrain of the Air Massif rising to an elevation of over 2000 meters. Most of the rocks here are intrusive and their erosion has provided much of the sediments in the basin. Uplift of the Air has tilted the sediments in the forelands shallow to the west. Generally the sediments are clastic containing minor carbonates. The sediments were laid down in fluvial and deltaic settings. The general direction of transport is assumed to have been from east to west and in the area of interest a more NE to the SW direction of transport would have prevailed. The sediments identified within the GAC permits range in age from Cambrian to lower Cretaceous. The following strata -from bottom to top- as recognized in drill holes and surface mapping underlie the GAC property. Pre Cambrian basement is exposed in the Air Massif some 15 km to the east. The oldest rock drilled on the GAC grounds is coarse grained granite inside the DASA graben at depths of over 700 meters. Cambrian to Devonian sediments exist in this part of the Tim Mersoi Basin. Some have also been identified in the drilling at DASA. These are predominantly sandstones and conglomerates, possibly including Devonian glacial deposits. The Carboniferous fluvio-deltaic Tagora Formation of Upper Visean age can be observed in many of the deeper GAC drill holes. The lower Tagora, up to 180 meters thick, contains sandstones representing the Guezouman Formation. This is a major uranium carrier in the Akouta area (Cominak underground mine-Orano). The upper Tagora, up to 140 meters thick, often commences with a thin layer of conglomerate overlain by the sandstones of the Tarat Formation. The uranium in the Somair open pit mines at Arlit (Orano) is hosted in the Tarat. The top of the Carboniferous is completed by sandstones and siltstones of the Madaouela Formation (Madaouela uranium - GOVIEX). The Carboniferous in the entire basin is characterized by reducing conditions displayed in predominantly greyish colours; pyrite and organic matter providing ideal conditions for the precipitation of uranium. Permian sediments are generally characterized by an abundance of arkosic sandstones containing significant volcanic debris. Reddish colours and abundant calcite are dominant. This indicates an oxidizing milieu. Around the project area the thickness of the Permian strata varies considerably and reaches a maximum thickness of some 300 meters. Initially the Triassic shows a continuation of the Permian conditions commencing with conglomerates overlain by sandstones. The Triassic sediments, over 200 meters thick, contain masses of volcanic debris such as tuffs. Massive analcimolite intercalated with sandstone layers are found on top reflecting a very active eruptive volcanic phase. The Jurassic commences with the Tchirezrine 1 Formation (Tch1) the channel sedimentation of a large river flowing from north to south. Graben syn sedimentary tectonic has caused variations in thickness. In general the Tch 1 is quite similar to the higher following Tchirezrine 2 Formation (Tch2) except that it does not contain uranium mineralization. The Tch2 reaches thicknesses of 40 to 200 meters. It was laid down in a fluvial-deltaic and lacustrine environment. The sediments are predominantly coarse grained, poorly cemented sandstones and micro conglomerates with cross bedding at the base. The formation was affected by syn sedimentary tectonics and later by shearing. This has contributed to the considerable thickness reported in the GAC drilling in some drill holes. The rocks are rich in analcimolite and organic matter including coal beds; a most favourable environment for uranium precipitation. This formation contains much of the uranium discovered on the GAC property and in the huge Orano Immouraren uranium deposit nearby. The Cretaceous begins with the Assaouas Formation, up to 30 meters thick, consisting of re-worked older quartz rich sediments and is overlain by fine grained sandstones and argillites. The following Irazher Formation consists of reddish mudstones and silts which cover much of the basin, but is confined within the GAC property to the Asouza Graben. The thickness, at times over 300 meters, is marked by syn-sedimentary tectonics within the graben with important lateral variations in thickness. The stratigraphic column of the project area culminates with the barren sandstones of the Tegama Formation which lies with a prominent unconformity on the Irazher sediments. Tegama sandstones are present in two bigger hills inside the Asouza Graben. Structural Geology The Tim Mersoi basin developed as a result of N-S and E-W compression with NNW-WNW sinistral shears originating from counter clockwise rotation in the NE of the basin. The intersection between these structures contains rotational deformation causing dome and basin structures. This mechanism has created horst and graben structures. Major movements are related to N-S zones which strike parallel to the eastern and the western edges of the Air Massif. The compressional sinistral strike slip movements have caused three main structural directions which are N-S, N40º-80º and N90º-140º. Where these directions meet, their continual movement has opened up ideal pathways for circulating uranium bearing fluids; pre requisites for the formation of deposits. The N-S fault system is a major crustal structure of regional scale and is displayed in the fold-fault of In Azaoua-Arlit. A N30° family of structures is most evident on surface in the basin. They appear in the Air Massif in the east and truncate at the In Azaoua-Arlit lineament in the west. In the sedimentary cover the deformation is characterized by flexures creating, in some instances, a substantial vertical displacement in the order of 100-200 meters. The N70º-80° and N130º-N140°E series of faults are brittle structures. The N70º-N80°E faults are conjugate to the N130º-N140°E directions and are present mainly in the southern half of the Tim Mersoi basin. During the Carboniferous both families of structures controlled the sedimentation in the basin. These faults played a major structural role in the regional context of the basin by localizing large scale dextrous strike-slip faults. Fold-like structures are revealed along sectional variations in the dip of the strata. According to geological drilling data the thickness and dip variations in some strata from west to east are linked with synsedimentary tectonic activity. The DASA site corresponds to a major structural intersection of the Adrar-Emoles flexure and the Asouza fault which has resulted in the doming and creation of the Asouza (DASA) Graben. Much of the uranium is found here, especially along its southern flanks. The intersection formed a dome and at its opening the Asouza Graben was created moving the Cretaceous formations to the same topographic elevation as the surrounding Jurassic sandstones. Major NE-SW vertical faults are associated with the Asouza Graben and characterized by significant vertical displacement of several hundred meters between the centre of the graben and its shoulders. The creation of the graben prevented the erosion of the Tegama and Irhazer Formations that are normally found much farther to the west in the deeper areas of the Tim Mersoi basin. The Tch2 Formation was also preserved here and is significantly eroded on the sides of the graben. This vertical displacement has had a major impact in the continuation of potential host rock geology and has also provided feeder faults and mineralization traps for ore forming fluids as evidenced by veining within the sandstones. The NNW-SSE faults observed NW of the graben are particularly interesting. They cut the sandstone formations of the Tch2 inducing significant vertical displacement with evidence of fluid circulation enacting localized alteration and copper mineralization in analcimolite formation of the Tch2. Paleography The development of the paleography has had a major influence on the sedimentation and the lithology of the host rocks where uranium is found today. During the deposition of the Lower Carboniferous this part of the Tim Mersoi Basin was quite stable with very little subsidence. Volcanism commenced towards the top of the Lower Carboniferous in the Air Massif. Increasing precipitation in the Upper Carboniferous is manifested in the Tagora series with its fluvial-deltaic cycles. Paleo valleys and channels existed with marshy zones that were filled with fine grained sediments and large accumulation of organic matter. In the Permian, desertic conditions usually prevailed while in the Triassic less desertic environments appeared. Structural activity caused lineaments to evolve which in turn created variations in the thickness and facies of the sediments. During the Jurassic, tectonic adjustments occurred and a wide north-south trending trough developed. It was limited in the west by the N-S trending Arlit fault, the Madaouela fault in the north and the Magagi fault in the south. Volcanic activity was wide spread and the depositional environment changed to real fluviatile-lacustrine scenarios. The flow directions maintained their main SW to NE vector. During the Tch2 deposition large amounts of organic matter were incorporated into the sediments. The sandstones often show whitish greyish or greenish colours indicating a much higher reduction potential for uranium. This is most obvious in the massive mineralization seen at DASA. Uranium Mineralization and Economics All known uranium mineralization in Niger is located exclusively in sediments of the Tim Mersoi basin and occurs in almost every important sandstone formation, although not always in viable concentrations. The uranium in many of the deposits of the basin is generally oxidized. Thin section work and petrographic studies on DASA samples have revealed that the uranium host rocks vary in oxidization. The original cement between the grains of quartz and feldspar consisted of sericite and carbonate which were replaced during later stages by goethite and amorphous Fe-hydroxides. The quartz and the feldspar grains contain micro fractures filled in part with U rich oxide. The latter also rim some of the silicates. Uranophane in the form of radiating aggregates forms cement between the silicates and partly replaces them. Five main uranium bearing minerals have been identified in DASA samples: Carnotite K₂ (UO ₂) ₂ (VO₄) ₂ x 3H₂O; Uranophane (Ca(UO₂)₂ SiO₂O ₇ x 6H₂O U –rich titanite (U,Ca,Ce)(Ti,Fe)₂O₆: Torbernite (Cu(UO₂)₂(PO₄)₂ x 8 H₂O Autunite (Ca (UO₂)₂(PO₄)₂ x 12 H₂O All known uranium occurrences and deposits in Niger are classified as the sedimentary tabular and roll front sandstone type. Sandstone hosted uranium deposits are marked by epigenetic concentrations of uranium in fluvial/lacustrine or deltaic sandstones deposited in continental environments. They are located frequently in the transition areas of higher to lower flow regimes such as along paleo ridges or domes. Impermeable shale or mudstones often cap, underlie or separate the mineralized sandstones and ensure that fluids move along within the sandstone bodies. DASA is unique amongst the uranium deposits in Niger. It shows higher grades and accumulations than virtually any other known deposits. It contains economic reserves in both of Niger’s main uranium bearing formations (Carboniferous and Jurassic) and displays a very strong structural component (DASA graben) which has enhanced both grade and thickness of the mineralization. The origin of the uranium at DASA is very likely from two main sources; leaching of uranium during the erosion of the Air Massif for the Carboniferous ores and leaching of the volcanic tuff and ash intercalations for the Jurassic ores. This began as pre-concentrations during the early sedimentation. Favorable reducing environments such as organic matter rich lower flow regimes containing sulfides, Fe minerals and amorphous humate as well as favourable lithological settings played their parts. The first strati form ore bodies emerged from this setting. Subsequent structural deformation and fluid movements within coarser grained organic and sulfide rich sediments initiated roll front like re- distribution and concentration over several stages. The uranium followed favorable lithological and structural surroundings and traps creating the present shape of the ore bodies. The grade and thickness of the mineralized intersections differentiates DASA from most other sandstone deposits worldwide. Some of the better intersections assayed (XRF) are hole 476 with 4462 ppm U₃O₈ over 94.5 meters, hole 478 with 7033 ppm U₃O₈ over 42 meters, hole 256 with 3307 ppm U₃O₈ over 110 meters and hole 312 with 2811 ppm U₃O₈ over 76 meters. A NI 143-101 compliant report by CSA Global Pty. Ltd. in 2017 listed indicated reserves of 21.4 million pounds with an average grade of 2608 ppm U₃O₈ using a cut-off of 1200 ppm U₃O₈ . The inferred reserves were calculated as 49.8 million pounds at 2954 ppm U₃O₈ again using the 1200 ppm U₃O₈ cut-off. This makes DASA potentially a 70 million pound plus deposit. The deposit is open along strike NW-SE and down dip. Ongoing exploration work is expected to increase the reserves further. It is possible to develop DASA within a short time frame producing ore from both open pit and underground operations. CAPEX to production would be low with an estimated investment of 50 million US dollars to development as the ore would be processed at the nearby Orano mine sites in Arlit where all necessary facilities, such as a mill already exist. To this extent GAC signed a Memorandum of Understanding (MOU) with Orano in 2017. The infrastructure, both within and surrounding the GAC property is excellent. Easy access to a major road system linking to the port of Cotonou in Benin, West Africa is already being used for the shipment of the production from the Orano mines in Arlit. Electricity is available from an existing high power line crossing the property and a large pool of experienced mine workers provides a source of labour. The discovery of the DASA deposit has given rise to new incentives for exploration in the Tim Mersoi basin. There is considerable potential to find additional DASA type deposits, not only on the GAC property, but also in other parts of the basin.

Speaker: Dr Peter Wollenberg (Global Atomic Fuels)

45 ADVANCES IN HYPERSPECTRAL REMOTE SENSING TECHNOLOGY FOR THE EXPLORATION OF HYDROTHERMAL TYPE URANIUM DEPOSITS IN CHINA: A CASE STUDY IN THE XUEMISITAN AND LONGSHOUSHAN AREAS

1 INTRODUCTION Hyperspectral remote sensing technology has unique technical advantages in mineral identification[1], by which the obvious effects in metal mineral exploration have been made at home and abroad[2,3].Since 2008, With the introduction of the internationally advanced CASI(Compact Airborne Spectrometer Imager)/ SASI(Shortwave Airborne Spectrometer Imager)/TASI (Thermal Airborne Spectrometer Imager) airborne hyperspectral measurement system to Beijing Research Institute of Uranium Geology,CNNC,China, the researches and application to uranium exploration using hyperspectral remote sensing technology had entered a new stage of rapid development [3]. Xuemisitan area in Xinjiang, is an important Cu-Fe-Au-W-Mo-U-Be metallogenic belt in northern Xinjiang, China. The mineralizations are mainly related to volcanic and magmatic hydrothermal activities. In the belt, a volcanic type U-Be-Mo polymetallic deposit named Baiyanghe Deposit and a series of uranium mineralizing dots, anomalies had been discovered before. Therefore, there are good uranium polymetallic ore-forming conditions and high prospecting potential in Xuemisitan area. In Baiyanghe uranium deposit and its surrounding area, there mainly developed Devonian and Carboniferous volcanic rocks, granite, granite porphyry, diabase vein and so on. The uranium ore bodies were mainly located within the 50 meters zone of the contact zone between microcrystalline granite porphyry called Yangzhuang body and the underlying intermediate and acid volcanic rock of upper Devonian Talbahaitai Formation (D3t). Main hydrothermal alteration minerals are hematite, hydro muscovite, carbonate, fluorite, silicitization and so on[4].The Longshoushan uranium polymetal metallogenic belt is located in Gansu province, China, where the U, Th, Cu, Ni, Fe, Au, Ag and other minerlizations had been discovered before. There existed good metallogenic conditions and great prospecting potential. The main strata were Proterozoic metamorphic rock and upper Paleozoic Devonian, Carboniferous, and Permian system. The magmatic activity in Caledonian period was strong, and there were many intrusive rock bodies, such as ultrabasic rocks, intermediate rocks, acid rocks and alkaline rocks. Hydrothermal activity was strong in the area, and the main hydrothermal alterations related to uranium mineralization were albitization, carbonation, chloritization, hematitization, silicification, sericitazation. The alkaline metasomatic type uranium deposits, such as Jiling, and the siliceous belt type uranium deposits named Gemigou, and the uranium deposits related to the alkaline body named Luchaogou had been discovered in this zone before. Above two areas are well exposed and suitable for the research and application of hyperspectral remote sensing technology to uranium exploration, which can promote new breakthrough in uranium exploration. 2 HYPERSPECRAL DATA AND PROCESSING METHODS The hyperspectral remote sensing data used in this study include CASI/SASI/TASI airborne hyperspectral data acquired in 2011 and 2017 respectively, ground-based spectrometric data and borehole core spectrometric data. The spatial resolution of CASI data was 1.0 m, and its spectral resolution was 20 nm, the spectral coverage was 404~1047nm. For SASI data, the spatial resolution, spectral resolution and spectral coverage was 2.0 m, 15 nm, and 950~2450 nm respectively.For TASI data, they were 2.0 meter, 125 nm, and 8000~11500 nm respectively. The ground and borehole core hyperspectral data were obtained by using Field Spec Pro FR portable spectrometer of ASD Company of the United States. The spectrum of ASD data ranged from 350 to 2,500 nm, with spectral resolution of 3 nm in 350 to 1,050 nm and 8 nm in 1050 to 2500 nm respectively. In order to extract the altered mineral information from the obtained airborne hyperspectral data, the processes of radiation correction, geometric correction, atmospheric correction, spectral reconstruction, separation of temperature and emissivity and mineral mapping were performed. For ground and borehole core spectrometric data, the main processes were spectral curve analysis, mineral identification and statistical analysis. After extraction of mineral information, the field verification and chemical analysis of samples were needed to be carried out to ensure the accuracy of hyperspectral mineral mapping. 3 MAIN ADVANCES Through the researches and application of the hyperspectral technique to uranium exploration in China, recent years some new advances on hyperspectral remote sensing technology of uranium exploration and its application have made as the following. 3.1 Hyperspectral remote sensing technology suitable of hydrothermal type uranium exploration Through introducing the CASI/SASI/TASI airborne hyperspectral remote sensing technology into uranium exploration domain systematically, a set of airborne hyperspectral detection technology for uranium exploration, which combining data acquisition, mineral mapping, information analysis, model construction and exploration prospecting, were established. The detection technology specifically include CASI/SASI/TASI hyperspectral data acquisition technology, CASI/SASI airborne hyperspectral data processing and mineral mapping technology, TASI airborne thermal infrared hyperspectral data processing and identification technology of quartz-silicon zone, information analysis technology for airborne hyperspectral mineral mapping, model construction technology for uranium deposit using hyperspectral information, and prediction technology for uranium exploration using hyperspectral information. Among them, the information analysis technology for airborne hyperspectral mineral mapping, model construction technology for uranium deposit using hyperspectral information, and prediction technology for uranium exploration using hyperspectral information are the most important new advances. The information analysis technology mainly include the genesis analysis technology of Al-high sericite, Al-medium sericite and Al-low sericite identified by airborne hyperspectral, the mineral assemblage analysis technology based on the concept of favourable metallogenic geochemical barrier, and metallogenic environment analysis technology. Through researches, a new idea about the genesis of Al-high sericite, Al-medium sericite and Al-low sericite Al- sericite was proposed systematically. Namely, Al-high sericite was considered to be formed in the relatively high temperature and acid hydrothermal fluid environment, while Al-low sericite was formed in relatively low temperature and alkaline hydrothermal fluid environment. In the same time, 3 kinds of new mineral assemblage of hyperspectral altered minerals were proposed to predict the favorable volcanic rock type uranium prospecting area. The uranium prediction technology for uranium exploration using hyperspectral information includes the method based on above 3 kinds of mineral assemblage, method based on uranium deposit location model and the method by integrating mineral mapping information and airborne radioactive information. 3.2 Analysis on hyperspectral characteristics in Baiyanghe volcanic type uranium deposit Using different scale of hyperspectral remote sensing data from airborne, ground, drillhole, the hydrothermal alteration types in surface and depth of Baiyanghe uranium deposit and its surrounding area were identified. After that, the hyperspectral characteristics of uranium deposit and their hydrothermal fluid activities in surface and deep of uranium deposit were analyzed and studied. (1) There existed alteration minerals such as pyrophyllite , dickite, alunite, kaolinite, Al-high sericite, Al-medium sericite, Al-low sericite, hematite, silicification, and so on, in deposit and its around area. According to the spatial distribution of these minerals, they can be divided into three alteration areas: northern alteration area, deposit alteration area and southern alteration area. In northern alteration area, a set of acidic hydrothermal alteration groups composed of pyrophyllite, dickite, alunite and Al-high sericite were developed. Al-high sericite, Al-medium sericite, hematite and silicitization were mainly developed in deposit alteration area, while Al-low sericite and Al-medium sericite were developed in southern alteration area. Analysis showed that the northern alteration area was a set of mineral assemblage of advanced argillic belt formed by volcanic gas and liquid boiling [5], and it formed from an ascending magma hydrothermal fluid [6] and indicating that the metallogenic fluid may have risen to a shallow hydrothermal depth. Therefore, the northern alteration area is a possible volcanic structure and regional hydrothermal fluid activities centre in Baiyanghe and its surrounding area. Baiyang uranium deposit alteration area was characterized by the strong development of Al-high sericite, Al-medium sericite, and was the obvious fluid activity area located in the side of the fluid activity center in the regional hydrothermal system. The southern alteration zone also was an obvious hydrothermal fluid activity area with more decreasing temperature farther from the fluid activity centre. (2) In uranium deposit area, the hydrothermal alteration temperature was considered to be higher in the middle and west than in the east, higher in the northern margin than in the southern margin.The northern margin was the contact zone between Yangzhuang sub-volcanic body and Devonian intermediate and basic volcanic rock, the alteration temperature was higher in the middle and west part than in the east. This idea was based on the following hyperspectral mineral information and the genesis analysis of Al-high sericite, Al-medium sericite and Al-low sericite above mentioned. The SiO2 content extracted from airborne thermal hyperspectral data was comparatively lower in the central and western part than that in the eastern part. In the northern margin contact zone, there developed Al-high sericite and Al-medium sericite. While in the southern edge there developed Al-low sericite and Al-medium sericite. Moreover, in the northern margin contact zone, the alteration minerals varied from Al-high sericite to mixture of Al-high sericite and Al-medium sericite, the Al-OH absorption wavelength of sericite altered mineral changed from the relatively short wavelength in central and western regions to the relatively long wavelength in the east. In vertical profile from the contact zone, the Al-OH absorption wavelength of sericite had the same change from near contact zone to far from contact zone. (3)There were at least two typical ways of hydrothermal fluid activity in the deep of Baiyanghe uranium deposit. Based on the minerals characteristics and sericite Al-OH absorption wavelength change identified from drillhole core hyperspectral data, two typical ways of hydrothermal fluid activity in deep of BaiYanghe uranium deposit were discovered. They are called Direct-flow type and Separate- flow type. The former had the characteristics of continuous and directional Al-OH absorption wavelength change from 2195nm to 2208nm to 2215nm. It reflected the temperature of the hydrothermal fluid varied gradually from the relative high in the deep to the relative middle in the vicinity of the contact zone and then to the relative low into granite porphyry. Two drillholes of ZK5432 and ZK5630-1 located in the main mineralized area in the central and western region were characterized by this type. It may be related with diabase vein, which were more developed there. The latter had the characteristic of changing Al-OH wavelength from 2200 nm in contact zone to 2210nm in the deep and to 2215 nm in the shallow, respectively. It reflected the relative high temperature of the hydrothermal fluid in the vicinity of the contact zone, decreased toward two sides of the deep and upper respectively. ZK 3310 and ZK2710 located in the eastern part of deposit were belonged to the type. This type of temperature change of hydrothermal alteration was also consistent with that existed in northern margin of deposit above mentioned. They were the same fluid activity patterns appeared in different horizontal and vertical profiles respectively. (4) Relationship between uranium mineralization and hydrothermal fluid activity. From the spatial distribution of uranium mineralization and anomalies in Baiyanghe deposit and its surrounding area, it can be found uranium mineralization had good relationship with hydrothermal fluid activity. First, uranium mineralization has certain relationship with regional hydrothermal activity centre. The identification of hydrothermal activity centre is very important to predict the regional uranium exploration area with benefit ore-forming condition. Second, uranium mineralization was closely related to the relatively high temperature of hydrothermal fluid. ZK5432 and ZK5630-1 with good mineralization had the direct-flow type of fluid activity way, and it may be related to the invasion of basic rock vein and diabase vein. Therefore, this provides new evidence to prove the close relationship between uranium mineralization and basic vein in the Baiyanghe uranium deposit area. Thirdly, the uranium mineralization and enrichment in borehole core were mainly in the transitional zone between Al-high sericite and Al-low sericite alteration, where the hydrothermal activity was from relatively high temperature to relative middle temperature, hydrothermal properties from acid to neutral and weak alkaline. Therefore, uranium mineralization may be closely related to the change zone of hydrothermal fluid temperature and acidity and alkalinity. 3.3 Analysis of hyperspectral characteristics of alkalic metasomatic and siliceous belt uranium deposits By analyzing the characteristics of different types of uranium deposits in Longshoushan area using airborne hyperspectral information, the preliminary ore-forming features were found. (1)The hydrothermal alteration characteristics in Longqiangshan area was strong in the east and weak in the west, strong in the Southeast and weak in northwest. Hydrothermal alteration was closely related to faults with north-west trend, north-north-west trend and east-west trend. The hydrothermal alteration strength was relatively weak in the main uranium prospecting area. Hydrothermal alteration mainly distributed in the outer of the contact zone between granite, alkali rock bodies and old Metamorphic rock. Alteration was relatively weak in the interior of granite bodies. (2) The Jiling alkalic metasomatic type uranium deposit was located in the contact zone between granite and diorite, and the ore body is located in the red alaklic metasomatic alteration bodies albllized. The main alteration minerals in and around Jiling uranium deposit are hematite, Al-medium sericite, Al-low sericite, chlorite, carbonate, serpentine and silicification. Among them, chlorite, carbonate and serpentine mainly distributed along the ore-controlled reoinal big fault named Malugou. The secondary faults mainly developed some Al-medium sericite and Al-low sericite alteration. The hydrothermal alteration generally was weak in surface of deposit and strong in outer of deposit. Along the north-west trend Maligou fault, SiO2 content decreased obviously in the norwest part. (3) Gemigou deposit and Lucaogou deposit were considerated to be in the same hydrothermal activity system. The former is located in the contact zone between granite body and metamorphic rock, and the fault structure named Gemigou ore-controlled fault. while the latter is located on the interior side of contact zone between alkaline rock body and metamorphic rock. The former is remarkalbely characterized by silicification, kaoliniztion, Al-high sericite and carbonate, while the latter is characterized by the obvious alkaline rock body with alkaline feldspar identified by thermal infrared hyperspectral. From the margin of alkaline body in the south to granite to metamorphic rocks in north, there existed different alteration zone of fe-rich chlorite, carbonate and Al-low sericite, Al-high sericite and kaolinite and silicification. 3.4 Uranium exploration prediction According to the hyperspectral characteristics of volcanic type uranium deposit in Xuemisitan area and different type uranium deposits in Longshoushan area, the favourable uranium prospecting area were predicted. In the Xuemisitan area, the hydrothermal activity centre was selected in regional scale at first. Then, these areas developed Al-high sericite and Al-medium sericite, especially further existed hematization, acidic rock, basic rock vein were outlined as the target areas. Based on this new idea, several new uranium mineralization anomalies were discovered. It had been proved that there are good uranium mineralization and obvious ore-controlled fault in the deep in one predicting area by trenching. In Longshoushan area, the favorable areas were also predicted, which still need to be verified next. In addition, using hyperspectral remote sensing technique, the prediction results for Cu-Au prospecting in Xuemisitan are terrific obvious. 4 CONCLUSION The hyperspectral remote sensing technology has made obvious achievements in identifying hydrothermal alteration minerals, analysing hydrothermal alteration and fluid activity law, judging ore-controlled structure in the Xuemisitan and Longshoushan area, which provided an important new technology for uranium exploration, and had promoted new breakthroughs in uranium and polymetallic mineral exploration. In the future, it is necessary to strengthen the comprehensive analysis of alteration minerals, structure and lithology identified by hyperspectral remote sensing. It is very important to combine hyperspectral information with fluid metallogensis and uranium ore-forming theory, so as to excavate the prospecting information underlied in hyperspectral remote sensing data deeply. Only do that, hyperspectral remote sensing technology can be server for uranium exploration more effectively. REFERENCES [1] Kruse, F. A., Use of Airborne Imaging Spectrometer data to map minerals associated with hydrothermally altered rocks in the northern Grapevine Mountains, Nevada and California, Remote Sensing of Environment. 24, 1(1988)31-51. [2] Phil,B., David,H.,et al., Hyperspectral Mapping of Mineral Assemblages Associated with Gold Mineralization in the Central Pilbara, Western Australia, Economic Geology.97(2002) 819-826. [3] Liu,D.C.,Tian,F.,et al., Application of hyperspectral remote sensing in solid ore exploration in the Liuyuan-Fangshankou area. Acta Geologica Sinaca, 91,12(2017)2795-2812(in Chinese). [4] Ye,F.W.,Zhang,J.L., et al., Application of airborne hyperspectral remote sensing technique to uranium prospecting: A case study of Baiyanghe area, Xingjiang. Hyperspectral Image and Signal Processing: Evolution in Remote Sensing (WHISPERS), 4th Workshop (2012)1-5. [5] Hu,S.X.,Ye,Y., Petrology of the metasomatically altered rocks and its significance in prospecting. Beijing: Geological Publishing House(2004)1-214(in Chinese). [6] Je,F.W.H.E., Antonio,A.J.,T.J.R., Evolution of an intrusion-centered hydrothermal system: FarSoutheast-Lep-anto porphyry and epithermal Cu-Au deposit, Philippines. Economic Geology, 93,4(1998)373-404.

Speaker: Dr Fawang Ye (Beijing Research Institute of Uranium Geology)

46 Uranium Potential of Singhbhum Shear Zone, India: Future Prospects

INTRODUCTION The Singhbhum Shear Zone (SSZ), Jharkhand, India is one of the major uranium producing provinces of India, which hosts several uranium deposits. The SSZ uranium province has potential to host large tonnage of uranium resources besides metals like Cu, Ni, Mo, REE, Fe and Mg, etc. The proven uranium resource in the province as on July, 2017 is 64392tU3O8 (54604tU). The producing centres namely Jaduguda (from 1968), Bhatin (from 1986), Narwapahar (from 1995), Turamdih (from 2003), Bagjata (from 2008) and Mohuldih (from 2012) have been developed as underground mines and Banduhurang (from 2009) as open cast mine from this province. Recent conceptual work carried out by Atomic Minerals Directorate (AMD) based on new exploration strategies, has paved the way for resource addition in adjoining blocks of existing mining centres, thereby extending the life-span of the mines. Besides, conceptual exploration strategy has given encouraging results and has helped in identifying potential new zones. A few significant discoveries have come to light which are reorienting the exploration programme to enhance the resource base of SSZ from its present level to a much higher level. Present paper describes a few of them and plan for future exploration by AMD. GEOLOGICAL SETTING The SSZ is a 200km long arcuate belt of high strain characterized by multi-phase deformation, intense ductile shearing, multiple metasomatic features including imprints of sodic metasomatism and polymetallic mineralization [1]. It participated in the subsequent ductile deformations which obliterated a majority of earlier features [2]. The arcuate shaped SSZ involves various lithounits of Archaean to Neo-Proterozoic period. The oldest rocks representing ≥ 3.4 to 2.6 Ga period are Older Metamorphic Group (OMG), Older Metamorphic and Tonalite Gneiss (OMTG), unclassified mafic-ultramafic rocks occurring as enclaves within Singhbhum Granitoids, Banded Iron Formation (BIF) of Badampahar – Gorumahisani Belt, acid volcanics and ultramafic dykes of 2.6 Ga [3] which have suffered the SSZ related deformation especially along the arcuate belt. Probably uranium proto-ore was supplied from these Archaean lithologies and got concentrated in overlying Quartz-Pebble-Conglomerate (QPC), occurring at the base of Iron Ore Group (IOG) and also Dhanjori Group. The IOG comprises conglomerate, phyllites-shale-wacke, quartzite, Banded Magnetite Quartzite (BMQ), ultramafics, acid volcanics, tuffaceous units, grits, etc. Dhanjori Group comprises volcano-sedimentary sequence containing quartzite-conglomerate, mafic ultramafic flows and intrusives with tholeiitic (pillowed) basalt interlayered with tuffs (2.1 Ga) overlying the IOG. The rocks of Dhanjori Group are overlain by Singhbhum Group which comprises quartzite-conglomerate (oligomictic and polymictic), feldspathic schist, granite mylonite, sericite-quartz-schist, chlorite-quartz-schist (and their mineralogical variants), metabasic sills, mica schists and quartzites. The lower part of Singhbhum Group comprising the Chaibasa Formation represents a metasedimetary package in which non-diastrophic structures are preserved despite many deformational episodes. Deep to shallow marine turbidite, peri-tidal shallow, or even a totally fluvial depositional environment, have been proposed. Perhaps more than one environment coexisted in the region. The upper part of Singhbhum Group constitutes the Dhalbhum Formation comprising phyllites and ortho-quartzites have been interpreted as a meandering channel system [1]. Apart from the extensive Singhbhum Granite of different phases, several younger isolated granitic bodies are also exposed along the SSZ, such as Chakradharpur Granite (CKPG), Arkasani Granophyre (AG) and Soda Granite (SG) (now seen as feldspathic schists). Several younger mafic and ultramafic bodies have been emplaced all along the shear zone. These bodies vary in age, and therefore show repeated tapping of mantle during the process of shearing or even in post-shearing period. The rocks of SSZ are characterized by compositional banding subparallel to major foliation. Large scale fold structures with sub horizontal to low plunging axes are seen on the northern side of SSZ. The shear zone is characterized by presence of small scale reclined folds, strong foliation as well as a strong set of downdip lineation of tectonic origin. Mylonites are commonly present in almost all rock types that are involved in shearing. These can be classified as L-S type tectonites [4]. Gentle warps along N-S axial planes mark a late deformation event postdating the shearing event. The shear zone rocks have been affected by progressive and retrogressive metamorphism. The grade is green schist in central part which has major uranium deposits. The chlorite-quartz schist and quartz-chlorite-schists are the major host rock for uranium and copper mineralization. NATURE OF URANIUM MINERALISATION The uranium mineralization is confined to the arcuate SSZ from Duarpuram in the west to Baharagora in the southeast. The arcuate shape is possibly due to the fact that Singhbhum Craton acted as buttress against stresses from NNE direction. The resultant structure is an anticlinorium of isoclinally folded rocks dipping consistently north and marked by a prominent shear zone with crushed and mylonitised rocks [5]. This has provided an ideal situation for mineralizing fluids to form shear controlled hydrothermally generated metamorphite type of deposits in addition to proto-ore and QPC environment. The metamorphite deposits occur as disseminations, impregnations and veins along shear planes within or affecting metamorphic rocks of various ages. These deposits are highly variable in size, resource and grade [6]. The deposits of Central Sector of SSZ (Narwapahar, Turamdih and Mohuldih) are peneconcordant, gradational strata bound and hosted in relatively lower metamorphic grade of rocks, whereas the deposits of eastern sector (Jaduguda, Bhatin, Bagjata and Kanyaluka) are discordant and vein-like associated with host rocks of relatively higher grade of metamorphism. Uranium mineralization is confined to Chaibasa-Dhanjori interface depending upon intensity of shear. In most of the cases mineralization is bottomed at the lowest unit of Chaibasa Group or upper part of Dhanjori metasediments. Quartz-sericite to sericite-quartz schists have been considered as the marker for bottom of uranium mineralization [7]. The uranium mineralization in SSZ is present in sheared low grade metamorphic rocks, viz., quartz-chlorite schist or quartz-biotite schist. However, it is absent in hornblende – (or actinolite) schist. This feature indicates that favourable rocks for U-mineralization are of green schist facies rather than epidote-amphibolite facies or rocks of ultrabasic composition (actinolite schist) [8]. Uranium mineralization is represented by uraninite, minor pitchblende, brannerite, U-Ti complex, which occurs in many instances in association with sulphide mineralization of chalcopyrite, minor bornite, chalcocite, covellite and molybdenite and oxides like magnetite, ilmenite, titano-magnetite, etc. The mineralogy is complex and the chemistry of the ores, particularly U and Cu, is greatly influenced by the host rock involved in shearing. Shear zone transgressing to Dhanjori Group (Jublatola) is richer in U, Cu, Ni, Mo [(±) Bi, Au, Ag, Te & Se], whereas in schists and quartzite of Chaibasa Formation it is poorer in above metals. Peneconcordance of ore bodies with host lithologies is seen in Chaibasa Formation [9]. CONCEPTS ON ORE GENESIS Various modes of occurrence for uranium mineralization have been reported from SSZ. Titanium oxide-uranium oxide grain aggregates found in Jaduguda-Bhatin deposits are related to QPC-type of environment where primary and secondary brannerite have been reported [10]. Three generations of uraninite have been seen in SSZ in which last phase is post-sulphide mineralization. The refractory uranium bearing minerals (allanite, xenotime, monazite, sphene, etc) and uranium associated with apatite-magnetite veins are the product of pneumatolytic – hydrothermal metasomatism probably related to younger granitic phases referred earlier (AG and SG). The uraninite associated with feldspathic schist (~SG) in Narwapahar-Turamdih sector has been correlated with metasomatic feldspathisation process and subsequent remobilization to form ore bodies [11]. On the basis of various observations, it was proposed that geochemical source of U was Singhbhum Granitoid, whereas the basic rocks of Dhanjori Group provided Cu, Ni and Mo for the formation of U-Cu deposits of SSZ [12]. Mahadevan [9] has concluded that U was enriched in Singhbhum Granite by partial melting of the upper mantle/ lower crust around 2900-3000 Ma. This continued till 1900Ma (Mayurbhanj and Nilgiri Granitoid) and 1420 Ma (SG). QPCs at the base of IOG and Dhanjori Group show evidence of detrital accumulation of uranium bearing minerals. These U-concentrations along with host rocks got folded into a major synclinal sequence prior to involvement in shearing episodes. Shearing episodes have further remobilised and reconstituted uranium mineralization concomitant with the early folding events, F1 and F2. The localization of U-Cu lodes with predominant platy minerals, particularly chlorite, is controlled by deformation and metamorphism of Chaibasa and Dhanjori rocks simultaneously. The younger granites namely CKPG, AG and SG along with younger basic units, formed by partial melting of lower crust – upper mantle interface generated geothermal gradient [9]. Mantle metasomatism or crustal contamination of upheaving melts cannot be ruled out in such cases, which would have generated diverse type of uranium mineralization hitherto not known. The chemical and structural characteristics of various uraninites differ from east to west and from north to south i.e. along and across the strike of the SSZ. The uraninite composition varies from UO2.31 to UO2.44 and cell dimension from 5.42 Ǻ to 5.45 Ǻ [11]. Larger cell dimension has been found in eastern and western part of the SSZ while it is comparatively smaller in Central Sector (Jaduguda). URANIUM MINERALISATION-NEW CONCEPT/ ENVIRONMENT (i) QPC Related U-Mineralisation: The potentiality of QPC as a paying horizon for U ± Au is yet to be established in Singhbhum Province. The QPC at the base of IOG and Dhanjori have been known from SSZ area. They have been involved in shearing episodes as well but retained their primary features in some shadow zones. Recent attempt by faster non-core drilling upto depth of 300m has provided insight to QPC-related horizons and their continuity in lenses. The exploration in western half of SSZ (Jamshedpur as centre) has resulted in identification of subsurface conglomerate bands with U-Th mixed anomalies at shallower level while uraniferous bands are found at deeper level (250-300m depth). Repeated nature of Th, U+Th and U-enriched bands at Gura and occurrence of intermittent yet significant QPC horizon over a considerable stretch of 35km along Udalkham-Manikbazar- Simulbera sector has strengthened the concept of exploration for QPC type of mineralization. Magnetite is predominant in these conglomerates and hematite is absent. Similarly, deformed uraniferous conglomerate of Jaduguda occurring above Dhanjori meta-basic/ basalt and its probable western continuity at Nimdih and further towards west at Chirugora, and its eastern continuity in Rakha mines, has generated interest to explore the whole belt where QPC is missing on surface. The concept is being tested with the help of huge non-core and core drilling programme of AMD. (ii) Arkasani Granophyre Related U-Mineralisation: The SSZ bifurcates into two arms at Narwapahar and continues further westwards where Bangurdih-Gurulpada sector forms the southern segment of the shear while Sankadih-Galudih forms the northern shear plane of SSZ. The surface uranium occurrences defining an E-W trend along Banaykela, Gurulpada, Mahalimurup, Dhadkidih, Dugridih, Nilmohanpur, Ukri and Bijay areas are confined to southern shear while Sankadih, Saharbera, Sarmali and Tirildih are situated along northern segment. The northern shear has association of Arkasani Granophyre (AG) and Soda Granite (SG) as evidenced on outcrop level. Recent efforts in exploring the soil covered area between Sankadih and Galudih by non-core drilling has established uranium mineralization over a strike length of 360m upto depth of 120m in two series with grade ranging between 0.021 and 0.043%U3O8. Ground geophysics helped in identification of borehole location and understanding of target depths. This has established 800m strike length located west of main Sankadih ore block. The correlatable uraniferous mineralization is confined to Arkasani Granophyre / Feldspathic schist. The subsurface continuity in this unit has generated new concept to explore Arkasani Granophyre magmatic-hydrothermal related mineralization adjacent to SSZ. The shear-controlled chlorite-biotite-quartz schist hosted uranium mineralization at Sankadih occurs near the contact of AG. Even schistose rocks occurring within the AG show presence of uranium [13]. This phase of uranium mineralization has been correlated with major episode of deposit formation in SSZ. The emplacement of AG and SG is syn- to post-major shearing phenomenon. The chalcopyrites developed in the schist show magmatic (+0.9 to + 1.4 δ34 S o/oo, n=2) and metamorphic (+2.6 to 3.4 δ34 So/oo, n=3) parentage, indicating later remobilisation under metamorphic conditions [13]. In other words, it is interpreted that AG has brought magmatic and metamorphic effects to shear zone rocks and probably supported in recycling of U-mineralisation in subsequent episodes. The concept developed has been tested. The investigations have resulted in encouraging values of uranium mineralisation related to AG. (iii) Serpentinised Peridotite Hosted U-Fe-Mg-Cr-Ni-Mo-REE-C Mineralization: In pursuit of developing new concept and to satisfy our quest for knowledge a few boreholes were planned to extend beyond the quartz-chlorite and quartz-sericite-schist (marker for bottoming of uranium mineralization in SSZ) of Chaibasa Formation in Kudada-Turamdih area. The investigation recorded a new type of environment where polymetallic (U-Fe-Mg-Cr-Ni-Mo-REE-C) mineralization hosted by serpentinised peridotite has been established in four boreholes of Kudada (south of Turamdih Group of deposits). The corresponding surface mineralization has been located in the Kudada Protected Forest Area. The peridotite is emplaced at the interface of IOG and Chaibasa Formation, as Dhanjori Group of volcano-sedimentary rocks appear to be absent in this sector. The possibility of the peridotite to be representative of IOG or Dhanjori cannot be ruled out. The host peridotite comprises relict olivine (after serpentinisation) and pyroxenes (after chloritisation) of 200-300 micron size. Presence of chromite and magnetite have been established. Uraninite (subhedral to anhedral) varying from a few microns to 600 microns are disseminated within the serpentinised peridotitic ground mass. Clustering of uraninite (~ 3 grains) are common feature. Unit cell dimension of uraninite range from 5.4498 to 5.4650 Ǻ (n=2) and matches well with other uraninite of SSZ showing high temperature of crystallization. XRD studies have confirmed uraninite and traces of beta-uranophane and monazite. Other ore minerals are magnetite, molybdenite, cobaltite (CoAsS), nickeline (NiAs), vaesite (NiS2), cerussite (PbCO3), pyrite, chalcopyrite and chamosite. Talc and fluorapatite occur as gangue [14]. Chemical analysis (n=10) of peridotite shows MgO (18-28%), FeO (3-17%), Fe2O3 (t) (2-23%), Cr (1623-3165ppm), Ni (221-1347ppm), Mo (<10-485ppm), Co (43-633ppm) and V (36-230ppm). REE (t) is enriched upto 1457ppm (n=5) when compared to non-mineralized host rock (558 ppm, n=4). The geological environment for uranium mineralization intercepted in Kudada-Turamdih area is an unusual one and not reported from SSZ, and hence requires in-depth studies. Recent investigations have enhanced the potentiality of SSZ for a mega deposit hitherto unknown, developed due to work carried out recently. (iv) Tirukocha Fault Related Exploration: The eastern part of SSZ records a few prominent faults related to brittle deformation as a post-shearing phenomenon. The Tirukocha Fault between Bhatin and Jaduguda, and Gohala Fault between Bagjata and Kanyaluka have affected the uranium mineralization. Both the faults have been represented in Total Magnetic Intensity (TMI) Image for central part of SSZ prepared by AMD. The integrated studies carried out based on geological mapping and collection of subsurface data from boreholes and underground Jaduguda mines, suggests its oblique slip nature. The surface manifestation of Tirukocha fault is identified by the clear displacement of the quartzite unit of Chaibasa Formation in Jaduguda by about 1km dextrally on plan. The level plan made on marker quartzite depicts a lateral displacement of about 1.07km with a vertical separation of 570m [15]. These measurements are significant understanding for exploration in Jaduguda-Tirukocha area where substantial tonnage is unexplored. The concept is tested and a few boreholes have picked up mineralization based on above understanding. Exploration so far indicates that richer grades are extending further east. This calls for meticulous planning in the east where the ore body and the fault plane make an intersection line plunging steeply towards northeast direction. Calculation of the intersection of the two planes indicates that intercepts of better grade (G) and thickness (T) values can be expected further eastward with each deeper series. CONCLUSION The sustained studies leading to the generation of additional geophysical, mineralogical, geochemical inputs have been integrated with new concepts on exploration, thereby developing an exploration strategy in SSZ for next five years. The strategy, inter alia, includes the concepts on: (i) QPC related uranium mineralization. (ii) Arkasani Granophyre related uranium mineralization. (iii) Altered peridotite hosted polymetallic mineralization. (iv) Mineralisation related to brittle tectonics along Tirukocha Fault. Atomic Minerals Directorate for Exploration and Research (AMD) has already envisaged substantial coring and non-coring drilling to prove at least 15,000 t U3O8. REFERENCES [1] MAHADEVAN, T. M., Geology of Bihar & Jharkhand Geol. Soc. Ind. 2002. [2] GANGOPADHYAY, P.K., SAMANTA, M.K., Microstructures and quartz-c axis patterns in mylonitic rocks from the Singhbhum Shear Zone, Rakha Mines area, Bihar, Ind. Jour. Geol. 70 (1-2), 1998, 107-122. [3] GUPTA, A., BASU, A., Structural evolution of Precambrians in parts of North Singhbhum, Bihar, Rec. Geol. Surv. Ind., 35, 1985, 13-24. [4] SARKAR, S.C., The problem of uranium mineralization in Precambrian metamorphic shear tectonites - with particular reference to the Singhbhum Copper-Uranium Belt, Eastern India, IAEA-TECDOC-361, Vienna, 9-20. [5] BHOLA, K.L., Radioactive deposits in India. Proceeding on “Symposium on uranium prospecting and mining in India” by DAE, GOI, 1965, 17-59. [6] URANIUM 2016: Resources, Production and Demand, NEA No. 7301, OECD 2016, 2016, 525-529. [7] PANDEY PRADEEP, et.al. Uranium deposits of Turamdih-Nandup area, Singhbhum district Bihar and their spatial relationship, Expl. Res. Atom. Min., 7, 1994, 1-13. [8] DHANA RAJU B., DAS, A.K., Petrography and uranium mineralisation of the Proterozoic schistose rocks from Jublatola, Singhbhum district, Bihar, Eastern India, Expl. Res. Atom. Min., 1, 1988, 41-56. [9] MAHADEVAN, T.M., Characterization and genesis of the Singhbhum Uranium Province, India, IAEA-TC-450.5/18, 1988, 337-369. [10] RAO, N. K., RAO, G.V.U., Uranium mineralization in Singhbhum Shear Zone, Bihar, II occurrence of Brannerite, Jour. Geol. Soc. Ind., 24, 1983, 489-501. [11] RAO, N. K., RAO, G.V.U., Uranium mineralization in Singhbhum Shear Zone, Bihar, I. Ore mineralogy and petrography. Jour. Geol. Soc. Ind., 24, 1983, 437-453. [12] RAO, N. K., RAO, G.V.U., Uranium mineralization in Singhbhum Shear Zone, Bihar, IV Origin and geological time frame. Jour. Geol. Soc. Ind. 24, 1983, 615-627. [13] KUMAR, SHAILENDRA, et.al. Sulphur isotopic study on chalcopyrite from Sankadih, western Singhbhum Shear Zone, Jharkhand, India, Expl. Res. Atomic Min. Hyderabad 16, 2006, 45-49. [14] SINHA, D. K., et al. Serpentinised peridotite hosted polymetallic U-Fe-Mg-Cr-Ni-Mo-REE mineralization in Kudada-Turamdih area, East Singhbhum district, Jharkhand: A new environment of metallogeny in the Singhbhum Uranium Province (Under review). [15] PANT SWATI, et.al. A note on Tirukocha Fault, SSZ, India (in preparation)

Speaker: Dr D. K. SINHA (GOVERNMENT OF INDIA DEPARTMENT OF ATOMIC ENERGY ATOMIC MINERALS DIRECTORATE FOR EXPLORATION AND RESEARCH)

47 URANIUM EXPLORATION BY REMOTE SENSING METHODS IN THE KALEYBAR AREA, NORTH-WESTERN REGION, ISLAMIC REPUBLIC OF IRAN

Kaleybar area is located in Alborz-Azerbaijan zone northwest Iran, there is Cu-Fe-Au indices in this area; according to the earlier studies, this area can be considered for radioactive elements mineralization; also according mentioned study, radioactive anomalies are related to clay and silica Alterations, so these alterations can be used as a key to investigate other parts of Kaleybar area. In other side, remote sensing methods have made a good progress in detection and separation of alterations in recent years. Shortwave infrared (SWIR) bands from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) with the wavelength between 1.65 and 2.43 µm has a good potential for mapping hydrothermal alteration minerals. In this study False Color Composite (FCC), Band Ratio (BR), Principle Component Analysis (PCA), Spectral Angel Mapper (SAM) methods where used to detect and separate Alterations. As result, 4 new areas where detected with clay alteration. After radiometry of these areas, 2 areas where identified as anomaly areas. Recent methods where used in this study and had good results for alterations detection and separation in Kaleybar area. These methods can be used as a key to research in similar areas.

Speaker: Dr Jalil Iranmanesh (Atomic Energy Organization of Iran)

Health, Safety, Environment and Social Responsibility

Conveners: Mr Dennis Amos MWALONGO (Tanzania Atomic Energy Commission), Dr Gabi Schneider (Namibian Uranium Institute)

48 SUSTAINABLE WATER RESOURCE MANAGEMENT AT A URANIUM PRODUCTION SITE

ABSTRACT Uranium mining and processing facilities have the potential to contaminate the groundwater, although the identification of these impacts is not straightforward. In U mineralization areas, distinguish geogenic sources of contamination from the U mining activities remains an ongoing challenge. In this context, the identification of the impact sources is essential to define the protection criteria to be adopted (planned or existing exposure situations). The only uranium production center in Brazil is located in Caetité (Bahia State) and explores a single deposit in an area where other uranium anomalies have been mapped. The impact of this installation on local water resources and the high concentrations of U found in some wells have been sources of concern for the local community and regulatory authorities. This situation was used as case study integrating the concept of sustainability and best practices in a national project (BRA7010) supported by the IAEA launched to improve the understanding of the interaction between the hydrogeological system and human health. The results indicate a fast groundwater turnover, suggesting these aquifers are most vulnerable to contamination. However, the estimated effective doses due to groundwater ingestion are below the 1 mSv.y-1 and do not represent significant radiological impact. Keywords: uranium mining, radiological impact assessment, hydrogeological system, human health risk assessment 1.INTRODUCTION Uranium mining and processing (the front-end of the nuclear fuel-cycle) have the potential to affect the workers, the public, and the environment. The impacts of these activities depend on site-specific conditions, and the efforts made to mitigate and control potential impacts. Therefore, the operation of these facilities in accordance with modern international best practice is a key aspect in reducing radiological impacts. In most respects, uranium mining has the same potential to affect the environment as any other metal mining, and protection systems must be implemented to avoid any off-site pollution. However, additional controls need to be applied to deal with radioactivity associated with the uranium ore. The radon exhalation from mill tailings has frequently been identified as the primary cause of radiological impacts from this type of installation. However, significant potential environmental risks may also be associated with releases of contaminants from these facilities to surface and groundwater [1]. In arid and semiarid regions where the water is scarce, and the groundwater is the most valuable resource, this situation can be worsened. The Brazilian uranium production center is located in a sensitive semiarid area of the Northeastern region of the country (in Caetité/Bahia State), where the sustainability of mining and milling operations, as well as the survival of the local community, are highly dependent on the availability of groundwater resources. This installation faces not only the challenges associated with the sustainable use of water but also the mitigation of potential contamination processes due to mining activities. Thus, since the beginning of the operation of this facility in 2000, the local community has been concerned with the impact of the U production activities on water resources [2]. This conflict situation has led to the judicialization of these relations causing interruptions or delays in the operation of this installation threatening the Brazilian Nuclear Program. The characterization of the impacts of U mining and processing on the quality and sustainability of the groundwater use is a complex task and requires that both the natural baseline of the groundwater chemical composition and the functioning of the hydrogeological system be well understood in advance. Much of this complexity is related to the fact that in areas of uranium mineralization it is difficult to distinguish whether the high U concentrations observed in some wells come from the water-rock interaction or are originated from some industrial activity [3]. The long time lags observed in hydrogeological systems between polluting activities and the detection of contamination in groundwater can also make it difficult to identify the impacts. Another question that needs to be answered is if the groundwater is safe to be used for different purposes, and what are the risks (radiological and non-radiological) associated with these uses, with special concern to chronic water ingestion. All concepts and aspects described above were integrated into a logical framework and applied to the Uranium production center of Caetité (Uranium Concentrate Unit – URA) through a national project (BRA7010). This project was developed in technical and financial cooperation with the International Atomic Energy Agency (IAEA) and was attended by the research institutes of the nuclear regulatory authority (Brazilian Nuclear Energy Commission – CNEN) and the Federal University of Rio de Janeiro – UFRJ, besides the collaboration of the uranium mine operator (Nuclear Industry of Brazil – INB). This project was launched to improve the understanding of the interactions between the hydrogeological system and human health in a watershed called the Caetité Experimental Basin (CEB). The purpose of this paper is to synthesize the main results obtained by the BRA7010 project with a focus on the protection criterion used. 2. STUDY AREA The Caetité Experimental Basin (CEB) covers an area of approximately 75 km2 and lies between latitude 13o56’36”S and longitude 42o15’32”W. This basin is drained by the Vacas stream, which belongs to the Contas river, one of the main hydrographic basins in the state of Bahia. This stream is ephemeral, flowing for a few hours or a few days after the rainfall event. The nuclear installation (URA) occupies a small part of the CEB and accounts for the entire uranium supply that is used by Brazilian nuclear reactors. The low-grade U ore is mined by open pit, and the chemical extraction process is performed by heap-leach with sulfuric acid followed by solvent extraction operations. The Lagoa Real complex (LRC) is the main stratigraphic unit of CEB and comprises alkaline granite bodies to sub alkalines, orthogneisses, albitites, and leucodiorites. The uranium mineralization is associated with albitite bodies and shear zones, being uraninite the main ore mineral. The INB is exploring one (AN-13 with 17.000t of U) of the 38 mapped anomalies in the region [4]. The main soil classes found in the CEB are Oxisols, Ultisols, and Inceptisols. The CEB’s main economic activities comprise agriculture in small farms (with the production of manioc, corn, sugar cane and black beans), and grazing (cattle that are also raised along with pork and poultry) [5]. The climate is defined as hot semiarid with an average annual rainfall of 750 mm (measured from 2000 to 2013). The 200 families residing within the CEB are heavily dependent on the water supply from the tubular and dug wells[6]. 3. METHODOLOGICAL APPROACH The establishment of the methodological approach used in this project was preceded by an assessment of the state of the science produced about the CEB. Existing geological, hydrological, meteorological and chemical data were compiled and evaluated. The main source of data came from the reports produced by the well drillers, hydrogeological studies and environmental/effluent monitoring programs conducted by the INB. The academic publications and databases from the National Institute of Meteorology (INMET) and the Global Network of Isotopes in Precipitation (GNIP) were also used. The general approach adopted in this project included: i) Isotope hydrology techniques complemented by conventional techniques (from hydrogeology and hydrochemistry) to generate reliable data for the aquifers’ characterization, ii) Soil hydrology techniques to understand the water infiltration mechanisms across the unsaturated zone, iii) Groundwater modeling, iv) Water quality diagnosis (based on national and international standards), and v) human health risk assessment of radiological and non-radiological contaminants due to groundwater ingestion using US EPA Superfund risk and dose assessment methodologies. 4. RESULTS AND DISCUSSION The direction of groundwater flow follows the topography with a general sense from west to east [7]. Soil texture was very similar among soil types and land-use classes. Soils from all classes and under all types of uses and coverings presented high infiltration rates [8]. The results obtained from a transect installed along a hillslope (1.5 km long) in the CEB, measuring soil water matrix potential in the soil profile up to 3.0 m depth, showed that the amount of water stored in the soil decreases when vegetation cover density increases. During wet periods, hillslope topography is the most important factor controlling soil moisture distribution, while during dry periods, soil properties play the major role [9]. The isotopic data (18O and 2H) provided evidence that recent precipitation was the main source of groundwater recharge, suggesting that the aquifer system in the CEB has a relatively fast turnover time. Localized recharge of water evaporated from superficial water daw were also identified. The three methods used to estimate recharge had concordant results. Using Chloride Mass Balance (CMB) and modeling with Visual Balan v. 2.0 (VBM) the estimated multiannual averaged recharge values was less than 8%, while by means of the Water Table Fluctuation (WTF) method the estimated annual recharge presented values of up to 20% of rainfall. Due to climatic and geo-environmental conditions, the percolation of infiltrating water through the river beds seems to be the most important recharge mechanism of the CEB. Preliminary results concerning the groundwater flow regime simulated using FEFLOW code showed that the flow direction follows the topography with maximum velocity around 7.93x10-3 m.d-1. Most of the groundwater samples can be considered fresh water type (<1000mg.L-1). Na+ and Ca2+ were the dominant cations, while HCO3- and Cl- were the principal anions. The distribution of U in groundwater is controlled by the presence and proximity of areas of uranium anomalies. This means that U concentration drops to background levels with increasing distance from anomalous areas. However, the U decay products do not follow this pattern, and their distribution seems to be associated with local geochemical processes. Geochemical diagrams revealed that the chemical weathering of the aquifer rocks (mostly silicates) and Ca-Na exchanges were the dominants mechanisms in controlling the chemical composition of the groundwater within the CEB. Evaporation process was important only for few samples. The suitability of groundwater for drinking in the CEB and others basins (Contas River Basin – CRB, and San Francisco River Basin - SFRB), was evaluated considering the standard and the guideline established by Brazilian Ministry of Health [10] and the World Health Organization [11], respectively. The chemical constituents of drinking-water analyzed were Sb, As, Ba, B, Pb, Cu, Cr, F, Ni, NO3, Se, U, Al, Mn, Fe, Zn, Na, Cl, SO4, pH, and TDS. Concentrations of Al, Sb, As, B, Cd, Pb, Cu, Cr, Mn, Ni, SO4, and Zn for all samples were below the guided values (GVs) recommended by the WHO and the Maximum Contaminant Levels (MCLs) established by the Brazilian Ministry of Health (BMH) for drinking purposes. All groundwater samples in the SFRB comply with the regulation. Concentrations of F, NO3, U, and Mn exceeded the limits not only within the CEB, but also in the CRB, while the other contaminants Ba, Na, Cl, Fe, TDS, and pH exceeded the limits only within CEB. However, not all wells are used for human consumption. The human health risk analysis in both screenings (conservative and non-conservative) showed the direct ingestion of groundwater was the most significant exposure pathway for radioactive and chemical pollutants. No radionuclide was identified as potentially of high priority in future investigations, and only the nitrate was considered as a potentially high priority contaminant in a non-conservative approach. The estimated mean effective dose due to the intake of 238U, 226Ra, 210Po, 210Pb, 232Th and 228Ra in groundwater (considering an annual water consumption of 730 L) was less than 1 mSv.y-1. In line with the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (the BSS), drinking water is considered as a commodity associated to existing exposure situation, and a reference level of about 1 mSv.y-1should be applied. However, under the influence of a nuclear installation as the URA (a typical planned exposure situation), where exposures and risks are subject to control, a dose limit of 1 mSv.y-1 for public exposure cannot be exceeded. Although the dose values are the same, the mechanism for controlling exposures are different. 5. CONCLUSIONS Groundwater from the fractured rock aquifers in the CEB follows the topography with a general sense from west to east. Soils from all classes and under all types of use and coverings present high water infiltration rates. Isotopes studies data indicate that the origin of the groundwater (before evaporation) corresponds to the recent precipitation and that this system has a relatively fast recharge, and a greater vulnerability to contamination from surface activities. The three different methods used to estimate the recharge confirm the low average recharge rates (less than 8% of precipitation) commonly found in fractured aquifers under semiarid climate. Hydrochemical studies reveal that the chemical weathering of the silicates, ion exchange mechanisms and to a lesser extent evaporation processes are the dominant factors controlling the chemical composition of the groundwater within the CEB. Water quality studies reveal that the non-compliance values of Ba, Na, Cl, Fe, Mn, TDS, and pH are restricted to a few wells within the study area, and most of these wells are not used for human consumption. The high-nitrate concentrations found in several wells scattered around the study area are results of anthropogenic contamination on the groundwater (mainly animal manure or manure piles). The concentration limit established for nitrate by the Brazilian Ministry of Health is 5 times more restrictive than the value established by the World Health Organization. On the other hand, the occurrence of high fluoride concentration in groundwater seems to be associated with geogenic sources as the dissolution of minerals containing F. There are no health hazards associated with natural radioactivity in this groundwater, since all doses are below 1 mSv.y-1. However, if the chemical toxicity of uranium is taken into account, some wells are not safe to use for drinking. The human health risk assessment performed to local communities ratifies the analysis of water quality and identifies nitrate as the only potentially high priority contaminant of concern in non-conservative approach The criterion of protection and control to be adopted (planned or existing exposure situations) should be established taking practical considerations into account. REFERENCES 1. FERNANDES, H. M., GOMIERO, L. A., PERES, V., FRANKLIN, M. R., & SIMÕES FILHO, F. F. L., Critical analysis of the waste management performance of two uranium production units in Brazil--part II: Caetite production center. Journal of Environmental Management, 2008. 88(4): p. 914-925. 2. FINAMORE, R., Uranium mining in Brazil: The conflict in Caetité, Bahia, in EJOLT Factsheet 2014. p. 4. 3. MORGENSTERN, U. AND C.J. DAUGHNEY, Groundwater age for identification of baseline groundwater quality and impacts of land-use intensification – The National Groundwater Monitoring Programme of New Zealand. Journal of Hydrology, 2012. 456–457(0): p. 79-93. 4. CARELE DE MATOS, E. Uranium Concentrate Production at Caetité, BA, Brazil in Symposium on Uranium Production and Raw Materials for the Nuclear Fuel Cycle - Supply and Demand, Economics, the Environment and Energy Security. 2005. Vienna, Austria: IAEA-CN-128/41 extended synopsis. 5. FERNANDES, H. M., LAMEGO SIMOES FILHO, F. F., PEREZ, V., FRANKLIN, M. R., & GOMIERO, L. A., Radioecological characterization of a uranium mining site located in a semi-arid region in Brazil. Journal of Environmental Radioactivity, 2006. 88(2): p. 140-157. 6. ARAÚJO, V. P., SOBRINHO, G. A. N., FREITAS, L. D., & FRANKLIN, M. R., Groundwater isotopic variations in a uranium mining site: subsidies for contamination studies. Brazilian Journal of Radiation Sciences, 2017. 5(2): p. 01-23. 7. SANTOS, A.C.S., Hidrogeoquímica de águas subterrâneas de uma bacia hidrográfica sob influência de uma mineração de urânio, in Programa de Pós-Graduação (Stricto Sensu) em Radioproteção e Dosimetria. 2014, Instituto de Radioproteção e Dosimetria (IRD). p. 203. 8. FRANKLIN, M. R., FERNANDES, N. F., SOBRINHO, G. A. N., & SILVA, A. C., Hydrological changes induced by land-use modifications in uranium mining area (in preparation). 9. FERNANDES, N.F., MOTA, P.O., FRANKLIN, M.R., SOBRINHO, G. A. N., MOTA, J.G., The Effects of Topography, Soil Properties and Vegetation on Soil Moisture Distribution Under Semi-Arid Conditions (in preparation). 10. MINISTÉRIO DA SAÚDE, Portaria Nº 2.914, de 12 de dezembro de 2011. Dispõe sobre os procedimentos de controle e de vigilância da qualidade da água para consumo humano e seu padrão de potabilidade. 2011, Ministério da Saúde (MS). p. 34. 11. WORLD HEALTH ORGANIZATION, Guidelines for drinking-water quality - 4th ed. 2011, World Health Organization (WHO).: Geneva, Switzerland. p. 564.

Speaker: Dr Mariza Franklin (Brazilian Nuclear Energy Commission (CNEN) - Institute of Radiation Protection and Dosimetry (IRD))

49 URANIUM MINING WASTE, RISK PERCEPTION BY POPULATIONS AND ENVIRONMENTAL REMEDIATION IN PORTUGAL

Mining of radioactive ores for radium and uranium production took place in Portugal from 1908 up to 2001. Over the years, several companies produced salts of radioactive elements according to mining laws at the time. Following closure of the last uranium mine and milling facilities at Urgeiriça, local populations and the municipalities claimed for surveillance and responsibility on the legacy of uranium waste. An environmental radioactivity assessment and a public health assessment were carried out in the years 2003-2005. Based on the results and recommendations, the Government approved an environmental remediation plan. Local communities have been listened, intervened in the process, and contributed to solve radiation protection and environmental contamination issues. Up to the present, more than half of the former uranium sites were remediated, milling waste confined, mine water treatment stations installed or upgraded. At the same time a radiation monitoring programme of uranium areas is carried out by the LPSR/IST and the results annually delivered to Government and rendered public. Results has shown effective reduction of ambient radiation doses, treatment of acid and radioactive mine drainage before discharge, and abatement of radiation exposure in several areas.

Speaker: Prof. Fernando P. Carvalho (Instituto Superior Técnico/Laboratório de Protecção e Segurança Radiológica,)

50 ADVANCED QUANTITATIVE GAMMA SPECTROMETRY SOFTWARE FOR OPTIMIZED ENVIRONMENTAL ASSESSMENT DURING ‘CRADLE-TO-GRAVE’ URANIUM EXPLOITATION MANAGEMENT

INTRODUCTION Reliable, fast and cost effective assessment of various environmental parameters related to exploration, mining, production and decommissioning/remediation is an essential input parameter for the “cradle-to-grave” (“exploration-to-remediation”) uranium management. In the present paper ANGLE software for advanced quantitative gamma-spectrometry is briefly outlined and its applicability to that aim discussed. In any gamma-spectrometric measurement with semiconductor or scintillation detectors, the question of converting the number of counts (collected in a full energy peak) into the activity of the sample/source cannot be avoided. There are, in principle, three approaches to this problem [1]: o Relative, where one tries to imitate as good as possible the source by a standard (or vice versa), while keeping the same counting conditions for the two. Paid enough care, the result is, in general, so accurate that cannot be surpassed by other methods. However, we all know what "enough care" means in practice. Combined with the inflexibility in respect with varying source/container parameters (shape, dimensions, material composition), this represents raison d'être of the other approaches, as follows. o Absolute, like “Monte Carlo” calculations (MC), yielding full energy peak efficiency for a given counting arrangement. It is essentially statistical treatment of the events which photons undergo – from being emitted by a source atom until the interaction with the detector active body – including the treatment of the so produced electrons, positrons and other subsequent energy carriers. This approach is beautifully exact, on condition that we consider sufficiently large amount of incident photons, and that we know the details about a huge number of physical parameters characterizing the process. After many years of practice, still these are limiting factors for its applicability. o Semi-empirical, trying to conciliate the previous two. Semi-empirical models commonly consist of two parts: (i) experimental (producing one kind or another of reference efficiency characteristic of the detector) and (ii) relative-to-this calculation of peak efficiency. Inflexibility of the relative method is avoided in this way, as well as the demand for some of the physical parameters needed in MC calculations. Numerous variations exist within this approach, with emphases either to experimental or to computational part. Most of them (over)simplify the physical model behind, i.e. the treatment of gamma-attenuation, geometry and detector response. Stemming from the above, ANGLE purpose is to allow for simple, but accurate determination of the activities of gamma spectroscopic samples for which no “replicate” standard exists, in terms of geometry and matrix. It employs a semi empirical “efficiency transfer” (ET) approach, which combines advantages of both absolute and relative methods to determine sample activity by gamma spectrometry. In doing so, practical limitations of the latter methods are reduced, while the potential for systematic errors in the former is minimized [1, 2]. The physical model behind is the concept of the effective solid angle – a parameter calculated upon the input data on geometrical, physical and chemical (composition) characteristics of the source, the detector and counting arrangement (“geometry”). These three parameters are accounted for through a simultaneous differential elaboration, which leads to complex mathematical expressions – however easily managed by means of numerical integration with ordinary computers (PCs). A sound theoretical foundation in the above sense is hence laid in the beginnings of ANGLE development [1-4]. ANGLE is conceived and developed at the University of Montenegro, while commercially distributed by AMETEK-ORTEC, U.S.A. [5]. International cooperation has been an essential part during its evolution. Numerous scientific and technical papers, as well as Ph. D. theses, have emerged from ANGLE progression and utilization. OUTLINE OF ANGLE SOFTWARE All relevant information about ANGLE – including theoretical background, features, downloads, references, papers, questions, etc. – is found in much detail at its web site [6]. During its development, care was taken to reflect and take into account numerous users (gamma-spectrometrists’) needs, perspectives and feedback. User communication/support was thus an important part of the software development. Four main versions emerged since 1994 (current one being ANGLE 4), with nearly 300 updates. ANGLE 4 main features can be summarized as: o high accuracy – typical uncertainties at results obtained (quantitative gamma-spectrometry report) are of the order of a few percent – even introduced by input data, not the software itself; o broad range of applicability (e.g. in environmental monitoring, fuel cycle and nuclear industry, waste management, regulatory control, nuclear security and safeguards, medicine, research and education, etc.); o ease of use; there is a highly user oriented and intuitive interface, supported by graphical scaled visualization; o all parameters characterizing efficiency calculations are shown at one screen, thus easy to control and comprehend; o short computation times, which are an order of magnitude shorter than those of MC methods – even the most complex calculations are executed within minutes on ordinary PC machines; o flexibility in respect with input parameters and output data; o easy communication with another software – thus, can be regarded as a modular software; o suitability for teaching/training purposes; o calculates detection efficiencies for most common counting arrangements; o software supports:  semiconductor and scintillation detectors  closed end, open end, planar, well-type detectors  cylindrical, Marinelli, disc, point sources  various source containers  any source dimension  any matrix composition o detector calibration is done by the user; o there is no need for detector factory characterization and.or re-characterization o it is compatible with most common (ORTEC’s and Canberra’s) spectrum emulation software (GammaVision, Genie2000); o one copy of the software can serve all detectors in the lab, regardless of detector type, age and manufacturer; o transparent, hands-on software (no “black box” for the user) – all parameters of the detector, sample, counting geometry etc. are under control and subject to modification; o practical educational and training tool for gamma-spectrometry courses at all levels; o highly convenient for scientific research; o software design is aimed at bringing user to a higher level of gamma-spectrometry practice; o preview possibility for input data; visualizes counting arrangement (detector, source, geometry) and indicates potential systematic errors (blunders) o enables easy programming of huge batch jobs for efficiency calculations; suitable for monitoring, research (e.g. error propagation studies), optimization, etc. o has a modular nature – made to easily fit into more complex programs, which supply data to it and/or make use of its output results o highly informative web site o software architecture offers potential for accommodating other efficiency calculation methods of semi empirical or absolute (MC) type o its current scope of applicability can readily be extended to further/particular user's needs and/or fields of interest – it can be thus regarded as an “open ended” computer code; o multi language interface; currently exists in English, French, Spanish, Russian, Chinese and Japanese, but new languages can readily be added by translating (through a dedicated subroutine) an Excel file of cca 700 short strings A key aspect and difference from other approaches, which greatly enhances practicality, is that no “factory characterization” of the detector response is required. In fact any HPGe detector may be used so long as some basic knowledge concerning its construction is available. These technical data are normally supplied to the customers by detector manufactures, in form of accompanying data sheets, or can be obtained upon request. Care should be taken for the data to be as accurate as possible, since the accompanying uncertainties are propagated into final analytical results as systematic errors. As to reliability, let us mention here an IAEA organized intercomparison exercise, which was conducted in 2010 by European Commission JRC IRMM (Geel, Belgium) [7]. Ten laboratories took part, applying nine prominent efficiency transfer calculation codes: semiempirical (source derived) and absolute (Monte Carlo). The exercise revealed that systematic errors (differences occurring between experimental and calculated efficiency results) are, for the most part, not due to the calculation methods/procedures themselves (including attenuation coefficients, cross sections and other physical parameters used), but more to uncertainties in input data (detector, source, materials, geometry). ANGLE was one of participating codes, scoring 0.65% average discrepancy from the exercise mean values, with no evidence of systematic bias. APPLICABILITY TO URANIUM EXPLOITATION MANAGEMENT ANGLE applicability in uranium exploitation management is evident and straightforward – its simplicity, flexibility and fast performance allows for quantitative analyses of large numbers of samples in short periods of time, regardless of type, origin, size, shape, matrix composition etc. In practice, this translates into ability of quantitatively analyzing thousands gamma-spectroscopic probes within the counting capacity limits of the equipment – including samples of geological, environmental, industrial, biological, medical… or whatsoever origin, as these may occur during uranium exploitation management – from exploration to remediation phase (“cradle-to-grave”). This constitutes a considerable source of reliable first-hand information, which is essential in the decision makings. Applying ANGLE in uranium related matters is not a new story. Namely, in its various forms, ANGLE has been in use for 25 years now in hundreds of gamma spectrometry oriented laboratories worldwide, including many dealing with different aspects of uranium exploitation – either directly (in exploration, mining, processing, environmental and workplace monitoring, QC/QA, etc. facilities) or indirectly (e.g. within regulatory, health, research, educational or other institutions) [8]. However, a sort of topical (uranium) standardization – for instance in form of a dedicated “U” module – would be a welcome future development in this respect. ACKNOWLEDGEMENTS Kind and valuable assistance from the colleagues of the University Centre for Nuclear Competence and Knowledge Management (UCNC) in preparing this manuscript is highly appreciated. REFERENCES [1] Jovanovic, S., Dlabac, A., Mihaljevic, N., Vukotic, P., ANGLE: A PC code for semi-conductor detector efficiency calculations, J. Radioanal. Nucl. Chem., 218 (1997), pp. 13 20. [2] Jovanovic, S., Dlabac, A., Mihaljevic, N., ANGLE v2.1 – New version of the computer code for semiconductor detector gamma efficiency calculations, Nucl. Instr. Meth. A 622 (2010), pp. 385 391. [3] Vukotic, P., Mihaljevic, N., Jovanovic, S., Dapcevic, S., Boreli, F., On the applicability of the effective solid angle concept in activity determination of large cylindrical sources, J. Radioanal. Nucl. Chem., 218 (1997), 1, pp. 21 26 [4] Moens, L., De Donder, J., Xilei, Lin, De Corte, F., De Wispelaere, A., Simonits, A., Hoste, H., Calculation of the absolute peak efficiency of gamma ray detectors for different counting geometries, Nucl. Instrum. Methods Phys. Res., 187 (1981), 2 3, pp. 451 472 [5] AMETEK-ORTEC, U.S.A., http://www.ortec-online.com [6] ANGLE software for quantitative gamma-spectrometry, http://angle4.com [7] Vidmar, T., Celik, N., Cornejo Diaz, N., Dlabac, A., Ewa, I.O.B., Carrazana Gonzalez, J.A., Hult, M., Jovanovic, S., Lepy, M.C., Mihaljevic, N., Sima, O., Tzika, F., Jurado Vargas, M., Vasilopoulou, T., Vidmar, G., Testing efficiency transfer codes for equivalence, Appl. Radiat. Isot. 68 (2010), pp. 355 359. [8] ANGLE software – Prominent Users, http://angle4.com/references.html

Speaker: Prof. Slobodan Jovanovic (University of Montenegro, Centre for Nuclear Competence and Knowledge Management (UCNC))

51 DEVELOPMENT, EVOLUTION AND IMPLEMENTATION OF ENVIRONMENT PROTECTION STANDARDS FOR URANIUM MINING IN THE AUSTRALIAN TROPICS

The Ranger uranium mine is surround by dual World Heritage Listed Kakadu National Park. Kakadu is recognised for its significant cultural and environmental attributes. Because of this, the Ranger mine is subject to very stringent environmental protection standards. These standards are developed and overseen by the Australian Government through its Supervising Scientist Branch, which is part of the Department of the Environment and Energy. For 40 years the Supervising Scientist Branch has undertaken site-specific monitoring and research into the impacts of uranium mining on the sensitive environment surrounding the Range mine site. The collected data was used to derive site-specific water quality compliance objectives that have helped to ensure the protection of the environment from effects of mining operations. The data is now being used to develop closure criteria for the rehabilitation of the Ranger site, which is scheduled to be complete by 2026. This presentation will provide an overview of the Supervising Scientist Branch’s monitoring and research programs and demonstrate how the collected data has been used to ensure protection of the environment throughout the operation and after the rehabilitation of Ranger uranium mine.

Speaker: Ms Kate Turner (BSc)

52 A RISK BASED APPROACH TO URANIUM MINING REHABILITATION

The Supervising Scientist is established to protect the environment from the effects of uranium mining in Northern Australia, including overseeing the operation and closure of the Ranger uranium mine. Ranger has operated since 1980 and is surrounded by the dual World Heritage listed Kakadu National Park. Uranium milling operations at Ranger must cease by 2021, with rehabilitation work to be completed by 2026. A risk-based program of assessment and research has been developed by the Supervising Scientist Branch to ensure the protection of the environment throughout the decommissioning and rehabilitation process, between now and 2026. This presentation will provide details of the risk assessment and planning work undertaken by the Supervising Scientist Branch to systematically identify the knowledge needed to ensure environmental protection, the project work required to address these needs, align these with the mine rehabilitation schedule and inform the regulatory assessment process.

Speaker: Mr Keith Tayler (Australian Government)

15:40 Break

Health, Safety, Environment and Social Responsibility

Conveners: Dr Gabi Schneider (Namibian Uranium Institute), Prof. Jim Hendry (University of Saskatchewan)

53 IAEA Coordination Group for Uranium Legacy Sites (CGULS): Strategic Master Plan for the Environmental Remediation of Uranium Legacy Sites in Central Asia

Uranium mining and processing activities have been carried out in Central Asia since the mid-1940s, particularly in the mountainous areas above the Syr Darya River and the Ferghana valley, where the borders of the Kyrgyz Republic, Kazakhstan, Tajikistan and Uzbekistan intersect. Many of these activities ceased in the 1990s, leaving numerous sites containing uranium and other hazardous and radioactive wastes in populated areas. Left un-remediated, these uranium legacy sites (ULS) pose a hazard to future generations. To move forward CGULS developed and is implementing a Strategic Master Plan (SMP) for environmental remediation of ULS in Central Asia. The SMP sets out a strategy for adoption and a master plan for implementation for the remediation these ULS. The SMP addresses three main activities: 1. Systematic and comprehensive studies to assess the current status of each ULS and to propose appropriate and effective remediation solutions. 2. Remediation solutions implemented according to international standards and good practice. 3. Countries develop the capacity to implement remediation projects and assume long term stewardship of the remediated sites. The first step of site evaluation and remediation solutions design is underway; the next step, the actual implementation of the remediation work, requires additional funding.

Speaker: Ms Michelle Roberts (IAEA)

54 Five Years After The UPSAT Mission: Progress and challenges

Regulating Uranium extraction industry is complex process which involves multi-regulators with different requirements. Tanzania had several regulators with less experience in uranium mining domain. Different government departments’ legislation and regulations lacked clarity and consistency. Overlapping mandates between different government departments complicated to the operator to which laws should follow. International Atomic Energy Agency (IAEA) Uranium Production Site Appraisal Team (UPSAT) was an assistance requested to address this challenge. UPSAT was first assistance mission of its kind in African soil. The mission assessed the following five primary parameters, the regulatory system, Sustainable uranium production life cycle, Health, Safety and Environment (HSE), social licensing and Capacity building. This paper presents the progress and development made since 2013 mission execution.

Speaker: Mr Dennis Amos Mwalongo (Tanzania Atomic Energy Commission)

55 URANIUM MINING REMEDIATION IN AUSTRALIA’S NORTHERN TERRITORY

INTRODUCTION AND HISTORY Uranium was first identified in the Northern Territory (NT) in the late part of the nineteenth century [1]. However, it was only in the years immediately after World war Two that the mineral took strategic importance and exploration efforts really took off. The discovery of the Rum Jungle deposit by Jack White in 1949 is generally accepted as the start of the modern era of uranium mining in the NT [2]. Located about 75km south of Darwin the Rum Jungle mine operated from 1954 to 1971 and produced 3,530 t of uranium oxide and 22,000 t copper. A number of smaller mines in the vicinity also contributed to the development of the industry. However, when contracts were fulfilled or deposits worked out, little effort was put into remediation of the sites and many were simply abandoned. In some cases these legacy sites were relatively benign but others became sources of contamination; usually due to the development of acid and metalliferous drainage (AMD) arising from the sulphides in the remaining waste rock piles. Only in later years did legislation and public concern lead to action being taken. Some of those actions are described later in this paper. THE SECOND MINING ROUND After the “rush” of the 1950s the taste for uranium seemed to quieten down until the prospect of uranium as a fuel for nuclear power became firmly set in people’s minds. In the later 1960s exploration returned to locations which had been successful previously. The NT was one of those areas, especially around the Pine Creek geosyncline. The results of the exploration effort in the Alligator Rivers Region (ARR) were the deposits at Ranger, Jabiluka, Nabarlek and Koongarra. But by the time the development proposals were being formulated a new paradigm had been established with respect to mining, environmental management and remediation. Society was no longer prepared to accept that mining, especially uranium mining, would be a one-time user of land in the NT. The result was Australia’s first environmental inquiry, the Ranger Uranium Environmental Inquiry (RUEI). This is perhaps better known as the Fox Inquiry after the Chairperson, Mr Justice Fox. The Inquiry produced two reports [3, 4] which decided that (a) Australia could become involved in nuclear fuel cycle activity by mining uranium, but that would be the limit of the involvement; and (b) that the four identified deposits in the ARR would be able to proceed to development, subject to the process of environmental impact assessment required under recently promulgated laws. Only two of the four identified uranium resources have been developed to date, Nabarlek and Ranger [5];both sites are subject to strict environmental regulation set down in the Environmental requirements from the Commonwealth Government (ER). Koongarra has been returned, unworked, at the request of the Aboriginal Traditional Owners of the land to become a part of the surrounding world heritage listed Kakadu National Park. Jabiluka was investigated and an EIS submitted but the site been put back into long term care and maintenance with the disturbed areas now in an advanced state of remediation following the removal of all infrastructure and the backfilling of the underground development trial workings [6]. MODERN REMEDIATION Small scale operations from the 1960s in the South Alligator Valley had been simply abandoned when production quotas were filled. About 13 mines and three processing sites produced approximately 850 tonnes of uranium oxide in this programme [7]. The sites were left un-remediated until the area was designated to be included in Stage 3 of the Kakadu National Park, at which time a series of hazard reduction works (HRW) were undertaken to improve public safety both physically and radiologically [8]. As part of a longer term lease agreement with the Aboriginal Traditional Owners in 1999 a programme was begun to undertake the planning and implementation of the various mining and processing sites in the valley [9]. This programme was begun eventually in 2007 and completed in 2008 with the various small containments built under the earlier HRW programme being opened up and the contents relocated to a central customised central containment built to modern standards. The containment was instrumented and monitoring is ongoing. Various reports have been made regarding the success of this project and presented at international meetings [10, 11]. The Nabarlek mine operated between 1979 and 1988; mining of the relatively high grade ore was undertaken in one dry season and the stockpile was processed over the following ten years at a production rate of about 1000t of U3O8 annually [12]. From the outset the mine had a plan of remediation and a fund to cover the cost of the works was guaranteed. After about a year or so the mine employed a decommissioning engineer whose main task was to ensure the plan was kept up to date and every opportunity for progressive remediation was taken up. One of the environmental requirements (ER) for uranium mines in the ARR was that all mill tailings had to be returned to the mined out pits at the end of the mine life. In the case of Nabarlek the ore body was excavated entirely in 1979 and then processed over the following ten years with tailings being returned directly to the pit. In 1989 the mine was mothballed in case another ore body could be found. However, this was not the case and the mine was decommissioned and remediated in 1995 with the final work of seeding the site being completed before the onset of the wet season in December 1995. Since then the site has continued to revegetate with varying degrees of intervention from successive lease holders. Some exploration activity has been based at the site and in the surrounding areas since that time although the minesite has been allowed to continue to remediate. Revegetation has been moderately successful despite severe damage from a tropical cyclone in 2006 [12]. The Rum Jungle uranium and copper mine operated from 1954 to 1971 [2] and produced 3,530t U3O8 and 20,222t Copper. The site was abandoned with little remediation apart from a token effort in 1976. Ongoing AMD production resulted in significant impacts in the Finniss River. As a result $18.6M was spent on remediation between 1983 and 1986 and the program was hailed as best practice at the time. Sadly the works did not completely solve all the issues and by 2000 the situation was deteriorating. A series of investigations began in 2004 which eventually resulted in the NT and Commonwealth Governments entering into a National Partnership Agreement (NPA) in 2009 which was the beginning of a long term comprehensive program to characterise the site and develop new designs for its remediation. Under the NPA and successive project agreements a wide variety of studies have been under taken to obtain data which has facilitated a comprehensive characterisation of the site, assisted in improving the day-to-day management of the site and enabled development of an improved remediation plan for the site. A major feature of the programme has been the extensive consultation with the Aboriginal Traditional Owners of the land and their inclusion in the process of determining final land form and land use objectives. The project has also provided business development opportunities for the land owners which has resulted in small business ventures being created and developed at the project, which have then gone on to compete successfully in the local market. The final design data are currently being collected and contracts let to develop the final remediation plan; this includes preparation of an Environmental Impact Statement for assessment under NT and Commonwealth legislation. This work is due to be completed in 2019, with the production of costed designs for the final remediation program. CURRENT ACTIVITY The Ranger Uranium Mine, operated by Energy Resources of Australia Ltd (ERA), is, after 36 years, the longest producing uranium mine in Australia. Located about 250km east of Darwin, the mine is surrounded by, but not part of, Kakadu National Park. Operating since 1980 the mine has produced more than 125,000 tonnes of uranium oxide to date. ERA finished open pit mining in 2013 with the end of work in Pit 3. The previous pit, Pit 1, was backfilled with tailings between 1996 and 2004, in accordance with the ERs. In 2017 work started on completing the back filling Pit 1 using waste rock to commence construction of the final land form. Details of the final land form design are yet to be finally agreed with Aboriginal Traditional Owners but the requirement is that the area could be incorporated into Kakadu National Park if desired, without the need for any special management [11]. ERA is continuing to process ore from existing stockpiles on site. The present administrative arrangements require ERA to cease production and processing in January 2021 and to have completed remediation of the site by January 2026. Since 2013 ERA has continued to implement progressive remediation works as and where it has been possible to do so, compatible with the last of the processing operations. When mining ended in Pit 3 work began immediately on preparing the void to be used as a disposal site for mill tailings. The main part of this programme was the placing of 33 M t of waste rock in the base of the pit to provide a level floor for deposition of tailings. Since 2015 mill tailings have been deposited directly to this pit. As well as the tailings in Pit 1 ERA also has a tailings dam approximately one kilometre square containing nearly 23 M t of tailings. Since 2016 work has been underway transferring these tailings into Pit 3 using a custom built dredge. This operation is scheduled to last until 2021. At that time the excess process water will be disposed of through treatment and the tailings allowed to dry out and stabilised using prefabricated vertical drains. The final land form construction will then begin using waste rock with the final surfaces being made of material containing less than 0.02% uranium oxide, i.e. non-mineralised material. All this work is due to be completed in 2025 to allow planting to be completed by 2026, as required by the present administrative arrangements. The Ranger site currently has a considerable inventory of process water which cannot be released from site. A brine concentrator, built in 2013, treats process water to produce 1.8GL of clean distillate per year, which is suitable for controlled release. The residual brines are to be injected into the void space in the back fill at the base of Pit 3. Other, less contaminated, waters on site are passed through conventional water treatment plants (reverse osmosis) and the permeate is released in accordance with the appropriate approvals. As the climate has marked wet and dry seasons, discharge of clean water is only permitted when creeks and rivers are running. During the dry season, when ephemeral rivers have ceased to flow, water may only be released through evaporation. ERA are introducing turbomisters during the dry season as a way of enhancing natural evaporation losses for treated water. The progress of the remediation work is overseen by a Minesite Technical Committee (MTC) which comprises ERA, the NT DPIR, the Supervising Scientist and, to represent the Aboriginal traditional Owners, The Northern Land Council and the Gunhdjeimi Aboriginal Corporation. The Commonwealth Government Department of Industry, Innovation and Science attends meetings as an observer. ERA is producing a Mine Closure Plan as a document for publication to the community; standards and criteria for the remediation programme are developed in consultation with the MTC members and other interested parties as appropriate. CONCLUSION Uranium mine remediation in Australia’s Northern Territory has come a long way from the days of simple abandonment that were the normal procedure only 50 years ago. Recent and current sites are being remediated in accordance with current leading practice and considerable attention is paid to consultation with stakeholders to ensure all concerns are understood and have the opportunity to be addressed. The efforts have not stopped there with a number of legacy uranium sites being cleaned up as well. There have been valuable lessons learned at every stage of this story and they are in turn being applied to the future work programmes for remediation of these and other mines in the region. REFERENCES [1] Department of Primary Industry and Resources (DPIR) (2018) Rum Jungle Mine History-Discovery and Exploration. https://dpir.nt.gov.au/__data/assets/pdf_file/0017/261512/Discovery_and_Exploration.pdf. Accessed February 2018. [2] https://dpir.nt.gov.au/mining-and-energy/mine-rehabilitation-projects/rum-jungle-mine (accessed February 2018) [3] Ranger Uranium Environmental Inquiry. First Report. Australian Government Publishing Service, Canberra, 1977 [4] Ranger Uranium Environmental Inquiry. Second Report. Australian Government Publishing Service, Canberra, 1977 [5] Waggitt, P. (2017). Update on uranium mining in the Northern Territory, Australia 2017. Presentation at the IAEA-UMREG meeting of the Uranium Mining and Remediation Exchange Group (UMREG), Bessines , France 16-18 October 2017(Powerpoint and abstract only). [6] Waggitt, Peter (2012). The Northern Territory’s Uranium Industry: Past, Present and Future. In proceedings SWEMP 2013. 13th International Symposium on Environmental Issues and Waste Management in Energy and Mineral Production, New Delhi, India. 28-30 November 2012. [7] Waggitt PW (2000) The South Alligator Valley, Northern Australia, Then and Now: Rehabilitating 60’s uranium mines to 2000 standards. in proceedings of the SWEMP 2000 Conference, Calgary, Canada. May30 – June 2, 2000. pub: Balkema. [8] Waggitt PW (1996) Hazard reduction works in the upper South Alligator Valley. Proceedings of the SPERA Specialist Workshop - Radiological aspects of the rehabilitation of contaminated sites (RARCS), Jabiru NT 20-22 June 1996. Pub. South Pacific Environmental Radiation Association. [9] Needham S & Waggitt P (1998) Planning Mine Closure and Stewardship in a World Heritage Area-Alligator Rivers Region, Northern Territory, Australia. in Proceedings of the Long Term Stewardship Workshop, Denver, CO, 2-3 June 1998. US Department of Energy, Grand Junction Office (CONF-980652). [10] Waggitt, Peter & Fawcett, Michael. (2008). Implementation of Uranium Mine Remediation in Northern Australia. Australia’s International Uranium Conference, Adelaide 18-19 June, 2008. Australasian Institute of Mining and Metallurgy (AusIMM), Melbourne (CD-ROM). (Powerpoint and abstract only [11] Waggitt PW (2000) Nabarlek uranium mine: From EIS to decommissioning. in Proceedings, URANIUM 2000 - International Symposium on the Process Metallurgy of Uranium. Saskatoon, Canada 9-15 September 2000. Pub. Canadian Institute of Mining, Metallurgy and Petroleum, Montreal, Canada.

Speaker: Mr Peter Waggitt (Department of Primary Industry and Resources of the Northern Territory)

56 ASSESSMENT OF THE IMPACT OF URANIUM PRODUCTION WASTE STORAGE FACILITIES ON THE ENVIRONMENT BASED ON THE RESULTS OF HYDROGEOLOGICAL MONITORING AND NUMERICAL MODELING

INTRODUCTION The largest uranium mining enterprise in Russia, Public Joint-Stock Company Priargunsky Industrial Mining and Chemical Union (PJSC PIMCU) was established in 1968. Uranium mining is carried out by underground mining on the basis of operating mines, and ore processing is carried out at a hydrometallurgical plant[1] ], which began operating since 1976. Simultaneously with the commissioning of the GMZ, a sulfuric acid plant was started. The sulfuric acid was produced from pyrite cinders. Since 2009, the sulfuric acid plant has been switched to block sulfur. The wastes with a residual radioactivity caused by processing uranium ore are deposited in a ravine in two tailing dumps, neutralized with calcareous water. A cinder storage facility for the wastes produced by pyrite roasting process at the sulfuric acid plant is located in the same ravine. These wastes are characterized by high sulfate ion concentration and a lack of radioactivity. All these storages are a wet type, in the landscape its represents as cascade of three lakes. Leaks through earthen dams within the limits of normative losses are intercepted by a system of drainage wells in the lower tail of the storage facility dam and are returned into the technological process. Monitoring of leakages from them is carried out by 196 observation wells. To inform the public about the state of the environment in the area where the enterprise is located, summarized results are published in annual environmental reports [2]. Wells field situated near a river is located within the study area provide water for a city with a population of 45 thousand people. Water is obtained from first aquifer of the intermountain artesian basin. The exploration wells are located in 12 kilometers from storages. For over 40 years of the storages existence a contamination plume in the aquifer has formed by the filtration through earth dams. The plume does not exceed area of the sanitary protection zone of these three storages. As practice shows, the leaks through earth dams are very common for the wet type of tailings in old mines of hydrometallurgical plants (in Germany, USA, Canada, Niger, Australia, etc.) [3]. The main objective of this study was a conservative forecast of the spread of contamination plume towards the water intake. The forecast was carried out with two assumptions that from now on (from 2015), the collection of waste into the storage facilities is stopped and the interception of contaminated water by drainage wells in the lower tail of the cinder storage dam is stopped. Conservative approach means maintaining the concentration of pollutants in the sources at a constant level for the entire forecast period. DESCRIPTION The geological structure of the territory involves two structural floors. The lower floor is represented by Proterozoic and Early Paleozoic metamorphic rocks, Riphean, Vendian and Paleozoic granitoids. The upper floor contains Mesozoic (J-K) terrigenous strata of sedimentary and sedimentary-volcanic rocks that fill up depressions and calderas, Upper Jurassic small intrusions of the Kukulbei complex and subvolcanic rocks genetically related to the Late Jurassic and Cretaceous volcanism. The research area is located within an intermountain depression. The intermountain artesian basin is associated with this depression. This basin consists of a few aquifers which are hydraulically connected and formed an aquifer system. The upper part of a cross-section consists of conglomerates, sandstones, siltstones (Lower Cretaceous rocks) that overlap with Quaternary sediments of alluvial, limnetic and proluvial genesis, which are the main collector of fresh groundwater used for the city's water supply. For generalize purpose once considered all types of groundwater in this basin as parts of unite aquifer system, but conditionally divided by the types of water-bearing rocks and their filtration properties. Systematic observations of the state of the environment on the territory of PJSC PIMCU began in 1973. Hydrogeological monitoring is currently carried out in 196 observation wells. Data analysis of groundwater level dynamic shows, that the longest observed steady period was the last 14 years. The groundwater average depth for this period is no deeper than 5 m on the most of the research area, which leads to a high rate of the evapotranspiration. The well field situated nearby the river doesn’t make a significant impact on groundwater level, because pumping wells obtain water what before was discharging by evapotranspiration and the river. Also, it is important to mention that near the location of tailings dumps are stand out a mine drainage, that cause a local groundwater depression and prevents the spread of contaminated water. METHODS Based on the created GIS project, digital elevation model, digitized geological maps, engineering geological well logs and hydrogeological monitoring data, a three-dimensional geological model (GM) was created in the GMS software package. The GM was used as the basis for filtration and solute transport models. In the transport solute model, sulfate ion is selected as an indicator of groundwater contamination, since it has the greatest migration capacity compared to other contaminants in storages. Based on the analysis of the data of the geological site structure model was performed with a 4-layer. The area of the model is 4283 sq. km; the boundaries of the model are determined by the boundaries of the catchment basins. To verify hydrodynamic and transport solute model, ground water levels and concentration of sulfate ion from observation wells located in the ravine were used. Once obtained a good convergence of field and model data. The deviations of the model and measured concentrations of the sulfate ion are within the limits of the determination errors. RESULTS AND DISCUSSION The simulation results indicate that the contamination plume from the first tailing dump is stable and partially discharged in the mine drainage. The contamination plume from the second tailings dump is less influenced by the mine drainage and its slowly spreading along the ravine toward the river. The cinder storage facility, which closes the cascade of simulated lakes, has the main role in the groundwater contamination process. As it was mentioned above the cinder storage facility is a main source of sulfate ion contamination that is the reason why sulfate ion is a very suitable indicator for this particular model. The prediction modeling of remediation actions showed that in the case of complete elimination of the cascade of man-made lakes the currently existing plume of pollution will migrate at a significantly lower rate and gradually degrade due to hydrodynamic dispersion. Reduction of the sulfate ions concentration to the values of MPC for drinking water (500 mg / l) will take about 300 years CONCLUSION Conducting facility-focused monitoring allows implementing the concept of controlled pollution. This concept includes an information analysis system for facilities of the nuclear power industry based on facility-focused monitoring system of subsurface state, hydrodynamic and solute transport modeling and as a result an informational geo-ecological report. Conclusions: 1. The current state of groundwater in the area of waste storages shows that the groundwater contamination does not exceed the boundaries of the sanitary protection zone for all kind of manmade pollutants; 2. The primary manmade contamination of groundwater is the sulfate ion coming from the cinder storage facility; uranium pollution mainly is intercepted by the mine drainage. Therefore sulfate ion was used in the solute transport model as an indicator of contamination spread; 3. Conservative forecast shows the spread of contamination in the groundwater from the tailing dumps does not reach the water supply wells even at the horizon of the forecast of 300 years. REFERENCES [1] www.priargunsky.amz.ru [2] Environmental Safety Report PJSC PIMCU 2015 (www.rosatom.ru) [3] INTERNATIONAL ATOMIC ENERGY AGENCY, Technologies for the treatment of effluents from uranium mines, mills and tailings. IAEA-TECDOC-1296, IAEA, Vienna (1996).

Speaker: Ms Natalia Kurinova (Federal State Budgetary Institution "Gidrospetsgeologiya")

57 Development of mine water quality, subsequent sediments contamination and passive 226Ra treatment in Zadní Chodov, Czech Republic – case study

INTRODUCTION The uranium deposit Zadní Chodov was discovered using a car-borne gamma survey in the year 1952. In 1958, the uranium mining area Zadní Chodov was established, covering 7.16 km2. During operation, 5 mining shafts were constructed on the deposit [2]. Shaft No. 1 with a total depth of 401.6 m was closed in 1963, the shaft No. 2, reaching depth 761.8 m was closed in 1989. Shaft No. 3 was excavated to 28th floor level in depth of 1263.2 m. Furthermore, there were shafts No. 12 (780.4 m depth) and No. 13 (1083.8 m depth). As with many other ore deposits in the Czech Massif, local uranium ores were exploited by using method of cut-and-fill stopping and gradual top-slicing stoping under a man-made ceiling. MINING HISTORY Uranium ore was mined at the site for 40 years and the total production exceeded 4,000 t U (the 6th largest deposit in the Czech Republic). The exploration activities were completed in 1988, and mining operation ceased in 1992, concurrently with many other mines during the first wave of ordered mining activities reduction. The mine was closed, the surface area mitigated, while waste dumps material was processed into crushed aggregates. In February 1993, the underground water pumping was discontinued and spontaneous flooding of mine was allowed. MINE WATER TREATMENT Due to the mine flooding, in March 1995 the water streamed to the surface, yielding 15 L/s. To resolve these circumstances, a Hydrogeological Study of the Region was performed aimed to asses a final management system for the water outflow and subsequent treatment [5]. A drainage system was built in the area of concern, connected to an accumulation pond followed by a decontamination station (water treatment plant). The captured mining waters were continuously sampled prior to entry, while the dissolved contaminants, especially Uranium and Radium, were monitored. The initial high Uranium and Radium concentrations associated with the first flush effect had in first five years (1995 – 2000) a declining trend. In November 2001, a borehole HVM-1 was drilled from the surface to the second mine level, from the area with the lowest surface elevation (from the "melioration ditch") and thus was created a new pathway, allowing efficient, spontaneous runoff of the mine water to the surface, while reducing the water level inside the mine. This was done to eliminate any previous outflows and enable the deposit to be gravitationally drained. In 2010, the mine water reached quality which allowed its release into the watershed, without pumping and cleaning. Since then, the mine water has been experimentally discharged without cleaning into the melioration ditch that leads to the Hamer Creek, however the mine water treatment plant (decontamination station) is still on standby and ready to be activated if necessary. MINE WATER, SEDIMENTS AND LEGISLATION FRAME The initial high Uranium and Radium concentrations associated with the first flush effect had in first five years (1995 – 2000) declining trend. Nowadays mining water has a low content of dissolved solids (ca 300-350 mg/L) and hydrochemistry has greatly stabilized. Unat. (less than 0.1 mg/L on average) and 226Ra (1,600 mBq/L on average) concentrations do not show significant anomalous variations since 2010. In accordance with valid Czech legislation in the field of radiation protection, the quality of the discharged mine water is continuously monitored and concentration of 226Ra is also monitored in the sediments along the melioration ditch up to the Hamer Creek estuary. Currently along approximately 900 m of the stream there are 11 monitoring locations. Measured concentration values are compared with reference levels. Particular attention is paid to the accumulation of 226Ra in the sediments along the upper segment of the melioration ditch. If the values of the Radium concentrations in the sediments would consistently exceed the reference levels, and the contamination would spread towards the Hamer Creek, the situation would have to be addressed. One possible solution would be reactivation of the decontamination station. Therefore, a preliminary exploration of the area was launched in 2017 to test other potentially useful methods of "cleaning" mine water on the site. ENVIRONMENTAL IMPACT ASSESSMENT Through the year 2017, an in-situ gamma spectrometric survey of the area, surrounding the mine water outflow, was conducted to determine the background values of natural radionuclides and localized possible anomalies of 226Ra or Unat mass activities. This was carried out mainly in locations of the previous water exhausts and in the area of the melioration ditch. The monitored locality is minimally populated and presently used as a grazing pasture for cattle. The gamma spectrometry method did not show exemption levels of radionuclides in the soil, the only possible source of cattle contamination could be the pasture watering system. Based on known concentrations of radionuclides in water, a commitment effective dose was estimated for a representative person, resulting from the meat consumption of cattle, grazing on the site under observation, in the usual pasture regime. At the recommended consumption of 20 kg of beef from Zadní Chodov area, the estimated commitment effective dose was calculated at less than 1 μSv. WATER VOLUME-LIMITED TREATMENT EXPERIMENTS Experimental treatment of the outflowing mine water using adsorbents was started in May 2017, based on studies documented in [1, 3, 4, 6, 7]. Two different adsorbents – peat and zeolites (grain size 1-1.25 mm, 2.5-5 mm and 4-8 mm), was placed at the bottom of the 200 L volume barrels. A part of the borehole whole volume of water entered the barrels bottom and passed through the adsorbent layers and finally overflown the barrels. The water flow rate was measured continuously. The peat had low effectiveness from beginning of the experiment and was washed out due to its low specific weight. The treatment using zeolites grain size 4 – 8 mm resulted in very low efficiency and thus both experiments were terminated. Next step was the use of smaller adsorbent pellets (grain size 1-2.5 mm and 2.5-5 mm) starting in June 2017. The testing continued for 4 months and the water samples for radionuclides concentration measurement (before and after treatment) were taken 5 times per week and later 3 times per week. The relative effectiveness of 226Ra treatment was calculated. DISCUSSION The water flow rate in barrels was approximately 0.25 L/s, effective height of barrels was 80 cm and the thickness of the zeolite layer was 20 cm. Taking into account that zeolite layer decrease effective flow volume by about 50 percent, the time interval for contact between water and zeolite is estimated to be 1 minute 40 seconds. In case of zeolite with grain size 1.0-2.5 mm the average initial adsorption ability reached 70%, which after 3 month of experiment duration decreased to level of 40%. In comparison the zeolite of grain size 2.5-5 mm had average initial adsorption ability approx. 80%. The linear trend describing radionuclides concentration decrease indicates adsorption ability about 50% after 4.5 months of operation. The average water flow rate from the drilling well HVM-1 was from October 2016 to September 2017 14.92 L/s. It could be expected that with increasing of the adsorbed radioactive contaminants (and minerals) the adsorption ability of the zeolites will decrease. In case of desired higher water flow rate the amount of required adsorbent must increase proportionally, to maintain the same treatment effectiveness. So far performed introductory experiments do not enable correct estimation of direct dependence between amounts of zeolite used, water throughput and treatment efficiency. Given the above mentioned parameters interdependence, for cleaning mine water using throughput of 15 L/s would require 60 times higher volume of adsorbent to achieve 50% capture effectiveness for 226Ra. That corresponds to 3 tons of zeolite utilization during each 4 month period. COST BENEFIT ANALYSIS In the years 2008 - 2010, the average annual cost of running the mine water treatment plant (using the conventional barium chloride active treatment process) was on the order of millions CZK. Searching for less expensive alternative, a zeolite-based cleaning technology could be passive, greatly reducing the operating costs. If we will consider the use of common “pool mixes” and the adequate amount of approximately 10 ton, the cost of adsorbents consumption can be at the level of hundred thousand CZK per year. In that case it is necessary to add the cost of maintenance, control, monitoring, removal of contaminated materials and landfill. All these operations are expected to be one order less expensive than water treatment plant in operation. CONCLUSIONS On the basis of the available data, the passive method of mine water treatment at the site of Zadní Chodov, using zeolite adsorbents, appears to be potentially applicable. Mining water at the site has low mineralization with a low proportion of suspended matter, which has a positive effect on the life of the sorbent [4]. For the first experiments, commonly available “pool mixes” of adsorbent based on clinoptilolite were utilized. However, it would be desirable to utilize adsorbents based on synthetic zeolites which could have much higher efficiency for adsorption of 226Ra. Higher efficiency and capacity of the adsorbent would, of course, mean overall cost saving, lower consumption, simplification of the loading, unloading and transport process, while reducing the amount of "waste" to be deposited at the tailings pond. Assembling a technological unit utilizing the zeolite technology will be the subject of further deliberation. The main issues will be: - Choice between settling tank and closed piping system - Ensuring a uniform flow through the adsorbent - avoiding preferential path formation - Testing the effectiveness of different types of adsorbents - Adsorbent recycling options - Use of a wetland system - the natural way of the mine water cleaning These and other tasks are planned for the next stages of testing the mine water treatment process in Zadní Chodov and assumes that the findings will also be used at other localities, where the deposition of mine water can cause ecological load. REFERENCES [1] BARESCUT, J., CHAŁUPNIK, S., WYSOCKA, M. Radium balance in discharge waters from coal mines in Poland the ecological impact of underground water treatment. Radioprotection, 44-5 (2009), 813-820. [2] DIAMO, s. p.. Závěrečná zpráva o ložisku Zadní Chodov. DIAMO, státní podnik – správa uranových ložisek, o. z. Příbram (1996). [3] CHAŁUPNIK, S. Impact of radium-bearing mine waters on the natural environment. In Radioactivity in the environment (Vol. 7, pp. 985-995). Elsevier (2005). [4] CHAŁUPNIK, S., FRANUS, W., WYSOCKA, M., GZYL, G. Application of zeolites for radium removal from mine water. Environmental Science and Pollution Research, 20-11 (2013), 7900-7906. [5] ŠTROUF, R. Hydrogeologická studie podchycení plošného výronu důlních vod na lokalitě Zadní Chodov. MS, AQUATEST – Stavební geologie a.s., (1999). [6] WANG, S., PENG, Y. Natural zeolites as effective adsorbents in water and wastewater treatment. Chemical Engineering Journal, 156-1 (2010),11-24. [7] WENDLE, G. Radioactivity in mines and mine water-sources and mechanisms. Journal of the Southern African Institute of Mining and Metallurgy, 98-2 (1998), 87-92.

Speaker: Mr Jirí Wlosok (DIAMO, state enterprise)

Underground and Open Pit Uranium Mining and Milling

Conveners: Mr Christian Polak (AREVA MINES), Dr Mark Mihalasky (U.S. Geological Survey)

58 COMPREHENSIVE EXTRACTION SCHEME FOR MULTIMETAL RECOVERY FROM METASOMATITE–ALBITITE HOSTED LOW GRADE INDIAN URANIUM ORE

COMPREHENSIVE EXTRACTION SCHEME FOR MULTI-METAL RECOVERY FROM METASOMATITE-ALBITITE HOSTED LOW-GRADE INDIAN U ORE INTRODUCTION India is making focused efforts to reach human development index (HDI) of 0.9+, a number considered to indicate decent state of living, from its present index value of 0.6 by 2040 [1]. Meeting the projected HDI necessitates amongst others, the strategies for utilization of various energy resources in a sustainable way. The contribution of nuclear energy in the overall mix is very critical in achieving the target HDI primarily due to its low carbon foot-print and local availability of fertile thorium resources [1]. The installed capacity of nuclear power plants of India at the end of 2017 was 6780 MWe [2]. It is planned to increase this to about 35000 MWe by the year 2022, comprising mainly of PHWRs and LWRs with minor contribution from Fast Breeder Reactor (500 MWe) and Advanced Heavy Water Reactor (300 MWe) [3]. It is reported that the identified Conventional uranium resources in India so far are sufficient to support 10-15 GWe installed capacity of PHWRs operating at a lifetime capacity factor of 80% for 40 years [3]. Continuous efforts are being made by different agencies in India to increase the indigenous uranium production for realizing the fuel demand which include exploration for new deposits, establishing of new mills and augmentation of existing mills. Majority of the Indian uranium occurrences discovered so far fall in low-grade category [4,5]. Maximum utilization of mined ore or comprehensive extraction is an ideal approach for exploitation of lean tenor ores as it addresses the sustainability principles as well as commercial viability terms. Successful cases in this respect which are familiar for uranium ore processing fraternity are the Palabora copper mines (South Africa) [6] and Olympic Dam poly-metallic copper mines (South Australia) [7] and the Jaduguda uranium mines (India) where a Byproduct Recovery Plant (BRP) was in operation for recovering useful metals like Cu, Ni, Mo and magnetite values [8]. With growing interest in rare earth elements for green energy applications many phosphate mine operators are looking into recovery of rare earths in addition to the already established schemes for phosphate and uranium values [9, 10, 11]. Amongst the most promising new uranium findings explored by the Atomic Minerals Directorate for Exploration and Research (AMD), the uranium exploration Agency in India, the Rohil-Ghateswar uranium ore deposit, Sikar district, Rajasthan is prominent one [12]. The Rohil - Ghateswar uranium ore is a metasomatite type deposit hosted by albitised metasediments of Delhi Supergroup in north-west India. The metasomatite uranium occurrences in India are reported to contribute about 3.3% of the total uranium resources and the most important amongst them is the Rohil multi-metal uranium ore which is reported to contain Cu, Mo, Ni and Co values. This paper gives details of the process development studies carried out for multi-metal recovery from the Rohil – Ghateswar low-grade uranium ore. ORE SAMPLE AND CHARACTERISATION A composite feed for the experimental studies is prepared by judicious mixing of split core bore-hole ore samples of different locations of Rohil – Ghateswar ore deposit. The XRD and optical microscopic study of the feed indicated uraninite as the chief uranium bearing phase with traces of brannerite and davidite. The other minerals identified are: chalcopyrite, molybdenite, pyrite, pyrrhotite, riebeckite, quartz, traces of albite, biotite, boulangerite, chlorite, covellite and goethite. Chemically the ore sample showed U3O8 0.04%, Cu 0.14%, Mo 0.024%, total S 4.3%, FeO 13%, SiO2 58.9%, CaO + MgO 6.7%, Na2O 4.3%, K2O 1.04% and Loss of Ignition 4.3%. Amongst the sulfides pyrrhotite content is about10% and pyrite 1.1%. Uraninite is mostly liberated however occasionally uraninite of very-fine size is associated with non-pyrrhotite sulphides. The Bond’s Work Index of the sample is 21.4 kilo Watt h/metric ton. PROCESS DEVELOPMENT The predominant presence of siliceous minerals in the Rohil ore led to the option of choosing sulfuric acid based hydrometallurgical processing scheme for the recovery of uranium values. However, the presence of excessive content of sulfide minerals, particularly the pyrrhotite and pyrite in the ore necessitated a step of physical beneficiation to be integrated with chemical extraction process. Similarly a scheme suitable for recovering copper and molybdenum values in the ore inspite of their low concentration needs to be evaluated due to their vital utility in different futuristic materials. The occurrence of the Rohil-Ghateswar ore body in water-arid region makes design of process scheme for multi-metal recovery a challenging task. Different options have been formulated for achieving the objective of maximum recovery of multi-metals with minimum fresh water requirement. The options include: Option I: Comminution – physical separation of all the sulfide minerals (magnetic + froth flotation) – hydrometallurgical recovery of uranium values – tailings disposal. Option II: Comminution – separation of ferro-magnetic pyrrhotite by physical separation (magnetic) – hydrometallurgical recovery of uranium values – tailings disposal. Option III: Comminution – hydrometallurgical recovery of uranium values – separation of sulfide minerals from leach residue by physical separation (magnetic + flotation) - tailings disposal. Option IV: Comminution – separation of ferro-magnetic pyrrhotite by physical separation (magnetic) – hydrometallurgical recovery of uranium values – gravity separation of leach residue for non-magnetic heavy sulfide minerals recovery – tailings disposal. Option I helps in prior removal of sulfides which are detrimental during leaching of uranium values and simultaneously offer exclusive Cu-Mo sulfide minerals pre-concentrate besides yellow cake. Further the negative effects of acid mine drainage (AMD) are also minimized. However, the two disadvantages here are (i) loss of some uranium values in the sulfide float due to their composite nature and (ii) need for larger volume of water during froth flotation and difficulty in effective recycling of flotation reagent water consisting of residual collector reagent and frother. Though treatment of the reagent water post-flotation on biologically activated carbon (BAC) column is reported to remove organics, the process is nevertheless expensive. Option II yields higher uranium recovery, requires relatively less water due to absence of froth flotation but the problem of AMD persists due to left-over sulfides (Cu-Mo and pyrite) in leach residue or solid tailings. Option III too needs higher volume of water but gives sulfide-free tailings and slightly higher or similar uranium recovery like Option II. Though the surface of sulfide minerals may undergo partial chemical modification due to previous chemical leaching (Option II), the availability of specific collector reagents for mixed oxide-sulfide minerals (unlike alkyl xanthates) would minimize Cu-Mo losses. The major advantage of Option IV is maximum uranium and by-products recovery with minimum water inventory due to easy recyclability of water used in both magnetic and gravity separation stages. The experimental studies were carried out by optimizing various parameters of each unit operation both in physical separation and hydrometallurgical processes. Pyrrhotite values were separated using wet low-intensity magnetic separator (applied magnetic field 4 kilo Gauss), while pyrite, chalcopyrite and molybdenite were pre-concentrated using froth flotation with ‘alkly xanthate – pine oil’ reagent combination. Gravity separation was conducted on wet shaking table using slimes deck. Uranium values were recovered in the form of uranium peroxide by adopting the following unit operations in sequence namely, conventional agitation leaching with sulfuric acid-pyrolusite reagents – filtration – ion exchange purification – multi-stage precipitation viz. initially the iron-gypsum cake at pH 3 followed by precipitation of uranium peroxide. Separation and purification of uranium from the leach liquor was carried out on a strong base anion exchange resin in sulfate form but eluted with chloride reagent. The overall recovery of uranium for different options was 80 – 83%. The U3O8 assay of uranium peroxide product was 73.8%. The mass and water balance computations showed fresh water necessity of about four times more when flotation of sulfides is incorporated in the process flowsheet over the scheme which relies on specific-gravity difference for pre-concentration of Cu-Mo values. A recovery of about 75% was obtained with respect to Cu & Mo by-products at the pre-concentration stage of the Rohil ore. The sulfide mineral concentrate consists of Cu, Mo, and Fe with traces of Ni and Co. Anand Rao et al have demonstrated sulfation roasting - leaching process for quantitative separation of Cu, Mo, Ni and Co values keeping the Fe oxide phases as insolubles. [13]. Roasting converts sulfides of Cu, Ni and Co to their respective sulfates, and transforms the sulfides of Mo and Fe to their respective oxides by carefully controlling the roasting temperature. The sulfates of Cu, Ni and Co are soluble in mild acidic aqueous medium and MoO in alkaline medium, whereas FeO is insoluble. A forward integration approach helped in treating low-grade concentrates itself for maximizing overall recovery of Cu & Mo. REFERENCES [1] KAKODKAR, A. Low Carbon Pathways for India and the World. Springer Nature Singapore Pte Ltd. 2017. K.V. Raghavan and P. Ghosh (eds.), Energy Engineering, DOI10.1007/978-981-10-3102-1_1.(http://www.anilkakodkar.in/presentations/ lectures/Plenary_lecture_at_INAE-CAETS_Convocation_at_New_Delhi.pdf) [2] http://www.npcil.nic.in/content/302_1_AllPlants.aspx [3] URANIUM 2016: RESOURCES, PRODUCTION AND DEMAND, NEA No. 7301, © OECD (2016) 254 – 268. [4] PARIHAR P S. Uranium and thorium resources in India: UNFC system. (2013) http:// www.unece.org/fileadmin/DAM/energy/se/pp/unfc/UNFC_ws_India_Oct2013/5b.2_Parihar.pdf. [5] SARANGI,A.K.(2014).https://www.unece.org/fileadmin/DAM/energy/ se/pp/unfc_egrc/egrc5_apr2014 /1May/13_Sarangi_IndiaUraniumUNFC.pdf [6] https://en.wikipedia.org/wiki/Palabora [7] https://en.wikipedia.org/wiki/Olympic_Dam_mine [8] BHASIN, J.L. “Mining and milling of uranium ore: Indian scenario”. Technical committee meeting on impact of new environmental and safety regulations on uranium exploration, mining, milling and management of its waste; Vienna (Austria); 14-17 Sep 1998. IAEA-TECDOC-1244, Vienna (2001) 307 – 331. [9] DUTTA,T. et al. “Global demand for rare earth resources and strategies for green mining”. Environmental Research 150 (2016) 182–190 [10] ANDROPOV, M.O. et al. “Extraction of rare earth elements from hydrate-phosphate precipitates of apatite processing”. IOP Conf. Series: Materials Science and Engineering 112 (2016) 012001 doi:10.1088/1757-899X/112/1/012001 [11] ZHANG, P. “Comprehensive recovery and sustainable development of phosphate resources”. Procedia Eng. 83 (2014) 37-51. [12] YADAV, O.P. et al, “Metasomatite-albitite hosted uranium mineralization in Rajasthan”, Exploration and Research for Atomic Minerals, 14 (2002) 109-130. [13] ANAND RAO et al. “Studies on recovery of copper, nickel, cobalt and molybdenum values from a bulk sulphide concentrate of an Indian uranium ore”. Hydrometallurgy 62 (2001) 115–124

Speaker: Dr SREENIVAS T. (Bhabha Atomic Research Centre)

59 Modern uranium open pit grade control

The Langer Heinrich mine resource definition work was based around radiometric logging of drill holes and this has been carried through to mining grade control. The resource model is an MIK estimation with a variance adjustment based on expected mining parameters. Due to the large block size of 50mx50m, infill to 12.5mx12.5m to allow for detailed mine planning is undertaken. This intermediate stage is designed to provide accurate information for mine planning and scheduling for a forward 12 month period and significantly reduces the risks associated with mining a highly variable and nuggety deposit. The blast hole logging process is a one man operation using logging equipment installed on a small four wheel drive vehicle. This allows easy access to close spaced blast holes without the risk of damaging hole collars. The data is downloaded at the end of each shift and is processed to an equivalent uranium grade value using software developed on site. The resulting uranium values are then used to define grade control blocks via conditional simulation software. All material of ore grade is hauled to the ROM pad via a radiometric discriminator system to add a final level of selectivity to the mining process.

Speaker: Mr David Princep (Paladin Energy Ltd)

60 PRELIMINARY STUDY ON URANIUM ORE GRADE CONTROL TECHNIQUES FOR THE HUSAB MINE, NAMIBIA

The Husab mine is situated within the Namib Desert in the Erongo region of western-central Namibia, only 6km south of the Rossing mine owned by Rio Tinto, approximately 60km east of the coast town of Swakopmund and less than 100km northeast from the Walvis Bay Port, the largest deep water port in the southwestern Africa and thus it has convenient traffic conditions and extremely favorable infrastructure conditions for development. As the most important uranium discovery in the world since 2000, the Husab mine has total uranium resource of nearly 300,000 tons of U3O8 with ore reserves of 300 million tons containing 156,000 tons of U3O8 at average grade of 518ppmU3O8. The Husab mine is the first ultra large uranium mine under the construction and operation by China General Nuclear Power Corporation (thereinafter “CGN” for short). Since its mine construction and pre-stripping commenced in 2013, its ore mining commenced in May 2015 and the first barrel of uranium oxide was produced on 31th Dec., 2016, indicating that the Husab mine had been constructed and put into production successfully since CGN acquired it in 2012. The Husab mine has a designed annual mining capacity of over 100 million tons, an annual ore processing capacity of 15million tons and an annual output of 6500tons of U3O8 and it will be the largest open-pit uranium mine with the largest mining capacity and ore processing capacity in the world. Over more than one year’s mining production and operation, the production management, equipment maintenance and technical management system have been fully established at the Husab mine and its operation activities such as the operation of process plant and mining production and so on has gradually gone to the right way. However, due to the larger variations in the shapes of ore bodies than expected, the inaccuracy of measurement of uranium grade, large-scale mining fleets and the precision loading errors etc., lots of outstanding issues have been identified in the fields of the consistency between the grade of resource model and that of mined ore and the control on dilution and loss in the course of mining such as high dilution and loss ratios, large variation in the grade in the mining process. These issues will have important bad effect and even impede the stable production of the Husab mine and thus it is urgent to carry out the study on key techniques of uranium ore grade control for the Husab mine to solve these issues from its mining production. This study focuses on the whole process of mining production and has conducted the following research work including the establishment of geological resource – grade control model system, the optimization on the mining production procedures, the application of controlled blasting technology with a higher precision and its optimization, the application of rapid and accurate grade measurement by down-hole gamma logging. This research work will effectively improve the ore dilution and loss in the course of mining production and further improve the production capacity and its economics of the Husab mine. ADVANCEMENT ON THE STUDY OF ORE GRADE CONTROL TECHNIQUES FOR THE HUSAB MINE 1) Establishment and improvement of “three stage” resource – grade control model system At the moment, the “two stage” resource – grade model system has been adopted at the Husab mine, that is, geological resource model (MIK model) based on exploration database and grade control model (GC model) based on down-hole gamma logging data from blasting holes. The annual plan for mining production, blasting block design, mining and stripping production plan and blasting hole design are proposed based on the MIK model and the mining block definition (composite model) and loading plan are proposed based on the GC model. But due to the fact that the drilling exploration grid is mostly 25m×25m to 50m×50m or larger and the fact that the MIK model is not updated using the mining production data, the MIK model has a low accuracy and reliability with respects to the mining production and thus it cannot be used to effectively guide the annual mining production plan, blasting block design, blasting hole design and its optimization. At the same time, however, the unreasonable model parameters reduce the accuracy of GC model and thus it cannot well define the ore-waste boundary so as to meet requirements of loading and ore blending. On the basis of extensive discussions and sites to other large scale open-pit mines and combined with the actual mining production of the Husab mine, this study proposes the hierarchical, segmental and stable “three stage” resource – grade control model system consisting of resource/reserve model – interim model – grade control model that can be updated dynamically. The grade control model is created based on down-hole gamma logging data from blasting holes by interpolating the ore grade for the block model of a specific blasting block and is used to guide the definition of mining blocks, wire connection for blasting, ore loading and blending. The geological resource model is created by using the geological database incorporating drill-hole data from resource drilling and blasting hole from mining production, it interpolates the ore grade distribution for all the ore bodies within the mining district with an updated within each year or once two years and it is used for the optimization on the ultimate open pit boundary, mid- and long-term mining and stripping plan and annual mining production plan. The interim model proposed in this study is a transitional model between the geological model and grade control model that establish the interconnection of the geological model and grade control model to form an inherent geological model system. This interim model is created by using down-hole gamma logging data from blasting holes drilled for 2~3 benches above the current bench and resources drill-hole data below the current bench, it interpolates the grade distribution for the downward one or two benches from the current bench; it is used for the monthly and weekly mining and stripping plan, blasting block design and blasting hole design and thus improves the blasting and mining efficiency. 2) Optimization and improvement of mining production procedures Since the pre-stripping commenced in 2013 and the ore mining commenced in 2015, a set of intact mining production procedures have been established and the whole mining capacity also increases gradually. But there is still much uncertainty in the whole mining production without the more accurate resource – grade control models in different scales for guidelines and thus it is difficult to meet requirements on the tonnage and grade of ore to be mined so as to ensure the smoothness of mining production at the Husab mine. Hereby, the geological resource models are re-created and updated for the first stage of mining areas in Pit #1 and #2 based on understanding of the mine geology and combined with the geological information and grade data, further define the spatial distribution of ore bodies and exhibit the grade distribution, which will provide guidelines for preparing the mid- and long-term mining plan and annual mining plan. The interim model proposed in this study provides more accurate ore-waste boundaries within the benches to be mined and thus it lays a better foundation for preparing the monthly and weekly mining plans, blasting block design and blasting hole design. The more scientific and reasonable grade control models and accurate ore-waste boundaries will greatly enhance the blasting efficiency and the output of mined ore and reduce the ore dilution and loss and at the same time, it is also very favorable to ore blending directly within the pit to reduce the ore re-transport. 3) Application of advanced controlled blasting technology and its optimization Up to present, the mining production still focus on increasing the stripping capacity at the Husab mine and is not completely transited to focus on mining capacity to provide the ore in tonnage and expected grade required by the process plant. Therefore, the relatively simple blasting technology and blasting scheme are adopted currently at the Husab mine. Neither different blast schemes are adopted according to the differences in mechanical properties of rocks within different blasting blocks and nor the advanced blasting technology is adopted to effectively separate the ore and waste. Thus it is required to improve the blasting efficiency. In this study, the quality of rock masses has been assessed on the basis of studying the physical and mechanical properties of main ore and rocks within the mining district and the rock masses are divided into two categories according to their blastability: one is rock masses of easy to blast consisting of near-surface loose and poorly cemented sandstone and calcrete; the other is rock masses of difficult to blast consisting of underground hard and intact granite, marble, gneiss, schist and quartzite. The ore and rocks are classified as the rock types of difficult to blast at the Husab mine. On the basis of analyzing the blasting parameters currently used at the Husab mine and considering the requirements of ore loading, hauling and primary crushing of ore, it is believed that the current blasting parameters are effective for blasting within the areas of ore and thus relatively reasonable . But it is not reasonable that these parameters are used for blasting within the areas of waste without any modification and they could be improved greatly. Consequently, lots of research work has been conducted to improve blasting parameters used for blasting within the areas of waste, the desktop analyses and digital stimulation are also proceeded and the next step to carry on the field trial on site and then they are applied at the Husab mine. In addition, it is difficult to control the ore dilution and loss due to the fact that there is no interim model and accurate grade control model to guide the mining production and the special technologies, such as pure blasting, separating blasting and slag-remaining blasting, are not applied at the Husab mine and at the same time, the field trial of blast-induced movement monitoring does not provide a good result. It is proposed in this study to adopt different blasting technology and schemes to control the blasting and successfully separate the ore and waste according to the distribution of ore and waste and their scale within the mining area based on the more accurate interim – grade control models. For the blocks with a large scale and area of ore and waste, it is proposed to individually design blasting holes on the block of ore or waste and then blast to successfully separate the ore and waste when the ore area or waste area meets the requirements of an individual block; when the area or waste area is not large enough to be designed an individual block, it is proposed to modify the blasting parameters such as the blasting hole design, charge structure, blasting delay time and initiation mode to generate physical zones of easy to identify in visibly such as zones with visible difference in sizes within the ore or waste areas and flutes at the boundaries of ore and waste and thus, the ore and waste are finally separated to guide the ore loading and reduce the ore dilution and loss. 4) Application of uranium grade measurement technology by down-hole gamma logging At the moment, the uranium content of ore is determined dominantly by the chemical method of analysis and assisted by the radiometric measurement at the majority of uranium mines in the world except those in China and in the Commonwealth of Independent States. It not only takes a long time but also expensive to determine uranium by the chemical method of analysis and thus it is difficult to ensure the smooth operation at the Husab mine. A set of intact radiometric measurement technology and method system has been established including the technology, equipment, operation manuals and technical standards etc., through over tens of years’ efforts especially the practices in the exploration and production of uranium mines in China. Since early the Husab mine was put into production, the radiometric measurement system and related operation manuals and standards has been established gradually, including key equipment facilities such as down-hole gamma logging system, truck scanner system, belt scanner system at the primary crushing station and corresponding calibration of technical parameters and the construction of standard calibration models on the site. Consequently, it ensures the grade of ore will be determined accurately on time to fully meet the production requirements at the Husab mine. CONCLUSIONS A set of intact mining production procedures and technical standards have been established preliminarily since the Husab mine was put into production. The continuous research achievements in this study shows that the effective results have been achieved in the fields of the resource – grade control models, optimization on the mining production procedures, controlled blasting technology and radiometric measurement technology and thus the mining capacity and efficiency has been improved effectively and the ore dilution and loss has been reduced obviously, laying a strong foundation for the ramp-up production of the Husab mine.

Speaker: Mr Wenming DONG (CGN Uranium Resources Co Ltd)

61 Cost Effective Heap Leaching, the case study of Mutanga, Zambia

GoviEx Uranium Inc (“GoviEx”) holds several contiguous mining and prospecting licences in Southern Zambia that are grouped as the Mutanga Project. The deposit comprises of shallow sandstone hosted uranium ore. The Mutanga Project contains a mineral resource of 96.2 million tonnes (“Mt”) of ore at an average grade of 283 ppm U3O8 containing 60.0 million pounds (“Mlb”) of U3O8 in six deposits (Mutanga, Dibwe East, Dibwe, Gwabe, Njame, and Njame South), located over 65 km strike. Processing of the ore has been demonstrated to be effective using sulfuric acid leaching with ion exchange recovery of uranium. Test work has confirmed heap leaching is viable and permeability of the ore is good with low acid consumption at 3-18 kg/t. The process is robust, simple and has a low environmental profile. Overall uranium recovery varies with recoveries from each of the deposits averaging 74 to 94%. An important aspect of improving project economics is to rely on a central process recovery close to the main deposits of Mutanga and Dibwe East and using satellite heaps and adsorption circuits to obtain uranium and transport to the main recovery plant. This allows a large cost saving in transport of ore and allows for optimization of heap conditions in each of the heaps focused on the locally mined ore. For Mutanga-Dibwe East leach pad, pregnant leach solution will be pumped to the adjacent central process plant for stripping and concentrating uranium. For the other deposits pregnant leach solution will be pumped to an adsorption plant where uranium will be stripped of uranium and loaded onto resin. Approximately 24,000 litres per day of resin will be transported by truck to the central process plant for concentrating, barren resin will be trucked back to satellite operations. Uranium production recovery is expected to be on average of 2.4 Mlbs U3O8 per annum of uranium contained in uranium oxide. Life of mine capital cost for the project is low at USD167M and operating costs of approximately USD20/t of ore processed (equivalent to USD31/lb). The return on the project has reasonable post tax Net Present Value of USD114M (at 8% discount) and internal rate of return of 25% based on a uranium price of USD58/lb U3O8. In order to achieve this with a low grade deposit required lateral thinking about exploiting efficiencies of the different ores and removing redundant processes in order to deliver a realistic project. Such an approach can improve project economics (even at low uranium prices) and provide sustainable mining operations.

Speaker: Mr Robert Bowell (SRK Consulting (UK))

Wednesday, 27 June

Advances in Exploration

Conveners: Mr Luis LOPEZ (CNEA (Argentina)), Martin Fairclough (International Atomic Energy Agency)

62 Quantitative Mineral Resource Assessments of Roll-Front and Calcrete Uranium in Southern Texas and the Southern High Plains Province of the United States: Results and Simple Economic Filter Analysis

INTRODUCTION The U.S. Geological Survey (USGS) recently completed two uranium mineral resource assessments in the south-central United States (U.S.) as part of a re-evaluation of domestic resources previously considered by the 1980 National Uranium Resource Evaluation program [1]. These new assessments include: (1) in 2015, an assessment of undiscovered roll-front uranium resources in Tertiary coastal plain sediments of southern Texas [2]; and (2) in 2017, an assessment of undiscovered calcrete uranium resources in Pliocene and Pleistocene carbonate-rich sediments of the Southern High Plains region of Texas, New Mexico, and Oklahoma [3]. Roll-front uranium in southern Texas has been recognized since the mid-1950s. Calcrete uranium, however, a deposit style known elsewhere around the world but previously unreported in the U.S., was only brought to the attention of the USGS in 2015 after two small deposits (Buzzard Draw and Sulphur Springs Draw) and several prospects were recognized in northern Texas in the mid-1970s [4]. METHODS AND RESULTS The roll-front assessment was conducted using a combination 3-Part quantitative [5] and Weights-of-Evidence qualitative mineral potential modelling [6] methods, and identified 54,000 tU, with 85,000 tU estimated mean undiscovered. The calcrete assessment was conducted using the 3-Part quantitative method, and identified 1,000 tU, with 15,000 tU estimated mean undiscovered. Collectively they total about 155,000 tU. DISCUSSION AND CONCLUSIONS If these identified and estimated undiscovered uranium resources are economic, and if the identified resources are mined and undiscovered resources found and produced, this represents over 8 years of U.S. civilian nuclear power reactor fuel requirements. The application of a simple economic filter based on the Pareto principle, and using uranium resource data from the IAEA global UDEPO database [7] and a USGS-compiled database for southern Texas [8], was used to investigate whether the undiscovered uranium resources could be economic in relation to known and(or) produced regional and global uranium resources. Given the uranium resource endowment (size) of deposits regionally and globally, and the current market prices for uranium (October, 2017; approximately $20 USD per pound U3O8 or $52 USD per kg U), the results suggest that: (1) the undiscovered calcrete uranium resources are not likely to be economic at the present time; and (2) the undiscovered roll-front resources are economic in context of regional (southern Texas) uranium production considerations and setting, but marginally- to sub-economic when regarded in a larger, global context. REFERENCES [1] U.S. DEPARTMENT OF ENERGY, An assessment report on uranium in the United States of America, U.S. Department of Energy Grand Junction Office, Grand Junction, Colorado, USA, Report Number GJO-111(80), 160p. (1980). [2] Mihalasky, M.J., Hall, S.M., Hammarstrom, J.M., Tureck, K.R., Hannon, M.T., Breit, G.N., Zielinski, R.A., and Elliot, Brent, Assessment of undiscovered sandstone-hosted uranium resources in the Texas Coastal Plain, 2015, U.S. Geological Survey Fact Sheet 2015–3069, 4 p. (2015), http://dx.doi.org/10.3133/fs20153069. [3] Hall, S.M., Mihalasky, M.J., and Van Gosen, B.S., Assessment of undiscovered resources in calcrete uranium deposits, Southern High Plains region of Texas, New Mexico, and Oklahoma, 2017, U.S. Geological Survey Fact Sheet 2017–3078, 2 p. (2017), https://doi.org/10.3133/fs20173078. [4] Van Gosen, B.S., and Hall, S.M., The discovery and character of Pleistocene calcrete uranium deposits in the Southern High Plains of west Texas, United States, U.S. Geological Survey Scientific Investigations Report 2017–5134, 27 p. (2017), https://doi.org/10.3133/sir20175134. [5] Singer, D.A., and Menzie, W.D., Quantitative mineral resource assessments: An integrated approach, Oxford University Press, New York, New York, USA, 219 p. (2010). [6] Bonham-Carter, G.F., Geographic information systems for geoscientists: Modelling with GIS, Pergamon Press / Elsevier Science Publications, Tarrytown, New York, USA, 398 p. (1994). [7] INTERNATIONAL ATOMIC ENERGY AGENCY, World Distribution of Uranium Deposits (UDEPO), IAEA-TECDOC-1629 (2009; 2012 online edition), https://infcis.iaea.org/. [8] Hall, S.M., Mihalasky, M.J., Tureck, K.R., Hammarstrom, J.M., and Hannon, M.T., Genetic and grade and tonnage models for sandstone hosted roll-type uranium deposits, Texas Coastal Plain, USA, Ore Geology Reviews, v. 80, p. 716–753 (2016), https://doi.org/10.1016/j.oregeorev.2016.06.013.

Speaker: Dr Mark Mihalasky (U.S. Geological Survey)

63 Long term trends for global uranium exploration

The global search for uranium started in earnest at the end of World War 2 and continues through to today. Over the intervening seven decades, a total of $72 billion (in constant 2017 US Dollars) has been spent exploring for uranium. This has led to the discovery of over 1230 deposits (where uranium is the primary metal) containing a total of 11.1 Mt of U. This equates to an average unit discovery cost of US $6.49 per Kg U. The paper looks at when, where and who found these deposits. It also assesses the trend over time in the location of these discoveries, unit discovery cost, metres drilled per discovery, deposit style and the average size. Data has also been compiled on how many of these deposits that have successfully been developed into mines, and the associated time delay between discovery and development. It is noted that, in recent decades, the conversion rate has been getting progressively slower and lower. This, combined with the current low uranium prices, has adversely affected the amount of exploration carried out. This is also of serious concern to end-users – as it raises the issue of whether (or not) the industry is able to find and deliver sufficient metal to meet its requirements in the longer term. In practice, the uranium market will balance itself through the pricing mechanism. Higher prices will stimulate higher levels of exploration activity (and the amount of metal found). Higher prices will also enable existing projects to be economically developed. Given the above, and assuming that the historical discovery and conversion performance trends continue into the future, estimates were made of the likely amount of uranium that could be found and developed over the next 20 years under a range of different demand and price scenarios. Depending on the scenario chosen, the author estimates that the uranium price needs to rise to $156 or $252/kg U (equal to $61 to $99 per lb of U3O8) for the industry to be in-balance in the longer term.

Speaker: Mr Richard Schodde (MinEx Consulting)

64 PROSPECTIVITY ANALYSIS OF THE MOUNT ISA REGION (QUEENSLAND, AUSTRALIA) FOR METASOMATITE-TYPE URANIUM

Results of quantitative mineral resource assessment (QMRA) and mineral prospectivity analysis (MPA) for metasomatite-type (albitite-type) uranium deposits in the Mount Isa region of Queensland, Australia, are discussed. The study illustrates the process of using a geological model and various input data to define areas prospective for undiscovered uranium resources. The approach was fundamentally knowledge-driven and required use of geological judgment in choosing appropriate input layers, in assigning fuzzy membership values and in deciding the most appropriate methods of combining the input layers. The prospectivity mapping was successful in that known deposits, particularly larger examples, fall within pixels categorized as highly prospective. Ultimately, however, the success of the approach will need to be judged by the success of ongoing mineral exploration in areas deemed to have prospectivity. A comparison of regional and detailed studies illustrates the scale dependency of the input parameters, with some input layers being appropriate for the regional analysis but not for the more detailed one. Prospectivity maps generated by the fuzzy gamma and vectorial fuzzy logic techniques are similar. The latter technique may, however, provide better discrimination of areas prospective for large (rather than medium or small) deposits. A further benefit of this technique is that there is no need to produce intermediate combinations of input layers and no necessity for a gamma parameter. This results in a simplified process and makes subsequent applications of the technique more repeatable and comparable. This work also used MPA as the basis for defining a prospective tract which was the input for QMRA. A global regression model of total ore tonnage estimated undiscovered ore tonnage for the entire Mt Isa North tract at 83 Mt.

Speaker: Dr Andy Wilde (Deep Yellow Ltd)

65 Using continent-scale spatial targeting to delineate permissive areas for sandstone-hosted uranium

INTRODUCTION An ambitious sandstone-hosted uranium mineral prospectivity model covering the entire Australian continent hints at undiscovered mineral potential. Australia was chosen to demonstrate the usefulness of huge-scale multi-criteria analyses due to the relatively large volume of publicly available data covering the entire continent and because it is host to a considerable number of spatially distributed and economically significant deposits (e.g., Beverley, Manyingee, Bigrlyi). It is important to note that although all of the deposits under consideration are similarly classed as ‘sandstone-hosted’, significant differences exist in their host rock and mineralisation ages, mineralogy and in their underlying mineralising processes. Can a single predictive model really be expected to account for the distribution of all these genetically diverse systems? Traditional approaches to mineral potential mapping involve interpretation of individual maps, or manual overlay of groups of ‘predictor maps’ to delineate favourable exploration areas. In the (not so distant) past, simple overlays were commonly performed using light tables and analogue interpretation methods (i.e., a pencil). An inevitable consequence of the rapid advancement in both the availability of vast, high-resolution digital data sets and the inexorable growth in computing power has been that geographical information systems (GIS) and spatial analysis have rapidly become ubiquitous in mineral exploration. Traditional approaches have been supplanted by the use of GIS and digital overlays, allowing for the rapid interpretation of a huge variety of spatial data with an ever increasing assortment of analytical techniques. Multi-criteria spatial targeting is now being deployed routinely in the search for, and assessment of areas that have potential to contain economic concentrations of desirable minerals [1-9]. The ultimate goal of this study is to reduce a wide range of complex conceptual models of ore genesis to their most fundamental mappable components. These basic elements are then reconstructed in a targeting model which aims to imitate the thought processes of the exploration geologist. The underlying challenge is to construct a single mathematical model which adequately describes the distribution of known sandstone-hosted uranium deposits across a wide variety of terrains, ages and mineralisation (sub-)styles for an entire continent. The success criteria are that the model must be capable of effectively ‘re-discovering’ all areas of known mineralisation, yet it must be discerning enough that it doesn’t highlight vast areas which are confidently regarded as having limited upside potential. Areas highlighted by such a model which lie outside of known mineralised zones logically possess all of the critical components of sandstone-hosted uranium mineralising systems. These areas are potentially under-explored and may be worthy of further investigation. METHODS AND RESULTS The basic premise of this GIS-based mineral prospectivity analysis (MPA) is the recognition of the essential criteria of sandstone-hosted uranium deposits [10] and translation of those criteria into quantifiable spatial parameters which can then be handled mathematically. The first step is to acquire and assess any spatial data that may be turned into useful proxies for components of the mineralisation genetic model. This generally requires a thorough audit of all publically available data. Data sets that were selected as being of potential use for the construction of the Australia-wide MPA include: • surface geology (1:1m, 1:5m & 1:2.5m scale) • crustal elements • Australian geological provinces • metamorphic grade and ages • structural data • radiometrics • digital elevation models (SRTM and derivatives) • drainage pathways • sedimentary basin extents and thicknesses • paleo-channel distribution Australian explorers have access to an extraordinary amount of publicly available, multi-disciplinary data sets of very high quality. However, not all these data are useful for their straightforward inclusion in a continent-scale MPA. Some lack sufficient resolution, while others are too data-rich to be practical at the continent scale without significant modification. A holistic mineral systems approach [11 - 13] is used to classify and combine the data so that a meaningful output can be generated. This approach considers all geological factors which control the generation and preservation of mineral deposits (including sources of metals, ligands and energy, fluid migration pathways and focusing mechanisms, and chemical and/or physical causes for precipitation at the trap site). A range of ‘predictor maps’, which represent mappable components of the mineralisation system under consideration, are derived from the spatial data. For this study, predictor maps are designed to represent individual components of the ‘Source’ (e.g., basement, uranium-enriched felsic igneous rocks), ‘Transport’ (e.g., faults, drainage pathways) or ‘Trap’ (e.g., reduced sediments, morphological barriers) parts of the mineral system. The creation of predictor maps and the subsequent analysis was performed in ESRI ArcGIS (Version 10.4.1). Data preparation and the creation of predictor maps commonly involve some simplification and interpretation. For example, complex geology data can be re-classified into simpler stratigraphy and lithology predictor maps, each comprising a manageable number of classes. Multi-ring buffers can be constructed around features (e.g., granite bodies) to test proximity effects, with each concentric buffer being treated separately in the model. Thresholding can be used to simplify geophysical and other raster data into classes that can be handled more readily in the mathematical model. The construction of some of the 26 predictor maps used in this study is briefly outlined in this presentation. A knowledge-driven approach (Fuzzy Logic) relies entirely on expert input to assign weights to individual predictor maps and their components to account for the relative importance of each feature in the mineralising system. A relatively simple method is used to calculate ‘Fuzzy Membership’ values in this study. ‘Class weights’ (0-10) are assigned to each feature within a predictor map based on the relative prospectivity of the feature. Additionally, ‘Map weights’ (0-10) are assigned to each predictor map based on the relative importance of the component it represents in the genetic model, and confidence in the underlying data. Multiplying the class by the map weights for each feature in a predictor map gives a ‘class score’ for that particular feature; dividing the class score by 100 results in a ‘Fuzzy Membership’ value between 0 and 1 for the feature. This is done for every feature in every predictor map. This is the value that is used in the final analysis. The (vector) predictor maps are converted to numerical raster grids based on the Fuzzy Membership value, allowing mathematical operations to be carried out on the newly created ‘stack’ of rasters on a cell-by-cell basis. A logic network combining the input predictor rasters is carefully constructed such that it follows sound geological reasoning appropriate to the targeting model. The judicious use of Fuzzy ‘AND’, ‘OR’, ‘SUM’, ‘PRODUCT’ and ‘GAMMA’ logic operators allows quite complex relationships between components to be expressed in the model, reflecting the way in which a geologist might think but extrapolated up to the scale of the analysis (continent-scale in this example) and over a multitude of simultaneous input criteria. In our model, the three major mineral system components (Source, Transport and Trap) are treated separately before being combined in the final stage of the logic network. Solving the logical arguments for each corresponding cell in the stack of weighted predictor map rasters, results in a numerical grid that is interpreted to represent spatial variations in prospectivity. This can then be reclassified and displayed as a colour-coded, multi-class favourability map. DISCUSSION AND CONCLUSION We consider the fuzzy logic mineral prospectivity model presented herein to be a successful first-pass GIS-based analysis for sandstone-hosted uranium deposits on the Australian continent. Crucially, the majority of known sandstone-hosted uranium deposits and provinces occur within areas of elevated to very high favourability in the resulting favourability map, demonstrating the geological validity of the model. Additionally the model identifies several regions that should contain all the ingredients for sandstone-hosted uranium but may have been overlooked or underexplored by previous explorers. However, the model has substantial limitations that must be kept in mind when interpreting the resulting favourability map. At the continental scale and due to the necessary use of highly simplified and modified versions of the spatial data, substantial uncertainties in the properties of the inputs remain. This is particularly true of the heavily modified geology (simplified lithology and stratigraphy) predictor maps but affects all data sets to some extent. Due to these uncertainties, the continental-scale model presented herein is not considered useful for delineating specific exploration targets but is particularly effective at identifying broader permissive areas, as well as regions of elevated favourability within these zones. It is also important to note that the output generated from this model represents just one of an infinite number of possible solutions. Every step in the process, including initial data selection, predictor map design, assigning weights to features and maps and construction of the logic network was driven by a very small group of ‘experts’. While we maintain a high level of confidence in our analysis, the opinions of alternative ‘experts’ are likely to differ (at least somewhat). A significant advantage of this type of analysis over more traditional approaches is that it allows for rapid iterative modification. New data, weights or modified logic network designs that target specific deposit types, or that consider alternate genetic models (for example) can be readily accommodated and tested. The MPA methodology has the ability to quickly reduce the search space, highlighting specific zones of elevated mineral potential. These targets can then be ranked and prioritised for more detailed follow-up, ground-truthing or higher resolution MPA. At a continental scale, such target zones effectively highlight so-called ‘permissive tracts’ [14], representing geological regions that have potential to host undiscovered mineral deposits. The delineation of a permissive tract can contribute to estimating the potential number and size of undiscovered mineral deposits in an area, which has a variety of important economic, land, resource and environmental planning applications [15 – 16]. The continent-scale Fuzzy Logic MPA for sandstone-hosted uranium in Australia demonstrates that GIS-based targeting concepts can be used to objectively delineate and visualise permissive areas for uranium, thereby dramatically reducing the search space and assisting with area selection and decision making processes. This study demonstrates how multiple specifically designed and weighted input predictor maps can be combined using a carefully constructed logic network to create a spatial representation of relative favourability for a specific mineral deposit type at the continental scale. This study clearly benefits from the relatively large volume of high quality, relevant and publicly available spatial data for the Australian continent. However, this type of study is possible in areas where less (or different) data are available because the analysis is built up around to the type of mineralising system under consideration and according to the available data. The veracity of any MPA depends heavily on the quality of suitable input data (“rubbish in – rubbish out”) so questionable data should be rejected as part of the preliminary data assessment. A simpler model is always preferable to one containing erroneous data. If performed carefully and meticulously, GIS-based Fuzzy Logic mineral prospectivity modelling can provide an extremely powerful visualisation and decision-making tool. A comprehensive account of the methods used in this study, including the rationale for using particular data sets, the construction of predictor maps, assigning fuzzy membership values and construction of the logic network is presented as a chapter in an upcoming IAEA TecDoc on “Spatial and quantitative modelling of undiscovered uranium resources” [17]. REFERENCES [1] TURNER, D.D., Predictive GIS model for sediment-hosted gold deposits, North-Central Nevada, USA, Proceedings of Exploration 97: Fourth Decennial International Conference on Mineral Exploration (1997) 115–126. [2] HARRIS, J.R., WILKINSON, L., HEATHER, K., FUMERTON, S., BERNIER, M.A., AYER, J., DAHN, R., Application of GIS Processing Techniques for Producing Mineral Prospectivity Maps – A Case Study: Mesothermal Au in the Swayze Greenstone Belt, Ontario, Canada. Natural Resources Research 10, No. 2 (2001) 91–124. [3] PORWAL, A., CARRANZA, E.J.M., HALE, M., Extended weights-of-evidence modelling for predictive mapping of base metal deposit potential in Aravalli Province, Western India, Exploration and Mineral Geology 10 (2001) 273–287. [4] LUO, X., DIMITRAKOPOULOS, R., Data-driven fuzzy analysis in quantitative mineral resource assessment. Computers and Geosciences 29 (2003) 3–13. [5] NYKÄNEN, V., SALMIRINNE, H., Prospectivity analysis of gold using regional geophysical and geochemical data from the Central Lapland Greenstone Belt, Finland Geological Survey of Finland, Special Paper 44 (2007) 251–269. [6] JOLY, A., PORWAL, A., MCCUAIG, T.C., Exploration targeting for orogenic gold deposits in the Granites-Tanami Orogen: mineral system analysis, targeting model and prospectivity analysis, Ore Geology Reviews 48 (2012) 349–383. [7] LISITSIN, V.A., GONZÁLEZ-ÁLVAREZ, I., PORWAL, A., Regional prospectivity analysis for hydrothermal-remobilised nickel mineral systems in western Victoria, Australia, Ore Geology Reviews 52 (2013) 100–112. [8] LINDSAY, M., BETTS, P.G., AILLERES, L., Data fusion and porphyry copper prospectivity models, southeastern Arizona, Ore Geology Reviews 61 (2014) 120-140. [9] CHUDASAMA, B., PORWAL, A., KREUZER, O.P., BUTERA, K., Geology, geodynamics and orogenic gold prospectivity modelling of the Paleoproterozoic Kumasi Basin, Ghana, West Africa. Ore Geology Reviews 78 (2016) 692-711. [10] INTERNATIONAL ATOMIC ENERGY AGENCY, World Distribution of Uranium Deposits (UDEPO) with Uranium Deposit Classification, Vienna, IAEA-Tecdoc-1629 (2009) 126pp. [11] WYBORN, L.A.I., HEINRICH, C. A., JAQUES, A.L., Australian Proterozoic mineral systems: essential ingredients and mappable criteria, Australasian Institute of Mining and Metallurgy Annual Conference Proceedings (1994) 109–115. [12] KNOX-ROBINSON, C.M., WYBORN, L.A.I., Towards a holistic exploration strategy: Using geographic information systems as tool to enhance exploration, Australian Journal of Earth Sciences 44 (1997) 453-463. [13] JOLY, A., PORWAL, A., MCCUAIG, T.C., CHUDASAMA, B., DENTITH, M.C., AITKEN, A.R., Mineral systems approach applied to GIS-based 2D-prospectivity modelling of geological regions: Insights from Western Australia. Ore Geology Reviews, 71 (2015) 673-702. [14] SINGER, D.A., Basic concepts in three-part quantitative assessments of undiscovered mineral resources, Nonrenewable Resources 2, vol 2 (1993) 69–81. [15] CUNNINGHAM, C.G., ZAPPETTINI, E.O., VIVALLO S., WALDO, CELADA, C.M., QUISPE, JORGE, SINGER, D.A., BRISKEY, J.A, SUTPHIN, D.M., GAJARDO M., MARIANO, DIAZ, ALEJANDRO, PORTIGLIATI, CARLOS, BERGER, V.I., CARRASCO, RODRIGO, SCHULZ, K.J., Quantitative mineral resource assessment of copper, molybdenum, gold, and silver in undiscovered porphyry copper deposits in the Andes Mountains of South America, U.S. Geological Survey Open-File Report 2008-1253 (2008) 282 p. [16] SINGER, D.A., JAIRETH, S., ROACH, I., A three-part quantitative assessment of undiscovered unconformity-related uranium deposits in the Pine Creek region of Australia. IAEA TecDoc, Spatial and Quantitative Modelling of Undiscovered Uranium Resources (in preparation). [17] BIERLEIN, F.P., BRUCE, M.D., A continent-scale GIS-based assessment of the distribution and potential for sandstone-hosted uranium deposits. IAEA TecDoc, Spatial and Quantitative Modelling of Undiscovered Uranium Resources (in preparation).

Speaker: Mr Matthew Bruce (Thunderbird Metals)

66 Spatial analysis of prospectivity for surficial uranium deposits: a case study in British Columbia, Canada

INTRODUCTION Surficial uranium (U) resources exist in the southernmost part British Columbia (Canada). The known U resources in the region (hereafter denoted as SBC) are comprised by four surficial U deposits and 32 small prospects/showings. The prospectivity of the SBC for surficial mineralization has, however, not been entirely evaluated yet. Here, results of spatial analysis of prospectivity for surficial U in the SBC, using a geographic information system (GIS) and following the mineral systems approach [1], are presented. SURFICIAL U MINERAL SYSTEM IN THE SBC In the SBC, surficial U mineralisation consists of fluviatile and/or lacustrine/playa U occurrences within loose, pervious fluvial sediments of Late Miocene age along paleodepressions or paleochannels [3]. The mineralisation is composed largely by uranyl carbonates [2] and/or uranous phosphates such as autunite, ningoyite and saleeite [3]. The rocks that are probable sources of U in the SBC include small units of uraniferous pegmatites in the Shuswap Metamorphic Complex of Palaeozoic age, granitoids of Jurassic–Cretaceous and Eocene–Oligocene age, and volcanic rocks of Eocene age [2], [3]. Data on reactive U content of rocks [3] suggest that Okanagan granites/pegmatites of Jurassic–Cretaceous age are major sources of U in the SBC. The release of U from the potential sources has probably been favoured by repeated tectonism and multiphase intrusions that have taken place in the SBC during the ancient geologic past [3]. Tectonically deformed intrusive rocks cut by interconnected faults/fractures also favoured deep-seated flow and wide-distribution of U-bearing groundwater, which ultimately permeated pervious sediments along paleodepressions or paleochannels [2]. The U, in these surficial environments, exists as soluble uranyl carbonate complexes carried by oxygenated alkaline groundwater [4]. Flow of groundwater is focused through pervious paleodepressions or paleochannels filled with permeable fluviatile sediments. Energy for flow of groundwater is chiefly due to gradient along paleodepressions or paleochannels. In playa/lacustrine environments, organic-rich sediments act both as physical and chemical traps for surficial U formation [2]; whereas in pervious zones of channel fluviatile environments, organic-rich soils or sediments act both as physical and chemical traps In either environment, surficial U forms mainly by either evaporation or reduction. The latter is due to bacteria or to sediments that are rich in organic matter. However, because no common U minerals are known in the SBC, the role of evaporation in the SBC is less likely, as groundwater is not saturated with respect to typical U phosphates [5]. Thus, in the surficial U mineral system in the SBC, adsorption onto organic-rich sediments is the most probable factor of surficial U mineralisation, followed by reduction owing to bacteria or organic-rich sediments [2], [5]. SURFICIAL U MINERALISATION: CRITERIA FOR TARGETING, SPATIAL PROXIES The deposits/occurrences of surficial U in the SBC are alike but dissimilar to the most significant surficial U deposits worldwide, namely calcrete-hosted carnotite [6], [7], [8], [9]. Therefore, mapping of surficial U prospectivity in the SBC will make use of criteria for targeting and respective spatial proxies that somewhat differ from those used exactly for the same purpose in the Yeelirrie area (Australia) [1]. The criteria for targeting that were used here include: (a) source rocks for U; (b) pathways; and (c) traps. A single U source targeting criterion, namely felsic volcanic or intrusive rocks with reactive U, was used. The corresponding spatial proxy used was presence of and/or proximity to felsic volcanic or intrusive rocks with reactive U. Instead of using Euclidean distance to model proximity, fuzzy proximity (representing probability-like values) was used because the fuzzy set theory [10] was used here for mapping surficial U prospectivity. To model fuzzy proximity, Euclidean distances were transformed through a logistic function [11] to non-linearly decreasing values ranging from 1 for the nearest distance to 0 for the farthest distance. Three maps of fuzzy proximity to probable U-source rocks (i.e., Jurassic–Cretaceous Okanagan Batholith, Eocene–Oligocene Coryell Plutonic suite, Eocene Volcanics) were combined into a single map of fuzzy proximity to U-source rocks, by applying a weighted fuzzy algebraic sum operator whereby the weights are defined from the reactive U content of each of the three rock units. A single pathways criterion, namely Tertiary to Recent paleochannels, was also used. The corresponding spatial proxy used was fuzzy proximity to paleochannels. The paleochannels were remotely-sensed using a digital elevation model and night-time ASTER thermal infrared data [12], [13]. For chemical traps, two criteria were used: (1) bicarbonate contents of fluvial waters; and (2) U-rich groundwater. The respective spatial proxies used were: (1) fuzzy alkalinity of fluvial waters, modelled by applying a non-linear logistic function to data on stream water pH [14]; and (2) fuzzy U-abundance of fluvial waters, modelled by applying a non-linear logistic function to data on U content of fluvial waters [14]. Bicarbonate contents of strongly alkaline fluvial waters in the SBC range from 50 to 600 ppm. This considerably boosts the ability of soils/sediments in paleodepressions of paleochannels to concentrate U [2]. Dispersion of U from source rocks and its enrichment in surface water and groundwater permits huge quantities of this element to reach trap areas wherein surficial U mineralisation ensues. For physical traps, two criteria were used: (1) nearly-stationary fluvial water in paleodepressions or paleochannels [1]; and (2) size of source area [1]. The corresponding spatial proxies used were: (1) presence of and fuzzy proximity to nearly-level topographic depressions, modelled by applying a non-linear logistic function to topographic slopes derived from a digital elevation model; and (2) fuzzy flow accumulation, modelled by applying a non-linear logistic function to sizes of catchments derived from a digital elevation model. Because surficial U precipitates from nearly-stationary fluvial water in paleodepressions or paleochannels [1], depressions in the topography with level or nearly-level slopes were used as spatial proxies because it can be expected that substantial fluid modification occurs in such locations but not in locations having dissimilar topographic characteristics. Because locations where fluvial water flow accumulates from huge U-source rock areas are prone to amass, enrich, and precipitate more U, a map of flow accumulation was used as spatial proxy because it represents areas that may contain significant potential U-source rocks for surficial U mineralisation. MODELLING OF REGIONAL-SCALE SURFICIAL U PROSPECTIVITY The spatial proxies generated were combined in systematic way that mimics the interaction of processes involving sources, pathways and traps, which result in surficial U mineralisation. This was achieved by adapting an inference engine that symbolise hypotheses or knowledge regarding the interactions of a variety of processes that are relevant to a surficial U mineral system [1], [15]; thus, a mineral systems approach. Therefore, a fuzzy inference engine was used to model regional-scale surficial U prospectivity in the SBC according to the above-discussed surficial U mineral system and regional-scale criteria for targeting (and respective spatial proxies) for surficial U mineralisation in the SBC. Considering its simplicity and flexibility, the fuzzy set theory [10] is regarded by [16] to be the most appropriate for integrating spatial data to model the interaction of certain geologic processes. For every step in the fuzzy inference engine used, a suitable fuzzy operator was used to combine at least two spatial proxies to mimic the interaction of at least two processes pertinent to surficial U deposit formation. The fuzzy inference engine and the fuzzy operators that were used formed a sequence of logical rules that successively combined the fuzzy spatial proxies, and they also served to negate the influence of spatial proxies with significant uncertainty. As mentioned earlier, a map of integrated U sources spatial proxy was derived by using a weighted fuzzy algebraic sum operator to combine the potential U-source rocks spatial proxies. A map of integrated chemical traps spatial proxy was derived by using fuzzy AND operator to combine the U-abundance and alkalinity of fluvial waters spatial proxies. That is because both U-abundance and alkalinity of fluvial waters are needed for surficial U deposits to form. A map of integrated physical traps spatial proxy was derived using fuzzy OR operator to combine the flow accumulation and nearly-level depressions spatial proxies. That is because adequate physical constrain on surficial U deposit formation may be provided by either catchments with voluminous flow accumulation or nearly-level depressions. Finally, a map of surficial U prospectivity was derived by using fuzzy AND operator to combine the pathways spatial proxy with the integrated U sources, chemical traps, and physical traps spatial proxies. That is because formation of surficial U deposit requires all the processes symbolised by these spatial proxies. Experiments on different map combinations were then performed to determine (a) sensitivity of the prospectivity to input spatial proxies, (b) which spatial proxies are best predictors, and (c) which prospectivity map can be best used to guide further exploration for surficial U deposits in the SBC. The predictive performance of each out prospectivity map [17] was determined by using the four known deposits and 32 prospects/showings of surficial U in the SBC. RESULTS AND DISCUSSION The two best maps of surficial U prospectivity that were generated here are inclusive of the proximity to potential U-source rocks spatial proxy, indicating the significance of data on reactive U content of rocks in modelling of surficial U prospectivity and the efficacy of the weighted fuzzy algebraic sum operator to integrate such kind of data in spatial analysis of surficial U prospectivity. The two best prospectivity maps are exclusive of the nearly-level depressions spatial proxy, indicating the inadequacy and thus inaptness of this spatial proxy in modelling of surficial U prospectivity in the region, or the better efficacy of the flow accumulation spatial proxy. However, if, among the traps spatial proxies, only the U-abundance of fluvial waters spatial proxy was combined with the pathways and potential U-source rocks spatial proxies, the output surficial U prospectivity map is just very slightly inferior to the two best prospectivity maps. This demonstrates that either the flow accumulation spatial proxy or alkalinity of fluvial waters spatial proxy just has very little influence on the predictive capacity of prospectivity mapping even though they are important criteria for targeting of surficial U in the region. Nevertheless, the results show that alkalinity of fluvial waters is more efficient than U-abundance in fluvial waters as spatial proxy of U-transporting ability of surface waters. These limitations demonstrate that the prospectivity model requires updating when more appropriate data become available. The two best-performing prospectivity maps derived here suggest presence of undiscovered surficial U resources in the SBC. However, the identified prospective areas mostly identified are those where the known deposits/occurrences of surficial U are mostly present in the SBC. This indicates that two best-performing prospectivity maps carry type II (or false-negative) error with respect to possible undiscovered resources of surficial U in other parts of the SBC, whereas the two worst-performing prospectivity maps carry type I (or false-positive) error with respect to the known deposits/occurrences of surficial U in the SBC. The type I and type II errors are equivalent to over- and under-estimation of prospectivity, respectively. Avoiding type I error is crucial as this will render failure to discover new deposits, whereas type II error will render missed chance for discovery of new deposits. CONCLUSIONS The above-discussed methodology for spatial analysis of regional-scale prospectivity for surficial U in southern British Columbia (Canada) is quite straightforwardly implementable by using a geographic information system. A more intricate fuzzy inference system consisting of more elaborate logical rules representing expert reasoning for delineating zones prospective for surficial U [1] is likely to be as instructive for researchers with more profound insight to the surficial U system in the region. REFERENCES [1] PORWAL, A., DAS, R.D., CHAUDHARY, B., GONZÁLEZ-ÁLVAREZ, I., KREUZER, O., "Fuzzy inference systems for prospectivity modeling of mineral systems and a case-study for prospectivity mapping of surficial uranium in Yeelirrie area, Western Australia", Ore Geology Reviews 71, 839-852 (2015). [2] CULBERT, R.R., BOYLE, D.R., LEVINSON, A.A., "Surficial Uranium Deposits in Canada", In: "Surficial Uranium Deposits", IAEA-TECDOC-322, IAEA, Vienna, pp. 179-191 (1984). [3] BOYLE, D.R., "The Formation of Basal-type Uranium Deposits in South Central British Columbia", Economic Geology 77, 1176-1209 (1982). [4] CULBERT, R.R., LEIGHTON, D.G., "Uranium in alkaline waters – Okanagan area, British Columbia", CIM (Canadian Institute of Mining & Metallurgy) Bulletin 71, 103-110 (1978). [5] TIXIER, K., BECKIE, R., "Uranium depositional controls at the Prairie Flats surficial uranium deposit, Summerland, British Columbia", Environmental Geology 40, 1242-1251 (2001). [6] CARLISLE, D., "Surficial uranium occurrences in relation to climate and physical setting", IAEA-TECDOC-322, IAEA, Vienna, pp. 25-35 (1984). [7] CAMERON, E., "The Yeelirrie calcrete uranium deposit, Western Australia", IAEA-TECDOC-322, IAEA, Vienna, pp. 157-164 (1984). [8] MISRA, A., PANDE, D., KUMAR, K.R., NANDA, L.K., MAITHANI, P.B., CHAKI, A., "Calcrete-hosted surficial uranium occurrence in playa-lake environment at Lachari, Nagaur District, Rajasthan, India", Current Science 101, 84-88 (2011). [9] KHOURY, H.N., "Geochemistry of surficial uranium deposits from Central Jordan", Jordan Journal of Earth and Environmental Sciences 6, 11-22 (2014). [10] ZADEH, L.A., "Fuzzy sets", IEEE Information and Control 8, 338-353 (1965). [11] YOUSEFI, M., CARRANZA, E.J.M., "Fuzzification of continuous-value spatial evidence for mineral prospectivity mapping", Computers & Geosciences 74, 97-109 (2015). [12] STAMOULIS, V., "ASTER night-time thermal infrared data: interpreting subsurface features from high resolution data", MESA Journal 43, 36-39 (2006). [13] THAKUR, S., CHUDASAMA, B., PORWAL, A., GONZÁLEZ-ÁLVAREZ, I., "Sub-surface paleochannel detection in DeGrussa area, Western Australia, using thermal infrared remote sensing", Proceedings SPIE 9877, Land Surface and Cryosphere Remote Sensing III, 98772C (May 5, 2016), doi:10.1117/12.2223626. [14] LETT, R., "Regional Geochemical Survey Database", GeoFile 2011-07, British Columbia Geological Survey (http://www.empr.gov.bc.ca/Mining/Geoscience/PublicationsCatalogue/GeoFiles/Pages/GF2011-7.aspx) (2011). [15] CARRANZA, E.J.M., HALE, M., "Geologically constrained fuzzy mapping of gold mineralization potential, Baguio district, Philippines", Natural Resources Research 10, 125-136 (2001). [16] BARDOSSY, G., FODOR, J., "Geological reasoning and the problem of uncertainty". In: Cubitt, J., Whalley, J., Henley, S. (Eds.), Modeling Geohazards: IAMG2003 Proceedings, Portsmouth UK. Portsmouth University, UK (2003). [17] AGTERBERG, F.P., BONHAM-CARTER, G.F., "Measuring performance of mineral-potential maps", Natural Resources Research 14, 1–17 (2005).

Speaker: Prof. John CARRANZA (UNIVERSITY OF KWAZULU-NATAL)

Uranium Newcomers

Conveners: Dr Brett Moldovan (IAEA), Mr Dennis Amos MWALONGO (Tanzania Atomic Energy Commission)

67 Deploying Technology and Management of Sustainable Uranium Extraction Projects

Through its Technical Cooperation programme, the IAEA is supporting a major, four-year interregional project on deploying technology and management of sustainable uranium extraction projects. Fifty-two of the IAEA’s Member States are involved, from 2016-2019 inclusive. This project is in continuation of the interregional project on supporting uranium exploration and production that was active during 2012 – 2013. The main activities are Workshops and Training Courses held in the Member States, with both general and specialized topics in the themes of the project, and to provide inputs that can help leverage the value-addition of the uranium value chain and build business models that adaptive to a wide range of local conditions. At the half-way point, the activities of the project are summarized and the activities for the last two years are set out, which have been refined based on feedback from the participants and the specialized experts who have assisted the IAEA.

Speaker: Dr Jing Zhang (IAEA)

68 Supporting Sustainable Development of Uranium Resources in Africa

The IAEA contributes to the balanced development of uranium resources in Africa by facilitating the application of good practices in uranium production cycle, from exploration to closure and remediation, which in turn contribute to the socioeconomic development of the region. From 2014 it enacted a major, four-year regional Africa project through its Technical Cooperation (TC) programme on supporting the sustainable development of uranium resources. This project, RAF2011, was in continuation of a regional Africa uranium-themed project that was commenced in 2009, and the work will be continued with a follow-on regional project from 2018. The main activities were general and specialized workshops and training courses held in African Member States, supporting the sustainable development of uranium resources there. A Uranium Production Site Appraisal Team (UPSAT) review mission was undertaken for the first time in Africa (in Tanzania) under the framework of this project. This paper summarizes the activities of the project and looks forward to planned activities for the follow-on project, which have been refined based on feedback from the participants and the specialized experts who have assisted the IAEA with this project.

Speaker: Dr Peter H. Woods (IAEA)

69 Uranium from domestic resources in Poland

INTRODUCTION Uranium mining activities in Poland took place in Sudetes since the end of the 1940s until 1968. Industrial plants R-1 in Kowary carried out the processing of uranium ores till 1973. Outside Sudetes region, uranium was also found and mined from the Staszic pyrite deposit in Rudki, the Holy Cross Mountains. Total production of uranium in these times in Poland is estimated at about 650 t [1]. The mining activities resulted in remains of some 100 dumps, mostly abandoned, of waste rock and ore totalling approximately 1.4 x 106 m3 as well as one tailing pond, which has been the object of a remediation project partly funded by the European Commission aid in 2001 [2]. In the Polish Lowland, in the area of Podlasie Depression (NE Poland), concentrations of uranium were discovered in the Lower Ordovician Dictyonema shale. In the 70s of last century, there was found about 1400 tons of uranium at an average content of 250 ppm and 3800 tonnes of uranium of the ore content of 75 ppm ("Rajsk" deposit). Even then, this occurrence was considered as non-economic. The most interesting uranium mineralization on Polish territory occurs is in the Lower and Middle Triassic rocks of the central parts of Peribaltic Syneclise (N Poland). The highest concentrations were found in the sandstone-conglomerate continental series of Upper Bundsandstein, where for the layer of thickness of about 3.4 m, the average uranium content is 0.34%, with a maximum content exceeding 1.5%. Uranium is accompanied by other metals, like V, Mo, Pb and Se. In January 2014 Polish Government adopted the Program of Polish Nuclear Energy [3]. One of the objectives of this Program is the assessment of domestic uranium deposits as a potential source of uranium for Polish nuclear reactors. The studies on the prospects of recovery of uranium from domestic resources are in progress keeping in mind the inevitable growing uranium demand and perspectives of the global uranium market. CONVENTIONAL RESOURCES OF URANIUM IN POLAND Poland, like most countries in the world, has only the resources of low-grade uranium ores. In the period of 1948-1972, there were 5 mines extracting uranium ores. Four of them were located in the Sudetes, and only one outside of this region - in Rudki near Nowa Slupia, in the Holy Cross Mountains [1]. The uranium content in these deposits was typically about 2,000 ppm. Currently, no uranium mine is working in the country. In the second half of the 20th century, the Polish Geological Institute (PGI) made numerous assessments of prospects for exploration of uranium ore deposits in Poland [4]. According to the PGI estimates, the Ordovician Dictyonema shales of the Podlasie Depression (NE Poland) seem to be the most prospective, with uranium concentration in the 75-250 ppm range and the sandstones of Peribaltic Syneclise (Paslek-Krynica Morska), where uranium concentration reaches even 1, 5%. These deposits, as a potential source of uranium for Polish nuclear power plants, were investigated by the PGI and the Institute of Nuclear Chemistry and Technology (INCT) as part of the Operational Programme – Innovative Economy (POIG) project implemented in 2010-2013. Within the framework of the POIG project, Polish uranium deposits and their exploitation options were reassessed. Based on the archival ore samples from previously tested boreholes, various technological schemes and methods of obtaining uranium from Polish ores were examined with an initial economic assessment of the studied processes. Optimal leaching conditions for uranium from both Dictyonema shales and sandstones as well as uranium separation from other metals, like rare earth elements (REE) that have undergone leaching into the aqueous phase, have been found [5-8]. It has been shown that it is possible to sequentially separate these metals from the solution by means of ion exchange [9]. Uranium can also be separated using solvent extraction [10]. An alternative to solvent extraction carried out in traditional reactors or columns is extraction using membrane contactors, which constitute modern separation systems, allowing for two processes to be carried out: extraction and reextraction in one installation [11, 12]. An effective and selective extractant plays an important role in the extraction process. In recent years, great interest in new extracting agents of uranium like calixarene derivatives is shown [13]. The project developed a synthesis path for these compounds. They may also find other applications in the nuclear fuel cycle, e.g. for the separation of fission products and minor actinides from spent nuclear fuel. By using a membrane module with a helical flow in the uranium ore leaching process, high U leaching rates were obtained. In this system it is possible to simultaneously separate the leachate from the remaining solid phase (parent rock) [14]. Such a method of conducting the leaching process, with the simultaneous filtration of the sludge in the membrane contactor with the helical flow, became the basis for the patent application in the Patent Office of the Republic of Poland and the European Patent Office [15]. In 2014, Poland completed geological and technological analysis and modelling of the process of uranium extraction from low-grade Ordovician Dictyonema shale (black shale-type). Analysis has shown that the costs of obtaining raw material for production of 1 kg of uranium would be several times higher than the current market price of that metal [16]. URANIUM FROM UNCONVENTIONAL SOURCES Although uranium concentrations in unconventional sources are low, all together they are inexhaustible sources of uranium for future use. One of these sources are phosphates, which constitute the raw material for the production of chemical fertilizers. These rocks contain the largest concentrations of uranium from all unconventional uranium deposits occurring in the world. In Poland, phosphorites are found in vicinity of Annopol, the Holy Cross Mountains. The exploitation of phosphate rock in the country began in the interwar period and was discontinued in the 1970s. The mine in Chalupki was closed in 1961, and in Annopol in 1971. At present, domestic demand for phosphate rock is entirely covered by import from countries such as Algeria, Senegal, Morocco, Egypt, Tunisia and Syria. In the technology of phosphate fertilizers, the first stage is the production of phosphoric acid. In this process, ground phosphorites are treated with sulfuric acid, as a result of which phosphoric acid and insoluble calcium sulphate (gypsum) precipitate contaminated with the remaining raw material are obtained. Phosphogypsum after washing with water is directed to heaps as waste. Most of uranium contained in phosphorites goes to phosphoric acid. In Poland, in the 1980s at the Institute of Nuclear Chemistry and Technology and at the Wroclaw University of Technology, a technology for recovering uranium from phosphoric acid was developed for expected use in Chemical Works in Police. According to this technology, uranium can be extracted from phosphoric acid in a coupled extraction-re-extraction process. The mixtures of mono- and dinonyl-phenylphosphoric acids (NPPA) and D2EHPA and TOPO were used as extracting agents in this process. In 2015, the Institute of Chemistry and Nuclear Technology together with PwC Sp. z o.o, as part of the Bridge Mentor project (NCBiR), prepared a preliminary analysis of the possibilities of obtaining uranium from industrial phosphoric acid by the hybrid method, which was a combination of solvent extraction with membrane processes. The project was presented at Chemical Works in Police (at present AZOTY Group). Phosphogypsum usually contains many different components like heavy metals, among them also some amounts of uranium. During the production of phosphate fertilizers, part of the uranium contained in phosphate rock passes to solid waste and is collected in heaps. In Poland, phosphogypsum dumps are located in Police, Wizow and Wislinka near Gdansk. These landfills are heterogeneous in chemical terms, because over the years, various raw materials have been used for the production of phosphate fertilizers. In phosphogypsum samples from the landfill in Wislinka collected in 1997, uranium concentration was 4.03 ± 0.08 mg / kg, while in the samples from 2007 – only 0.65 ± 0.05 mg / kg [17,18]. The heap in Wizow, which is a residue from the production of fertilizers from apatites from the Kola Peninsula (magmatic rocks), does not contain uranium, but has a significant concentrations of REE. Uranium from phosphogypsum can be recovered by washing with sulfuric acid [19,20]. In some parts of the world there are carbon deposits with elevated uranium content. The average uranium concentration in Polish coal from mines located in the Upper Silesia, Lower Silesia and Lublin regions is approx. 2 ppm. Research conducted at the Polish Geological Institute did not show differences in content depending on the origin of coal [21]. Uranium can also be obtained from coal ash; its content in coal ash from Polish coal-fired power plants amounts to several ppm [22]. Another source of uranium can be the copper industry. Similarly, as in the Olympic Dam mine in Australia, uranium can be obtained as a by-product during the production of copper by KGHM. The studies of copper industry waste as an alternative source of uranium was conducted by INCT as part of the POIG project. The content of U in the tested waste samples was not high, while the occurrence of other valuable metals was observed [23]. The recovery of uranium and other metals from industrial waste, by-products and phosphates is currently being investigated by the INCT as part of a project coordinated by the International Atomic Energy Agency. Determination of uranium content in the fluids from hydraulic fracturing of shales in the process of searching for natural gas deposits, carried out in Poland, was performed at INCT. The highest U concentration found in the fluid samples was 3.5 ppm. The possibility of recovering uranium from these wastewater has been demonstrated [24]. The other possible secondary source of uranium can be uranium tailings and old dumps which were abandoned after exploitation of uranium mines in Sudetes. Reserves of uranium in waste heaps from prospecting and extractive operations in this region in the years 1948-1967 are estimated at 10 to 30 tU. CONCLUSION Research projects conducted in Poland in recent years have confirmed the presence of low-grade uranium deposits in Poland. Methods for its extraction from black shale and sandstones in the framework of the POIG project were developed. The results collected as part of the project confirmed that currently there is no economic justification for the exploitation of Polish ores with low uranium content, but the situation may change with the continuing development trend of nuclear energy in the world and gradual depletion of uranium resources in rich ores. The secondary sources of uranium in the country were also assessed. The most promising ones are waste from the copper industry and phosphoric acid obtained in the production technology of phosphate fertilizers. In May 2012, September 2013 and October 2013, three concessions for prospecting for polymetallic uranium deposit for a private company were granted (“Radoniow”, “Wambierzyce” and “Dziecmorowice” areas in southern region of Lower Silesia). At present, geological exploration of uranium ore is not conducted in Poland. REFERENCES [1] MIECZNIK, J. B., STRZELECKI, R., WOLKOWICZ, S., Uranium in Poland – history of prospecting and chances for finding new deposits), Przeglad Geologiczny, vol. 59, nr 10, (2011), 688-697 (in Polish). [2] G.E.O.S. Freiberg Ingenieurgesellschaft mbH, Remediation of the low-level radioactive waste tailing pond at Kowary, Poland. Final Report, European Commission, (2002). [3] RESOLUTION No. 15/2014 of COUNCIL OF MINISTERS, Program of Polish Nuclear Energy, Warsaw (2014). [4] NIEC, M., Polityka Energetyczna, Wystepowanie rud uranu i perspektywy ich poszukiwan w Polsce, Tom 12, Zeszyt 2/2 (2009) 435-451. [5] KIEGIEL, K., ZAKRZEWSKA-KOLTUNIEWICZ, G., GAJDA, D., MISKIEWICZ, A., ABRAMOWSKA, A., BIELUSZKA, P., DANKO, B., CHAJDUK, E., WOLKOWICZ, S., Dictyonema black shale and Triassic sandstones as potential sources of uranium. Nukleonika; 60 (2015) 515-522. [6] FRACKIEWICZ, K., KIEGIEL, K., HERDZIK-KONECKO I., CHAJDUK, E., ZAKRZEWSKA-TRZNADEL, G., WOLKOWICZ, S., CHWASTOWSKA, J., BARTOSIEWICZ, I., Extraction of Uranium from Low-grade Polish Ores: Dictyonemic shales and Sandstones, Nukleonika, 58 (2012) 451-459. [7] GAJDA, D., KIEGIEL, K., ZAKRZEWSKA-KOLTUNIEWICZ, G., CHAJDUK, E., BARTOSIEWICZ, I., WOLKOWICZ, S., Mineralogy and uranium leaching of ores from Triassic Peribaltic Sandstones, Journal of Radioanalytical and Nuclear Chemistry, 303 (2015) 521-529. [8] ZAKRZEWSKA-KOLTUNIEWICZ, G., HERDZIK-KONECKO, I., COJOCARU C., CHAJDUK, E., Experimental design and optimization of leaching process for recovery of valuable chemical elements (U, La, V, Mo and Yb and Th) from low-grade uranium ore, Journal of Hazardous Materials, 275 (2014) 136-145. [9] DANKO, B., DYBCZYNSKI, R. S., SAMCZYNSKI, Z., GAJDA, D., HERDZIK-KONECKO, I., ZAKRZEWSKA-KOLTUNIEWICZ, G., CHAJDUK, E., KULISA, K., Ion exchange investigation for recovery of uranium from acidic pregnant leach solutions, Nukleonika, 62 (2017) 213-221. [10] KIEGIEL, K., ABRAMOWSKA, A., BIELUSZKA, P., ZAKRZEWSKA-KOLTUNIEWICZ, G., WOLKOWICZ, S., Solvent extraction of uranium from leach solutions obtained in processing of Polish low grade ores, Journal of Radioanalytical and Nuclear Chemistry, 311 (2017)589-598. [11] ZAKRZEWSKA, G., BIELUSZKA, P., CHAJDUK, E., WOLKOWICZ, S., Recovery of uranium(VI) from water solutions by membrane extraction, Advanced Materials Research Vol. 704 (2013) 66-71. doi:10.4028/www.wcientific.net/AMR.704.66 [12] BIELUSZKA, P., ZAKRZEWSKA-TRZNADEL, G., CHAJDUK, E., DUDEK, J., Liquid-liquid extraction of uranium(VI) in the system with a membrane contactor. Journal of Radioanalitical and Nuclear Chemistry, 299 (2014) 611–619. [13] KIEGIEL, K., STECZEK, L., ZAKRZEWSKA-TRZNADEL, G., Application of calix[6]arenes as macrocyclic ligands for Uranium(VI) – a review Journal of Chemistry Volume 2013, Article ID 762819, 16 pages, http://dx.doi.org/10.1155/2013/762819. [14] MISKIEWICZ, A., ZAKRZEWSKA-KOLTUNIEWICZ, G., DLUSKA, E., WALO, P.F., Application of membrane contactor with helical flow for processing uranium ores. Hydrometallurgy, 163 (2016)108–114. [15] ZAKRZEWSKA-TRZNADEL, G., JAWORSKA-SOBCZUK, A., MISKIEWICZ, A., LADA, W., DLUSKA, E., WRONSKI, S., Method of obtaining and separating valuable metallic elements, specifically from low-grade uranium ores and radioactive liquid wastes, EP2604713, (2015). [16] GALICA D., DUNST N., WOŁKOWICZ S.: Wykorzystanie cyfrowego modelu zloza i harmonogramu produkcji do stworzenia koncepcji zagospodarowania zloza uranu „Rajsk”. Wiadomosci Gornicze nr 2 (2016) s. 94–99. [17] SKWARZEC, B., BORYLO, A., KOSINSKA, A., RADZIEJEWSKA, S., Polonium (210Po) and uranium (234U, 238U) in water, phosphogypsum and their bioaccumulation in plants around phosphogypsum waste heap at Wislinka (northern Poland), Nukleonika, 55(2) (2010) 187−193. [18] OLSZEWSKI, G., BORYLO, A., SKWARZEC, B., The radiological impact of phosphogypsum stockpile in Wislinka (northern Poland) on the Martwa Wisla river water, J. Radioanal. Nucl. Chem., (2015) DOI 10.1007/s10967-015-4191-5. [19] SCHROEDER, J., LEWANDOWSKI, M., KUZKO, A., GORECKI, H., ZIELINSKI, K., POZNIAK, T., ZIEBA, S., GORECKA, H., PAWELCZYK, A., WYSOCKI, A., Sposób przemywania fosfogipsu, Patent nr PL 116006 B1 (1983). [20] GORECKI, H., KUZKO, A., GORECKA, H., PIETRAS, L., Sposob oczyszczania fosfogipsu, Patent nr PL 119692 B1 (1984). [21] BOJKOWSKA, I., LECH, D., WOŁKOWICZ, S., Uran i tor w weglach kamiennych i brunatnych ze zloz polskich. Gospodarka Surowcami Mineralnymi, T. 24, Z. 2/2 (2008) 53‐65. [22] CHWISTEK, M., CHMIELOWSKI, J., KALUS, J., ŁACZNY, J., Biochemiczne lugowanie uranu z weglowych popiolow lotnych, Fizykochem. Probl. Mineralurgii, Vol.13(1981) 173-183. [23] SMOLINSKI, T., WAWSZCZAK, D., DEPTULA, A., LADA, W., OLCZAK, T., ROGOWSKI, M., PYSZYNSKA, M., CHMIELEWSKI, A.G., Solvent extraction of Cu, Mo, V, and U from leach solutions of copper ore and flotation tailings, Journal of Radioanalytical and Nuclear Chemistry, 314(1) (2017) 69–75. [24] ABRAMOWSKA, A., GAJDA, D. K., KIEGIEL, K., MISKIEWICZ, A., DRZEWICZ, P., ZAKRZEWSKA-KOLTUNIEWICZ, G., Purification of flowback fluids after hydraulic fracturing of Polish gas shales by hybrid methods, Separation Science and Technology, (2017) DOI: 10.1080/01496395.2017.1344710

Speaker: Prof. Grazyna Zakrzewska-Koltuniewicz (Institute of Nuclear Chemistry and Technology)

70 Uranium exploration and mining activities of Turkey as a newcomer

Countries embarking on a nuclear power programme that called “a newcomer” need to make sure that the development of their legal, regulatory and support infrastructure keeps pace with the construction of the power plant itself. This is the only way to ensure that the programme proceeds in a safe, secure and sustainable way, concluded participants of a workshop on nuclear power infrastructure development. Through several initiatives, the transfer of information and knowledge from states with extensive experience in uranium mining and production to "newcomers" to the sector. Growing demand from a much anticipated nuclear power renaissance and consequent soaring prices for nuclear fuel have recently spurred greater investment in uranium exploration in an increasing number of countries. Nuclear power is an inevitable option for Turkey to meet energy security. Turkey has distinctly progressing its nuclear energy program in nuclear milestones. As being aware of that uranium mining and activities would be a significant role in the nuclear power plant projects. This paper wholly investigated the recent uranium exploration activities, drilling efforts, identified conventional resources, environmental activities and regulatory regime of Turkey with the details. INTRODUCTION Background: uranium for nuclear power Uranium resources are an integral part of the nuclear fuel cycle. To increase the capability of interested Member States for planning and policy making on uranium production, the IAEA works together with the OECD Nuclear Energy Agency (NEA) to collect and provide information on uranium resources, production and demand. With uranium production ready to expand to new countries, efforts are being made to develop transparent and well-regulated operations similar to those used elsewhere to minimise potential environmental and local health impacts [1]. The general energy policy of Turkey focuses on the supply of secure, sustainable and affordable energy by diversifying energy supply routes and source countries, promoting usage of domestic resources and increasing the energy efficiency and renewable energy usage to decrease the energy intensity of production. Nuclear energy is considered for diversification of electricity generation and also for mitigation of GHG emissions from energy sector. The Akkuyu NPP project started with the IGA between Turkey and Russia for construction and operation of 4 VVER-1200 reactors in Akkuyu site situated on the Mediterranean coast of Turkey. A comprehensive EIA report had been prepared by the PC taking into consideration the requests from a wide range of stakeholders which was approved in December 2014. EMRA had granted electricity generation licence in June 2016 which will form the basis of the PPA. The revised site parameters report was approved by TAEK on February 2017 and granted limited work permit for construction of non-nuclear safety related facilities in October 2017. The full construction of the first unit is planned to start in the first quarter of 2018 with the grant of construction licence by TAEK. The other nuclear power plant project IGA which includes construction and operation of 4 ATMEA1 reactors in Sinop site and development of nuclear industry in Turkey was signed between Turkey and Japan in 2013 and ratified in 2015. EÜAŞ ICC established in November 2015 will participate to the project as shareholder of the project company which will be established based on the results of the feasibility study. The feasibility study started in July 2015 and the further support from Japanese government was provided with the MoU signed between MENR and METI in September 2016. The feasibility study is expected to be completed in the first quarter of 2018. The strategic goal of nuclear energy usage is mentioned in the strategic plan of MENR under the goal for optimum energy resource diversity. Turkey has a high energy import and fossil fuel dependency which makes it vulnerables to external shocks in global markets. Nuclear energy is considered as one of the options together with local resources and renewable energy to sthrengthen the energy sector in Turkey. Radioactive minerals have been historically explored in Turkey which requires further studies for their feasibilities to start production [2]. As a result the strategic plan includes the target for reserve determination of radioactive minerals together with their respective feasibility studies for usage in the nuclear energy sector [3]. DESCRIPTION General Directorate of Mineral Research and Exploration (MTA) Uranium exploration in Turkey began in 1956-1957 and was directed towards the discovery of vein-type deposits in crystalline terrain, such as acidic igneous and metamorphic rocks. As a result of these activities, some pitchblende mineralisation was found but these occurrences was not accepted as economic deposits. Since 1960, studies have been conducted in sedimentary rocks which surround the crystalline rock and some small orebodies containing autunite and torbernite mineralisation have been found in different parts of the country. In the mid-1970s, the first hidden uranium deposit with black ore, below the water table, was found in the Koprubaşı area of Manisa. As a result of these exploration activities, a total of 9 129 tonnes U3O8 (7 740 tU) in situ resources were identified in the Manisa-Köprübaşı (2 852 tonnes U3O8; 2 419 tU), Uşak-Eşme (490 tonnes U3O8; 415 tU), Aydın-Koçarlı (208 tonnes U3O8; 176 tU), Aydın-Söke (1 729 tonnes U3O8; 1 466 tU) and Yozgat-Sorgun (3 850 tonnes U3O8; 3 265 tU) regions. Eti Mine Works General Management (Eti Maden) State-owned organization Eti Maden is responsible for a total of six uranium mine sites with uranium resources. Geological exploration has been performed by MTA at these sites in the past. Between 1960-1980 uranium exploration was performed by aerial prospecting, general and detailed prospecting on-site, geologic mapping studies and drilling activities. These uranium sites were transferred to Eti Maden as possible mines which can be operated by the state under law number 2840 on the “Operation of Boron Salts, Trona and Asphaltite Mines and Nuclear Energy Raw Materials” (10 June 1983). Recent and ongoing uranium exploration and mine development activities General Directorate of Mineral Research and Exploration (MTA) In 2012, granite, acidic igneous and sedimentary rocks around Manisa, Denizli and Aydın (an area of approximately 5 000 km2) were explored for radioactive raw materials. Exploration for radioactive raw materials was also performed in sites licenced by MTA inside Manisa, Uşak and Nevşehir. In 2013, granite, acidic igneous and sedimentary rocks around Aydın and Denizli (an area of approximately 5 000 km2) will be explored for radioactive raw materials. Exploration for radioactive raw materials was also performed in sites licenced by MTA inside Manisa, Uşak and Nevşehir. In 2014, Exploration for radioactive raw materials was conducted in sites licenced by MTA inside Manisa, Uşak and Nevşehir. In 2015, Exploration for radioactive raw materials will be conducted in sites licenced by MTA inside Manisa and Nevşehir [4]. Private sector exploration Adur, a wholly owned subsidiary of Anatolia Energy, a Turkish uranium exploration company with current and active drill programmes at the Temrezli and Sefaatli uranium sites, has carried out exploration and resource evaluation drilling with a total of 206 drill holes completed for a total drill advance of over 26 000 m since 2011 in both Şefaatli and Temrezli projects. Over 16 000 m of drilling was in Temrezli region. Until now, 112 holes have been completed in Temrezli project. The drilling in Temrezli, mostly twinning the earlier MTA drill holes but also in-fill and step-out holes, confirmed work conducted in the 1980s and extended the uranium mineralisation to the north-east over a strike length of more than 3 000 m. In 2011, CSA Global Pty Ltd prepared a JORC compliant mineral resource estimate for the Temrezli deposit of 13.282 Mlb U3O8 (6 025 tU) (measured, indicated and inferred) in situ uranium at an average grade of 1 157 ppm (0.117% U3O8). Preliminary metallurgical bottle-roll leach test work confirmed MTA’s earlier work and returned 93% and 90% uranium recovery was obtained by using an acid or alkali leach method, respectively. Several hydrological test wells were constructed at Temrezli since 2012 in order to assess the regional groundwater conditions and to conduct hydraulic testing of the mineralised horizons at a scale typically seen at in-situ recovery (ISR) operations. Test work was performed by HydroSolutions, a US-based hydrogeologist with considerable experience in ground water conditions relating to uranium ISR operations throughout western United States. The test confirmed the aquifer has sufficient flow rate for ISR mining. Regional exploration identified new areas of mineralisation, at West Sorgun and Akoluk. The rotary and diamond drill programme tested a number of regional sites that are considered prospective for Eocene-aged sediment-hosted uranium mineralisation, similar to what is seen at the Temrezli uranium deposit. Since early stage studies indicate that the Temrezli uranium deposit will be amenable to ISL mining, a preliminary economic assessment (PEA) contract was awarded to US based WWC Engineering of Sheridan, Wyoming. The PEA is completed and followed by PFS study which was awarded to Tetra Tech, US origin company PFS was completed and issued in early 2015 which indicated that the project is economically feasible to proceed, with a total expected recovery of 9.7m lbs. over 12 years, with operating costs of less than USD17 per lb U3O8 (USD44.2 per kg U). Adur initiated the Environmental Impact Assessment (EIA) process by preparing and submitting a Project Description to the Ministry of Environment and Urban Planning in 2015. Adur will also initiate the permitting process with Turkish Atomic Energy Commission regarding licensing Temrezli site as a nuclear facility since ISR operations are considered as nuclear facilities. In 2015, the permits and licenses will be obtained prior to initiating the construction in early 2016. DISCUSSION AND CONCLUSION  Identified conventional resources (reasonably assured and inferred resources) Identified conventional uranium resources in Turkey determined from exploration activities performed by MTA in the past are listed below, with the addition of JORC compliant resources identified through recent work by Adur exploration, described in more detail: • Manisa-Köprübaşı: 2 419 tU in ten orebodies and at grades of 0.04-0.05% U3O8 (0.034 0.042% U) in fluvial Neogene sediments. • Uşak-Eşme: 415 tU at 0.05% U3O8 (0.042% U) in Neogene lacustrine sediments. • Aydın-Koçarlı: 176 tU at 0.05% U3O8 (0.042% U) in Neogene sediments. • Aydın-Söke: 1 466 tU at 0.08% U3O8 (0.068% U) in gneiss fracture zones. • Yozgat-Sorgun: 4 633 tU at 0.117% U3O8 in Eocene deltaic lagoon sediments. Temrezli (Yozgat / Sorgun) uranium deposit is one of Turkey’s largest and highest grade uranium deposits, with a JORC compliant Mineral Resource estimate of 13,282 Mlb of contained uranium at an average grade of 1,157 ppm (0.117%) U3O8 with an average depth of 120 m.  Undiscovered conventional resources (prognosticated and speculative resources) Temrezli Project: The ongoing exploration and development drillings is to be continued and is expected to increase the resource by a potential of 1-3 Mlb U3O8. Şefaatli Prospect: exploration and development drillings is being conducted in 2015 and is expected to increase the known uranium resource values by approximately 5-6Mlb U3O8. The recent drill results include 1,10m at grade 2,150ppm e U3O8 from 39m [4].  Unconventional resources and other materials None reported, but grassroots exploration is in place. REFERENCES [1] The Red Book 2014: Resources, Production and Demand A Joint Report by the OECD Nuclear Energy Agency and the International Atomic Energy Agency/Turkey Updated Chapter 2016 [2] T.R. Ministry of Development 2013: “The tenth Development Plan” T.R. Ministry of Development [3] T.R. Ministry of Energy and Natural Resources Strategic Plan 2015 - 2019 [4] ALKAN M. GÜLMEZ A. ULUSOY M. A Review of Uranium and Thorium Studies in Turkey, IMMC 2016: 18. International Metallurgy and Materials Congress

Speaker: Mrs Sibel GEZER

71 A milestones approach to uranium mining and development: an IAEA initiative

OVERVIEW Many IAEA Member States without current uranium production activity have expressed interest in uranium mining, in order to meet their or other countries’ energy needs. To introduce or reintroduce uranium mining and processing, a wide range of issues needs to be considered. With the assistance of experts from around the world, the IAEA is preparing a guide setting out a milestones approach to the uranium production cycle. This will assist Member States to take a systematic and measured approach to responsible uranium mining and milling. The information in the guide will be provided within the context of other IAEA guidance and materials relevant to development of the Uranium Production Cycle, including the IAEA Safety Standards and Safety Guides Series. Although not the emphasis of the guide, the vital importance of appropriate radiation protection, security and non-proliferation safeguards is acknowledged. In the development of the guide, four generalized stages with associated milestones of preparedness are being considered (subject to amendment): • Those considering exploration or mining of uranium for the first time, or after many years, but without an identified project. • Those seeking to initiate/ reinvigorate uranium mining with one or more identified projects. • Established producers of uranium wishing to enhance existing capacity/capability. • Historic producers with closed sites in the stage of closure and rehabilitation/remediation or aftercare. The situation of Member States will be unique, at least in detail. It is also acknowledged that a given Member State may simultaneously be in more than one of these generalized stages. Nevertheless, the report will comment on common threads and good practices, and assist a Member State to identify areas within a stage where they are less prepared, and give advice for a way forward towards a later stage. However, an important consideration with uranium mining and milling is that uranium ore may or may not be present in a particular Member State. Hence, even with excellent work in uranium exploration, with good policies, legislation, regulation and well-trained experts, a Member State may remain in the earliest stage. This is in contrast to the milestones approach for some other purposes, where the opportunity to progress through the various milestones to their successful implementation is more generally applicable, should a Member State choose. ACKNOWLEDGEMENTS The uranium production milestones guide will be designed for use around the world, but the specific involvement of African Member States and IAEA’s Technical Cooperation Regional Africa Projects to launch the work is acknowledged. To date, the following experts from around the world have been directly assisting the IAEA in the preparation of the milestones guide. Abbes, N., Groupe Chimique Tunisien, Tunesia Blaise, J.R. , Consultant, France Brown, G., Boswell Capital Corporation, Canada Dunn, G., Hydromet Pty Ltd, South Africa Hama Siddo Abdou, Ministère des Mines, Niger Hilton, J., Aleff Group, United Kingdom Itamba, H., Ministry of Mines and Energy, Namibia Lopez, L., CNEA, Argentina Mwalongo, D., Tanzania Atomic Energy Commission, United Republic of Tanzania Consultancy Meetings were held in Vienna, Austria on 12–14 December 2016 and 4–7 September 2017. It is intended that a full draft document will be made available for comment to the IAEA’s member states during 2018. BIBLIOGRAPHY EUROPEAN COMMISSION, FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS, INTERNATIONAL ATOMIC ENERGY AGENCY, INTERNATIONAL LABOUR ORGANIZATION, OECD NUCLEAR ENERGY AGENCY, PAN AMERICAN HEALTH ORGANIZATION, UNITED NATIONS ENVIRONMENT PROGRAMME, WORLD HEALTH ORGANIZATION, Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards, General Safety Requirements Part 3, IAEA Safety Series No. GSR Part 3, IAEA, Vienna (2014). INTERNATIONAL ATOMIC ENERGY AGENCY, Steps for preparing uranium production feasibility studies: A guidebook, IAEA-TECDOC-885, IAEA, Vienna (1996). INTERNATIONAL ATOMIC ENERGY AGENCY, Environmental Impact Assessment for Uranium Mine, Mill and In Situ Leach Projects, IAEA-TECDOC-979, IAEA, Vienna (1997). INTERNATIONAL ATOMIC ENERGY AGENCY, Occupational radiation protection in the mining and processing of raw materials, Safety Guide RS-G-1.6, IAEA, Vienna (2004). INTERNATIONAL ATOMIC ENERGY AGENCY, Guidebook on Environmental Impact Assessment for In Situ Leach Mining Projects, IAEA-TECDOC-1428, IAEA, Vienna (2005). INTERNATIONAL ATOMIC ENERGY AGENCY, Assessing the Need for Radiation Protection Measures in Work Involving Minerals and Raw Materials, Safety Reports Series 49, IAEA, Vienna (2007) INTERNATIONAL ATOMIC ENERGY AGENCY, Establishment of Uranium Mining and Processing Operations in the Context of Sustainable Development, IAEA Nuclear Energy Series No. NF-T-1.1, IAEA, Vienna (2009). INTERNATIONAL ATOMIC ENERGY AGENCY, Best Practice in Environmental Management of Uranium Mining, IAEA Nuclear Energy Series No. NF-T-1.2, IAEA, Vienna (2010). INTERNATIONAL ATOMIC ENERGY AGENCY, Specific Considerations and Milestones for a Research Reactor Project, IAEA NP-T-5.1, IAEA, Vienna (2012). INTERNATIONAL ATOMIC ENERGY AGENCY, Milestones in the Development of a National Infrastructure for Nuclear Power, IAEA NG-G-3.1 (Rev. 1), IAEA, Vienna (2015). INTERNATIONAL ATOMIC ENERGY AGENCY, Nuclear Security in the Uranium Extraction Industry, IAEA- TDL-003, IAEA, Vienna (2016).

Speaker: Dr Peter H. Woods (IAEA)

10:40 Break

Underground and Open Pit Uranium Mining and Milling

Conveners: Dr Luminita Grancea (OECD NEA), Dr Ziying Li (Beijing Research Institute of Uranium geology)

72 Overview of Uranium Heap Leaching Technology in China

With the merits of low power, reagent and water consumptions and low operational cost, heap leaching of uranium ores has become the most widely used technological process for natural uanium production in China. Of the proved uranium reserves in China, hard-rock minerals of low uanium grade take a large proportion and these reserves are mainly located in southern China and suitable for heap leaching. Study on heap leaching of uranium ores has been emphasized in the past decades in the country and some technical achievements have been made and already applied in commercial production. The present status of uranium heap leaching application in China, including the ore characteristics and technological processes for typical processing mills and some new technological developed and applied is introduced in this paper. Some existing problems in practical operation are also discussed.

Speaker: Mr Pingru Zhong (Beijing Research Institute of Chemical Engineering and Metallurgy)

73 Development of Alkali leaching technology: Key to Self Sufficiency in Uranium Production in India

INTRODUCTION Geological investigations for uranium deposits initiated in India during 1949-50 have led to the discovery of a number of favourable geological basins in the country. First uranium deposit located at Jaduguda in Singhbhum Shear Zone in the eastern state of Jharkhand continued to attract investments in exploration and mining of uranium for over five decades. However, extensive exploration in other parts of the country has brought to light more uranium deposits / occurrences in South Cuddapah basin (Andhra Pradesh), North Cuddapah Basin (Telangana), Mahadek basin (Meghalaya), Bhima basin (Karnataka) and Delhi Supergroup of rocks (Rajasthan) in addition to Singhbhum Shear Zone (Jharkhand). Uranium mining in India, the front end activity of the Indian nuclear power programme, has always been challenging considering the uranium deposit characteristics in the country. Indian uranium deposits in general are of medium-tonnage and low-grade. Detailed studies of geological characteristics of these deposits are undertaken for selection of proper mining method and technology. Ore processing technology is subjective to mineralogical and metallurgical characteristics of the ore and hence determination of suitable technology and process parameters is crucial for successful operations of these deposits. Of all the above areas, South Cuddapah basin in Andhra Pradesh accounts for about 49% of Indian uranium resources, occurring in carbonate hosted rock which calls for development of alkali leaching process route. Part of this resource extending over a strike length of 6.6 km is under development at Tummalapalle. An underground mine with a capacity to produce 3000 tonnes of ore per day with a plant of matching capacity based on alkali leaching has been set-up. ALKALI LEACHING TECHNOLOGY AT TUMMALAPALLE The ore zones at Tummalapalle are confined two thin distinct bands within a thick pile of carbonate rocks - massive limestone, intra-formational conglomerate, dolostone, shale and cherty limestone. The mined out ore, after conventional crushing and grinding (80% passing 74 micron) are thickened, re-pulped and subsequently subjected to alkali leaching by sodium carbonate and sodium bicarbonate solution. Leaching is carried out under high pressure and temperature conditions in autoclaves in series with a nominal residence time of 6.5 hrs. The leached slurry is then filtered in Horizontal Belt Filter (HBF) and the desired concentration leached liquor is achieved through repeated recirculation and washing. The washed cake in the form of slurry is disposed in tailings impoundment facility. The leached filtrate, after clarification and pre-coat filtration is subjected to precipitation with the addition of sodium hydroxide. The final product, at a pH of 12 or above is precipitated as sodium di-uranate (SDU). Extensive laboratory and pilot plant studies have been undertaken to develop this process parameters and flow sheet. The process has undergone several up-gradations in different areas for better leaching and precipitation efficiency. A major breakthrough has been recently achieved for settling and complete recovery of precipitated product by commissioning the Re-dissolution System facility wherein part of the product is sent to precipitation tanks. Regeneration of sodium carbonate and sodium hydroxide treating barren liquor before recycling has been taken up. The plant will also produce sodium sulphate as by-product. Uranium tailings management is an integral part of the uranium mining industry. In view of effective utilization of available and acquired land and ease of handling and monitoring of tailings, UCIL has recently proposed the concept of Near Surface Trench disposal of uranium tailings which consists of an earthen Construction with the use of impervious & geo-synthetic liners along with arrangements for withdrawal of excess water and temporary coverage of top surface during heavy rain. This method will lower the transportation cost as well as increase the stability and life of the structure. Successful implementation of this concept will benefit new uranium mining projects in the country in terms of time and cost. A further detailed study on the concept and its implementation is currently being undertaken. CONCLUSION India has had a long commitment to nuclear energy since the establishment of the Atomic Energy Commission in 1948 and the Department of Atomic Energy in 1954. Nuclear energy plays a critical role in addressing energy challenges, meeting massive energy demand potentials, mitigating carbon emissions and enhancing energy security. The three-stage nuclear power programme being pursued to develop nuclear power in India is consistent with India’s unique resource position of limited uranium and large thorium reserves and hence, uranium production plays a vital role in this growing indigenous nuclear power program of the country. The alkali leaching technology adopted for processing of low grade ore at Tummalapalle is the result of extensive research work of the Department of Atomic Energy. Carbonate hosted uranium mineralization accounts for lion’s share of the Indian uranium inventory, therefore, successful operations and extraction of uranium at Tummalapalle shall enable to develop more uranium deposits in this area (South Cuddapah basin in Andhra Pradesh). Newer areas in other geological basins amenable to acid leaching have also been taken for development to meet the requirement of uranium in coming decades. BIBLIOGRAPHY GUPTA, R. and SARANGI, A. K., “Overview of Indian uranium production scenario in coming decades”, International Seminar on Asian Nuclear Prospects (ANUP-2010), Energy Procedia, Volume 7, pp. 146-152 (2011) GUPTA, R. and SARANGI, A. K., “A new approach to mining and processing of a low grade uranium deposit at Tummalapalle, Andhra Pradesh, India”, IAEA Technical Meeting on “Uranium Small-Scale and Special Mining and Processing Technologies” Vienna during 19th – 22nd June 2007. SARANGI, A.K. and KRISHNAMURTHY, P., “Uranium metallogeny with special reference to Indian deposits”, Trans. Min. Geol. and Met. Inst. India, Vol. 104. (2008) SURI, A.K., “Innovative process flowsheet for the recovery of uranium from Tummalapalle ore”, Bhabha Atomic Research Centre (BARC), Newsletter Issue no. 317, Nov. - Dec. 2010. SURI, A.K., PADMANABHAN, N.P.H., SREENIVAS, T., et al., “Process development studies for low grade uranium deposit in alkaline host rocks of Tummalapalle”, IAEA Technical Meeting on Low Grade Uranium Deposits, Vienna, March 29-31, 2010.

Speaker: Mr C. K. Asnani (Uranium Corporation of India)

74 Coagulation of Colloidal Silica from Uranium Leach Solutions for Improved Solvent Extraction

Colloidal silica generated in the leaching process by contacting clays and concrete with sulphuric acid has caused operational problems in solvent extraction (SX) at Cameco’s Key Lake uranium mill throughout its history. This colloidal silica stabilizes aqueous continuous emulsions in SX, resulting in increased solvent losses and operational downtime. Silica coagulation was investigated in 2014 with POLYSIL RM1250, a polyethylene glycol coagulant. Lab results showed excellent clarification of the process solution, but subsequent mill trials were unsuccessful. In 2015 the problem shifted from optimizing solution clarity to measuring the changes in phase separation performance under both organic and aqueous continuous mixing with varying POLYSIL doses. This analysis showed aqueous continuous separation performance was equivalent to organic continuous separation performance at doses approaching 300 ppm, significantly higher than anything previously tested. A follow-up pilot study confirmed the lab results, but also discovered an inverse relationship between acid concentration and separation time, suggesting less acid would be required in the mill process. A mill trial with POLYSIL RM1250 was performed in 2017 with doses ranging from 170-300 ppm. The mill trial was successful in reducing SX solvent consumption by 85% and overall acid and lime consumption by 7%.

Speaker: Dr Brett Moldovan (IAEA)

75 Investigation of Key Parameters for Effective SDU Precipitation

INTRODUCTION While precipitation of sodium diuranate (SDU) has been practiced commercially from leach liquors since the 1950’s, there is very limited information on the impact of operating conditions on the efficiency of uranium precipitation from the “low-tenor’ liquors that are produced from the carbonate leaching of carnotite in calcrete ores. ANSTO Minerals recently carried out a program of work investigating direct SDU precipitation from carbonate/bicarbonate leach liquors. A number of variables were examined to assess their impact on the precipitation efficiency, including carbonate feed concentrations, terminal caustic concentration and seeding. In addition to a batch test work program, a continuous mini-plant was also operated. WORK PROGRAM Test work was completed on pregnant leach solution (PLS) produced from bulk leaching of a carnotite in calcrete ore. Two different leach regimes were used to generate PLS with differing concentrations of Na2CO3 and NaHCO3 (high bicarbonate - 12 g/L NaHCO3, 33 g/L Na2CO3 and; low bicarbonate – 7 g/L NaHCO3, 31 g/L Na2CO3). The uranium concentration was ~ 1 g/L U3O8 in both cases. The same solutions were used in both batch laboratory-scale tests and in a continuous mini-plant. Laboratory batch tests were conducted by heating the PLS to the target temperature (70 or 80 °C) and adding a pre-determined quantity of SDU seed or uranium stock solution, to achieve a target total U3O8 concentration (1-6 g/L U3O8). Typically, a 2 h seeding time was allowed at temperature to promote dissolution of the seed. After the seeding time, NaOH (50 wt% solution) was added to consume the NaHCO3 and obtain the target caustic concentration (6 or 8 g/L) in solution. Samples were withdrawn regularly for analysis by ICP for U and V concentrations. RESULTS AND DISCUSSION Impact of Bicarbonate and Total Carbonate Concentrations A series of tests were completed examining the impact of total carbonate concentration in the PLS on SDU precipitation. The total Na2CO3 ranged from 38 – 78 g/L, after reaction of all of the NaHCO3 with NaOH. Lower uranium in barrens was achieved from solutions containing lower carbonate concentrations. When considered in the context of an entire flowsheet and the preceding leach conditions, this is an important observation. Bicarbonate is required for uranium extraction but it is also generated during the leaching of carnotite in calcrete ores. The chosen Na2CO3/NaHCO3 reagent concentrations at the start of the leach will therefore define the composition of the PLS being fed downstream to SDU precipitation. The higher the terminal bicarbonate concentration in leach, the more caustic required to neutralise it (Equation 1), resulting in a greater total Na2CO3 concentration. NaHCO3 + NaOH -> H2O + Na2CO3 Equation 1 A higher concentration of bicarbonate in the PLS was shown to increase the dissolution of seed, resulting in a higher dissolved uranium concentration prior to precipitation. However, the improved dissolved uranium concentration prior to precipitation was offset by the increased total carbonate concentration obtained, resulting in higher concentrations of uranium in barrens. Impact of Seeding Seeding is recognised as an important component of SDU precipitation in a continuous operation and our results support the need for seeding. The best uranium in barrens achieved in tests completed in the absence of seeding was 163 mg/L U3O8 (138 mg/L U) whereas the presence of seeding under the same operating conditions reduced the uranium in barrens to 57 mg/L U3O8 (48 mg/L U). Comparison of target seed concentrations (4 and 6 g/L U3O8), however, showed that while there was a reasonable improvement in the amount of dissolved U after seeding at 6 g/L U3O8, the final difference in U in barrens was minimal. It should be noted that with greater seed dissolution, more caustic is subsequently required to re precipitate the uranium (Equation 2). 6 NaOH + 2 Na4UO2(CO3)3 -> Na2U2O7 + 6 Na2CO3 + 3 H2O Equation 2 Further testing looked at the impact of “total dissolved” uranium concentration on precipitation (over the range of 1-6 g/L U3O8), by spiking the PLS with a uranyl carbonate solution rather than seeding with solid SDU product. A dissolved U3O8 concentration of 3 g/L was shown to be optimum for producing the lowest uranium in barrens, with the lowest consumption of caustic. There was a small kinetic impact on precipitation at higher concentrations (4, 5 or 6 g/L U3O8), which may permit a reduced reaction residence time, although at the cost of higher caustic consumption. Impact of Caustic Concentration A higher terminal caustic concentration has a positive impact on the kinetics of precipitation. Considerably lower uranium in barrens were observed at 8 g/L NaOH, compared to 6 g/L, particularly after the first 30 minutes of precipitation. With increasing residence time, the gap narrows, although the final uranium in barrens after 8 hours precipitation was still lower at 8 g/L NaOH (by 9 – 16 mg/L U). This result suggests that operating at a lower NaOH target may be offset by increasing the precipitation residence time and has the added benefit of reducing costs due to a lower caustic requirement. Impact of Temperature Comparable tests completed at 70 and 80 C showed a significant increase in seed dissolution at the higher temperature, therefore increasing the concentration of dissolved uranium in solution. The subsequent impact on SDU precipitation, however, was not significant. CONCLUSIONS The carbonate and bicarbonate concentrations in the feed liquor were determined to have a significant impact on the success of SDU precipitation. Our investigations have shown that a higher total carbonate concentration in the feed solution is a key factor impeding SDU precipitation, resulting in an increased concentration of uranium in the barren solution. The concentrations of the preceding leach reagents (Na2CO3 and NaHCO3) are therefore important as this will define the total carbonate concentration in the SDU precipitation circuit. The caustic concentration was demonstrated to have a kinetic effect on the precipitation reaction and consequently residence time may also be critical, depending on the terminal caustic concentration selected for a given flowsheet. Higher temperature was shown to improve the dissolution of seed but did not show a significant impact on the final precipitation result. Greater seed dissolution was also achieved in the PLS which contained a higher concentration of bicarbonate but the resulting total sodium carbonate concentration was higher from this PLS and this had a negative impact on the precipitation and final U in barrens. Seeding was demonstrated to be necessary for effective precipitation. The complex relationship between dissolved uranium concentration and the presence of seed on SDU precipitation has been investigated to fully define the nature and amount of solid seed required.

Speaker: Mr Mark Maley (ANSTO Minerals)

Uranium Newcomers

Conveners: Dr Alexander Boytsov (Uranium One Group), Prof. Richard Schodde

76 An integrated Capacity Building Approach to Uranium Production Cycle Milestones for regional Asia Pacific Technical Co-operation

Asia-Pacific region is the major consumer of mineral raw materials including uranium and other its associated mineral resources materials. However, production of the required raw materials which are required for many sectors including energy production and agro-industries are not sufficient to meet the demand. This is many due to predominantly low grade, unconventional and relatively technologically difficult to process mineral ore available in the region. Radioactive and associated mineral resources that could be extracted as co or by product far outweighs the conventional mining projects in the region. But the regional capacity to address challenges in economic, environmental and social returns and formulate a well-defined project through the life-cycle is found lacking. Creating a base line capacity and knowledge management platform to address the deficiency in those areas will greatly assist MSs in the region. The IAEA through the technical cooperation (TC) regional project RAS2019 – “Conducting the Comprehensive Management and Recovery of Radioactive and Associated Mineral Resources” provides capacity building in core technology in uranium production, feasibility and macro-economic aspect of uranium production, facilitate exchange of information and good practices, and also provide opportunities for dissemination of R&D results through publication and participation in international conferences.

Speaker: Mr Syahril Syahril (IAEA)

77 Uranium potential in Nigeria

INTRODUCTION The Nigeria Atomic Energy Commission (NAEC) was established by Degree 46 (Now Act 46) in August, 1976 and became operational in July, 2006 as a specialized National Focal Agency with the mandate for the promotion and development of atomic energy and for all matters relating to the peaceful uses of atomic energy. The Commission was further mandated to: Prospect for and mine radioactive minerals; manufacture or otherwise produce, buy or otherwise acquire, treat, store, transport and dispose of any radioactive substances. The uranium potential in Nigeria is considered to be in commercial quantity with several known uranium occurrences [1-2]. Given the limited uranium exploration carried out in Nigeria to date, a greater potential is presumed to exist based on spot observations and the knowledge of favorable geological environment for uranium deposits (sandstone and unconformity-related deposit types) [1,3}. GEOLOGICAL SETTING OF NIGERIA The geology of Nigeria is composed of 4 main groups [3-4], namely: 1. The Basement Complex, 2. Younger Granites, 3. Sedimentary series and 4. Tertiary-Recent volcanic rocks. The Basement Complex is made up of the migmatitegnesis complex, pegmatites, the schist belts composed of metasedimentary and metavolcanic rocks and the pan- African granitoids comprising the Older Granites and the associated charnockitic rocks. The Younger Granites are of Jurassic age and they are found as ring-complex outcrops within the Basement Complex areas [3-4]. NIGERIAN URANIUM OCCURRENCES Uranium potential in Nigeria occurs in sandstone-hosted and vein-type mineralization. Sandstone-hosted deposits occurs in sedimentary/volcano sedimentary sequences in structurally controlled Bima sandstone at Zona and Dali, while the vein-type mineralization occurs in the deformed migmatites and granitoids at Gubrunde, Kanawa, Ghumchi, Mika and Monkin-Maza deposits [5-7]. Substantial Uranium mineralization occurs in the Ririwai area of southern Kano. According to Obaje et al [8], uranium occurred in peraluminous and peralkaline granites and the content of uranium in peraluminous granite lies between 16 and 32 ppm. Mika, Gumchi, Zona and Mayo Lope areas of Adamawa State have good uranium exploration prospect localized in the mylonitized, sheared and brecciated fine-grained to porphyritic granites. Analysis of cores from 40 drilled holes gave values of 2,000 ppm uranium content [2]. HISTORY OF URANIUM EXPLORATION IN NIGERIA In Nigeria Uranium exploration started in 1973. Uranium has been found in six states of the country. The six states are Cross River, Adamawa, Taraba, Plateau, Bauchi and Kano. The mineralizations are Guburende, Kanawa, Zona, Dali, Mika, and Monkin-Manza and were all discovered by three government agencies [9]: 1. GEOLOGICAL SURVEY DEPARTMENT (GSD) In 1974, GSD discovered the uraniferous pyrochlore in Ririwai hills in Kano State and Kigo hills in Plateau State. The Grade is 0.012% uranium oxides. 2. THE DEFUNCT NIGERIAN MINING CORPORATION The Defunct Nigerian Mining Corporation Exploration campaigns in Kogi State (North Central Nigeria) collaborated with NUMCO in the exploration of some areas in North Eastern Nigeria in 1980. 3. NIGERIAN URANIUM MINING COMPANY (NUMCO) Established in 1979 with the mandate to explore and exploit all available uranium ore deposits in Nigeria. It was in public/private partnership with Total Compagnie Miniere of France, which owned 40% of the company as a technical partner. In 1989, Total pulled out of the partnership as a result of lack of funding. The company carried out exploration programmes at both the reconnaissance and semi detailed levels. Areas of activities covered about 112,346 Km² in the North Eastern Nigeria bordering the Cameroun [2]. Areas of interest include Gubrunde, Mika and Ghumchi all underlain by the rocks of the basement complex; and Mayo Lope area which is underlain by the Cretaceous continental sedimentary rocks [9]. FINDINGS AND CURRENT PROGRESS At the end of the various exploration campaigns; Uranium reserve at Mika was put at about 52T U. Grade was 0.63% U. At a vertical depth of 130m. Uranium reserve at Ghumchi was estimated at 100T U Grade was 0.9 % U. At a vertical depth of 200m Cut-off was 0.03% U [2]. Presently, the mandate for the exploration of Nigeria Uranium is vested in the Nigeria Atomic Energy Commission. Currently the Nigeria geological Survey Agency (NGSA) and three university research centres are carrying out limited exploration of uranium in the potential areas due to limited funds. CONCLUSION Uranium exploration in Nigeria is still in progress. They are being carried out by NGSA and three universities research centers under the coordination of NAEC with limited funds. At present the investigated deposit size and potentials are still insufficient to motivate the resource drilling and feasibility studies. A classical geophysical method applicable to faults detection is also needed. Economic viability of extraction has not been determined due to insufficient information. NAEC is therefore, calling on all serious investors in this area to come to Nigeria and invest in this uranium potential that exist in commercial quantity. REFERENCES [1] MINISTRY OF SOLID MINERALS DEVELOPMENT, “An Inventory of Solid Minerals Potentials of Nigeria; Prospectus for Investors” (1996), pp.1 – 15. [2] NUMCO,” Nigerian Uranium Mining Company Annual Reports” (1983, 1986). [3] OGEZI, A. E., Nature, Exploration and Exploitation of Metallic Mineral (ore) Deposits in Nigeria and Prospects in the Chad Basin. workshop proceedings, Univ. of Maiduguri (2006), pp.19-33 [4] MALLO, S. J., The Nigerian Mining Sector: An Overview. Continental Journal of Applied Science, Vol. 7 (2012), pp.34-45 [5] ADEKANMI. A. A, OGUNLEYE. P.O, DAMAGUM, A.H. and OLASEHEINDE, O., Geochemical Map of Uranium Distribution in the Residual Soil of GRN Cell Number N08 E05. Unpublished Report, Nigerian Geological Survey Agency (2007). [6] IGE, T. A., OKUJENI, C. D. and ELEGBA, S. B., Distribution Pattern of REE and other Elements in the Host Rocks of the Gubrunde Uranium Occurrence, Northeastern Nigeria. Journal of Radio-analytical and Nuclear Chemistry, Vol. 178 (1994), pp.365-373. [7] FUNTUA, I.I. and OKUJENI, C.D., Element Distribution Patterns in the Uranium Occurrence at Mika, Northeastern Nigeria. Chemie der Erde, Gustav Fischer Verlag Jena (1996), 245 – 260. [8] OBAJE S.O., OJUTALAYO A., OGEDENGBE O. and OKOSUN E.A., Nigeria’s Phosphate and Uranium Mineral Occurrences: Implication for Mineral Investment, Journal of Environment and Earth Science Vol.4, No.1, 1-10 (2014). [9] DADA, S. S., and SUH, C. E., Finding Economic Uranium Deposits and the Nigerian Energy Mix. Workshop proceedings, Univ. of Maiduguri (2006), pp.34-43

Speaker: Mr Justine Karniliyus (Nigeria Atomic Energy Commission)

78 Uranium/Thorium Resource Assessment in Saudi Arabia

ABSTRACT As part of the ambitious Saudi’s vision 2030, the minerals sector has been considered as one of the key industries in the Kingdom. Uranium, among all minerals, has received an intensive attention due to its strategic value in securing the nuclear fuel for future reactors. Uranium occurrence was indicated by prospecting surveys made in 1979-1984. These surveys have identified 9 nominated exploration areas, with 35 inner sites. Studies also revealed five important geological environments of uranium resources. The project “Uranium/Thorium Resource Assessment in the Kingdom” was launched in April 2017 as a collaboration between K.A.CARE and the Saudi Geological Survey. It is two phase’s project; general exploration and detailed exploration. Beside the self-sufficiency in fuel production, the project aims to encourage investment in uranium mining and enhance the human and technical local content in this area. The work includes the following activities: radiometric and magnetic airborne survey, geological survey, image processing of remote sensing interpretation, anomaly verification and evaluation, gamma-ray spectrometer and radon surveys, geophysical survey, trenching, borehole drilling, sampling, chemical analysis mapping, radiometric analysis mapping and Geo-database construction. Also, a systematic exploration drilling and core sampling will be developed in the prospecting targets. INTRODUCTION The project aimed to evaluate uranium and Thorium resources in the kingdom of Saudi Arabia according to JORC standards through two exploration Phases, the first phase is planned to be accomplished in two years to evaluate Uranium and Thorium resources (Inferred definitions) started in April 2017. The second phase will utilizes the results and recommendations from the previous exploration phase to reach resources estimation according to indicated and measured definitions, in three years. In the first phase, the project activities will concentrate on the nominated exploration areas and 35 inner sites defined from previous prospection exploration 1965-1987. The Project Partners are King Abdullah City for Atomic and Renewable Energy (KACARE) as project owner, Saudi Geological Survey (SGS) as exploration program manager, China National Nuclear Corporation (CNNC) as exploration contractor. The project scope of work and JORC compliance will be supervised for quality assurance and control by Geological Survey of Finland (GTK). DESCRIPTION Saudi Arabia Geology is consisting of two major units: Arabian Shield and sediment cover rocks that contributed to the existence of different geological environments and led to the presence of variety uranium and thorium Ores deposits. Uranium and Thorium ores deposits are found in different geological environments, and divided into several types based on their geological setting, therefore uranium and thorium may presences as major minerals in ores deposits and/or in other as secondary minerals with some precious metals ores such as copper, silver and rare earth metal elements. There are several studies and reports related to radioactive ores deposits and contamination phenomena have been done by many government institutes such as (Mineral Resources Ministry (DGMR), Saudi Geological Survey (SGS), King Abdulaziz City for Science and Technology (KACST)) and universities and consultants (Minatome, BRGM, USGS) more than 50 years ago. These studies show that the presences of uranium/Thorium ore deposits in the kingdom can by classified as follow: • Sandstone deposit • Veins deposit (Granite related deposit) • Intrusive deposit • Volcanic and caldera related deposit • Surficial deposit • Phosphorite deposit Airborne spectrometric survey was incorporated into Phase 4 of the prospection for uranium mineralization by MINATOME on behalf of the Ministry of Petroleum and Mineral Resources of the Kingdom of Saudi Arabia. The survey covered a surface area of approximately 26000 km2 divided into 9 areas. The airborne field operations were carried out by the Arabian Geophysical and Surveying Company (ARGAS) between December, 1981 (first flight) and March 26th, 1982 (last flight). During these field operations 28519 kilometers were flown: 26083 km along the 1 km line spacing grid initially scheduled, and 2436 km with a 0.5 km line spacing over areas where more detail was considered necessary on the basis of spectrometric results obtained during the survey or after geological reconnaissance. Measurements were made with a 256 energy channel spectrometer GR8O0D from GEOMETRICS with a detector of 2048 cubic inches. The spectrometric survey used in the prospecting stage records radioactivity in the uranium, potassium and thorium channels, to ascertain the uranium potential of these 9 areas and to contribute geological and radiometric information for their further study, and for another, to discover possible uranium anomalies or anomalous areas. In the first Phase of the project, CNNC the exploration contractor, plans to verify prospecting anomalies and uranium resources exploration in these 9 areas (35 inner sites) over three stages. In Stage (1), CNNC has been conducted the following technical work: (1) Geological route survey (1:50,000), cross section and mapping (Scales 1:10,000~1:5,000); (2) Gamma ray spectrometric measurements at different scales (1:10,000~1:5,000), on plane or along geological section; (3) Soil radon survey at different scales (1:10,000~1:5,000), on plane or along geological section; (4) The uranium/thorium or radioactive anomalies’ verification and evaluation; (5) In some places, the geological route survey, XRF and gamma ray spectrometric measurement and/or soil radon survey are integrated in profiles; (6) Remote sensing image processing, interpretation and field evaluation； (7) Geo-database construction； (8) Major and trace elements analysis, Microscopic analysis, SEM, EPMA and data processing of rock/ore samples； (9) Map compilation. Based on the geological conditions and previous work, CNNC plans detail investigations for stage (2); this include carrying out remote sensing interpretation, geological survey and anomaly verification, to find out the regional metallogenic conditions and preliminarily assess the U/Th mineralization potential. Next, is to perform the 1:10,000 or 1:5,000 geological mapping, ground gamma-ray spectrometric survey and radon survey in soil in key sectors, in order to evaluate the scale and U/Th contents of the mineralization and provide the basis for further geophysical, geochemical, drilling and borehole logging work arrangements. After the field work, the indoor laboratory analyses, map compilation and comprehensive research work need to be conducted. DISCUSSION AND CONCLUSION The current reconnaissance exploration reveal on discover of many uranium anomalies inside the nominated exploration sites and a discovery of a number of new uranium anomalies nearby the boarder of the exploration areas. In addition to the above success discoveries, the exploration program fails to verify some of uranium anomalies nominated in the previous prospection exploration and radiometric airborne survey. This failure may refer to the poor accuracy of GPS used in the previous prospecting program which leads to error in coordinates, beside the contribution of the combined effect of the relatively lower survey instrumentation sensitivities and their efficiency of the surveying parameters like airborne survey line spacing. The difficulties of the mountains topographies and wide speared of the exploration areas will add some limitations to verification of the uranium anomalies discovery, beside the complexities of the geological structures. In attempts to resolve these exploration difficulties and for more accurate uranium resources estimation, the following recommendations is to be implemented: • A new planned airborne survey radiometric (four channels radiometry spectrometry) combined with magnetic survey may be implemented. • Maintain/support the role of QA/QC supervisor to fulfill JORC code compliance. • Exploration contractor CNNC must plan the drilling program with higher precision, because diamond drilling are expensive and time consuming, so it should start only after comprehensive studies have been completed, that cover all prospective areas to allow targets to be ranked in terms of economic potential, and to ensure that no viable target is overlooked. • The project timeline may expand, if necessary. REFERENCES • Prospection for uranium mineralization in favorable areas of the kingdom phase4 airborne gamma ray spectrometer survey, interpretation report 1982. • Exploration and Evaluation of Uranium and Thorium Resources in the Kingdom of Saudi Arabia, Technical Progress Report No.1, BY Contractor Beijing Research Institute of Uranium geology, August 20, 2017. • Australian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves: The JORC Code 2012 Edition. • QA/QC Quarterly report , GEOLOGICAL SURVEY OF FINLAND & WGM, Q4 2017.

Speaker: Mrs Suzan Katamoura (King Abdullah City for Atomic and Renewable Energy)

79 Uraniferous potential and occurrences of Madagascar: an overview

I- INTRODUCTION Geologically, Madagascar is divided in two parts: (i) the 2/3 eastern part formed the crystalline bedrock which composed by six Domains, from North to South: Bemarivo, Antongil – Masora, Antananarivo, Ikalamavony, Androyen –Anosyen, and Vohibory. These are the Precambrian shield [1]. (ii) And the 1/3 left in the western part formed the sedimentary cover: from North to South, there are three important basins: Diego basin, Mahajanga Basin and Morondava basin. A small basin in the Eastern coast is also signalized. In additional of these basins: there is a lake basin in the center part. Uranium occurrences and uraniferous potential are hosted in two domains in crystalline bedrock: Antananarivo and Anosyen Domain. And in sedimentary cover: there are two deposits: in Morondava Basin and in lake basin. Two types of Uranium deposits appeared in crystalline bedrock and two another types in sedimentary cover. The present work develops these uraniferous potential and occurrences of Madagascar and proposed a new potential uranium deposit. II- DESCRIPTION OF OCCURRENCES AND URANIFEROUS POTENTIAL 1- URANIUM IN SEDIMENTARY COVER In sedimentary cover, there are two types of deposits: (i) sandstone Uranium deposit and (ii) surficial lacustrine deposit. 1.1 Sandstone Uranium deposit Makay and Folakara Uranium deposit are classified in Sandstone Uranium deposit. Geographically, Makay and Folakara deposit are located in North Western part of Madagascar, in Morondava basin. Makay in the Southern part and Folakara in the Northern part. From bottom to top, there are: Sakoa, Sakamena, Isalo I and Isalo II in Morondava basin. Uranium occurrences formed by carnotite found in Isalo II. Isalo II is composed by sandstone and fine clays. After geological prospecting, geophysical airborne survey and geochemical studies realized by CEA (Commissariat Français à l’Energie Atomiques); OMNIS (Office Militaire National pour les Industries Strategiques) in partnership with PNUD (Programme des Nations Unies pour le developpement) – IAEA (International Atomic Energy Agency) continued to undertake geological, geochemical and drilling work on 1979 – 1982, and evaluated its economic potential and estimated 272.000 tons of reserves [2]. 1.2 Surficial lacustrine deposit Vinaninkarena deposit can put in Surficial deposit type. Uranium occurrences formed by uranociricite is hosted in Lake Basin. Geographically, this deposit is situated in central part of Madagascar, south of Antsirabe. The uraniferous zone is located in the contact of crystalline bedrock and Southern part of the lake. This deposit is considered like secondary deposit after alteration – erosion – transport phenomena from crystalline bedrock (primary deposit). Since 1910, during thirty years, CEA evaluated 140.000 tons of Uranium in Vinaninkarena deposit [2]. 2- URANIUM IN CRYSTALLINE BEDROCK In the crystalline bedrock there are: (i) Metasomatitite deposits and (ii) Intrusive deposits 2.1 Metasomatite deposit Tranomaro uranium deposit is classified in metasomatite deposit [1]. Geographically, this deposit is located in southern part of Madagascar. And geologically, in Androyen - Anosyen domain, at Anosyen sub – domain. This Anosyan sub – domain is formed by metagabbros, granitic orthogneiss and their age were interpreted as paleoproterozoic. This deposit is placed in Tranomaro group, which is composed by calcomagnesian paragneiss, Werneritites, cipolin, leptynite with Uranium – Thorium and quartzite. This formation is crossed by three suits: (i) Dabolava suit (1000 MY), (ii) Imorona – Itsindro suit (820 – 760 MY) and (iii) Ambalavao suit (570 – 550 MY) [1]. Uranothorianite mineralization is associated with pyroxenites in granulite facies. The CEA and OMNIS have also taken an exploration work (cartography in small scale, mining work: trenches, pits, and geophysical airborne in this area) on 1947 – 1969. Since 1953 – 1967, OMNIS in partnership with IAEA estimated 50.000 tons of Uranium in Tranomaro deposit [2]. 2.2 Intrusive deposit Two areas are classified in this type: Ankazobe – Vohimbohitra and Antsirabe Uranium deposits which are located in Antananarivo Domain. This Domain is formed by Neoarchean orthogneiss and paragneiss with greenschist to granulite facies. This domain includes also three greenstones belts from West to East: Bekodoka – Maevatanana belt, Andriamena belt, and Beforona belt [1]. These three greenstones belt constitute Tsaratanana complex. These formations are crossed by Imorona – Itsindro suit (860 – 720MY) with ultrabasique to acid facies [1]. - Antsirabe uranium deposit Geographically, Antsirabe Uranium deposit is situated in East part of Antsirabe, central part of Madagascar (in Betafo town). Noted that Betafite, is a mineral ore of uranium and its name is from Betafo town. Three types of potassic – pegmatites are present in this area according to their enclosing formation. There are: o Pegmatite crossed the granites. Except the quartz, and mineral of pegmatite, this pegmatite is composed also by betafite, euxenite, columbite, pyrite, and garnet. o Pegmatite crossed the gabbros This pegmatite is appeared as veins filling the fracture; this is a pegmatite with magnetite, euxenite, betafite, and beryl. o Pegmatite crossed the crystalline bedrock This pegmatite filled also the fractures but in migmatite gneissic complex. Some exploration work has already carried out in this area: the first one is an airborne overflight on 1947 – 1969 by CEA. Government agency of Malagasy states (OMNIS) in partnership with UNDP (United Nations Development Programme and System) continue this work on 1976 – 2000 [2]. Thirty pegmatites were exploited in this area and have collected 50 tons of ore at an average ore grade 12 à 15 % U3O8 [1]. Pegmatite crossed the granite (Vavato granite 860 – 720MY) was the important Uranium occurrences [1]. - Ankazobe – Vohimbohitra Uranium deposits Geographically this deposit is located in the central part of Madagascar (X: 502 500 (m) – 519 800 (m) et Y:1 048 800 (m) – 1 082 300 (m)). This deposit is located in Andriamena belt with uraninite bearing pegmatite which composed by heterogenous formations, with various metamorphism degrees. But the gneissic complex in this area is in high degree [1]. This is very similar in Zimbabwe greenstone belt. “The 2014 Red Book notes 1400 tU as RAR in the $130-260/kg bracket, and also speculative resources of 25,000 tU.” [3]. Recently, Zimbabwe is believed to have uranium reserves of around 45.000 tonnes [4]. Robert F. Bacher and Hans J Morgenthau discovered that “The pegmatites in Madagascar are the only one that have furnished appreciable tonnage of Uranium minerals. Records indicate the sale of over 100tons of autunite and uranociricite ores” [5]. III- DISCUSSION AND CONCLUSION After geological study, exploration work by different entity (National and international), compared with Zimbabwe greenstone belt which is very similar in Andriamena belt and known that pegmatite in Madagascar are very rich in tonnage of Uranium minerals. Ankazobe –Vohimbohitra uranium deposit in pegmatite could present an important uranium pegmatite deposit. A deep exploration work in this area is needed. IV- REFERENCES [1]- Cartes géologique et metallogeniques de la République de Madagascar à 1/1 000 000, Projet de Gouvernance des Ressources Minérales de Madagascar, Juin 2012. [2]- http://www.omnis.mg. [3]- Resources, Production and Demand Paladin Energy Denison Mines Mantra Resources OECD NEA & IAEA, 2016. [4]- Daily Mail Reporter “mail online” http://www.dailymail.co.uk/news/article-2388685/Zimbabwe-signs-secret-deal-supply-Iran-uranium-build-nuclear- bomb.html#ixzz5834ueESi,10 août 2013. [5]- Robert F. Bacher, Hans J.Morgenthau, Bulletin of the Atomic Scientists, May 1950.

Speaker: Dr Vololonirina RASOAMALALA (Responsible of bachelor's degree - UNIVERSITY OF ANTANANARIVO - MADAGASCAR)

12:40 Lunch Break

Health, Safety, Environment and Social Responsibility

Conveners: Mr Dennis Amos MWALONGO (Tanzania Atomic Energy Commission), Mr Luis LOPEZ (CNEA (Argentina))

80 Effective Radiation Monitoring: Back to Basics

INTRODUCTION Radiation monitoring programs are a key aspect of the role of radiation practitioners in the uranium mining and mineral processing sector. An effective monitoring program enables ongoing assessment of the integrity of existing radiation exposure controls; an upward trend in monitoring results can indicate failure of controls or the need to design and implement additional controls. Outputs from radiation monitoring programs allow operations to demonstrate compliance with regulatory requirements, and provide a solid base of factual data that can be drawn upon for communication of relative risk or in the event of scrutiny from regulators, from the workforce, or from community representatives. Importantly, competent radiation monitoring conducted with a good awareness of the mining or mineral processing operation can provide feedback to assist in decisions which optimise both production and radiation exposures at the same time. BACKGROUND Uranium mining and mineral processing operations are regulated under a range of frameworks administered at international, national and local levels. Underlying the frameworks and regulatory systems is the ICRP “System of Radiological Protection”[1]. This consists of: • Justification – where a project should only proceed if the benefits outweigh the risks; • Optimisation – where doses and impacts should be as low as reasonably achievable (ALARA); and • Limitation – where absolute upper limits are established. To put this framework into practice, operations are generally required to implement a radiation management plan (RMP). In Australia the Mining Code [2], requires each operation to produce an RMP, which will typically include an outline of operational parameters, exposure pathways and controls, and a radiation monitoring program. Radiation management plans are structured so that compliance with the document demonstrates compliance with relevant regulatory frameworks, and are reviewed and approved by the appropriate regulatory body. Practicality and ease of implementation are key factors for successful RMPs. Radiation management is most effective when it takes a risk-based approach, specific to the operation – and the assessment of risk needs to be based on a comprehensive understanding of potential radiation exposure pathways. It is therefore essential that an operational radiation monitoring program is both relevant and effective with an end goal of being valuable both for demonstrating regulatory compliance and for informing operational radiation management decisions. Radiation monitoring programs in uranium mining and processing operations should aim to: • Characterise exposures; • Prove the effectiveness of controls; • Ensure that controls are commensurate with the risk; • Be practical; • Communicate results effectively. It is difficult to compare the effectiveness of monitoring program because they need to be suitable for the particulars of the operation. Traditional management KPIs may therefore be, to some extent, misleading for measuring the effectiveness of programs. Observation and review of monitoring in various uranium mining and mineral processing operations at all stages from exploration to closure indicates that while the effectiveness of a monitoring program is difficult to quantify, there are common factors which characterise good operational radiation management. Awareness of radiological characteristics (in other words “know your processes!”) Undertaking an evaluation of the radionuclide balance through process and effluent streams during the early stages of operation helps to ensure that potential radiation exposure pathways are understood. The differing characteristics of naturally occurring radionuclides can cause concentration or dilution as a consequence of chemical or physical properties – or as a consequence of ingrowth or decay depending on the age of products relative to the half lives of any radionuclides present. Characterisation of radionuclide deportment allows a radiation monitoring program to be correctly structured and adequately resourced with the correct equipment to measure potential exposures from the radionuclides that are expected to be present in any given area or circuit. Adaptability and Ability to Respond to Changing Conditions As operations naturally evolve over time, a flexible monitoring program that avoids complacency and maintains a curious and considered approach will help to ensure that changing exposure scenarios are captured. Ability to Undertake Investigative Monitoring (Moving from Compliance Monitoring to Risk Based Monitoring) Adequate resourcing is required so that radiation management can exceed basic compliance, to focus on industry best practice and optimisation of exposures. Using this approach, compliance is naturally achieved as a consequence. There are key differences between radiation monitoring for regulatory compliance and radiation monitoring to support a target of best practice radiation management. A focus on achieving regulatory compliance will promote a minimal approach which targets fulfilment of monitoring quotas. It seeks to demonstrate compliance and allows little scope to deviate from the prescribed program to capture any operational changes or un-programmed work. Mining and mineral processing operations are typically driven by cost optimisation, and in that climate it is often difficult to attract the additional resourcing that enables radiation monitoring and management to go beyond a basic compliance focus. The benefits of a robust and curious radiation monitoring program are not easily captured as an operational cost benefit or under traditional management KPIs, but are important for any operation with an interest in continuous improvement. When monitoring programs are resourced effectively with capacity for a flexible approach, measurements can be broadly considered under two categories. Compliance monitoring provides information satisfying regulatory scrutiny, demonstrating compliance, and for quantifying occupational, community and environmental exposures. Investigative monitoring focuses on proving controls, determining whether existing controls are performing effectively, and on identifying potential risk from exposures that may not be captured by a routine compliance monitoring program. Adequate resourcing for both monitoring streams enables an operation to optimise practices for radiation exposures rather than purely for cost. Identification of Problems for Timely Response To be effective and relevant and to support the principle of optimisation, a monitoring program should be cognisant of the actual risk associated with operational practices. The breadth and depth of a monitoring program should be adequate to identify any failure of controls or trends in exposure pathways, but should not persist in monitoring at a high frequency where actual risk is continuously shown to be low and where operational practices are static, without any potential for effect on occupational dose. This may require practitioners to revisit approved plans and engage with regulators, adapting the monitoring program to focus on new areas of concern and reduce monitoring in areas with consistently low risk of exposure. Maintenance of Technical Capacity (in other words “Make Sure People Know What They Are Doing”) Business efficiency requirements and advances in technology can drive uptake of technology and software, or outsourcing of maintenance to specialist contractors. These advancements reduce general workload, but can lead to dependence and a loss of basic technical ability. Uranium mining and mineral processing operations are often remote, located in areas far from specialist technical support, and the challenges of the remote environment can impede or even cripple a monitoring program that is not supported by appropriate expertise within the operation. Retaining an understanding of basic calculation and interpretation of results allows rapid calculation and assessment of results in the field or in the event of technological outage, and enables monitoring to provide feedback to the operation promptly. New monitoring equipment can incorporate both measurement and calculation of results, but to cover any periods when equipment is off site or unserviceable, retention of equipment and skills for simple monitoring methods ensures that a monitoring program can be maintained under any circumstances. In house repair of equipment may not meet the requirements of a standardisation or quality framework (e.g. ISO, NATA etc), but where measurements are not used for dose assessment the requirement for accuracy may be less important than the requirement to provide prompt feedback. Field repairs to equipment may have a small effect on efficiency or calibration, but the effect is unlikely to be significant and the end goal to optimise exposures may be better executed by providing rapid assessment. Operationally Useful, Engaged and Curious A competent radiation monitoring program should have capacity to engage with the operation as a whole, and to respond to permanent or temporary operational changes without impacting compliance monitoring programs. Radiation practitioners, equipped with information returned by a robust radiation monitoring program, should be actively engaged with operational decision makers to ensure that the need for controls is effectively communicated. Radiation monitoring data and the correct interpretation of legislation and of actual risk can be key to determining the need for control of any potential hazards, and in assisting in design of appropriate and effective controls. When changing exposure situations are identified quickly, operations can respond to implement interim controls and plan for installation of permanent control measures during planned maintenance outages. A delay in identification of an exposure issue can allow the situation to spiral, causing unplanned interruptions to operations and a loss of production. Having competent and trained staff who understand the operation and how to effectively monitor it ensures that when things go wrong (i.e. component or system failure), accurate information can be provided promptly to those needing to make decisions, thereby ensuring continued production. Operations with proactive radiation and hygiene monitoring regimes have demonstrated an ability to positively influence operational controls, and where operational limitations (such as throughput), exist due to concern around hygiene exposure, a comprehensive understanding of a process system can ensure operators have sensitive operational responses allowing greater production levels to be achieved. SUMMARY Radiation monitoring programs should not be regarded as purely a requirement for regulatory compliance. Monitoring results are invaluable in achieving continuous improvement objectives, and in determining controls required to reduce occupational exposures to employees. Monitoring can assist operations to optimise production, and can intercept failures early so that unplanned interruptions to production for maintenance or repairs can be avoided. The structure and focus of a radiation monitoring program informs and drives operational radiation management, and a monitoring program that actively engages with the operation has value both in the optimisation of radiation exposures and in supporting continuous improvement in all aspects of operation. REFERENCES [1] INTERNATIONAL COMISSION ON RADIOLOGICAL PROTECTION, The 2007 Recommendations of the International Commission on Radiological Protection. ICRP Publication 103. Ann. ICRP 37 (2-4) (2007) [2] AUSTRALIAN RADIATION PROTECTION AND NUCLEAR SAFETY AGENCY, Code of Practice for Radiation Protection and Radioactive Waste Management in Mining and Mineral Processing (2005)

Speaker: Ms Alice Jagger (Yarex)

81 “It’s Not All About the Radiation!” - Practical Radiation Management

INTRODUCTION For uranium miners and producers, the control of environmental, worker and public exposure to radiation is a critical management objective. Corporate obligations, statutory requirements and public expectations generally manifest as radiation management plans (RMPs). It is important for worker, public and regulator confidence that the RMP is practical and competent. From an operational perspective, it is also important that the RMP is an integral part of the broader health, safety and environmental management plans. This is because, in practice, the radiation risk is generally low in most uranium mining and processing operations and it is important to ensure that the radiation risks remain in perspective with other environmental and safety risks. This paper explores experiences from case studies at mining and processing facilities to identify practical tools for effective development and implementation of appropriate and quality RMPs and for ensuring that radiation risks remain in perspective. The authors experiences are from a range of operating facilities that have had to deal with the presence of naturally occurring radioactive materials. This includes uranium mines and processing facilities, through to rare earth producers, whose main exposures come from the Th232 decay chain, through to other mining operations where NORM is present. Experiences are generally common across the sectors, although, the expertise and competencies in the uranium sector greatly exceeds that in other sectors. BACKGROUND The radiation exposure to workers in the modern uranium mining and processing industry have been demonstrated to be low and well controlled [1]. Extensive efforts in the early decades of the life of the industry acted to identify and quantify the risks and establish standards that greatly improved conditions. This resulted in the current high standards of radiation protection that exist in the industry today. Such controls included minimising exposures to radon decay products in uranium mines with effective ventilation, through to ensuring that final product dusts are eliminated or contained. Legacy sites continue to be problematic but provide a constant reminder of the costs and risks of not providing adequate levels of control for radiation. EFFECTIVE RMPS The RMP is an important document and there are a number of practical factors that can be considered to ensure that it remains relevant and fit for purpose. These factors are based on practical experiences elsewhere. Clarifying the Role of the RMP In some cases, an RMP is developed to purely comply with regulatory requirements. In these cases, the RMP is seen as a compliance document rather than a practical management plan for radiation at the site or operation. Legislative requirements and guidance documents are useful and should be used as the platform or the framework for the RMP, however, the content and details should be developed and owned by the operator. Ownership of the RMP and its content is important, because at the end of the day, the operator has primary responsible for the safety and wellbeing of the workforce under their management and control - not the regulator. The operator is also responsible for protecting the environment and members of the public. Merely complying with regulations does not guarantee an adequate level of protection. At an operational level, the RMP should be practical and able to be used by management and workers alike. It should provide the necessary tools and justifications for implementing and enforcing controls. It should outline accountabilities and responsibilities and relevant training. It should also cover reporting requirements and incident investigations. Many guides exist on the minimum content for RMPs [2,3]. Sometimes, the RMP is incorrectly seen as being a Radiation Monitoring Plan, with radiation monitoring seen as the means for management. This has two consequences. It can provide a false sense of security because all that gets measures is all that exist in the monitoring plan. Secondly, the desire for investigative monitoring is lost is favour or compliance monitoring. Pure compliance monitoring can also result in complacency. If, for example, the routine radiation monitoring shows that results are low, no additional work in done and it is assumed that radiation is under control. Non Technical Characteristics of a RMP Experience shows that RMPs should also have the following characteristics; • Practical and able to be understood by operations personnel, • Balanced and consider the actual risks from radiation, • Appropriately conservative as not to be seen to be dismissive of radiation and able to provide confidence that the radiation levels are controlled, • It should exist within the broader site health safety and environmental management plans, • Of sufficient quality to provide confidence and also maintain recognised standards. It is relevant to note that none of the above characteristics give an indication of what should be in the RMP itself. The characteristics assume the technical component of the RMP and provide the framework for a the balance, quality and practicality of the document. Supported by Appropriate Knowledge and Competence An expected characteristic of uranium explorers, miners and producers is that there will be a high level of competence in radiation protection. However, what does this mean in practice? It means having sufficient internal knowledge to make informed decisions and staff who are competent to make the decisions. To support the RMP and understand the radiological risk, such knowledge that needs to be considered includes; • Characterisation of the materials being handled, from geological samples through to process materials and wastes – this includes characterising both the radiological and non radiological properties, • Understanding the natural background levels in the region and its variability in order to provide some perspective to the anticipated potential exposures, • Understanding the behaviour of radionuclides through the whole process. Competent staff should be able to; • Predict and measure the potential radiological impacts to workers, the public and the environment, using recognised international standards, • Effectively communicate with senior managers through to workers and the public, • Contribute to the broader discussion on radiation protection, rather than just complying with regulatory requirements, • Learn, • Be professional in all matters. Effective Two Way Communications The most significant portion of radiation management is communication and discussion. It is essential for a number of reasons; • Being able to identify problems before they arise, • Providing a non-confrontational means of information sharing, • Building knowledge. Communicating the existence and contents of the RMP to management, the wider workforce and to the community is important. It demonstrates the company’s commitment to formalising its approach to radiation management. It is equally important to communicate the results and reviews that occur under the RMP. A practical form of communication involves informal and regular discussions with the workforce, for example at lunch or while on the job. When management or the radiation adviser provides a presence in the workplace, it is easier for the workforce to engage in discussion. However, radiation and radiation protection is a complex area. In some situations, the radiation staff can be known as “boffins”, and sometimes make communications quite unnecessarily complex and difficult. Radiation does not need to be made any more complex than it already is and enabling workers and the public to ask questions is important. A saying is that “in radiation, there are no dumb questions !” Saying this up front enables people who genuinely have a question feel more at ease asking the question. A parallel situation occurs with the public in relation to environmental radiation and public dose impacts from the project. The overall intent is to ensure that there is an unconstrained space where questions can be asked and answered properly communicated. Maintaining Perspective An important part of a RMP is ensuring that it fits within the broader operational health, safety and environmental management plan. Apart from the presence of uranium, the exploration site, the mining operation and the processing facility are just industrial sites with their own particular hazards. Too often, the radiological risks are seen to take priority. Other chronic and acute hazards need to be properly recognised and there must be assurance that resources are properly allocated to controlling the higher risks. For most operations, the radiological risks are low. In some cases controls for radiation can act to control other workplace hazards. For example, ventilation acts to control exposures to radon decay products, but also provides protection against the buildup of dusts and gases (and heat for underground mines). CONCLUSION This paper has aimed to provide some practical considerations for the effective development and implementation of a RMP based on experiences at various mines and processing facilities. The key messages are that RMPs should; • Be more than a compliance document, • Be part of a broader health, safety and environmental management system, • Be supported by internal knowledge and competent staff. REFERNECES The matters outlined in this paper are from the authors experiences across a number of uranium and NORM related operations. [1] http://www.world-nuclear.org/information-library/safety-and-security/radiation-and-health/occupational-safety-in-uranium-mining.aspx [2] IAEA 2014: Radiation protection and safety of radiation sources: international basic safety standards. — Vienna: International Atomic Energy Agency, 2014. [3] ARPANSA 2005 Radiation Protection and Radioactive Waste Management in Mining and Mineral Processing. Radiation Protection Series. Canberra, Australian Radiation Protection and Nuclear Safety Agency

Speaker: Mr Jim Hondros (JRHC Enterprises Pty Ltd)

82 Action Levels for Airborne Natural Uranium in the Workplace: Chemical and Radiological Assessments

INTRODUCTION Intakes of natural uranium (U) present two hazards to workers, namely chemical and radiological. The consequence of too much intake can be chemically induced damage for which kidney is the primary target tissue, or radiogenic cancer for which lung appears to be the primary target tissue. The chemical damage to the kidneys depends on the concentration of U in the kidneys. Nephrotoxicity is thought to be the greater risk for inhalation of relatively soluble forms of natural U due to a high fractional absorption of U to blood and uptake and retention by the kidneys. The radiological risk of lung cancer depends on the radiation dose to the lungs. Lung cancer is thought to be the greater risk for inhalation of relatively insoluble forms of natural U due to extended retention of the inhaled material in the lungs. Neither the concentration of U in the kidneys nor the cumulative irradiation of the lungs can be directly measured, but both quantities can be assessed using biokinetic models. DESCRIPTION In the workplace the primary and most significant intake of U typically is from inhalation. Continuous measurements of the concentration of U in air at work locations can be used together with the most recent, internationally accepted models to estimate the concentration of U in the kidneys and the dose to the lungs from inhalation. We reviewed the scientific literature to evaluate the relation of the concentration of U in the kidneys to various levels of levels of damage to the kidneys and to propose a limiting kidney concentration (called primary chemical guidance in the following) for U as a chemical hazard [1-9]. We used primary guidance of the International Commission on Radiological Protection (ICRP) as a limit on intake of U as a radiological hazard [10]. These primary guidance levels for U as chemical and radiological hazards were used, together with best available biokinetic and dosimetric models [11-13], to derive “action levels” for U exposure in the workplace as represented by the concentration of airborne U. Two levels of primary guidance are proposed for the purposes of avoiding chemical effects of U and limiting its potential radiological effects to ICRP’s recommended levels defined in terms of effective dose. The lower level of primary guidance is used as the basis for determination of an investigation level (IL) of airborne U. An IL indicates the need to confirm the validity of moderately elevated measurements and adequacy of confinement controls and determine whether work limitations are needed. The higher level of primary guidance is used as the basis for determining an immediate action level (IAL). An IAL indicates that safety measures should be put into place immediately, including removal of workers from further exposure until conditions are acceptable. An action level is reached if model predictions based on current air monitoring data, together with best available information on the form of U in air, that either the limiting chemical guidance or the limiting radiological guidance could eventually be exceeded if the air concentration is not reduced. The lower level of primary guidance is 0.3 µg U / g kidney for avoidance of chemical effects and 2.0 mSv y-1 for limitation of radiological effects. The higher level of primary guidance is 1.0 µg U / g kidney for avoidance of chemical effects and 5.0 mSv y-1 for limitation of radiological effects. For each of several different levels of solubility of airborne U, ranging from highly soluble to highly insoluble forms, models were used to predict the lowest concentration of U in air that would eventually yield the limiting U concentration in the kidneys of a chronically exposed worker. For each solubility level, a similar calculation was performed to predict the lowest concentration of airborne U that would eventually yield the limiting annual effective dose to a chronically exposed worker. The biokinetic models (and dosimetric models in the case of radiological considerations) used in these calculations were those recommended in ICRP Publication 137 [13]. For intake of a given concentration of U in air, both the effective dose and the peak kidney concentration depend on the solubility of the U compound, so that the IL and IAL both vary with the solubility of airborne U. ILs and IALs were derived for each of the Absorption Types (solubility classes) for U addressed in ICRP Publication 137 [13]. That report defines five Absorption Types for U, representing a range of dissolution levels. In order of decreasing solubility the five levels are as follows: Type F (fast dissolution, e.g., UF6), Type F/M (somewhat slower dissolution than Type F, e.g., UO2(NO3)2), Type M (moderately soluble, e.g., UF4), Type M/S (somewhat slower dissolution than Type M, e.g., U3O8), and Type S (very slow dissolution; no examples are given in Publication 137 but presumably Type S would include high-fired oxides). DISCUSSION AND CONCLUSION To derive radiologically based action levels, we assumed that U contains 0.0057% 234U, 0.72% 235U, and 99.27% 238U by mass. Despite its small percentage of mass, 234U contributes significantly to the total dose, because its specific activity is on the order of 10,000 times greater than that of each of the other two nuclides. Effective dose coefficients for the assumed mixture of natural U isotopes were based on effective dose coefficients given in ICRP Publication 137 [13] for the individual isotopes. It was assumed that 234U, 235U, and 238U represent 50.45% 2.2%, and 47.35%, respectively, of inhaled U, based on their relative masses and specific activities of 2.32  108, 8.01  104, and 1.25  104, respectively [5]. The solubility of airborne U is a key variable regarding both the chemical and radiological risk to an exposed worker. If inhaled U is highly soluble, it is removed quickly from the lungs with a sizable portion being absorbed to blood and the remainder entering the alimentary tract. The absorbed U yields some radiation dose to systemic tissues, but most of the absorbed activity is removed in urine over a period of days. The main hazard from the absorbed U is thought to be its relatively high accumulation in the kidneys and its subsequent chemical effects on kidney tissue. If inhaled U is highly insoluble, much of it will be retained in the deep lungs for an extended period, possibly decades, and little will reach the systemic circulation. In this case, the main hazard from the inhaled U is expected to be its prolonged alpha irradiation of lung tissue, potentially leading to lung cancer. Thus, chemical toxicity to the kidneys is presumably the dominant risk from relatively soluble U in air, and radiological toxicity is presumably the dominant risk from relatively insoluble U in air. The chemical risk decreases and the radiological risk increases with decreasing solubility of airborne U. In terms of the Absorption Types defined in ICRP Publication 137, the chemical risk decreases in the order Type F > Type F/M > Type M > Type M/S > Type S, and the radiological risk decreases in the order Type S > Type M/S > Type M > Type F/M > Type F. The radiological risk depends on the isotopic composition of U in air, as 234U has a much higher specific activity than 235U or 238U. Calculations of chemical toxicity are simpler than those for radiological risk, because the chemical processes depend on the total mass of U in the kidneys and are independent of the isotopic distribution. Thus, for evaluation of chemical risk from a given concentration of U in air, it suffices to use a biokinetic model to predict the time-dependent mass of U in the kidneys. The biokinetic models applied are taken from ICRP Publication 137 and are the same as those used to predict the distribution of inhaled radioactivity. For a worker to be protected from both the chemical and radiological hazards of a given form of U, the lower of the limiting values based on chemical and radiological considerations should be applied. Chemically and radiologically based ILs and IALS were derived using the biokinetic models, dosimetric models, and Absorption Types for U defined in ICRP Publication 137 [13]. A particle size of 5 um AMAD was assumed. This is the ICRP’s default particle size for inhalation of radionuclides in the workplace. The derived radiological IL in µg m -3 for F is 1350; for F/M is 824; for M is 244; for M/S is 61.6; for S is 25.4. The derived chemical IL in µg m -3 for F is 30; for F/M is 56; for M is 81; for M/S is 167; for S is 253. For example, for Type M the chemically based IL is 81 µg m -3 and the radiologically based IL is 244 µg m -3, so the chemically based value of 81 µg m -3 is used as the IL. The derived radiological IAL in µg m -3 for F is 3376; for F/M is 2060; for M is 610; for M/S is 154; for S is 63.5. The derived chemical IAL in µg m -3 for F is 101; for F/M is 188; for M is 272; for M/S is 563; for S is 845. The more restrictive is shown in boldface. For example, for Type M/S the chemically based IAL is 563 µg m -3 and the radiologically based IAL is 154 µg m -3, so the radiologically based value of 154 µg m -3 is used as the IAL. If the solubility is unknown, the most limiting action level should be used. Based on the above values, the most limiting IAL value is the chemically based limit of 30 µg m -3, assuming a particle size of 5 µm AMAD. Ideally the limiting air concentration would be based on site-specific information on the particle size as well as the solubility of airborne U. There are several work environments where U may be inhaled in relatively high quantities. These include underground mining, surface mining, in situ leaching, phosphate processing, and heavy metal processing. Each of these has different characteristics of the solubility of the aerosols and the particle size. These characteristics must be identified and used to assess the applicability of models for the protection of the workers. In addition to U, there are other radionuclides that must be assessed and controlled. Radon and its progeny are particularly important for control in the workplace. REFERENCES [1] Dorrian, M. D.; Bailey, M. R. (1995). “Particle size distributions of radioactive aerosols measured in workplaces.” Radiat. Prot. Dosim. 60:119–113. [2] Foulkes, E. C. (1990). “The concept of critical levels of toxic heavy metals in target tissues.” Crit. Rev. Toxicol. 20:327–339. [3] Guilmette, R. A.; Parkhurst, M. A.; Miller, G.; Hahn, F. F.; Roszell, L. E.; Daxon, E. G.; Little, T. T.; Whicker, J. J.; Cheng, Y. S.; Traub, R. J.; Lodde, G. M.; Szrom, F.; Bihl, D. E.; Creek, K.L.; McKee, C. B. (Project Administrator) (2004). “Human health risk assessment of Capstone depleted U aerosols. Attachment 3 of Depleted U Aerosol Doses and Risk: Summary of U.S. Assessments” (Richland WA USA): Battelle Press, October 2004. [4] Leggett, R. W. (1989). “The behavior and chemical toxicity of U in the kidney: A reassessment.” Health Phys. 57:365–383. [5] Leggett, R. W.; Eckerman, K. F.; McGinn, C. W.; Meck, R. A. (2012). Controlling intake of U in the workplace: Applications of biokinetic modeling and occupational monitoring data. ORNL/TM-2012/14. January 2012. Oak Ridge National Laboratory, Oak Ridge, TN. https://info.ornl.gov/sites/publications/Files/Pub34411.pdf [6] McDiarmid, M. A.; Engelhardt, S. M.; Dorsey, C. D.; Oliver, M.; Gucer, P.; Wilson, P. D.; Kane, R.; Cernich, A.; Kaup, B.; Anderson, L.; Hoover, D.; Brown, L.; Albertini, R.; Gudi, R.; Squibb, K. S. (2009). “Surveillance results of depleted U-exposed Gulf War I veterans: Sixteen years of follow-up.” J. Toxicol. Environ. Health A. 72:14-29. [7] Morrow, P. E.; Gelein, R. M.; Beiter, H. D.; Scott, J. B.; Picano, J. J.; Yuile, C. L. (1982). “Inhalation and intravenous studies of UF6/UO2F2 in dogs.” Health Phys. 43:859–873. [8] Keith L S, Faroon, O M and Fowler, B A 2015 Chapter 59 – U In: Handbook on the Toxicology of Metals 4th edition, vol 2, G Nordberg, ed London: Academic Press pp 1307-45 [9] Stopps G J and Todd M 1982 The Chemical Toxicity of U with Special Reference to Effects on the Kidney and the Use of Urine for Biological Monitoring INFO 0074 Atomic Energy Control Board of Canada, Box 1046, Ottawa, K1P5S9 [10] ICRP (2008). International Commission on Radiological Protection. The 2007 Recommendations of the International Commission on Radiological Protection. ICRP Publication 103. Oxford: Pergamon Press. [11] ICRP (2015). International Commission on Radiological Protection. Occupational Intakes of Radionuclides: Part 1. ICRP Publication 130. London: Sage Publications. [12] ICRP (2016). International Commission on Radiological Protection. The ICRP computational framework for internal dose assessment for reference adults: Specific absorbed fractions. ICRP Publication 133. London: Sage Publications. [13] ICRP (2017). International Commission on Radiological Protection. Occupational Intakes of Radionuclides.Part 3. ICRP Publication 137. London: Sage Publications.

Speaker: Dr Robert Meck (Science and Technology Systems)

83 Radiological Aspects of Alkaline Leach Uranium In Situ Recovery (ISR) Facilities in the United States

Summary In Situ Recovery or In Situ Leach (ISR/ISL) uranium facilities, also referred to in the past as “uranium solution mining” have operated since the late 1960s in the US and in recent years have accounted for over 70 % of US production and internationally almost half of worldwide uranium supplies. This extended abstract presents a summary of the radiological characteristics of typical ISR processes being employed in the United States today that have traditionally used alkaline based lixiviants. The paper describes the health physics and radiological monitoring programs necessary to adequately monitor and control radiological doses to workers based on the radiological character of these processes. Although many radiological characteristics are similar to that of conventional mills, conventional-type tailings as such are not generated. However, liquid and solid by-product materials may be generated and impounded which can result in sources of occupational exposure. Some special monitoring considerations are required due to the manner in which radon 222 gas is evolved in the process. The major aspects of the health physics and radiation protection programs that have been developed at these facilities over many years are discussed and include: • Airborne monitoring for long lived radioactive dusts • External exposure monitoring primarily in areas in which large quantities of uranium concentrates are processed and where radium precipitates may accumulate • Surface area and personnel contamination surveillance • Bio-assay (urinalysis) programs commensurate with the metabolic characteristics of the uranium species produced • Radon/progeny monitoring, particularly at front end of process where radon is most likely to evolve from solutions returning from underground Background Uranium deposits in the U.S. typically amenable to ISR methods are usually associated with relatively shallow aquifers, about 30—150 meters subsurface, confined by non-porous shale or mudstone layers. Uranium was transported to present locations over geologic time as soluble anionic complexes by the natural movement of oxygenated groundwater. Uranium deposition occurred in areas where the groundwater conditions changed from oxidizing to reducing. This produced a roll front deposit with uranium concentrated at the interface between the oxidized and reduced sandstones. This interface is commonly known as the Redox Interface. In the U.S., commercial scale recovery of uranium in ISR facilities is achieved through the use of alkaline solutions, known as the lixiviant, to mobilize the uranium in situ for recovery from wells (some historical R&D efforts have used acid based lixiviants and this is being further evaluated by one US operator today). Lixiviant solutions are stripped of uranium at the surface and the barren lixiviant is refortified and recycled through the process back into the well fields. In the alkaline leach ISR process used in the US, groundwater is fortified with an oxidant (gaseous oxygen or hydrogen peroxide) and oftentimes an anionic complexing agent to solubilize the uranium within the ore body in situ. The oxidant converts uranium from the +4 (reduced) to the +6 (oxidized) valence state, making it amenable to complexation and solubilization. The lixiviant composition is usually maintained at a slightly alkaline pH, although early plants were operated at pH has high as 8 – 9. The local geochemistry and the relative importance of calcium species establish these specifics. The uranium is extracted from the lixiviant by adsorption onto anionic resin. The uranium is then chemically stripped from the resin and precipitated from the solution. In recent designs, the resin may be eluted directly in the ion exchange vessel or transferred to a separate elution column or tank. The uranium precipitate, formerly ammonium diuranate (e.g., using sodium or ammonium hydroxide) or more recently uranyl peroxide (using hydrogen peroxide) is conveyed to a product drying/packaging area where it is converted to the final uranium oxide product. At facilities using high temperature calciners (800 - 1000o C+), final products are typically U3O8 and/or UO2. In designs using lower temperature vacuum drying (e.g., 300 - 400 oC), the final products are typically uranyl peroxide (UO4) uranyl trioxide (UO3), their hydrates and/or combinations thereof (1,2). Some process strategies involve a final product of loaded resin or an intermediate precipitate only (satellite plant), and then ship this product to another uranium recovery facility for further processing. The final product may therefore be loaded resin, an inter¬mediate product or slurry or relatively dry oxide powder. Radionuclide Mobilization and Associated Process Radiological Characteristics Based on some early studies performed in the US at alkaline leach uranium solution mining plants (e.g., see 3) a relatively small percentage of the uranium progeny in the ore body is mobilized by the lixiviant and the majority of equilibrium radionuclides remain in the host formation (4). Note that such values may be process specific (e.g., alkaline vs. acid leach, pH, etc.) and may also be facility age dependent. In the US alkaline leach processes, it appears that the thorium 230 equilibrates and very little is removed by the process. The majority of the mobilized radium 226, 80-90%, estimated at 5-15% of the equilibrium radium calculated in the host formation, follows the calcium chemistry in these processes and results in radium carbonates / sulfates in calcite slurry bleed streams and associated wastes. Additionally, the ion exchange (IX) resin used in US ISR facilities is specific for removal of uranium. Appreciable amounts of thorium and other progeny are not expected in the process downstream of the IX columns (e.g., elution, precipitation, and drying circuits). The radionuclide mixture that can potentially become airborne and result in personnel exposure and area or equipment contamination in the precipitation, drying and packaging areas would be expected to be primarily a natural uranium isotopic mixture with a relatively small progeny component. Although in growth of the first few short-lived progeny (e.g., thorium 234, protactinium 234) is occurring, the in process residence time is small relative to radionuclide half-lives and therefore time required for appreciable ingrowth. Accordingly, little contribution from these primarily beta emitters is experienced in the radiological aspects of in process materials. In areas where solid wastes are processed, stored or during maintenance (resin tanks and columns, fabric and sand filters, clarifiers, etc.), mobilized radium 226 associated with calcium and carbonate chemistries may be an important external exposure and/or contamination source. Additionally, during some maintenance activities when systems need to be opened and/or penetrated, aged process material may be encountered containing scale and/or precipitates in pipes, tanks, pumps, etc., which can exhibit elevated beta activity due to ingrowth of short lived thorium 234 and protactinium 234. Additionally, large quantities of radon 222 gas can be dissolved in the lixiviant returning from under¬ground and is brought to the surface. That portion of the total dissolved radon which is above the solution's saturation value is released when encountering atmospheric pressures and temperatures and can also be released during the decay of radium contained in waste products (e.g., CaCo3 / gypsum) being processed and stored at the surface (4, 5, 6). However, despite potentially large quantities of the gas being evolved, it is “fresh radon” and the progeny equilibrium factors are typically quite low. Principal Exposure Pathways and Associated Monitoring Requirements The primary exposure pathways associated with ISRs were identified in the summary section and are discussed below. Airborne monitoring for long lived radioactive dusts (LLRD) - Since ISRs are essentially an aqueous process until drying and packaging, control and containment of spills in process areas via design consideration is essential to reduce the risk of resuspension of LLRD (essentially yellowcake dusts) in these areas. Additionally, during operations, it is important to affect expedient wash down and clean up of spills to minimize dried material becoming an inhalation hazard via resuspended dusts. Airborne monitoring for LLRD is necessary in back end process areas, e.g., beginning where the precipitate slurry is produced. Accordingly, LLRD exposure potential is primarily associated with the “yellowcake areas” of the process that include precipitation, drying and packaging. Applicable monitoring techniques include combinations of grab sampling, breathing zone sampling and continuous monitoring based on job functions and related radiological and work conditions. External exposure monitoring - External exposure monitoring (via survey and personnel dosimetry) is required primarily in areas in which large quantities of uranium concentrates are processed, packaged and/or stored. Additionally, depending on importance of calcium chemistry in situ and therefore radium mobilization, radium build-up can occur in resin tanks and columns, filter membranes from reverse osmosis water treatment units, fabric and sand filters, clarifiers, etc., where large quantities of radium bearing calcite wastes are precipitated, processed and stored. This can result in requirements for control and monitoring of external exposure during work near these processes, during filter changes and / or maintenance of these systems. External exposure (particularly extremity exposure) from short lived beta emitting uranium progeny (Th 234, Pa 234 e.g.) can occur during maintenance activities when systems are penetrated and / or opened. Accordingly, care should be taken and beta / gamma and/or beta exposure rate monitoring may need to be conducted on a case-by-case basis to assess degree of this potential hazard. Potential for exposure of hands and forearms during these activities must be considered, although these types of exposure events would be expected to be occasional and of relatively short duration (minutes or a few hours at a time). Surface area contamination surveillance and control – ISRs are primarily aqueous processes until product drying and packaging. Accordingly, these back end areas are typically the most important sources of potential surface contamination and resuspension. Standard contamination controls (containment, ventilation, radiological survey [areas and personnel]) and expedient response to process upsets involving spills or other loss of containment events minimizes the potential for this pathway. Contamination surveillance and control is necessary throughout plant and ancillary areas including of personnel and for the release of equipment and materials for unrestricted use into the public domain. Bio-assay (urinalysis) programs - As is the case with all uranium processing facilities, bioassay programs need to be designed commensurate with the metabolic characteristics of the uranium species produced. Modern ISRs in the US are producing peroxide-precipitated products dried by low temperature vacuum dryers. These products appear to be quite soluble and meet the ICRP 71 criteria for the Type F (fast) absorption category. For these products, chemical toxicity drives worker risk from intake - not radiation dose. (1,7,8,9). Accordingly, bioassay (urinalysis) programs at US ISRs involve frequent urinalysis sampling (can be weekly) and analysis for, in addition to uranium, the biomarkers associated with potential renal injury, e.g., glucose, lactate dehydrogenase (LDH) and protein albumen. Radon and Radon Progeny - Exposure to radon gas evolving in front end process areas from uranium bearing lixivants returning from underground are typically controlled since (1) these areas are of low occupancy and typically well away from other work areas and (2) it is relatively “fresh radon” and therefore the progeny equilibrium factors are typically quite low with the potential for worker exposure also low since the vast majority of dose results from the short lived progeny and not the radon gas itself. Depending on design specifics, local exhaust systems on front end tanks and vessels are sometimes necessary to collect and remove the fresh radon gas before significant progeny ingrowth can occur in work areas. Most of the gas is released within the first few process areas, wherever first exposed to atmospheric pressure. Depending on design specifics, this can be at surge ponds and tanks, at the tops of the ion exchange columns and/or at the interface between resin loading and elution processes. Process tankage and piping may need to be enclosed and maintained under negative ventilation where practical. In warm climates such as ISR facilities in South Texas, out of doors surge ponds and/or open top ion exchange columns are often used and therefore most of the gas is released out of doors. In colder climates (Wyoming, Nebraska), the solutions are piped under pressure directly from enclosed well field valve stations and surge tanks to in plant recovery vessels including the IX tanks themselves. Some of the first generation ISR plants (1970s) used in plant IX surge tanks and up flow, open top IX columns requiring use of local exhaust systems to remove the gas from the vicinity of in-plant vessels before progeny ingrowth became an occupational exposure concern. Recent designs tend towards use of enclosed, pressurized systems for lixiviant recovery and ion exchange using local exhaust on the vessels themselves to remove radon prior to significant progeny in growth. This greatly reduces the potential for radon / progeny exposure in plant areas. References 1. Brown and Chambers 2014. Brown, S and Chambers D. 2014. Worker Protection Implications of the Solubility and Human Metabolism of Modern Uranium Mill Products. Health Physics. Volume 107, Number 5. 2. USNRC 2014. United States Nuclear Regulatory Commission. Bioassay at Uranium Mills. Regulatory Guide 8.22. 3. Brown, S. 1982, Radiological Aspects of Uranium Solution Mining, In: Uranium, 1, 1982, p37-52, Elsevier Scientific Publishing Co. 4. USNRC 2009. United States Nuclear Regulatory Commission. Generic Environmental Impact Statement for In-Situ Leach Uranium Milling Facilities. NUREG 1910 5. Brown, S and Smith, R, 1980, A Model for Developing the Radon Loss (Source) Term for a Commercial In Situ Leach Uranium Facility, In: M Gomez (Editor), Radiation Hazards in Uranium Mining – Control, Measurement and Medical Aspects, Soc. Min. Eng., pp. 794-800. 6. Marple L and Dziuk T, 1982. Radon Source Terms at In Situ Uranium Extraction Facilities in Texas. In: Proceedings of the Sixth Annual Uranium Seminar. South Texas Minerals Section American Institute of Mechanical Engineers (AIME). Corpus Christi, Texas. September 11-14, 1982 7. Blauer and Brown 1980. Blauer M and Brown S. Physical and chemical parameters affecting the dissolution of yellowcake in simulated lung fluids. Paper number 177 in: Abstracts of 25th annual meeting Health Physics Society. Seattle: Pergamon Press. 8. USDOE 2009. United States Department of Energy. Guide of Good Practices for Occupational Radiological Protection in Uranium Facilities. DOE STD 1136 – 2009 9. SENES 2013. Evaluation of Default Annual Limit On Intake (Ali) for Yellowcake and Uranium Ore. Prepared for the Canadian Nuclear Safety Commission. July

Speaker: Mr Steven H Brown (SHB Inc)

84 A New IAEA Safety Report on Occupational Radiation Protection in the Uranium Mining and Processing Industry

INTRODUCTION The Fundamental Safety Principles IAEA Safety Standards Series No. SF-1, together with Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards IAEA Safety Standards Series No. GSR Part 3, set out the principles and basic requirements for radiation protection and safety applicable to all activities involving radiation exposure, including exposure to natural sources of radiation and brings challenges to the regulators, operators and workers in implementing the occupational radiation protection requirements [1, 2]. There has been more than 40 years of experience in applying international radiation safety regulations at uranium mines worldwide. Even though radiation safety regulations are among the most comprehensive and stringent in many uranium producing countries, there is still scope to enhance protection of occupationally exposed workers in terms of improving mechanisms to reduce occupational exposure, achieving informed personal behaviours, and applying best engineering controls, etc. While many uranium mining companies generally take active steps to reduce radiation doses and control exposures wherever and whenever they can, and often voluntarily adopt the most recent international recommendations on dose limits and necessary occupational radiation protection requirements before they become part of the regulations, consideration needs to be given to enhancing radiation protection of workers on an industry-wide and global basis. This is important as it supports the implementation of internationally consist standards and approaches regarding the protection of workers. In the last 60 years uranium has become one of the world’s most important nuclear fuels. It is mined and concentrated similar to many other metals. Uranium is a naturally occurring element with an average concentration of 2.8 parts per million in the Earth's crust. Traces of it occur almost everywhere. It is more abundant than gold, silver or mercury, about the same as tin and slightly less abundant than cobalt, lead or molybdenum. Natural uranium being the basic fuel for its first phase of nuclear power programme, an increase in the momentum of prospecting, mining and processing of uranium is inevitable. There are three main methods of producing uranium - underground mines, open pit mines, and in–situ-leach (ISL) (sometimes referred to as in situ recovery or ISR). Conventional mines, either underground or open pit mines have usually associated with a mill where the ore is crushed, ground and then leached to dissolve the uranium and separate it from the host ore. At the mill of a conventional mine or the treatment plant of an ISR operation, the uranium which is now in solution is then separated by ion exchange before being precipitated, dried and packed. This product uranium oxide concentrate (UOC) is also referred to as yellowcake and mixed uranium oxides – U3O8 and/or UO4. In addition, uranium can be recovered as a by-product from phosphate fertilizer production and from mining of other minerals including copper and gold where the ores contain economically exploitable quantities of uranium. In such situations, the treatment process to recover uranium may be more complex. With the current interest in nuclear power, there has been an increase in uranium exploration and also in the development of new uranium mining and processing facilities in many countries. World uranium production in 2012 was 58,344 t of uranium [3]. This uranium production occurred in nearly 20 countries at approximately 50 different mining and processing facilities. As a consequence, the numbers of workers in uranium mining and processing may increase substantially within a few years. During uranium mining and processing, workers may be exposed externally to gamma rays emitted from the ores, process materials, products and tailings, and internally exposed from the inhalation of long lived radioactive dust (LLRD), radon and radon progeny, and through ingestion, injection and absorption of contamination. OBJECTIVES OF THE SAFETY REPORT The objective of the Safety Report is to provide detailed information that will assist regulatory bodies and industry operators in implementing a graded approach to the protection of workers against exposures associated with the uranium mining and processing. This information will also serve as the basis for creating a common understanding, based on common knowledge, between the various stakeholders — such as regulators, operators, workers and their representatives, and health, safety and environmental professionals — of the radiological aspects of the various processes involved and the ways in which these aspects can be addressed appropriately and effectively. SCOPE OF THE REPORT The safety report describes the various methods of production used by the uranium industry and provides practical information on the radiological risks to workers in the exploration, mining and processing of uranium, on exposure assessment, and on management of exposure based on the application of the appropriate standards and good working practices. This information has been compiled from published literature, from unpublished data provided by contributors to the report and from numerous experts with extensive experience, notably in the various sectors of the uranium mining and processing industry. STRUCTURE The report comprises six sections. Following the introductory section, Section 2 gives an overview of the uranium industry and the general radiation protection aspects of uranium mining and processing stages and techniques. Section 3 summarizes the radiation protection considerations that apply to the uranium mining and processing industry in general and application of the international standards in particular, including the basic radiation protection principles, the graded approach to regulation and specific aspects of radionuclides in the uranium decay series. Section 4 addresses the general methodology for control with the introduction of occupational health and safety considerations, the hierarchy of control, the radiation protection principles and exposure pathways. Section 5 deals with the requirements and dose assessment, with discussion on general dose considerations for different types of exposure pathways. Section 6 introduces the essentials of radiation protection programmes to adequately protect the workers, illustrating the process, design and operation, principal exposure pathways, control mechanisms and monitoring and dose assessment for different uranium mining and processing stages and techniques. The report is supplemented by appendices describing the findings of the International System on Uranium Mining Exposures (UMEX) survey, and the technical details of various exposure pathways. REFERENCES [1] EUROPEAN ATOMIC ENERGY COMMUNITY, FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS, INTERNATIONAL ATOMIC ENERGY AGENCY, INTERNATIONAL LABOUR ORGANIZATION, INTERNATIONAL MARITIME ORGANIZATION, OECD NUCLEAR ENERGY AGENCY, PAN AMERICAN HEALTH ORGANIZATION, UNITED NATIONS ENVIRONMENT PROGRAMME, WORLD HEALTH ORGANIZATION, Fundamental Safety Principles, IAEA Safety Standards Series No. SF-1, IAEA, Vienna (2006) [2] EUROPEAN ATOMIC ENERGY COMMUNITY, FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS, INTERNATIONAL ATOMIC ENERGY AGENCY, INTERNATIONAL LABOUR ORGANIZATION, OECD NUCLEAR ENERGY AGENCY, PAN AMERICAN HEALTH ORGANIZATION, UNITED NATIONS ENVIRONMENT PROGRAMME, WORLD HEALTH ORGANIZATION, Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards, IAEA Safety Standards Series No. GSR Part 3, IAEA, Vienna (2014) [3] INTERNATIONAL ENERGY AGENCY, World Energy Outlook (2016)

Speaker: Mr H. Burcin Okyar (International Atomic Energy Agency)

Uranium Production by the In Situ Leaching (ISL) Process

Conveners: Mr Christian Polak (AREVA MINES), Ms Olga Gorbatenko (Kazatomprom)

85 MAJOR INNOVATIONS IN ISL MINING AT URANIUM ONE MINES IN KAZAKHSTAN

The successful innovative technical policy in conjunction with the unique by its geological and technical characteristics deposits, provide significant competitive advantage for Uranium One as the global company with the lowest cost uranium production. Uranium One gain broad expertise in the various aspects of ISL exploration and mining, including: uranium prospecting and exploration for sandstone hosted deposits from greenfield to mining phase; geological geo modelling and resources estimation; pilot ISL testing; feasibility and engineering studies at all stages of deposit development. The main areas of ISL innovative developments and efficiency improvements at Uranium One mines in Kazakhstan include: geological 3D modelling for resources estimation; ISL process modelling and simulation for projects design and its implementation in ISL process management; implication of modern methods for wells construction and restoration; estimation of additional technogenic and residual resources; rare earth elements and other valuable components recovery from leaching solutions. Uranium One attributable CIM compliant resources in Kazakhstan have tripled over 10 years through acquisitions, extensive exploration and by applying 3D modelling in resource estimation. Previous technical reports on NI 43-101 codex were based on geological information compiled from Kazakhstan national technical reports on resources (GKZ codex), which assumed polygonal geostatistical method for resources calculation. Uranium One has hired CSA Global to develop a robust methodology for 3D geological modelling and Mineral Resource and Ore Reserve estimation for roll-front deposits in Kazakhstan. This methodology was applied from 2012 through 2017 to Budenovskoye and South Inkai deposits modelling in Chu-Sarysu province, and Zarechnoye and Kharasan-1 deposits modelling in Syrdarya province. The ISL modelling complex includes the set of integrated systems: geological data room and geological model, technological data room and ISL process simulation model, technical-economical system, ISL development and wellfield design system, mining planning complex. The modelling complex may be applied for ISL process design and management at all stages of deposit development. The complex was developed by Russian Seversk Technological Institute and originally implemented at Russian ISL mine Dalur. In 2017 Uranium One has started pilot project on ISL process modelling and simulation at one of the areas of the Akbastau mine. The developed ISL model for main technical parameters has identified main issues for ISL process optimization in a short, mid and long-term period. The obtained results confirmed the high potential for simulating systems implementation at ISL mines in Kazakhstan. Wellfields design and installation is one of the most important component of ISL mine development. Drilling and wells installation costs comprise about 70% of mining CAPEX or 25-30% in the total uranium production cost. Major ISL mines in Kazakhstan use unified technique and design for technological wells drilling and installation. The stable performance of wellfield units largely depend on efficiency of wells work over procedures focused on wells flow rates restoration and on plugging impact elimination. Plugging is the process when a well-known screen loose its capacities and the ore bearing horizon loose its permeability. A new method for wells flow rates restoration is based on wells screen treatment by a mixture of reagents with the additive of ammonium bifluoride. The method has no alternatives for the restoration of problematic wells, when traditional methods of chemical treatments for flow rates recovery do not give significant results. Application of the method restore flow rates to original parameters and increase the workover cycle by 2.5 to 3 times. Estimation and development of additional technogenic (or newly formed) and residual resources within existing wellfields is a particularly vital issue for a life of mine extension. By technogenic resources we mean uranium concentrations formed due to leaching solutions exposure on primary mineralization and redeposition of dissolved uranium, including the remaining lenses of productive solutions. By residual resources we mean part of remained in situ and not affected by leaching processes uranium mineralisation. In 2016 Akdala mine completed research work focused on the forecast of areas with residual and technogenic resources [4]. Prospective areas for 419 tons of potentially residual resources were allocated within existing wellfield units. Further verification drilling confirmed the presence of residual and newly formed ores. 15 of 25 wells drilled in 2017 identified commercial uranium concentrations in leaching solutions and in hosting sediments. Off-balance resources of valuable by-product components (rhenium, scandium and rare earth metals) are identified in the contours of uranium resources at ISL mines in Kazakhstan. All valuable components are partially dissolved in sulfuric acid during ISL process. Six mines with Uranium One ownership pump out more than 120 million. cubes of productive solutions annually, which contain up to 1 mg/l of scandium and rhenium and 5-20 mg/l of rare earth elements [5]. Lanthanum, cerium and neodymium give the major input to rare earth elements. About 40t rhenium, 30t scandium, more than 2000t of rare-earth metals is pumped out annually with leaching solutions and returned back to aquifer. Major technologies of by-products extraction from sorption mother liquors has been developed. They assume by products sorption by cationic exchange resins or REE chemical precipitation. Rhenium is partially absorbed together with uranium by anionic ion exchange resins and its concentration in saturated resins may reach 950g/t [5]. The key technological challenge is a selection of sorbents, which provide selective extraction of valuable components free of radioactive metals impurities. REFERENCES [1] Boytsov A.V., Thys H., Seredkin M.V. Geological 3-D modelling and resources estimation of the Budenovskoye uranium deposit (Kazakhstan). Uranium Raw Material for the Nuclear Fuel Cycle: Exploration, Mining, Production, Supply and Demand, Economics and Environmental Issues. IAEA-CN-216 Abstract 038. Vienna, 2014 [2] Noskov M.D. et all. Application of geotechnical simulation for ISL uranium mining higher operational efficiency. Book of papers VIII-th International Conference “The topical Issues of the Uranium Industry”, pp.108-113. 03-05 August 2017, Astana, Kazatomprom. In Russian. [3] Noskov M.D. et.al. Intellectual technology of ISL uranium mining management. Book of papers VIII-th International Conference “The topical Issues of the Uranium Industry”, pp. 102-108. 03-05 August 2017, Astana, Kazatomprom. In Russian. [4] Nietbaev M.A. et al. Experience and prospects of newly formed and residual uranium resources development. Book of papers VIII-th International Conference “The topical issues of the uranium industry”, pp. 72-78. 03-05 August 2017, Astana, Kazatomprom. In Russian. [5] Kozhakhmetov S.K. et.al. The possibility of rare and rare earth metals by products recovery from pregnant ISL solutions at South Kazakhstan uranium deposits. The VI-th International Conference “The topical issues of the uranium industry”, pp. 452-456. 14-16 September 2010, Almaty, Kazatomprom. In Russian.

Speaker: Dr Alexander Boytsov (Uranium One Inc.)

86 THE FUNDAMENTAL RESEARCH AND INDUSTRIAL APPLICATION OF THE CO2 AND O2 IN SITU LEACHING PROCESS IN CHINA

Due to the advantages of less chemical reagent consumption and groundwater pollution, CO2 and O2 in-situ leaching(ISL) process became to be one of the important research field in uranium mining.China was the second country where CO2 and O2 ISL process has been put into production in the world.It is shown that the development and characteristics of CO2 and O2 ISL process in China,including main principle, technological process, wellfield design and production well construction,uranium processing, and so on.In the last, the industrial application status and development potential of CO2 and O2 ISL process in China are summarized. 1 DISCOVERED URANIUM RESOURCES STATUS AND DISTRIBUTION There are 21 uranium orefield distributied in 13 provinces,including Inner Mongolia, Xinjiang, Jiangxi, Guangdong,etc. Since 1994, the targets of exploration was changed from conventional mining deposits in southern China to in-situ leaching deposit in north of China.A plenty of medium-large scale sandstone uranium deposits have been discovered.As a result, the U resources/reserves increased rapidly since 2000. The identified resources(Reasonably assured resource and inferred resource)totally amounted to 370,900tU in China, while more than 2 million tU is predicted with a big potential. Uranium resource and share of different type uranium resources in 2016 were listed as follow:sandstone(56.9%,210,000tU),granite(23.6%,87,000tU)volcanicrock(11.1%,41,000tU),carbonaceous-siliceous-pelitic(7.5%,28,000tU),others(0.9%,3,500tU).The increased sandstone uranium resources mainly comes from six basins: Yili basin,Turpan-Hami basin, Ordos basin, Erlian basin, Songliao basin and Bayin Gobi basin, which all distributed in northern China. Yili basin and Songliao basin are the key and potential area in future. Most of sandstone uranium deposit in China are complex and about 70% of which are some adverse factors such as high carbonate content(>2.0%,CO2), low permeability(<0.17m/d), low grade t(~0.03%,with delineation of ore bodies 0.01%), ,high salinity groundwater(TDS,5~10g/L) and so on. 2 THE BRIEF DEVELOPMENT HISTORY OF CO2+O2 ISL CO2+O2 In-situ leaching process of uranium has been developed since 2000 in China. Some CO2+O2 leaching experiment have been carried out to simulate CO2+O2 leaching characteristics and some technical parameters were obtained. Since 2006, a field test and industrial test has been implemented in Qianjiadian uranium deposit, Songliao basin,Inner mongolia .The buried depth of ore body is 251.8~298.31m with a thickness of 6.46~15.75m, a mean grade of 0.025% and a mean uranium content of square meters of 3.95kg/m2. The modes of occurrence of uranium in Qianjiadian deposit are absorbed uranium, uranium minerals and uranium bearing minerals. The ratio of U(VI)/U(IV) is 0.266~1.116 and the average value is 0.761. The permeability coefficient of the ore-bearing aquifer is 0.025~0.223m/d and the depth of confined water is 5.29~7.06m. The type of water quality is a combination of HCO3-Na and HCO3-Cl-Na with range of the salinity of 3.10~5.7g/L, the pH of 7.2~8.4, the Eh of 100~200mV . A industrial-scale well field had been established ,including 10 production wells and 32 injection wells.Depengding on ore body geometry and surface topography, 7-sopt well patterns and 35m well spacing were used. For injection wells, the average flow rate is 2.8m3/h, the equivalent flow rates for recovery wells are 8.1m3/h, respectively. 3 CO2+O2 LEACHING PROCESS Both gasous oxygen and carbon dioxide are added to groundwater to produce lixiviant.Oxygen is typically added to maintain the strongly oxidizing conditions required to oxidize tetravalent uranium in ore minerals to hexavalent stage.The oxygen concentration will be changed from 150mg/L to 500mg/L with diffierent leaching stage, depending on uranium concentration and dissloved oxygen of lixiviant.Carbon dioxide is added for pH control and increasing bicarbonate concentration increasing. Carbon dioxide concentration will be changed from 100mg/L to 300mg/L. After 2a of operation, uranium recovery had been up to 53.1% with L/S ratio 2.64 ,while average uranium concentration was about 32mg/L. Specific consumption of CO2 was 10.8t/tU and specific consumption of O2 was 12.0t/tU.The flow rate of recovery well and injection well remained stable which was shown that Calcium carbonate scaling was not generated to play a adverse impact on field test. Uranium mobilization and processing excess water that must be properly managed.The production wells exctract slightly water than is re-injected into host aquifer.The production bleed is more than 0.3-1.0 percent of the circulation rate.The main purpose is to maintain the negative balance helps to minimize the potential movement of lixiviant. Some technical parameters: Well pattern:5-spot and 7-spot; Well-spacing:30-35m; Drilling hole structure:gravel filling type; Depth:240-320m; Lixiviant:100~300mg/LCO2+150~500mg/LO2; Recovery rate: more than 75%; Uranium extraction: ion-exchange process with fixed bed column; Water waste treatment:RO (reverse osmosis)and evaporation pond. 4 URANIUM PROCESSING The common ion-exchange resin is D261 widely used in ISL project in China and the ion-exchange circuit is accomplished in two fixed bed columns in series. Based on average uranium concentrations(about 32mg/L)，greater than 97 percent of the uranium ia extracted during the ion-exchage process.The lixiviant exiting the lixiviant columns normally contains less than 0.1 mg/L. Before entering the ion-exchange columns,CO2 was added into the prengnant solution with the concentration from 100 to 300mg/L.The purpose is to contorl the pH from 6.8 to 7.2 and increased the saturated resin load. The elution process is accomplished in a columns in series, by contacting the resin with a mixed solution of sodium chloride and sodium bicarbonate, thus obtaining an pregnant eluant solution with about 35-50g/L.Typical operational condition are 80-120g/L sodium chloride and 10-20g/L sodium bicarbonate.The is normally than 99.9%.After enough pregnant eluant solution is obtained, it is moved to the precipitation circuit. In the precipitation circuit, the pregnant eluant is typically acidified using hydrochloric to destroy the uranyl peroxide.The pH of pregnant eluant decreased to about 3.0-4.0 and is required to maintain in 4 hours accompanied by stirring. Caustic soda is then added to precipitate the uranium as sodium diuranate at pH 6.0-7.0.At last, the resulting slurry is sent to a plate-and-frame filter press where it is filtered and washed.Acorrding to the netural uranium product quality standard, the content of U is required to be equal or greater than 60% in solid material，the content of water is required to be equal or less than 30%。 During the process, some liquid waste were generated which may contain elevated concentration of radioactive and chemical constituents.Reverse osmisis was common used to segregated from it. Through reverse osmosis process,two fluids were yielded:Clean water (about 70 percent, Cl-<350mg/L)that can be reinjected into the aquifer ,and brine(about 30 percent) that can be transported into evaporation pond. 5 ISL MINES PRODUCTION STATUS AND POTENTIAL APPLICATION Due to the advantages of low operating cost, short loading period and less environment pollution，the proportion of uranium produced by in-situ leaching mines increased rapidly.In China, in-situ leaching production dominated uranium production accounting for 65.6% of word production in 2016，which was more than heap leaching(21.1%) and conventional mining(18.5%), the second and the third extracting process of uranium respectively. 2006-2009,the first CO2+O2 ISL project came to commerical operation at Qianjiadian uranium deposit in Inner Monglia.Because of the constantly discovery of ISL sandstone uranium resources, two CO2+O2 ISL mines have been put into operation respectively in Songliao and Yili basins now. Other two mines are being under pilot-scale test in Erdos and Erlian basins.They will be put into production soon. CNNC(China national nuclear corporation) shut down some high-cost underground and open-pit uranium mines in Southern China, focusing on the development of ISL sandstone uranium resources in Northern China,and plan to build three 1000t/a ISL uranium mines by 2020. 6 CONCLUSION Because of successful application results and strict environmental requirements, CO2+O2 ISL has become a priority option and the only option for sandstone type uranium deposit with high carbonate content and high salinity groundwater. According to the development plan,about 90% netural uranium production will be provided by ISL ,especially by CO2+O2.Some large-scale and green mines is under planning and implementation.

Speakers: Mr Yuan Yuan (Beijing research institute of chemical engineering and metallgury,CNNC), Prof. Yuqing Niu (Beijing Research Institute of Chemical Engineering and Metallurgy, CNNC)

87 STOCHASTIC MODELLING OF URANIUM ROLL-FRONT DEPOSITS BASED ON STREAMLINE SIMULATION

INTRODUCTION Rollfront deposits are an accumulation of minerals in reduced permeable sandstones or other sediments between mostly reduced and pervasively oxidized environments [1]. Rollfronts are classified as epigenetic mineral deposits, i.e. their genesis occurred after hosting environment was created, that that often can be found in arid areas and trapped within permeable sedimentary environments. Deposits of rollfront type are crucial to uranium industry. As much as 60% of the worldwide production from recoverable uranium resources in sandstone environments can be accounted to rollfronts [2]. Rollfronts can be found in various sandstone provinces including the Colorado Plateau, Wyoming, Texas Coastal Plain, Mali-Nigeria, Czech Cretaceous Plate, Chu-Sarysu, Syr-Daria, Moynkum, Inkai and Mynkuduk (Kazakhstan), Crow Butte and Smith Ranch (USA) and Bukinay, Sugraly and Uchkuduk (Uzbekistan), Kyzylkum [3, 4]. Uranium can be extracted from rollfront deposits in a safe and convenient manner with In-Situ leaching method (hereinafter ISL). 39% of all uranium produced in the world in 2016 could be accounted to Kazakhstan, where almost all uranium deposits are being developed with ISL [2]. Furthermore, Kazakhstan is the second largest country in the World by uranium resources with close to a million tons of recoverable uranium (1Mt U in 2013), almost 70% of which can be recovered using ISL technique [2]. One of the main difficulties in the exploration of uranium rollfront type deposits lies in the limited number of available exploration techniques that, at small scale, are generally limited to the drilling of numerous costly wells network patterns in perspective areas [4], which in itself is a long and costly process. Two basic approaches to modeling exist at the moment: the traditional interpretation of geophysical data with the subsequent connection of ore contours; and geostatistical 3D modeling [6]. Presently, there are a number of stochastic methods for modeling rollfront uranium deposits by Renard D., Beucher H. [7], Petit et al [8] and Abzalov et al [6]. Renard D. and Busher G. V, developed the technology of three-dimensional modeling of such deposits based on the model of "PluriGaussian Simulation" [7]. Unfortunately, current modeling techniques rarely account for the hydrodynamic and geochemical processes involved in the genesis of rollfront uranium deposits. The authors propose to supplement existing stochastic models with additional methods of computational hydrodynamics. METHODS AND RESULTS Rollfront deposits were formed due to dissolution of minerals from mountain rocks, their subsequent migration along porous canals and deposition in so-called geochemical barriers between oxidized and reduced medium. The formation of rollfront uranium deposits can be divided into three stages: leaching of uranium by oxygen rich meteoritic water, downstream migration of the dissolved chemical uranium components and precipitation of uranium in reduced environments. Upon reaching reduced environments, the dissolved uranium together with other elements such as iron and sulfurs precipitate as uranium minerals (such as pitchblende or coffinite), thereby forming a rollfront type deposit. It is important to note, that the re-deposition of minerals is a dynamic process sustained by a continuous flow of oxygenated meteoritic water which push minerals further downstream. In other words, in active deposits, minerals continuously dissolve from the upstream side of the mineralization zone and precipitate at the front. When no more oxygen is available in the water flow, often because it has been consummated previously by the oxidation of the organic matter before reaching the mineralized zone, the rollfront deposits stabilize. It is clear that the process of genesis of uranium rollfront deposits is highly linked to the infiltration process of dissolved uranium compounds. Therefore, honoring the hydrodynamics of infiltration processes can further increase the precision of any geostatistical approach that is used in modeling rollfront deposits. Well log information is usually used as input data for geostatistical modeling of rollfront uranium deposits. In addition to uranium concentration, such data commonly includes filtration properties of stratum. Application of various estimation methods such as inverse distance weighting or kriging are based on weight assignment to well data in order to determine value at any specific node on a computational grid. Weight assignment technique is a determining factor that differentiates one estimation algorithm from another. For instance, while in kriging based methods, variogram is used for weight computation, in inverse distance based methods (as the name suggests) the length of space between nodes is main influencing factor. In many implementations of aforementioned methods, search ellipsoid is used to gather input information from well log data. The form of this ellipsoid is usually dictated by anisotropy of a particular geological formation. In current work, based on filtration properties gathered from well data and natural head difference, streamlines of solution flow through stratum under consideration were determined. These streamlines were further used as a search shape for distance based methods, while variograms were calculated along the streamline by substituting distance variable with “time of flight” (a property specific to streamline simulation methods). To verify the stochastic modeling approach of uranium rollfront deposits based on streamline simulation, well log data from Kazakhstan deposits were used. In each verification iteration one or more well data were excluded from modeling input for later comparison between numerical and hard data. For further verification purposes, synthetic deposits were simulated based on reactive transport models by reproducing involved uranium rollfront deposit formation. DISCUSSION AND CONCLUSIONS Results show that in terms of error, as compared to conventional estimation algorithms stochastic modeling of uranium rollfront deposits based on streamline simulation provided qualitatively, as well as quantitively, better picture. In most of the cases, stochastic modeling based on streamline simulation provided lower average error for every node in computational grid, as well as slightly more accurate resource estimation. Modeling approach was further investigated for various well placement patterns to identify optimal distances between exploration wells. Overall, the aim of this work was to stochastically model rollfront deposits by honoring hydrodynamics properties of the stratum by constructing variograms along streamlines of groundwater flow to provide additional information on variability, as well as to redefine the process of weight assigned to hard data. In several cases stochastic modeling of uranium rollfront deposits based on streamline simulation provided results with higher accuracy as compared to conventional methods based on kriging or gaussian simulation. REFERENCES [1] ADAMS S. S., CRAMER. R. T., 1985. Data-process-criteria model for roll-type uranium deposits, Geological environments of sandstone-type uranium deposits, Report of the working group on uranium geology organized by the International Atomic Energy Agency, Vienna, Austria, 383-399 [2] ORGANISATION FOR ECONOMIC CO-OPERATION AND DEVELOPMENT NUCLEAR ENERGY AGENCY AND THE INTERNATIONAL ATOMIC ENERGY AGENCY, 2014. Uranium 2014: Resources, Production and Demand, Organisation for Economic Co-operation and Development, Paris and Vienna [3] TARKHANOV A. B., BUGRIEVA Y. P., 2012. Krupneishye uranovye mestorozhdeniya mira [Large uranium deposits of the world], Minerals Journal under All-Russian Research Institute of Mineral Raw Materials, Moscow, Russia [4] BROVIN K. G., GRABOVNIKOV V. A., SHUMILIN M. V., YAZIKOV V. G., 1997. Prognoz, poiski, razvedka I promyshlennaya ocenka mestorozhdeniy urana dlya otrabotki podzemnym vyshelachivaniyem [Forecast, search, exploration and industrial estimation of uranium deposits for production with in-situ leaching method]. Gylym, Almaty, Kazakhstan. [5] WORLD NUCLEAR ASSOCIATION, Uranium and Nuclear Power in Kazakhstan, 2017, http://www.world-nuclear.org/information-library/country-profiles/countries-g-n/kazakhstan.aspx [6] ABZALOV M., DROBOV S., GORBATENKO O., VERSHKOV A., BERTOLI O., RENARD D., BEUCHER H., 2014. Resource estimation of in situ leach uranium projects, Applied Earth Science. Transactions of the Institution of Mining and Metallurgy, London, UK, 123, 2, 70-85. [7] RENARD D., BEUCHER H., 2012. 3D representations of a uranium roll-front deposit, Applied Earth Science (Transactions of the Institution of Mining and Metallurgy) 121, 2, 84-88 [8] PETIT G., BOISSEZON H., LANGLAIS V., RUMBACH G., KHAIRULDIN A., OPPENEAU T., FIET N., 2012. Application of Stochastic Simulations and Quantifying Uncertainties in the Drilling of Roll Front Uranium Deposits. Quantitative Geology and Geostatistics, Springer Science+Business Media, Dordrecht, Netherlands, 321-332.

Speaker: Mr Daniar Aizhulov (Al-Farabi Kazakh National University)

88 LABORATORY AND ION EXCHANGE PILOT PLANT STUDIES SUPPORTING THE FIELD LEACH TRIAL AT THE HONEYMOON URANIUM PROJECT

INTRODUCTION The Honeymoon Uranium Project is an acid In-Situ Recovery (ISR) mine in South Australia. The project contains three deposits; Honeymoon, Jasons and Goulds Dam. The measured resource consists of a total of 6.5 Mlb U3O8 (2.9 kt U) at an average grade of 1720 ppm U3O8 (1460 ppm U), with total resources (measured + indicated + inferred) of 63.3 Mlb U3O8 (28.8 kt U) at 660 ppm U3O8. The mine was previously operated by Uranium One for approximately 18 months, producing ~335 t of U3O8, before being placed on care and maintenance in 2014 due to the persistently low uranium price and production issues. Boss Resources acquired the project in December 2015. As part of the plan for restarting the mine, Boss performed a successful Field Leach Trial (FLT) on an area of the deposit between August and December 2017. In support of the FLT, ANSTO Minerals performed a comprehensive laboratory testwork program. This included a study to optimize the leaching conditions, as well as column leaching of samples taken from the FLT area. The laboratory studies also identified an ion exchange (IX) resin capable of achieving significantly higher uranium loading than conventional resins under the elevated chloride concentrations in the Honeymoon leach liquor. As a result, ANSTO Minerals constructed and commissioned an IX pilot plant that operated for a 10 week period during the FLT. The success of this pilot plant means that IX could potentially be used as an alternative to the existing solvent extraction facility. This paper will present the results from the laboratory program, as well as highlighting the success of the FLT campaign and associated IX pilot plant operation. LABORATORY LEACHING PROGRAM A laboratory leaching program was performed using samples taken from the Jasons deposit, as well as samples taken from the FLT area. The program comprised two main parts, a leach optimization study, to determine the conditions for maximizing uranium extraction whilst minimizing acid and oxidant consumption, and secondly a series of column leaches simulating ISR conditions, to confirm the results from the optimization study and assess the leachability of the uranium in the FLT area. The leach optimization study, investigating the effect of pH, ORP and Fe addition, was performed in 2 L stirred tank reactors at a solids density of 50 wt% and a temperature of 30 °C for a period of 24 hours. The pH and ORP set-points were maintained by the automated addition of concentrated sulphuric acid and sodium permanganate. The results from the optimization study demonstrated that uranium extraction was strongly influenced by pH, with a pH of approximately 1.5 required for maximum extraction. This pH is considerably lower than that employed by the previous operators at Honeymoon, and indicates that the uranium recovery could potentially be significantly higher or kinetics significantly faster than that historically achieved. Tests at varying ORP set-point also demonstrated increased uranium extraction with ORP, however the effect was generally not as significant as for pH. Significantly, if the ORP was maintained at ≥475 mV (relative to a Ag/AgCl reference electrode filled with 3 mol/L KCl), then extensive oxidation of any pyrite present in the sample occurred, resulting in excessively high oxidant consumption. This demonstrates the impact that the presence of sulphide could potentially have in practice, with any ferric iron injected potentially being reduced upon contact with the sulphide. This could result in the rate of uranium extraction being retarded until the sulphide phase is significantly oxidized, with the ferric being consumed by the sulphide before reaching the uranium mineralogy. It is also possible that solubilized uranium could be subsequently precipitated by reducing conditions upon contacting the sulphide, and would not be redissolved until the sulphide is consumed and/or liquor of sufficiently high ORP reaches the precipitate. As a result of the leach program, the optimum conditions identified for leaching of the supplied ore samples were pH 1.5 and ORP 450 mV. In practice, it is likely that in order to minimize sulphide oxidation, it would be necessary to keep the ORP as low as possible whilst still being sufficiently high to achieve a an effective rate of uranium leaching. This could be potentially achieved by increasing the total iron concentration whilst maintain the injection ORP at 400-450 mV, meaning that uranium leaching would occur whilst sulphide oxidation would be minimal. Uranium extractions >90% were consistently achieved in leaches under optimized conditions. The gangue acid consumption in all tests was very low, less than 11 kg H2SO4/kg U3O8, indicating the acid costs in operation would also likely be low. As noted above, oxidant consumptions were high in tests at high ORP set-point, but under optimum conditions consumptions were typically less than 4 kg equivalent H2O2/lb U3O8, or <22 kg Fe3+/kg U3O8. COLUMN LEACHING A series of column tests were also performed on samples taken from both the Jasons deposit and the FLT area. These tests utilized horizontal columns of 1 metre length, with ore samples crushed to -2 mm packed tightly into the columns. The packed ore was irrigated by leach liquor, gravity fed into the column to achieve a target liquor flow rate of 2 m/day through the bed. The column tests investigated the impact of increasing uranium concentration in the feed on the rate of uranium extraction, simulating the effect of solution recycle (also known as solution stacking). Tests were also performed to confirm the effects of pH and ORP observed in the stirred tank tests, and also to confirm the optimum leaching conditions. The column tests utilizing feed liquors with varying uranium concentration (between 0 and 200 g/L U) showed a small decrease in the rate of uranium extraction with increasing concentration. The impact of pH and ORP on uranium extraction in the column leaches was variable, however extractions of >90% were consistently achieved throughout the tests, again demonstrating the amenability of the uranium mineralogy to leaching. Significantly, the calcium contents of the ore samples were very low, and there was no evidence of the precipitation of gypsum or any other calcium salts in the column tests. FIELD LEACH TRIAL The FLT was performed on site from mid-August until early December 2017, and utilized a wellfield approximately 1:10 the size of a typical production wellfield. This comprised of two well patterns with a total of 8 production wells and 2 extraction wells. The primary objectives of the FLT were to determine the necessary conditions required for effective uranium leaching (pH, ORP, Fe3+ concentration), the resultant reagent consumptions and to evaluate the effect of solution recycle in order to increase uranium tenor feeding IX. The wellfields were initially injected with liquor at pH 1.6 with 1.2 g/L Fe3+ added as FeCl3, resulting in an injection ORP of approximately 650 mV. Due to the unusually high pyrite content of the FLT area, the oxidant consumption was high, resulting in the Fe3+ addition being increased to approximately 2.5 g/L and an ORP of approximately 700 mV. This resulted in an increased rate of pyrite oxidation, allowing the uranium leaching rate to also increase. After the increase in Fe3+ addition, a stable U3O8 tenor of 75-85 mg/L was achieved as leaching continued at a steady rate for the remainder of the trial. Towards the end of the campaign, a role reversal was performed (where the injection and extraction wells were reversed), resulting in a maximum U tenor of 375 mg/L, the highest recorded at Honeymoon. Following the initial injection of liquor into the wells when the readily available acid consuming phases reacted, the pH of the liquor from the extraction wells stabilized at approximately pH 1.5. This confirmed the low acid consumption observed in the testwork program, and also demonstrated the effectiveness of uranium leaching at this pH. Similarly, calcium concentrations remained low in all extraction liquors throughout the campaign, and no issues were observed with gypsum precipitation throughout the operation. The successful FLT supported the observations and conclusions from the ANSTO Minerals leaching testwork. In addition to confirming the requirement for a lower pH than previously utilized, as noted above, the FLT also showed that localized regions of high sulphide content can impact on the consumption of Fe3+/oxidant and subsequently the rate of uranium extraction. Increasing the rate of uranium extraction was achieved by increasing the Fe3+ addition. ION EXCHANGE PILOT PLANT Laboratory testwork performed at ANSTO Minerals identified and tested a commercially available resin capable of high uranium loadings from liquors at the elevated chloride concentrations in Honeymoon groundwater. The successful results from this study allowed Boss Resources to evaluate the use of IX for the concentration of uranium from ISR liquors by operating an IX pilot plant campaign over a 10 week period during the FLT. The pilot plant was designed, constructed and commissioned by ANSTO Minerals personnel, and subsequently operated by Inception Consulting Engineers for Boss Resources. The pilot plant consisted of 21 fluidized column contactors divided between 3 modules of 7 contactors each. The function of each contactor (feed, wash or elution) was changed by relocation of feed and outlet hoses, resulting in the resin effectively flowing incrementally in the opposite direction of the liquor. The 21 contactors were divided into 14 loading and 7 elution contactors, representing this number of stages for each. Elution was performed using NaCl/HCl solution. A total number of 312 cycles were performed over the 10 week operating period. The adsorption circuit yielded excellent results, achieving 97% extraction from the PLS, with resin loadings under base case conditions averaging 26 g/Lwsr (wet settled resin) U3O8, with feed and barren concentrations of 50 and 1 mg/L U3O8, respectively. The elution circuit also produced good results, with eluted resin consistently below the target of 2 g/Lwsr U3O8, corresponding to 95-99% elution, during stable periods of operation. The maximum eluate concentration achieved was 2.4 g/L U3O8, corresponding to a resin loading of 28 g/Lwsr U3O8. The IX pilot plant performance overall was in agreement with the bench scale testwork carried out on synthetic liquors, for the PLS chloride concentration and acidities that were tested in the laboratory. Modelling of the IX circuit, based on results from the laboratory results, was validated by the uranium concentrations measured in the barrens and in the loaded resin. The success of the IX pilot plant campaign means that in future operation the existing solvent extraction facilities at Honeymoon could be replaced or supplemented by IX. The use of IX for uranium in elevated chloride liquors is a significant new development in the industry.

Speaker: Mr Mark Maley (ANSTO)

15:40 Break

Advances in Exploration

Conveners: Dr Alexander Boytsov (Uranium One Group), Dr Mark Mihalasky (U.S. Geological Survey)

89 REGIONAL SIGNATURES AND METALLOGENIC MODELS OF SANDSTONE HOSTED URANIUM DEPOSITS IN NORTHERN CHINA

INTRODUCTION Since new century, more exploration has been focusing on the sandstone-hosted uranium deposit in northern China, which is a major industrial exploration type besides granite and volcanic rock-related uranium deposits and become more and more important. Due to metallogentic, theoretical innovation and exploration technological progresses, new deposits have been discovered and more resources/reserve expanded in Meso-Cenozoic basins, such as Kujieertai deposit in Yili basin, Zaohuohao，Nalinggou, Daying deposits in northern Ordos basin, Basaiqi deposit in Erlian basin and Qanjiadian deposit in Songliao basin from the west to the east. Those sandstone-hosted uranium deposits form in different geo-tectonic settings and have different mineralization and regional signatures which can be used to select targets and evaluate uranium potential in exploration areas. Besides the traditional interlayered oxidation-reduction (redox) metallogenic model, some new metallogenic models have been established for the sandstone-hosted uranium deposits in north China, such as Metallogenic Superposition Model and Tectonic Activated Metallogenic Model, which have been of great importance to exploration and new discoveries of uranium resources. REGIONAL SIGNATURES The mineralization and regional signatures of those deposits have been generally summarized in North China. (1) Diversity of metallogenic sedimentary basins: The sandstone-hosted uranium deposits have been found in different types of basins. The northern China basins can be generally subdivided into western, middle and eastern parts based on their tectonic dynamic mechanism. The western part is dominated by intermountain basin such as Yili and Tuha basins within the Tianshan Mountains where a number of sandstone-hosted uranium deposits discovered; the middle part foreland basin like Ordos basin with large uranium deposits and continental margin rifted basin like Songliao basin with deposits in the eastern part. (2) Diversity of metallogenic sedimentary beds: The sandstone-hosted uranium deposits can be also found in different sedimentary beds, the major mineralization host rocks are Early to Late Jurassic sediments in age in the west, and Late Jurassic to Early Cretaceous sediments in the middle, Late Cretaceous sediments in the east. It is obvious that metallogenic sedimentary bed gets younger and younger from the west to the east, indicating higher erosion degree in the west due to stronger Himalayan Neo-tectonic movement impact especially on the northwestern China during Cenozoic era. (3) Diversity and multiple stages of metallogenic ages: Based on the systematicly geo-chronological studies on those major uranium deposits, uranium mineralization usually shows multiple stages in one deposit and younger age in the front of one roll-shaped ore body, and different uranium deposits often have different ages in different areas, in spite of their dominating Cenozoic ones. However, it is clear that uranium mineralization age is younger than the host rocks, and in general, the mineralization age gets younger from the east to the west, being associated with neo-geotectonics, showing opposite tendency of the host rock ages. In addition, the age data of uranium deposits show their undergoing more complicated processes in the middle part like Ordos basin (1). (4) Diversity of metallogenic fluids and processes: Uranium mineralization processes are dominated by meteoric water (fluid) to form typical redox zone controlling ore bodies in the west, and those processes are related to not only meteoric fluid but also oil-gas and hydrothermal fluids in the middle to the east, which make the formation processes and signatures of the uranium deposits more complicated such as alteration, ore bodies and compositions, e.g. pitchblende dominant in ores of the deposits in the west and both pitchblende and coffinite in the middle to the east (3) The formation of those sandstone-hosted uranium deposits and their regional metallogenic signatures in northern China are closely related to Himalayan geotectonic movement, which is due to subduction of Indian Plate tectonics towards the northwest and leads to continental-continental collision and rise of the Qinghai-Tibetan Plateau. This process started ca.55 Ma ago and is still going on (2). That collision results in the present signatures of the basins especially in the northwestern China and Central Asia, which has great impact on the sedimentary formation, hydrogeological process, paleoclimate change and movement of oil-gas fluids during Cenozoic period. Furthermore, it has fundamental impacts on the metallogenic processes of sandstone-hosted uranium deposits in northwestern China and Central Asia, leading to formation of world class sandstone-hosted uranium province. The role and impacts of the collision and Tibetan Rise on metallogenic processes of sandstone-hosted deposits can be generally described as below. A Deposition and erosion in Cenozoic period: Cenozoic sedimentary deposition provides possible new uranium bearing beds, and erosion or depositional interruption enable uranium oxidized to be immigrated easily, in addition, uplifting of the provenance rocks could provide uranium source, both of them are favorable for formation of sandstone uranium deposits. B: Formation of tectonic slope: The tectonic slope formed by the regional tectonic movement can provide a good hydrological condition for formation of the deposits, i.e., oxidized uranium-bearing meteoric fluid can move into the permeable sandstone bed and meet the reductant materials which make oxidized uranium be reduced again for uranium to precipitate in the redox zone to form deposits; the similarly formed fault in the discharge area can improve the hydrological condition and can be as channel for deep necessary reductants to come up into the potential ore bed. C: Formation of arid and semi-arid weather: This kind of weather has been formed due to the rise of Qinhai-Tibetan Plateau especially in the northwestern China, which is favorable for uranium immigration. D: Escape and upwards movement of oil and gas: During rising process of especially basins rich in oil and gas, they can move upwards the de-pressured areas where they act as reductants to form redox zone for possible uranium deposition; in addition, secondary reduction processes related to oil and gas can protect the existed ore body and lead to the secondary metallogenic process(4). METALLOGENIC MODELS The metallogenic models for the major sandstone-hosted uranium deposits have been summa-rized in the north China. (1) Interlayered redox metallogenic model This model is very popular like roll-front model and represented by Kujieertai deposits in the southern margins of Yili basin. The basement of Yili basin has a binary structure, i.e. Precambrian crystalline and Late Paleozoic clastic basement with relatively high uranium content of 4-14 ppm as source. The cover sedimentary strata are dominated by Triassic to Jurassic with undeveloped Cretaceous and younger rocks. The uranium ore-bearing bed mainly is Jurassic coal-bearing clastic formation with good mudstone(coal)-sandstone interbedded structure and usually located in fluvial and delta phase sediments with thickness of 25-40 meters. The favorable host rock is medium-coarse grained debris arkose with good permeability. Uranium mineralization can be found in 7 different sequences of the ore bed, extending ca. 10 kilometers in length. The deposit shows complicated roll-front shape with the ore grade changing from 0.01% to 0.2%. Uranium exists as dominant pitchblende and a few coffinite as well as absorbent forms; the associated elements are V, Se, Mo and Re etc.; metallogenic age is determined by multiple stages of 19Ma, 12Ma, 5Ma, 2Ma and 1Ma (1). (2) Metallogenic superposition model This model is represented by Zaohuohao sandstone-hosted sandstone type uranium deposit in north Ordos basin, it is located at the southern margin of Yimeng uplift block and its adjacent Hetao graben at the northern margin. Mesozoic sedimentary strata are mainly exposed, the Upper-Triassic Yanchang Formation is mainly composed of gravel-bearing sandstone interbeds with siltstone and mudstones, bearing oil- and coal-deposits, The Lower-Middle Jurassic Yanan Formation is mainly composed of coal-productive arkose, mudstone and siltstone. The Middle Jurassic Zhiluo Formation is the uranium-bearing ore bed, composed of gray, gray-green sandstone and mottled siltstone and mudstone, which is parallelly or locally angularly unconformably underlain by the Yanan Formation. The Upper and Tertiary strata are absent. Sedimentary strata show that the study area underwent multiple times of tectonic events, which were closely related to uranium mineralization (3). Zaohuohao deposit is a superlarge one . It is a special kind of sandstone-hosted uranium deposit, different from other ordinary sandstone type deposits because of itsis a newly discovered one The uranium deposit is of own unique signatures. It is generally controlled by a transitional zone between greenish and grayish sandstones, both of those two kinds of sandstones now indicate reduced geochemical environments. The greenish color of the paleo-oxidized sandstones mainly results from chloritization and epidotization related to oil and gas secondary reduction processes (4). The deposit genetically is different from ordinary sandstone uranium deposits, which is of more complex origin, undergoing not only paleo-oxidization mineralization process, but also oil-gas fluid and hydrothermal reworking processes. The metallogenic superposition model for this kind of uranium deposit has been established, i.e., the deposit underwent multiple mineralization processes and stages, such as tectonic multi-periodic “dynamic-static” coupling movements, superposition of paleo phreatic oxidation and interlayer oxidation mineralizations and composite transformation of oil-gas and thermal fluids. The metallogenic stages can be identified: A Preliminary enrichment stage at 170 Ma; B Paleo-phreatic oxidation stage at 160-135 Ma; C Paleo-interlayer oxidation stage at 125-65 Ma; D Oil-gas reduction +thermal modification at 20-8 Ma. Analytical data show that thermal modification of the deposit happened after the deposit formed. It is probably due to the modification that coffinite, selenium, sulfide minerals formed under relatively high temperature, leading to the superposed enrichments of elements like P, Se, Si, Ti and REE over uranium (3). (3) Paleo-channel metallogenic Model This model is represented by Bayinwula sandstone-hosted sandstone type uranium deposit in Erlian basin, it is located in Early Cretaceous paleochannel. The exposed crystalline rocks with high content uranium of 8-11 ppm to the north of the mineralization area can provide good uranium source for the deposit. The ore-bearing bed is characterized by braided paleochannel sedimentary system and the ore controlled by both interlayer and phreatic oxidation processes. The favorable host rocks are debris sandstone and arkose with a certain content of organic and sulphur materials. The ore body usually shows roll-front or tabular in shape with average thickness of 6.38 meters and ore grade ranging from 0.0113%-0.2477%. uranium exists in dominant absorbent form and pitchblende, associated with Re, Se, Mo, Sc and V etc. Metallogenic processes also show three major stages of 95 Ma with preliminary sedimentary enrichment (I), 65 Ma with dominant phreatic oxidation process (II) and 45Ma with phre-atic+interlayer oxidation process (III)(5). (4) Tectonic Activated Metallogenic Model This model is represented by Qianjiadian sandstone-hosted sandstone type uranium deposit in southwestern part of Songliao basin, it is located in both of the anticline wings which are formed by late activated tectonic event called Renjiang at the Late Cretaceous. The anticline structure plays a very important role in the formation of uranium deposit, which is also called “window structure”. The host beds are Late Cretaceous Yaojia Formation with dominant fine-grained sandstone. The provenance rocks like Mesozoic granites and acidic volcanic rocks with uranium content of 7-15 ppm can provide good uranium sources for mineralization. The late metallogenic processes are characterized by both oxidized infiltrating and reduced effusion fluids with oil-gas through the fault from the depth to form large tabular ore body. Qianjiadian deposit is also reformed by the hydrothermal fluid related to basic dykes at the age of 53Ma. Uranium mainly exists as absorbent form and pitchblende, the average ore grade is 0.0265%. The metallogenic age is also determined to be multiple stages of 96Ma, 67Ma, 53Ma, 40Ma (1). MAIN REFERENCES 1. Xia Yuliang, Lin Jinrong, Liu Hanbin et al. 2003. Metallogenic Geochronological Studies on the sandstone-hosted uranium deposits in major Basins, North China 2. Xu Zhiqin, Yang Jingsui, Li Haibing et al. 2011. Collision Geotectonics between India and Asia Continents. ACTA GEOLOGICA SINICA, 85(1): 1-33. 3. Li Ziying, Chen Anping, Fang Xiheng et al. 2008. Origin and Superposition Metallogenic Model of the Sandstone-Type Uranium Deposit in the Northeastern Ordos Basin, China. ACTA GEOLOGICA SINICA, 82(4): 745-749. 4. Li Ziying, Fang Xiheng, Chen Anping et al.2007. Origin of gray-green sandstone in ore bed of sandstone type uranium deposit in North Ordos Basin, Science in China, Series D, Vol.50, Science in China Press, Beijing, p165-173 5. Liu Wusheng, Kang shihu, Jia lichen et al. 2013. Metallogenic Paleochannel Type Uranium Deposit in Erlian Basin, North China, Uranium Geology, 29(6), 328-335.

Speaker: Prof. Ziying Li (Beijing Research Institute of Uranium Geology)

90 Mapping the World Distribution of Uranium Deposits

Since the publication of the first edition of the IAEA map - World Distribution of Uranium Deposits - more than 2 decades ago, the knowledge of the distribution of different types of uranium deposits has advanced significantly. This has allowed the creation of a more sophisticated and comprehensive database of world uranium deposits (UDEPO). Increased insights, such as a new deposit-type classification scheme, additional new discoveries as well as disaggregation of previously known discoveries, and enhanced GIS techniques have also allowed the generation of a new second edition map. This will provide a valuable decision-making tool for a wide variety of stakeholders interested in existing and potential new uranium discoveries.

Speaker: Martin Fairclough (International Atomic Energy Agency)

91 Spatial and quantitative modelling of uranium resources

Considerable effort has recently been directed towards enhancing and expanding the IAEA database for world uranium deposits, UDEPO. The database is now sufficiently comprehensive to allow use of the data for a wide range of applications, both spatial (such as global map production and mineral potential modelling) and quantitative. The latter application has been commonly been undertaken for a wide variety of mineral resource commodities, but rarely for uranium, using a variety of techniques including the Three Part Method pioneered by the United States Geological Survey. This, and other methods of using known deposit data to provide insights into undiscovered resources relies heavily upon robust statistical inputs. These include grade and tonnage models coupled with appropriate descriptive deposit models. In combination, these provide an opportunity for more defensible and systematic assessments of potential future uranium resources that assist with answering the questions of “where”, “how many” and “how much”.

Speakers: Dr Mark Mihalasky (U.S. Geological Survey), Martin Fairclough (International Atomic Energy Agency)

Uranium from Unconventional Resources

Conveners: Mr C.K. ASNANI (HINDU), Dr Luminita Grancea (OECD NEA)

92 Understanding of uranium extraction mechanisms from phosphoric and sulphuric media using DEHCNPB

Phosphate rocks are widely exploited for the manufacturing of phosphoric acid and fertilizers but they contain uranium (30-300 ppm). Therefore, recovering this uranium would enable the decontamination of phosphoric acid while valorizing uranium for the nuclear industry. New extractant molecules were investigated in the past few years to develop a new solvent extraction process. An amidophosphonate, the butyl-1-(N,N-bis-2-ethylhexylcarbamoyl)nonyl phosphonic acid (DEHCNPB), showed good uranium extraction efficiency while meeting U/Fe decontamination requirements (as demonstrated during pilot scale trials). Afterwards, DEHCNPB was also used for the extraction of uranium from conventional resources (from sulfuric lixiviation media). However, pilot scale trials showed poorer performances, as uranium leaks in raffinates were higher than expected. The oobjective here is to study uranium and iron extraction mechanisms from those two different media (phosphoric and sulfuric). Thermodynamical data were acquired such as: extraction isotherms, slope analysis, phosphates/ sulfates and water extraction. These data showed different behaviors depending on the initial medium. Spectroscopic techniques such as FTIR, NMR, ESI-MS and EXAFS were also investigated to study uranium-DEHCNPB complexes formed in the organic phase, enabling the determination of stoichiometries and coordination modes.

Speaker: Dr Cecile MARIE (CEA)

93 Selective Leaching of Uranium from Phosphates Ore

A leaching reagent (LR) has been successfully used (for environmental importance) to leach - (remove) - uranium from input phosphate ores prior to processing for production of phosphatic fertilizers (and phosphoric acid), without dissolution of any amount from the phosphate mineral. In (traditional) phosphate industry, rock phosphate is digested with sulfuric acid for production of phosphoric acid and phosphatic fertilizers. Thereupon, uranium present in rock phosphate would be transferred to the products, phosphatic fertilizers and phosphoric acid, and by-product (phosphogypsum). The uranium contaminations could enter the environment and possibly pose radiation exposure concerns through several pathways: From using fertilizers in cultivation of the agricultural lands, from using phosphogypsum as agricultural gypsum, and from using phosphogypsum as a building material. Phosphate rocks, superphosphate fertilizer and phosphogypsum contain uranium as a host of environmentally hazardous chemical element, and they contaminate the agricultural soils through the use in cultivation. Uranium apart from its radioactivity is chemo-toxic (its biochemical toxicity is estimated to be six orders of magnitude higher than the radiological toxicity), and because of these properties, it is considered as a disease causing element. Due to the extensive usage of these contaminated fertilizers, the danger posed to human health is very large. The geochemical pathways lead this toxic element (U) into food crops, soil, water, air and ultimately human body tissues via the food chain. Therefore, removal of U from input phosphate ores prior to processing for production of phosphatic fertilizers, is considered a very important operation in order to prevent disease in humans (through healthy environments) on one hand, and obtaining the valuable U element as a source of energy on the other hand. On the other hand, in case of processing rock phosphate for phosphoric acid production (wet phosphoric acid process) without uranium removal - by our (LR) - prior to processing, practically most of the uranium present in phosphate rock ends up in solution. Present commercial recovery of uranium from phosphoric acid is based on solvent extraction methods that have the following disadvantages, namely, 1) - Solvent extraction methods are expensive, especially because of the required prepurification of the phosphoric acid in order to assist phase separation, and the subsequent treatment of the acid to prevent attack of the rubber lining of phosphoric acid evaporation equipment. These previous acid conditioning stages are associated with large investment and operation costs. 2) - The treated phosphoric acid may be contaminated with organic solvents. 3) - The economy of the process is strongly affected by the uranium concentration, because the investment and operating costs depend on the acid throughput. 4) - Recovery of uranium from phosphoric acid in combination with direct production of concentrated (>45-52% P2O5) acid, i.e., the so-called hemihydrate process (>45% P2O5) is not possible on a commercial scale using solvent extraction techniques. We attained the preferred leaching conditions of uranium from the phosphate ore (without dissolution of any amount from the phosphate mineral) after performing several series of leaching experiments under different conditions.

Speaker: Mr Nahhar AL-KHALEDI (KUWAIT)

94 Overview and Update on the Seawater Uranium Recovery from Technology Development Sponsored by the U.S. Department of Energy

The ocean contains a large quantity of dissolved uranium (over 4 billion ton U) and has long been regarded as an inexhaustible uranium resource. However, due to its low concentration in seawater (3.3 parts per billion), developing a cost-effective recovery method remains a challenge. In October 2010, the U.S. Department of Energy, Office of Nuclear Energy (DOE-NE) held a workshop on “Technology and Applied R&D Needs for Nuclear Fuel Resources” to evaluate the emerging research areas that have the potential to significantly impact the future technology development needed to ensure the availability of natural uranium resources for global nuclear expansion. Based on the workshop report, DOE-NE assembled a multidisciplinary team from national laboratories, universities, and research institutes to start a technology driven, science-based research program focused on extraction of uranium from the most challenging but highest-payoff unconventional resource: seawater. The program objective is to develop advanced adsorbent materials that can simultaneously enhance uranium sorption capacity, selectivity, kinetics, and durability to reduce the technology cost and uncertainties. Through these efforts, the seawater uranium recovery technology costs have been significantly reduced. This presentation will provide an overview and update on the technology developments of the DOE-NE sponsored uranium extraction from seawater program.

Speaker: Dr Phillip Britt (Oak Ridge National Laboratory)

Poster Session

95 Advances in geophysical methods used for uranium exploration and their applications in China

INTRODUCTION Geophysics is one of the most useful technique for uranium exploration. It supports the development of geological theory through the definition of lithological, structural and alteration characteristics of metallogenic environments under evaluation. With the increasing of prospecting depth, the traditional radiometric will no longer be effective for uranium exploration. Despite uranium mineralization is not closely related with the observable gravity, magnetic and impendence anomalies. The application of gravity, magnetic and electromagnetic techniques can survey an area’s subsurface geological setting and can be effective in detecting the deeper uranium deposit. [1] The progression and development of geophysical methods in theory, measurement techniques, data processing, computer modelling and inversion have yielded improvements in the field of uranium exploration[1-2]. It is well known that the progress in geophysical methods have contributed to successful field investigations in the area of deeper deposits (including uranium) exploration. Xu et al (2013) has reviewed the latest advance and developing trend of geophysical and geochemical methods and techniques applied in uranium resources exploration in China[2]. Following such work, this paper summarizes the work done by East China University of Technology during the past decade, those works including 3D inversion of magnetic data and 3D EM methods have been carried out in Xiazhuang granite type uranium deposit [3-4], in Xiangshan volcanic type uranium deposits in China. [5] The results indicated that some of the objectives include the mapping of basement structures, rock interface and lithology recognition can be achieved. APPLICATION ON THE DEEP PROSPECTING OF URANIUM DEPOSITS IN XIAZHUANG We have performed a case study on the use of magnetic 3D inversion and EM image in Xiazhuang uranium ore field which is granite-related uranium deposit. In this area, the uranium deposits related to diabase are mainly located in the eastern part of the Guidong massive granite body [6-8]. This type of uranium deposits was named intersection-type which is located on the intersection points of diabase dykes swarming with near EW-strike and silicified fault system with NNE-extension. After some new discoveries located in the deeper have been obtained during the mining process, attention was taken to the Xiazhuang uranium ore field. Integrated geophysical methods including gravity, magnetic and EM were used to delineate the granite rocks and the faults in the deeper. The goal of this study was to test the applicability of the mentioned methods in the exploration of uranium and to predict for deep ore prospecting. In this manner, 8 profiles was assigned for AMT and gravity survey, 20Km2 magnetic surveying along an area on which several some uranium bodies exist in the deeper drill holes. After surveying those profiles, the acquired data were processed, 2D or 3D inversed and interpreted. The results effectively identifies the granite rocks at large depths and the imaged distribution of these units is consistent with information from local geology. Finally, by integration of the results from the gravity, magnetic and electromagnetic data, three locations were suggested for borehole drilling. And two of them meet uranium around 1000m while one is dry hole. After drilling in those locations, cores were studied and compared with the results obtained from the geophysical methods that resulted in confirmation of the geophysical finding. Furthermore, this work shows the availability of the geophysical methods to explore the deeper granite-hosted uranium deposit. APPLICATION ON THE GEOLOGICAL STRUCTURE SURVEY OF XIANSHAN VOLCANIC BASIN As the third largest volcanic-type uranium ore field in the world, Xiangshan volcanic basin is attracting great research interests and a large amount of industry investment all the time. We have performed a three dimensional geological structure survey and modeling project from 2011. The object of this project is to delineate the volcanic calderas which is still not confirmed over the past 60 years and to investigate the deeper geological structure of the basin. Based on the physical property measurement of around 1400 samples from drill core and along the geological profiles. 3D inversion of regional gravity and magnetic data were conducted and 19 profiles of Magnetotelluric(MT) covered the Xiangshan volcanic basin were carried out. The MT data was inverted using 2D and 3D inversion algorithm developed by our group [9-10]. With the integration of the geophysical survey results and with information from drill holes and local geology, a 3D geological and geophysical model was set up. And we got the following conclusions: Xiangshan volcanic basin has double basements, one is Metamorphic basement and the other is Caledonian granite basement. A low resistivity layer exists between the basement metamorphic rock sand the overlying volcanic-sedimentary rocks was inferred as an unconformity interface. A mushroom shape low resistivity geological body with a radius of around 2km located in Xiangshan mountain peak was inferred as the Ehuling Formation. Seven North-East-strike, four North-West-strike and one North-South-strike faults are delineated based on the geophysical results. CONCLUSIONS We implemented integrated geophysical survey for deeper uranium deposits exploration and 3D geological structure survey in south China. Combined with geological and borehole data, we provide support for deeper uranium exploration in those area. We conclude that geophysical methods can get qualified results using in uranium exploration. While the selection of geophysical methods depends on the physical properties of the target and its accompanied rocks, geological setting and the environments. Integration of several geophysical methods and other disciplines is necessary in most case in order to achieve more certain results. AKNOWLEDGMENTS These research works are financially supported by the National Natural Science Foundation of China (No. 41404057, 41674077 and 411640034), the Nuclear Energy Development Project of China. REFERENCES [1] INTERNATIONAL ATOMIC ENERGY AGENCY, Advances in Airborne and Ground Geophysical Methods for Uranium Exploration, IAEA Nuclear Energy Series No. NF-T-1.5, IAEA, Vienna (2013). [2] Xu G L, Wang H L, Zhao R R, et al., Latest Advance and Developing Trend of Geophysical and Geochemical Methods and Techniques Applied in Uranium Resources Exploration, Uranium Geology, 2013,29(6):344-351(in Chinese) [3] Li M, Fang G X, Zhang Z Y, Cao J C, The application of ground high-precision magnetic survey to the exploration of intersection-type uranium deposits, Geophysical and Geochemical Exploration (in Chinese) , 2012, 36(2), 355-359 [4] Ge K P, Liu Q S, Deng J Z, et al., Rock Magnetic Investigation and its Geological Significance for Vein-type Uranium Deposits in Southern China, Geochemistry, Geophysics, Geosystem, 2017,18,1333-1349. [5] Guo F S, Lin Z Y， Li G R, et al. Study on the Geological Structure of Xiangshan Uranium-bearing Volcanic Basin: Evidence from Magnetotelluric Sounding and GOCAD Modeling. Chinese J. Geophys. (In Chinese), 2017, 60(4):1491-1510. [6] Yang Y X, Wu X M, Lin J, et al. Soil thermoluminescence at XI-wang deposit, Xiazhuang uranium ore field, China. Journal of Radioanalytical and Nuclear Chemistry, 2004, 262(3):673-678. [7] Chen Y W, Bi X W, Hu R Z, et al. Element geochemistry, mineralogy, geochronology and zircon Hf isotope of the Luxi and Xiazhuang granites in Guangdong province, China: Implications for U mineralization, Lithos, 2012, 150, 119-134. [8] Cuney M, Barbey P. Uranium, rare metals, and granulite-facies metamorphism, Earth Science Frontiers, 2014, 5, 729-745. [9] Chen H, Deng J Z, Lv Q T, et al., Three-dimensional inversion of gravity and magnetic data at Jiujiang-Ruichang district and metallogenic indication: Chinese Journal of Geophysics, 2015, 58(12): 4478–4489 [10] Deng J Z, Chen H, Yin C C, et al. Three-dimensional electrical structures and significance for mineral exploration in the Jiujiang-Ruichang District: Chinese Journal of Geophysics, 2015, 58(12): 4465–4477

Speaker: Prof. Juzhi Deng (East China University of Technology)

96 Alternative Database for Domestic LOF Nuclear Materials and Fuel

INTRODUCTION The information of nuclear materials, only location outside facilities (LOF) in Thailand, total 93 facilities, was created as database in 2016 via Microsoft Access 2010. The data input was compiled from Office of Atoms for Peace (OAP) licensing information of nuclear materials. The nuclear material query template, both Thai and English, was also setup to survey for more material details. This necessary information was supposed to support law enforcement or regulatory investigations. The multimedia CourseLab demonstration module for the attractive descriptions, to complete OAP nuclear material license forms, was created for more understanding of the end users who have to fill that query template [1]. In 2017, the nuclear forensics database was created simply using Microsoft Access-2010, to be the prototype for developing the National Nuclear Forensics Library (NNFL). NNFL is the tool to support the National Nuclear Forensics Laboratory, which was established in 2013 under the Project No. 30, “Network of Excellence for Nuclear Forensics in South East Asia Region (2013-2014)”, assisted by EU CBRN CoE [2-3]. Additional databases were developed via Microsoft Access-2010, as 1) Additional nuclear forensics information, including LOF database of year 2016 [1]; and 2) OAP Nuclear Forensics Laboratory Inventory [4]. The Library data were summarized for some domain expertise, i.e. fresh fuel and irradiate fuel in nuclear fuel cycle stage, sealed source, and unsealed source, following NNFL Master Index [5], as well as their Microsoft Word-2010 templates. The algorithms for comparative analysis are on-going developed for interpretation between the information of the seized materials and of those existed in NNFL, to identify and report, for nuclear forensics conclusions of crime investigation in the events of nuclear security. METHODOLOGY To implement nuclear forensics investigation, 3 step procedures are required [6]. 1) Collection, packaging, and transport of seized nuclear/radioactive materials from terrorism or smuggling detection in nuclear security event. 2) Laboratory analysis for cataloguing characteristics and signatures of these materials 3) Data interpretation and analysis via nuclear forensics database and comparative algorithms in NNFL To support the mission plan of OAP nuclear forensics laboratory, this work was performed to develop NNFL as the following tasks [7]. 1) Data collection relating to OAP conventional radioactive and nuclear material database of licensing systems 2) Developing architecture as templates and databases cataloguing characteristics and signatures of materials holdings under regulatory control 3) Storage functions using Microsoft Access 2010 software 4) Algorithm setup for comparative analysis WORK PERFORMED The architecture of this nuclear forensics database prototype was designed and was constructed preliminary as 3 main Microsoft Access 2010 databases. The comparative analysis is also planned to be developed for data interpretation and analysis to complete NNFL systems. All performed work is briefly explained as the following. 1) Nuclear and radioactive materials information The nuclear and radioactive materials information was collected based on OAP conventional radioactive and nuclear material database of licensing systems. This information was sorted related to Material Master Index of IAEA NNFL-notional structure [5]. Because of only one nuclear facility, 2 MW research reactor, in Thailand, the domain expertise, fresh and spent/irradiated nuclear fuel, was recorded together as nuclear fuel element. Other domain expertises of nuclear or radioactive materials are sealed and unsealed sources, which can be found in hospitals, industrial plants, and research laboratories. The templates of nuclear fuel element, sealed and unsealed sources were created via Microsoft Word 2010 and Access 2010 [7] and were attached in this nuclear and radioactive materials database. 2) Additional nuclear forensics information, including LOF database (2016-2017) [1, 7] Other nuclear forensics information which is planned to collect, except LOF database (2016-2017), are concerning articles, IAEA documents, ISO, legislative work, nuclear forensics analytical summary reports, and templates. 3) OAP Nuclear Forensics Laboratory Inventory [4] The inventory database of Nuclear Forensics Laboratory is planned to be complied including the following information. a. General: List of buildings, floors, and rooms b. Analytical equipment information: List of analytical instruments/equipment & parameters, i.e. identification data, physical data, hazardous materials, radiological data, etc. c. Technical support information: List of technological systems, inventory materials, laboratory materials, radionuclides, etc. 4) Comparative algorithm Comparative analysis plan is setup to compare the obtained results which those in existing in NNFL [8-10], as the following procedures. a. Upload nuclear forensics analytical results, sample information and all available signatures, in the library system b. Interpretation via the algorithm for searching and findings: Searching: Data comparison - Choose only some signatures which are relevant to this case. - Flexible program and use only relevant signatures for searching Findings: Agreement among samples - Based on numerical data and simple words - Requested and identified samples DISCUSSION AND CONCLUSIONS The progress of this work is summarized as the following: 1) The architecture of the domestic forensic databases is setup and organized using Microsoft Access 2010 and Word 2010; 2) The algorithm setup for comparative analysis is on-going processed. 3) The collection of data/information of fresh/spent nuclear fuel, sealed sources and unsealed sources, will be performed in the long term project, for the whole country; 4) Accessibility and website link to another concerning domestic organizations may be performed after the establishment of national framework of nuclear forensics. Present Availability: 1) It takes time to collect all data/information following nuclear forensics database from the whole country, Thailand. 2) The methods for determination of signatures are in research and development for the standard method to support the determination of nuclear materials and radioactive materials by using Inductively Coupled Plasma Spectrometry (ICP-MS), Scanning Electron Microscopy with Energy Dispersive (SEM/EDX) and Gamma Spectrometry, in OAP nuclear forensics laboratory [11]. 3) There are only a few domestic radiological incident and criminal cases, so there are not a lot of seized samples for confirming trials in comparative analysis. The simulated scenarios are planned to be created for test runs, as well as the examples of analytical results. 4) However, the flexible program for searching and finding is planned to be developed, to complete NNFL for protection against nuclear terrorism in the future. ACKNOWLEDGEMENT The author would like to thank for all sources of technical information, mostly via internet search, and the cooperation from all concerned OAP personnel for the author’s applications to URAM 2018, IAEA. The advices and cooperation from URAM 2018 staff are also appreciated.

Speaker: Ms Jarunee Kraikaew (Office of Atoms for Peace)

97 An overview of geology and occurrence of unconventional uranium resource: potential recoveries from Precambrian basement and Cretaceous sedimentary rocks of Nigeria

INTRODUCTION Uranium occurs in Nigeria as conventional and unconventional resource in both Precambrian Basement and Cretaceous Sedimentary rocks. The history of exploration for uranium resources Nigeria started in North-Eastern Nigeria, by three major government Organizations. The Geological Survey of Nigeria (Now Nigerian Geological Survey Agency) in 1973, Nigerian Mining Corporation and Nigerian Uranium Mining Company, (NUMCO) from 1979, 1980, 1981, which was winded up in 2001. The areas discovered for Conventional Uranium deposits in Precambrian basement rocks in Northeastern Nigeria are Mika, (132 tU) at 0.63% U at 130m cut off of 0.03% U, Gumchi with (100 tU) at 0.9 % up to 200 m at cut off of 0.03% U, Gubrunde (60 tU) at 0.7% U and Cretaceous Bima Sandstone hosted Sedimentary rocks of Mayo lope and Zona areas, (130 tU) [9]. This paper is aim at evaluating the Uranium potential in Basement Complex of Central Nigeria as well as in the Sedimentary Phosphate rock, of illlumeden (Sokoto) basin North West Nigeria. This will also discuss an overview of Geology, and Occurrence of prospective Unconventional Uranium resource from intrusive Pegmatites North-central basement complex and Cretaceous (Maastrichtian-Paleocene), Sedimentary Phosphate rock, of North-West Nigeria, involving the integration of Geology, Geochemistry, recently acquired High resolution Airborne Radiometric, Magnetic and processing of remotely sensed Landsat 8 data set to delineate areas of high potential. The prospect of the Sedimentary phosphate rocks is located about 500km, Northwest of Abuja the capital of Nigeria. This deposits has been reported and studied by several authors [4, 8, 10, and 11]. The phosphate rocks occur in Paleocene Dange formation, Mastrichian Dukamanje, Taloka and Wurno Formation in Sokoto Illumeden basin. The Federal Government of Nigeria in 2016 through the Nigerian Geological Survey Agency as part of policy thrust to diversify its economy through Solid mineral sector and bridge the power supply need of the country commenced the Assessment of Uranium and Rare Earth elements (REE) and the project is ongoing for unconventional source of Uranium from Phosphate rock. The exploration has delineated about thirteen prospective areas [8,].The phosphate rock occur as irregular, cylindrical, sub rounded, elongate, hard, cream reddish concretions nodules interbedded with shales, clays, Siltstone and Gypsiferrous shale. The phosphate rocks resulted from ocean upwelling and high organic productivity during Cretaceous to Eocene. The Sokoto phosphate is linked to Tethys sea incursion during the Paleocene, that extend from Libya, Chad, Niger Republic and Sudan, [15]. METHODS AND RESULTS In the Sedimentary basin Gamma ray spectrometric measurements of radio-elements and lithologic logging was carried out with a portable hand-held RS-320 spectrometer along exposed sections on two out of the thirteen (13) prospective areas. Chemical analysis of Phosphate samples from Paleocene Dange formation at CETEM Laboratory indicated average Uranium concentration of 73.5U (ppm) and P2O5 34.5(ppm), Uranium radioactivity count gave 16.25U (ppm) on lateritic ironstone (Tertiary Gwandu formation), and Thorium was 20.2(ppm) to 30(ppm) in the Grey Shales (Paleocene Dange formation).The lith-spectrometric log showed increased in Uranium content in the Phosphatic Shale downward which signifies high potential with depth. The presence of pyrite nodule at the basal unit marked a redox condition for Uranium concentration towards the basal Maastrichtian Wurno formation. The phosphates rock in the basin contains uranium and further exploration for the un-conventional uranium resources is ongoing. Also within the Basement Complex of Nigeria, the identified pegmatite zone has enormous potential for Unconventional Uranium and Thorium resource. The Pegmatite zone is Apaku located about 150km south east of Abuja, the capital of Nigeria. The Ministry of Solid Minerals Development, in 1998, evaluated Pegmatites veins for their technology metal potentials, including, Tantalite (Ta), Columbite (Nb), Lithium (Li). Beryllium (Be) and Tin (Sn). This exploration work has led to the discovery of fourteen pegmatite blocks as prospective sources of unconventional uranium [6]. The Pegmatite area is quite extensive, covering an area of approximately 225km2. The Pegmatites ranges in size from 100m to 2km in length and 100 to 500m width. They are being massively worked by more than 500 different artisanal small scale miners, exploiting tantalite, Niobium, Tin, Lithium, Columbite, Beryl and REE. Several workers have shown that the Pegmatites are associated with the Pan-African orogeny and reactivation tectonic activity .The Pegmatite zone is part of a well-defined ENE-WSW trending zone of 400km stretched extending from Jos-Wamba-Jemma Central Nigeria extending to Ijero- Ibadan South-western Nigeria [1 6, 10]. The Apaku zone that has Uranium potential is 1.4 by 0.7 km (Length 1.4km X Breath 700m) it is one of viable Mineralized Pegmatite prospect. The work done in theses area by 6] involved interpretation of panchromatic aerial photographs as base map to delineate structures and lithologies, random regional Geological, Geochemical sampling of whole rock, weathered, fresh pegmatites and concentrate on scale of 1:50,000. Chemical analysis for Tantalum oxide (TaO), Niobium Oxide (NbO), Uranium Oxide (U3O8), Thorium Oxide (ThO), and other Major, Minor elements concentrations using Inductively Couple Plasma Mass Spectrometry (ICP-MS) and X-ray fluorescence (XRF). The results of chemical analysis indicate elevated values of Niobium oxide(NbO5) concentration of 14%,Tantaliteoxide(Ta2O),40%,ThoriumOxide(ThO)900(ppm),Uranium(U3O8)1900U(ppm),Tin(Sn)1500ppm. REMOTE SENSING AND GEOPHYSICAL DATA INTEGRATION The prospecting for uranium has been challenging in Nigeria, therefore remote sensing technology can bridge the gap possibly to discover new potential deposits and enhanced wider coverage of previous areas exploited by [6,9]. Remote sensing technology has been used to directly or indirectly discriminate Uranium bearing rocks and mapping hydrothermal alteration zone [13, 16]. The present study involved the integration of geochemical result, processing and interpretation of high resolution recently 2010 acquired airborne- geophysical data set. Landsat 8 Operational Land Imager (OLI), an enhanced resolution Multispectral image (band) as against the panchromatic aerial photographs used earlier in the study areas. Digital Image processing, (principal component analysis, (PCA, band ratio, (band 5/4 for clay mineral, 5/7 for hydroxyls and 3/1 for iron oxide and Color composite. The ternary image and composite as RGB based on distribution of the three radioelements, Uranium, Thorium and Potassium (U-Th-K) which reflect composition of the lithologies in the area. U /Th Ratios was used to track the possible host rock of the identified Uranium Anomaly, since Uranium is highly and thorium least mobile. The total magnetic intensity (TMI (1VD) grey scale was used to extract suspected shallow and deep-seated lineaments as possible Subsurface structural traps for uranium accumulation. Ground follow- up or field check was done to confirm the alteration zones. The minerals identified in the area are Kaolinitic clay (kaolinite) and Iron minerals are limonite and hematite, with disseminated pyrite in brecciated quartz. DISCUSSION Geologically, the Apaku area is underlain by Precambrian Migmatites, occurring with weathered low-lying Muscovite Schist/Phylites, and Metapellites, quartz veins, Granite-gneiss, and Medium to Coarse grained Granite within the North-eastern segment. Pegmatite veins occur as flat-lying out crops intruding the Precambrian Migmatite, Granite gneiss, Schist, Pan-Africa granite and Younger granites. The Uranium mineralization is associated with Granitic rocks occurring in the area, this is as a result of Pan-African orogeny, contact metamorphism and thermal effects. Uranium anomaly and Uranium-thorium ratios maps has confirmed the source of the Uranium from the Granites and Gneiss surrounding the study area. A NNE-SSW, NE-SW structural trend extracted from Magnetic TMI (1Vd) data indicate shallow and deep-seated lineaments as possible subsurface structural traps for uranium accumulation. The hydrothermal fluids must have been remobilized, and Uranium concentrated in presence of oxidizing fluids and reducing minerals pyrites [10, 12]. The plagioclase feldspars of the fresh granitic rocks has been hydrothermally altered, to Kaolinite, which form kaolinitic clays. The ferromagnesian mineral biotite’s, hornblende, amphiboles, were altered into to limonite and hematite, as observed at the base of grantic rock in the areas. This is enhanced by chemical weathering typical of tropical climatic condition with little to moderate rainfall, surface and groundwater in the presence of oxygen. The potential for Uranium recovery in Nigeria is very high, with average concentration Uranium in Cretaceous Phosphate Sedimentary rock, and Pegmatites veins. The occurrence of Uranium within the phosphate rock is supported by recent radiometric Airborne Survey in Cretaceous Sandstone (Continental terminae) in southern part of Illume den basin in Niger republic [5]. The Sokoto Basin is part of Southward continuation of Illumiden Basin, where Uranium in hosted in Agadez Sandstone of the Niger Republic. The Sediments in the basins is Surrounded by Precambrian crystalline and volcanic rocks, this are potential host of Uranium mineralization [10]. This uranium is probably source from Carbonaceous to Jurassic Peralkaline Younger Granitic rocks as seen occurring in Paleozoic ring complex of Niger republic, which is Petrological and geochemically associated with Mesozoic (Jurassic) ring complex of Nigeria [2]. The areas with high anomaly and geochemical results from the Cretaceous Sedimentary Phosphate rock and Pegmatites of the present study has shown a NNE-SSW,NE-SW structural trend similar to Niger republic with two major Regional tectonic structure in Alit-in-Azoual fault trending N-S and Madeoula fault trending NNE-SSW hosting most of the discovered uranium deposits [5]. CONCLUSION In conclusion, the discovery of High concentration of uranium in Apaku one of the Precambrian Pegmatites out of fourteen identified pegmatite blocks and Two out of thirteen prospect of Cretaceous Phosphate rocks in Sokoto Basin is a good development for Uranium investors and prospectors in Nigeria. When these areas are adequately exploited and new remote sensing prospecting techniques is adopted in Nigeria recovery of Unconventional resource is high. Ground follow- up or field check has confirmed, altered Granitic rocks in the Precambrian Basement area and Cretaceous Phosphate rocks correlate with areas of high uranium as shown by U/thorium ratios, Conductivity, Subsurface lineament, Ternary, and Geochemical results. The well-established deposits of uranium in the Niger Republic section of the Illumeden Basin which is contiguous with the Sedimentary Phosphate rock of Nigeria makes the potential of similar occurrence very high. Further work including feasibility studies is recommended in these areas that have good potentials for un-conventional uranium resource. References [1]. Abimbola A.F, Arisekola T.M, and Ogedengbe O. (2007) Mineralogical and Geochemical characteristics of Pegmatite bodies of Awo-Ede, South western Nigeria. Procedings of the Ninth Bienial SGA Meeting, Dublin 2007 [2]. Bowden P, Benerad J.N, Kinnard J.A, Whitely J.E, Abba SI (1981).Uranium in Niger-Nigeria Younger Granite Province : Mineralogical Magazine vol 44 379-389pp. [3]. Garba I. (2003). Geochemical discrimination of newly discovered rare metal pegmatite bearing and barren pegmatites in Pan African 600+ 150Ma basement of northern Nigeria. Appl Earth Sci Trans inst. Min and Metall 13 :287-292 [4]. Geological Survey of Nigeria (GSN, 1986). Phosphate Exploration in Sokoto Basin (Unpublished report) [5]. Jacobson RRE, Web. J S(1946). The Pegmatites of Central Nigeria. Géol. Surv Nig Bull 17 :61pp [6]. Madou Gagi Grema, and Aksar Abdelkarim (2016) ;(RAF 2011, Abuja Niger National Talk) Procedings of RAF 2011,18th November 2016. [6]. Ministry of Solid Minerals Development (1998) : Stage 2 and 3 Batch 1. Speciality métal Exploration programme in Udegi (Ogapato) area. Final report vol 4 Nigerian Mineral Appraisal and Monétisation Programme (NIMAMOP). [7]. Nigerian Géological Survey Agency(2010) : Airborne Geophysical Survey of Nigeria [8]. Nigerian Géological Survey Agency(2016) : Assesment of Uranium and Rare Elements from Sokoto area, North-west Nigeria (unpublished report) [9]. Nigerian Uranium Mining Company (NUMCO, 1980. Annual Report [10]. Obaje Nuhu George(2009). Geology and Mineral resource of Nigeria : Lecture notes in Earth sciences, pp152 [11]. Okosun E.A (1989b). The Preliminary petrological and geochemical charactirization of phosphorite [12]. Rahaman MA(1988). Recent Avances in the study of the basement complex of Nigeria. In : Geological Surv of Nigeria (ed) Precambrian Geol Nigeria, pp 41 [13]. Ramadan, T.M, Ibrahim T.M, Saidu A.D and Baiumi M (2013). Application of remote sensing in Exploration for Uranium Mineralization in Gabal Elsayal Area, South eastern Désert of Egypt. The Egyptian Journal of remote sensing and Space science 16, 199-210. [15]. Reyment R.A (1980) Biogeography of Saharan Cretaceous and Paleocence epicontinental transgression Cret res 1 299-327 [16]. Shalaby M.H, Bishta AZ. Roz ME and El zalakay M.A Intégration of geological and remote sensing for discovery of Uranium mineralization in granitic pluton Eastern Désert Egypt. [17]. Wright J (1970) Controls of mineralization in the older and younger tin fields of Nigeria. Econ Geol 65 :943-951. ACKNOWLEDMENT The Authors are grateful to the Staff and Management of Nigerian Geological Survey Agency, Ministry of Mines and Steel Development, Global Mineral Limited and other Stakeholders for their contribution to the succes of this work and publication.

Speaker: Mr SAMSON STANLEY MASPALMA (Nigerian Geological Survey Agency,Abuja,No 31 Shettima Ali Munguno Crescent Utako,P.M.B,616 Garki Abuja)

98 Application of UNFC to uranium resources discovered in Algeria

I. INTRODUCTION. The national mining sector is undergoing deep changes and fast evolution towards market economy. In this context, and in order to ensure the adequate and rigorous management of uranium resources discovered and evaluated in the Hoggar (southern Algeria), with a view to their development and integration into national economy in its current transition phase, a re-evaluation of these deposits and indices according to internationally accepted criteria, standards and models (NEA / IAEA, UNFC, CRIRSCO) turns out to be an unavoidable event. In this perspective and in order to contribute effectively to the preparation of this new stage, a first attempt to classify discovered and evaluated uranium occurrences in the Hoggar, according to generic specifications of the United Nations Framework Classification for Resources (UNFC) [1], is presented. It is developed with the aim of serving as a basis for the revival of uranium resources exploration and development program throughout the national territory. II. EXPLORATION WORK CARRIED OUT AND MINING DEVELOPMENTS UNDERTAKEN. The first evidence of uranium mineralization found in the Hoggar (Central Sahara, Algeria) was discovered in 1958 in Precambrian basement of Timgaouine-Abankor region during the implementation of the first Hoggar mineral exploration program undertaken by the Mining Research Bureau of Algeria (BRMA) between 1953 to 1960 [2, 3]. These first results were followed by the discovery of uraniferous indices around the circumscribed granite of Aït Oklan - El Bema in Tesnou region in the North of Timgaouine, by the Commissariat à l'Energie Atomique (CEA, France) between 1958 to 1960 [3]. These uranium occurrences identify with intrabatholitic vein-type mineralization, all of which are contained in the eastern branch of the pan-African chain (western Hoggar). In a second step (1969 - 1974), marked by a significant investment effort, the detailed exploration work undertaken by the National Company of Research and Mining (SONAREM) with the assistance of the Romanian partner GEOMIN, have allowed the development of known uranium indices in two economically important uranium deposits of Timgaouine and Abankor and the evaluation of the uraniferous resources of Tinef deposit of [4, 5, 6]. The extension of this exploration work to sedimentary cover of basins on the outskirts of Hoggar (Tassilis) resulted in the discovery of Tahaggart deposit and the indices of Timouzeline and Tamart N Iblis, uranium occurrences collected respectively in the Precambrian basement - Paleozoic cover interface, and in continental sandstone horizons of lower Devonian of the Tin Séririne sedimentary basin (Southeast of Hoggar) [7, 8, 9]. At the same time, with the continuation of general exploration of uranium in the Hoggar, development studies of Timgaouine and Abankor deposits, launched in 1976, were initiated in successive phases with the assistance of several specialized companies, for determine the technical, social and economic conditions for the exploitation of these two deposits. The main objectives of this first phase focused on: - The expertise of geological and hydro geological work undertaken by SONAREM; - The collection of ore samples for treatment trials; - The identification of the main development variants. This expertise, preceded by the work of the GTZ group (FRG), was entrusted to six (06) operators: DAVY Mc KEE - COTECNA (USA - Switzerland), KAISER (FRG), KILBORN (CANADA), TRACTIONAL - MINING UNION ( BELGIUM), STEC (FRENCH CONSORTIUM) and CHARTER - CKB (ENGLAND) [10, 11, 12, 13]. At the end of this first phase, completed at the end of 1977, SONAREM awarded in December 1978 two groups of companies (among the six of the first phase) the second phase. This one had for objectives: - The technical-economic optimization study; - Preparation of preliminary project files; The two groups selected for this second phase: - The association DAVY Mc KEE (USA), TRACTIONNEL (Belgium), UNION MINIERE (Belgium) and COTECNA (SWITZERLAND); - The FRENCH CONSORTIUM composed of STEC, SOGEREM, MINATOME and SOFREMINES. At the end of this second phase, the results obtained are presented as follows [14, 15, 16]: - Location: 20km apart from each other, the two deposits of Timgaouine and Abankor are 180km southwest of Tamanrasset; - Geological reserves: 21,000 tons of uranium metal with an average grade in place of 0.18%. - Recoverable reserves: approximately 14,000 tons of metal (ex-works); - Production capacity: with the use of an alkaline treatment process, 600 000 tons per year in all round products corresponding to 900 T / yr of uranium metal. - Life expectancy: 15 years on average based on recoverable reserves. With a Distance of 35km from Timgaouine, Tinef deposit is located in the same geological context as Timgaouine and has the same types of uranium mineralization [4, 10]. Work carried out on an area of 21km2 consisted of recognition soundings spaced 2 to 3km apart, narrowed to 1km (on the ground anomaly) and destructive soundings to 200x200m, tightened in the mineralized zones at 50x60 m and 25x50 m for the estimated category C2 reserves estimated at 374 000 t of ore at 0.1% U, ie 374 tU metal [4, 5]. In the North of this potential zone and situated in the same geological context, the El Bema-Aït Oklan-Tidjelamine, indices in the Tesnou region, have not been subject of detailed exploration work likely to give a preliminary assessment. Exploration work in the sedimentary basin of Tin Séririne (south-east of Hoggar) initiated by an airborne geophysical survey (spectrometry and magnetism) allowed, after verification carried out on the ground by soundings and ground survey works [7, 8, 9, 17]: - Confirm the existence of the small Tahaggart deposit whose metal tonnage is estimated at 1677 tons of uranium with a uranium content of 0.217%. - To individualize, in the area of Tamart-N-Iblis and Timouzeline, mineralized levels in the sandstones of the Lower Devonian. These indices thus suggest a great potentiality of this stratigraphic level. III. APPLICATION OF UNFC TO URANIUM RESOURCES DISCOVERED AND EVALUATED IN ALGERIA. The discovery and mining development of Timgaouine, Abankor and Tinef deposits in the Precambrian basement of the Hoggar and the Tahaggart deposit in the Tin Séririne sedimentary basin have gone through three stages: - Discovery of the Timgaouine, Abankor, Tinef and Tahaggart indices by general exploration work; - Discovery of the Timgaouine, Abankor, Tinef and Tahaggart deposits through detailed exploration work; - Technical-economic evaluation, mineral processing tests and mining works for the Timgaouine and Abankor deposits; - Evaluation of the uranium resources of the Tinef and Tahaggart deposit. These detailed investigations provided access to a good knowledge of these deposits to undertake the mining process. On the basis of this information, we have determined categories E, F and G as well as the class and subclass of Timgaouine, Abankor, Tinef and Tahaggart Projects. - E2: Probable economic viability of extraction and sale in the foreseeable future. - F2.2: Need for further evaluation of extraction feasibility through a specified development project or mining operation. - G1, 2, 3: Quantities associated with a known deposit that can be estimated with a high level of confidence. These four projects are classified in E2 F2.2 G1,2,3 Categories, POTENTIALLY COMMERCIAL PROJECT Class and DEVELOPMENT ON HOLD Sub-Class. After the discovery of the Aït Oklan - El Bema - Tidjelamine indices in the Tesnou region, north of Timgaouine, and the Timouzeline and Tamart-N-Iblis indices in the Tin Séririne sedimentary basin in the south of the Tahaggart region, only general exploration work was carried out in these two zones. On the basis of all the information collected, we have determined categories E, F and G as well as the class and subclass of the Tesnou and Tin Séririne projects. - E3: The assessment is at a very early stage to determine economic viability. - F3: Need to gather more data in order to confirm the existence of a deposit whose shape, quality and quantity make it possible to evaluate extraction feasibility. - G4: Estimated quantities associated with a potential deposit, calculated in the first analysis on the basis of indirect evidence. These two projects are classified in E3 F3 G4 Categories and EXPLORATION PROJECT Class. III. CONCLUSION. The notification of uranium resources discovered and evaluated in Hoggar (southern Algeria) according to the generic specifications of the United Nations Framework Classification for Resources (UNFC) provides access to a harmonization of multitude classification systems used by the various groups involved in different phases of exploration and development of these resources. Based on the Project concept, this uniform international system that meets the criteria of the market economy can be a relevant tool for reviving the revaluation and development program of uranium resources of the national mining sector. REFERENCES [1] UNFC-2009. United Nations Framework Classification for Fossil Energy and Mineral Reserves and Resources 2009, incorporating Specifications for its Application. ECE - Energy Series N°42, UNITED NATIONS, New York and Geneva, 57p., 2013. http://www.unece.org/energy/se/reserves.html. [2] BUREAU DE RECHERCHE MINIERE D'ALGERIE (BRMA), 1960. Carte géologique de l’Algérie 1/500 000e. Edition CNRS (BRMA, 1960). [3] BUREAU DE RECHERCHE GEOLOGIQUES ET MINIERES (BRGM), 1965. Les minéralisations du Hoggar. Publ. par l’Organisme Technique de Mise en Valeur des Richesses du Sous-sol Saharien. BRGM, 49p (1965). [4] SOCIETE NATIONALE DE RECHERCHE ET EXPLOITATION MINIERE (SONAREM), 1973 : Travaux de prospection et d’exploration géologiques exécutés dans la zone de Timgaouine-Abankor-Tinef pendant les campagnes 1971-1972 (Hoggar). 124p. (1973). [5] SOCIETE NATIONALE DE RECHERCHE ET EXPLOITATION MINIERE (SONAREM), 1974 : Rapport de l’expertise sur les gisements d’Uranium du Hoggar. TomeI, II et III. (1974). [6] LAIFA E., 1977. Les gisements uranifères (Timgaouine et Abankor) du Hoggar (Algérie) et l’altération des épontes de leurs gîtes. Thèse Maîtrise Sc. Appl. Génie Minéral, Univ. Montréal, Montréal juil. 1977. 1 vol., 254 p., 51 fig., 4 tabl., 22 pl. photogr. h.-t. [7] SOCIETE NATIONALE DE RECHERCHE ET EXPLOITATION MINIERE (SONAREM), 1974 : Rapport des travaux géologiques exécutés pendant les campagnes 1972-1974 sur le gisement de Tahaggart (Hoggar). Missions 1972-1974, 87 p. [8] SOCIETE NATIONALE DE RECHERCHE ET EXPLOITATION MINIERE (SONAREM), 1975 : Rapport des recherches géologiques exécutées pendant la campagne 1973-1974 dans la région de Tamart-N-Iblis. Mission 1973 - 1974, 45 p. [9] SOCIETE NATIONALE DE RECHERCHE ET EXPLOITATION MINIERE (SONAREM), 1975 : Rapport géologique sur les travaux exécutés pendant la saison 1974-1975 à Tamart-N-Iblis et Timouzeline. Mission 1974-1975, 28 p. [10] OFFICE ALLEMAND DE LA COOPERATION TECHNIQUE (GTZ) SARL. 1978: Etude technico-économique sur les gisements uranifères dans le Hoggar - Algérie, 1978. Rapport final pour SONAREM. (1978). [11] TRACTIONEL – UNION MINIERE, 1978: Mise en valeur des gisements d’uranium de Timgaouine et Abankor. Rapport final phase 1, TOME I et II. (1978). [12] CHARTER – CJB, 1978 : Etude de mise en valeur des gisements d’uranium de Timgaouine et Abankor. Rapport phase 1, 5 volumes. Charter/CJB Londres. (1978). [13] KILBORN, 1978 : Etude de mise en valeur des gisements de Timgaouine et Abankor (Hoggar). Rapport phase 1, 4 volumes. Kilborn (Canada). (1978). [14] DAVY McKEE-TRACTIONEL - UNION MINIERE – COTECNA, 1981: Mise en valeur des gisements d'Uranium de TIMGAOUINE et ABANKOR (HOGGAR). Rapport phase 2, établi pour SONAREM. 1981, Vol. I à VI. (1981). [15] CONSORTIUM FRANÇAIS STEC-SOGEREM-MINATOME- SOFREMINES, 1981 : Etude de mise en valeur des gisements d'Uranium de Timgaouine et Abankor. Rapport de fin d'étude des travaux géologiques complémentaires (1979). SONAREM - CONSORTIUM FRANÇAIS (2 volumes) 1981. (1981). [16] CONSORTIUM FRANÇAIS STEC-SOGEREM-MINATOME- SOFREMINES, 1981: Mise en valeur des gisements d'Uranium du Hoggar. Consortium Français. Rapport phase 2. Décembre 1981. Vol. I à VI. (1981). [17] MOKADDEM M., 1980. Le bassin de Tin Séririne et ses minéralisations uranifères (Hoggar, Algérie). Thèse Doct. 3ème cycle, Géol. struct. et appl., Univ. Paris Orsay. Paris 20 juin 1980, 1 vol., 133 p., photogr., fig., diagr. et tabl.

Speakers: Mr Allaoua KHALDI (Nuclear Research Center of Draria - Algiers - Algeria.), Mr Sid Ahmed MOKHTAR (Nuclear Research Center of Draria - Algiers - Algeria.)

99 ASSESSMENT OF THORIUM AND ASSOCIATED RESOURCES: PHILIPPINE INITIATIVES

The exploration for thorium in the Philippines has always been regarded as secondary to uranium and then tied up with the exploration of rare earth elements. With 70% of the country having been covered by reconnaissance geochemical surveys, the potential areas for thorium are the Ombo and Erawan coastal areas containing radioactive heavy minerals situated in north-western Palawan Island. Mineralogical examinations of these heavy minerals from panned concentrates of beach and stream samples showed major medium to coarse-grained euhedral brown-reddish allanite (74.0 – 81.8%) and minor fine-grained subhedral yellow monazite (2.4 – 11.6%). Field gamma-ray spectrometric measurements in Ombo and Erawan showed thorium varying from 2.2 – 770.5 ppm and 8.6 – 388.5 ppm, respectively. Thorium values by gammametric analysis in panned heavy beach and heavy stream sediment samples showed values ranging from 0.93 – 1.28% and 0.76 – 1.15%, respectively. X-ray fluorescence analyses for rare earth elements in both the panned heavy mineral stream and beach samples gave ranges of values of lanthanum (3.00 – 12.24%), cerium (5.00 – 21.07%), praseodymium (.04 – 1.71%), neodymium (2.00 – 6.51%) and yttrium (0.03 – 0.21%).

Speaker: Mr ROLANDO REYES (PHILIPPINE NUCLEAR RESEARCH INSTITUTE)

100 Benchmarking D2EHPA-TOPO Solvent Extraction Process for the Recovery of Uranium from Philippines Phosphoric Acid

INTRODUCTION Phosphates are the raw material for the production of phosphatic fertilizers. However, these minerals also contain naturally occurring radionuclides such as uranium, thorium and rare earth elements (REE), which ends up as heavy metal contaminants in fertilizers [1-3]. Philippines, being an agricultural country, has 9% of its the GDP and 27% of employment coming from agriculture [4]. To sustain the agricultural demands, fertilizers are necessary to keep the land fertile and productive. Recovery of uranium during phosphate processing plays an important role in mitigating the risk of environmental contamination by production of cleaner fertilizers, paving way to maximizing a mineral resource and opportunity to utilizing recovered strategic elements that are otherwise lost. Several methods are employed to recover uranium from phosphates (UxP), particularly from phosphoric acid. Among the most adapted method is the use of the synergistic mixture of D2EHPA-TOPO due to its selectivity and stability in different phosphoric acid systems [1-2]. The Philippines imports phosphate rocks from different countries, thus, the D2EHPA-TOPO process was benched marked as part of validating the process technologies that may be applied into the Philippine scenario. The study will also acquire technical data of the factors affecting the recovery rate and economics of the process. Recovery of uranium and other critical element from phosphate processing streams is a pioneering work in the country. This work aims to build core competency in the radioactive material/mineral recovery leading to the sustainable production of uranium in the country. METHOD Samples of phosphate rocks (Morocco rock, Togo rock, Egypt rock and Zin (Israel) rock), phosphoric acid (27%, 33%, 43% P2O5 content), phosphogypsum and fertilizer products (Urea, MOP (muriate of potash), NP (16-20-0 and 18-46-0) and NPK (14-14-14 and 16-16-8) fertilizer) were collected from the partner company, Philippine Phosphate Fertilizer Corporation (PHILPHOS) and were analyzed using AAS and Fluorimetry. Samples were also sent to Florida Industrial and Phosphate Research Institute for ICP-MS analysis of thorium and REE content. Solvent extraction of uranium from phosphoric acid was performed by contacting the phosphoric acid with a mixture of 0.5 M D2EHPA and 0.125 M TOPO dissolved in kerosene. The D2EHPA-TOPO Process involves two cycles of uranium extraction and stripping process wherein uranium is extracted and back-extracted in a multi-stage equilibrium manner concentrating the uranium before precipitation as yellowcake. The process parameters that affect the extraction and stripping efficiencies such as phosphoric acid concentration, optical density (acid clarity), oxidation-reduction potential (ORP), temperature and phase ratio were varied. Uranium concentration throughout the process was monitored to obtain the extraction and stripping isotherm. RESULTS AND DISCUSSION Detailed characterization of phosphate processing stream samples revealed that the source phosphate rocks contained uranium ranging from 66-145ppm with an average of 105 ppm U, 1-20 ppm Thorium and 108-1085 ppm total REE [3]. Uranium in the phosphoric acid varied from 66-109 ppm while the phosphogypsum contained around 2 ppm uranium indicating that majority of the uranium from phosphate rock distributes into the phosphoric acid phase. Thorium and REE, however, were found to redistribute into the phosphogypsum (1.25 ppm Th, 86-173 ppm REE). Analysis of nitrogen and potash fertilizer products has a combined U, Th and REE content of <1 ppm. Interestingly, it was notable that with increasing phosphate content in NP and NPK fertilizers, there was also an increasing trend in uranium concentration reaching up to 228 ppm [3], which is ~20 times the global uranium content in soils (0.3 - 11 ppm) [4]. Results of D2EHPA-TOPO process can be summarized into two parts: the uranium extraction and the stripping process. In both processes, extraction and stripping efficiencies were found to be inversely proportional to optical density. In the extraction process, increasing the phosphoric acid and temperature of the reaction would lower the extraction efficiency. Effect of temperature on the extraction of uranium indicates that the reaction is exothermic in nature. Increasing ORP also increases the extraction efficiency. On the other hand, uranium stripping efficiency increases with increasing phosphoric acid content and temperature of reaction. Uranium stripping was determined to be endothermic in nature. Lowering the ORP of the solution increases stripping efficiency. The extraction isotherm obtained from the equilibrium data of the uranium distribution in the organic and aqueous phase indicated that a recovery rate of 93% can be achieved in 3-ideal stages operating at a 4:1 aqueous to organic phase volume ratio. The experiment gave vital information on optimum acid concentration, temperature and other conditions needed to achieve an overall high recovery rate. The output of this research could serve as baseline data towards further development of UxP technology as well as a way to push for a positive policy decision in this regard by the National authority. REFERENCE [1] KHLEIFIA, N., HANNACHI, A., ABBES, N. Studies of uranium recovery from Tunisian wet process phosphoric acid. International Journal of Innovation and Applied Studies 3(4) (2013) 1066-71. [2] BELTRAMI, D., COTE, G., MOKHTARI, H., COURTAUD B, MOYER BA, CHAGNES A. Recovery of uranium from wet phosphoric acid by solvent extraction processes. Journal of American Chemical Society 114(24) (2014) 12002-23. [3] PALATTAO, B.L., RAMIREZ, J.D., TABORA, E.U., MARCELO, E.A., VARGAS, E.P., INTOY, S.P., DIWA, R.R., REYES, R.Y. Recovery of uranium from Philippine Wet Phosphoric Acid using D2EHPA-TOPO Solvent Extraction. Philippine Journal of Science 147(2) (2018) 275-284. [4] COUNTRYSTAT PHILIPPINES. Philippine Agriculture in Figures, 2016. Retrieved from http://countrystat.psa.gov.ph/?cont=3 on 6 Feb 2018.

Speaker: Mr Botvinnik Palattao (Philippine Nuclear Research Institute)

101 Biogeochemical Orientation Survey for Surficial Uranium Deposits, Laguna Sirven, Santa Cruz, Argentina

DESCRIPTION In Argentina, mineral ores are abundant but few studies of the chemical analysis of native vegetation growing in such areas have been reported. Uranium related activities begun in the 1950s. The Laguna Sirven project, located in Santa Cruz, Argentina has been identified by remote sensing to contain potential deposits of uranium. A study in Nov. 2014 resulted in the collection of soils and plant species, along with radiometric field data, from sites associated with a possible U-deposit. This study hopes to provide an insight into the potential of using remote sensing for mineral exploration of uranium and other mineral using possible indicator plant species (based on specific components – roots or leaves) and soil profiles. METHODS AND RESULTS Based on remote sensing data a sampling site was selected at Laguna Sirven, Santa Cruz, Argentina. Radar data obtained from the Endeavour Space Shuttle Radar Topography Mission (SRTM) provided a coarse digital elevation model. Various mineral index maps were generated based mostly on SWIR band data. These maps agree with the geology described for this area as a possible uranium deposit. This was used to confirm the sampling site investigated in this study. The region is extremely arid and the plant life of this region is comprised of low level scrub-like species varying in population numbers over the sampling site. Sampling site was selected based on the satellite information. After an initial inspection using the Radiation Solutions RS-230 BGO Super-SPEC handheld gamma ray spectrometer, surface soil (top 5 cm) and soil profiles (to a depth of approx. 90 cm) were collected. Approximately 500 g of soil were placed into labelled plastic bags and sealed. At the locations with the highest radiometric levels there was a scarcity of plants, with only the presence of small shrubs and low level surface grasses and moss-type species. Plant samples were selected where possible to represent the sampling site. Soil material was carefully removed from the roots and all of the plant sample(s) placed in separate paper bags, sealed and labelled. All samples were stored in a large plastic storage bin for transport back to the accommodation at Las Heras. Plant samples were dried (>20 °C) before packing in large plastic sealed bags for transport to the UK. After transportation of all the samples to the University of Surrey, it was deemed necessary to evaluate the analytical procedures, including sample preparation and instrumental analysis for uranium and other trace elements (Th, As, V, Fe, etc), which have been found to be present in acidic volcanic rocks [1], by inductively coupled plasma mass spectrometry (ICP-MS). The techniques most suitable for routine analysis are laser-ablation ICP-MS or traditional solution nebulisation ICP-MS [3]. Furthermore, ICP-MS has the further advantage of determining the isotopic composition and ratio of the sample (234U, 235U, 236U and 238U) [2]. In this research traditional solution nebulisation ICP-MS was used with a collision cell due to the need to determine other trace elements besides uranium and thorium in the samples. This is because it may be possible to obtain further mineralisation information be evaluating the composition of the sample, for other elements ‘associated’ with uranium, namely, Fe, Mn, V, As, Se, Zr, rare earths, etc.) [4] [5]. The preferred digestion method is dry ashing using a subsequent acid dissolution of the ‘ash’ with aqua regia for plants and aqua regia/hydrofluoric acid for soils before elemental analysis. Therefore, all uranium analyses were undertaken using aqua regia digestion of media due to the possible stability of uranyl (V) chloride species [6]. Furthermore, multi-element analysis by ICP-MS uses a set of standards from 1 to 750 µg/l. In order to enhance the accuracy for selected elements, especially U and Th which are found at low levels in digested plant and soil samples (0.05 to 30 µg/l), it was found to be necessary to use an appropriate linear dynamic range of standards. This provided good quality control (QC) calibration data for certified reference material (CRM) analysis with good levels of accuracy (agreement between calculated mean values and the certified reference values) and precision levels of < 10% relative standard deviation. The uranium values for plant samples in this study, based on the radiometric field measurements can be divided into ‘background or low mineralised’ areas and ‘mineralised’. Therefore, the ‘background or low mineralised’ uranium levels ranged over 0.01 to 0.47 mg/kg (dry weight), with a median of 0.05 mg/kg (d.w.). Similarly, the ‘mineralised’ values cover 0.01 to 2.05 mg/kg (d.w.) with a median of 0.32 mg/kg (d.w.). These values are in agreement with the limited number of reliable values available in the literature. Several studies have also reported the uranium concentrations in plants and plant components (roots, stems, leaves) as a function of different soil levels [7]. Uranium levels in plant parts clearly confirm the findings of Singh et al. (2005) with the highest uranium levels in roots > stems~leaves > flowers. The plant component levels do not show any accumulation of uranium as the values are typical of those reported by others as control sites after growth in soil with moderate levels (< 20 mg/kg) [7] [8]. Several studies have reported uranium levels for soils. Kabata-Pendias & Pendias (2000) provided a review of uranium levels in soils for various countries which ranged from 0.79 to 11 mg/kg (dry weight). The data for ‘background or low mineralised’ areas are in good agreement with the natural uranium levels in soils reported, ranging over 0.81 to 1.34 mg/kg (dry weight), with a median of 1.09 mg/kg (d.w.). Similarly, the ‘mineralised’ values cover 1.21 to 741.87 mg/kg (d.w.) with a median of 6.91 mg/kg (d.w.). Interestingly, it also reported thorium levels for soils ranging from 3.4 to 10.5 mg/kg (dry weight). Therefore, the data for ‘mineralised’ areas are in general agreement with these typical thorium values for soils. Similarly, these sites have interesting levels of arsenic and vanadium which are for ‘mineralised’ areas above the range of normal values reported for soils; arsenic <1 to 95 mg/kg (dry weight) with a typical mean of 2.2 mg/kg As (d.w.); and vanadium <7 to 300 mg/kg V (d.w.) with a typical average of 90 mg/kg V (d.w.) [1] DISCUSSION AND CONCLUSION A Pearson correlation analysis of the plant data confirmed the existence of statistically significant correlations between uranium and arsenic (tcal = 7.11 > tcrit = 2.68, p < 0.01) or uranium and vanadium (tcal = 5.97 > tcrit = 2.68, p < 0.01). The same pattern was observed for As and V but not for Th and Fe. The data is in good agreement with published uranium values for soils by Kabata-Pendias & Pendias (2000) and Gavrilescu et al. (2000). Based on the multi-element values it is possible to evaluate what is the possible mineralisation of these sites, namely, carnotite. Radiometric data collected during the field trip is in good agreement with the uranium values for plants and soils at Laguna Sirven. This confirms that the use of gamma radiation measurements for U, Th and K in the field are of use for identifying sampling sites for subsequent U/Th analysis. Moreover, this will aid in the identification of specific plant species for biogeochemical prospecting In summary, this data is in good agreement with the limited published values by Bowen (1979), Dilabio et al. (1980), Kaur et al. (1988), Vargas et al. (1997), Singh et al. (2005) and Favas et al. (2014). Remarkably, the highest uranium levels were found in plant roots, with the U, As and V results confirming that the site around Laguna Sirven is of interest for future uranium and associated elemental research. REFERENCES [1] Kabata-Pendias, A., Pendias, H., 2000, Trace Elements in Soils and Plants, CRC Press, Boca Raton, Florida, pp315. [2] Štrok, M., Smodiš, B, 2013, Soil-to-plant factors for natural radionuclides in grass in the vicinity of a former uranium mine. Nucl. Eng. Design, 261, 279-84. [3] Santos, J.S., Teixeira, L.S.G., de Santos, W.N.L., Lemos, V.A., Godoy, J.M., Ferreira, S.L.C., 2010, Uranium determination using atomic spectrometric techniques: An overview, Analytica Chimica Acta, 674, 143-156. [4] Aubert, D., Probst, A., Stille, P., 2004, Distribution and origin of major and trace elements (particularly REE, U and Th) into labile and residual phases in an acid soil profile (Vosges Mountains, France), Applied Geochemistry, 19, 899-916. [5] Uhrie, J.L., Drever, J.I., Colberg, P.J.S., Nesbitt, C.C., 1995, In situ immobilisation of heavy metals associated with uranium leach mines by bacterial sulphate reduction. Hydrometallurgy, 43, 231-9. [6] Volkovich, V. A., Aleksandrov, D.E., Griffiths, T.R., Vasin, B.D., Khabibullin, T.K., Maltsev, D.S., 2010, On the formation of uranium (V) species in alkali melts, Pure Appl. Chem., 82(8), 1701-1717. [7] Singh, S., Malhotra, R., Bajwa, B.S., 2005, Uranium uptake studies in some plants, Radiation Measurements, 40, 666 – 669. [8] Kaur, A., Singh, S., Virk, H.S., 1988, A study of uranium uptake in plants, Nucl. Tracks Radiat. Meas. 15 (1-4), 795-89.

Speaker: Ms Talia Berg (Hytec Alto Americas)

102 Challenges and Opportunities of Small Uranium Mines in the SMR Development Era

Abstract Many countries, in paticular in african region will still facing energy needs and gaps. They mostly use fuel power plant,and will be obliged to proceed to energy mix approaches in regard to fulfil end users needs. So Small and Medium Modular Nuclear Reactors(SMRs) technologies, using small quantitites of uranium fuel, will be a serious option for many least developped countries (LDCs) of Africa which do not yet have a profound knowledge of the whole nuclear power technologies fields and allied technoliges. By the way, a growing interest of small quantities of uranium mining sites will grow and become very strategic activities of cooperation and marketing for both new comers, expanders and providers of nuclear power services. INTRODUCTION With a population estimated in 2010 at 1.014 Billions, the african region inhabitants are foreseen to reach 1.318 billions and 1.780 billions respectively for the year 2020 and 2035[1, 2] . The statistics show that the population will double by 2050 (2.112 billions in 2052[1,2]), and with majority of people living in urban areas meaning, by the way, an increased demand of services like energy and electricity which are high priority needs for all social and economic developments of communuties and countries. People without decent access to energy are estimated to about 600 millions. The Energy access varies, approximately from 2% in to more than 95 % depending to the country [1-3]. The African reserves of Fuel and oil are estimated at over 130 billion barrels, representing 9.5% of the world's reserves, and more than 80% of these resources are located in the north and west of Africa [1, 4]. The Electricity consumption in many Least Developed countries (LDCS) in Africa is largely provided by fossil fuel with a contribution reaching over 75% ; this contribution of fossil power is followed by hydropower at around 22% ,nuclear and renewable power concurrence is considered at a level of 5% approximately[1-4]. Africa’s energy demand is far exceeded energy supply. The electrical energy demand is over 1,465 (GWh) for the year 2010, used only to serve 40% of the population [1]. The electrical demand will grow and pass to 2,401 and 2,717 respectively during the years 2030 and 2035[1, 2]. In regard of the reduction of energy resources, especially the diminution of fossil resources, it’s in need to see what options are to be considered by Africa and for Africa sustainable development. As of today only South Africa uses nuclear energy for power generation and is considered as expander of its nuclear power programme. A number of 21 countries have established politcal decisions to embark on nuclear power and it is foreseen that at least 10 among them will develop and operate their first nuclear power plant for electricity generation within the next 10 to 20 years and to became newcomers NPPs[1-3]. If so, this fact can be a way to encourage and expand nuclear power in more countries to enjoy nuclear power opportunity. APPROACHES AND ANALYSISES Nuclear power suppose many components considerations, like scientific and technological prepardess, financial capability and safety and security prepardness, responsibility and commitment in terms of safeguards among the countries and the whole world. One of these subcomponents is the uranium, the basis of the nuclear fuel, which constitue a basis of cooperation between nuclear operators and countries holding significant ressources of that yellow metal. The results of that kind of cooperation was just financial compensation, after exploitation and exportation of the uranium. So a new approach may be considered in a context of energy ressources dimimution and electrical energy demands rapid growth in LDCs of Africa and in a context of expansion and maturity of the SMRs technologies. This means that countries with uranium ressources and with small uranium ressources but sufficient for sustaining the commercial activities related to SMRs technology can develop a nuclear power program based on their uranium ressources with nuclear operators in a win-win approach, during the next decades. Known resources of uranium in 2015 are shared around approximately 16 countries ; Australia, Kazakhstan Russian fedreation concentrate over 52 % of all theses reserves. The african states having uranium reserves are mainly Niger, South africa and Tanzania[1, 3] . The current usage of uranium in the wold is over 63,000 tU/yr , especially used for nuclear applications like power reactor and research reactor. So significant interest in exploration effort, due partly to increased costs and maybe to geostrategic consideration are noted. During the period from 2004 to the end of 2013 about US$ 16 billions was spent on uranium exploration and deposit delimitationson over 600 projects. in this period over 400 new junior companies were established[3, 4]. The recycled uranium and plutonium is another source of investigation, and allows yearly production of 1700-2000 tU of primary supply, depending on whether just the plutonium or also the uranium is considered. It is forecasting to obtain to 3000-4000 tU/yr by 2020[3, 4]. Energy equivalence of natural uranium depends on the efficiency of uranium utilization,like: the rate of depletion of depleted uranium during the enrichment phase ;plus this rate is weak, the better we take advantage of the U235 component[4]. the rejection choice rate results from a compromise between the cost of uranium and that of the SWU (separation work unit) called also UTS (Unité de Separation),the rate of uranium combustion in a reactor and the possible reusage of the plutonium produced and the processing uranium from a reactor[4]. The values reached in the PWRs are greater than10,000 toe per tonne of natural uranium for a rejection rate of around 0.3% and without recycling processes[3]. So the energy equivalence is about 500 000 toe per tonne of natural uranium and in water reactors with no recycled plutonium, it is possible to have one ton of natural uranium to provide 420,000 GJ, or 10,000 toe, or 14,334 tec[2-4]. Nowadays most of reactor units capacity varies from 60 MWe to more than 1600 MWe,. At the same time there have been many hundreds of smaller and medium power reactors under operation, construction or planed [3,5,6]. The International Atomic Energy Agency (IAEA) consider as small, the reactor with power under 300 MWe ; in the meantime, the IAEA consider reactor with about 300- 700 MWe as medium reactor[5]. The IAEA calls today the small and medium reactors by the terms SMRs. Today, due partly to the competitive capital cost and safety the interest in SMRs is growing in somes countries with low income and small and medium size electrical grids[5,6]. A 2009 assessment by the IAEA under its Innovative Nuclear Power Reactors and Fuel Cycle (INPRO) program concluded that there could be 96 small modular reactors (SMRs) in operation around the world by 2030 in its high caseforecasting scenario , and 43 units in the low case[3]. The lack of profitability of the small sites are still changing and the interest of the nuclear operators and industrial may change because of many facts : - The interest in developping SMRs which use smaller quantities of uranuim ; - Possibilities for operators to exploit small sites by using the sames infrastrucutres with bordering countries ; The interest of cooperating with LDCs in african countries expressing political decisions and commitment to embark on nuclear power programme. In general, and as example, energy accessibility in Sub Saharan Africa is lower than the average level in whole Africa. For example, the search for uranium, which had a significant evolution in Senegal between 1965 and 1984, was relaunched in 2007 ; in the Eastern Saraya Research License. The graphitic shales of Mako and Dialé can also spark interest in uranium research and reserves found are estimated between 5,000- 10,000 tonnes[7]. Also, in Mali some 5,000 tonnes of uranium mine are located in Faléa, a municipality in a isolated region,close to the borders of Senegal and Guinea[8]. And in November 2012, a feasibility study prouve that Faléa areas contain about 12,000 tons of uranium, four times the production of the Arlit Areva mine in Niger in 2012[8]. In Guinea,the discovery analysises from Murchison's analysis of samples collected, in particular, from the Firawa site in Kissidougou at 600 km in southeast of Conakry give promising results ; many other Uranium Exploration Licenses in Guinea are issued[8, 9]. DISCUSSIONS Small sites of uranium in african countries and in many LDCs constitute a potential source of cooperation for energy for nuclear power, in a context of decresing of energy ressources in the Africa and especially in the sub saharian region for the coming years ( at the horizon 2035). But some requirement and provisions need to be taken to avoid lack of security and safety and to comply fully with safeguards. For successful and sustainable nuclear power programme these international legal instruments and guides have to be transposed at national, sub-regional and regional levels. The regional initiative under the Pelindaba Treaty under which the African Commission on Nuclear Energy (AFCONE) has been established, as the body responsible for, inter alia, ensuring compliance with states obligations need to be strengthened[10]. The FNRBA(Forum of Nuclear Regulatory Bodies in Africa,)with its 33 Members as of 2015 need to be supported in terms of human and financial resources. AFRA-NEST(Network for Education for Science and Technology) With support of AIEA and international cooperation and member states is also a way The African countries have to implement several Emergency Preparedness Review (EPREV) services in a number of Member States, and to fortifiy their cooperation for illicit trafficking of nuclear material. To limit potential risk of illicit traffic and to increase safety and safeguards levels, the International fuel reserves which are Low Enriched Uranium material (LEU) projects are very important and are serious support for LDCs of Africa in the next decades. There have been three major initiatives to set up international reserves of enriched fuel, two of them multilateral ones, with fuel to be available under International Atomic Energy Agency (IAEA) auspices despite any political interruptions which might affect countries needing them (Russian LEU reserve and the IAEA LEU bank in kazkstan).The third is under US auspices, and also to meet needs arising from supply disruptions[11] These initiatives have to be supported at highter level, by all IAEA member states. CONCLUSION The small uranium sites in africa, present growing interest by nuclear operator. Exploration and research licences are also increasing. In fact, the small uranium sites maybe sustainable when used for serving fuels for SMRs which need small quantities of fuel. SMRs maybe also an option or a mandatory option for somes countries in need of electricity consumption, in the context of diminution and ending of fuel ressources, in the next decades. But, safetyconsiderations need to be addressed now to avoid nuclear material proliferation, in future nuclear power plan in the region and indirectly during transport, fueling and re-fueling processes and waste processing. Attention need also to be made on site safety because safety of power plan maybe transposed to the safety of small sites mining. The political statibilities of many countries and zones is a major risks and concerns for proliferations and a fact that can discourage international cooperation of western countries for cooperating in regards to develop nuclear power programs in Africa. REFERENCES [1] AFREC, Presentation of Pr Elhag at the African Energy Conference, 30-31 may 2011, Cape Town, South africa,Adress: 02 Rue Chenoua, BP791, Hydra Algiers, Algeria, Email:afrienergy@yahoo.com; Website: www.afrecenergy.org [2]https://donnees.banquemondiale.org/indicateur/SP.POP.TOTLhttp://www.world-nuclear.org/ [3]http://www.world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-power-reactors/small-nuclear-power-reactors.aspx [4]Mémento sur l’énergie, edition 2017, Commissariat à l’Energie atomique (CEA), France, accessible au site web : http://www.cea.fr/multimedia/Documents/publications/ouvrages/memento-energie-2017.pdf [5]INPRO Methodology for Sustainability Assessment of Nuclear Energy Systems: Infrastructure INPRO Manual, IAEA Nuclear Energy Series No. NG-T-3.12, IAEA, 2014 [6]INPRO Methodology for Sustainability Assessment of Nuclear Energy Systems: Economics, INPRO Manual, IAEA Nuclear Energy Series No. NG-T-4.4, IAEA, 2014 [7]la Chambre des Mines du Sénégal (CMDS) :http://cmdsenegal.com/le-secteur-minier-au-senegal [8] Elisabeth STUDER – www.leblogfinance.com – 29 janvier 2013 [9]http://www.leblogfinance.com/2013/01/mali-luranium-faela-un-des-enjeux-du-conflit.html [10] the african treaty of Palindaba text : https://www.iaea.org/publications/documents/treaties/african-nuclear-weapon-free-zone-treaty-pelindaba-treaty. [11]status of Small and Medium Sized Reactor Designs - A Supplement to the IAEA Advanced Reactors Information System (ARIS), IAEA, September 2012.

Speaker: Mr Cheikh Amadou Bamba Dath (Univesity Cheikh Anta Diop)

103 CHARACTERIZATION OF URANIUM, THORIUM AND RARE EARTHS IN THE DECOMPOSITION PROCESS OF THAI MONAZITE ORE SAMPLES BY X RAY POWDER DIFFRACTION AND WAVELENGHT DISPERSIVE X RAY FLUORESCENCE TECHNIQUES

INTRODUCTION In Phuket and Phang-nga region of Thailand, monazite ore has been found in association with tin and beach sands deposits. The Thailand Institute of Nuclear Technology has performed the separation and purification of rare earth elements for industrial application. The principal process can be summarized as follows: in the first step, the monazite ore (325 mesh) was digested with 50 wt% NaOH at 140 °C for 3 h the reaction proceeds as: (Ce, RE, Th, U)PO4 + NaOH → (Ce, RE, Th, U)OH + Na3PO4 (1) The obtained hydrous metal oxide cake of Ce, RE, Th and U was dissolved in 35% w/v HCl. The HCl was used to neutralize and reacted with hydroxides to generate chloride compounds solution as follows: (Ce, RE, Th, U)(OH) + HCl → (Ce, RE, Th, U)Cl + H2O (2) The uranium (Na2U2O7) and thorium (Th(OH)4) can be obtained by the selective precipitation of the chloride compounds solution with 20% w/w NaOH at pH 4.5. The solvent extraction using 5%v/v of tributyl phosphate (TBP)/kerosene process was utilized to separate uranium and thorium. The extracted uranium was precipitated with NH4OH to form yellow cake or ammonium diuranate, (NH4)2U2O7. The ThO2 was produced by the extraction of solution from uranium extraction with 40%v/v TBP/kerosene [1]. The filtrated mixed rare earth solution was treated with BaCl2 and H2SO4 for removing of radium, Ra (a daughter product of uranium) and precipitated at pH 11 with NaOH. The obtained RE(OH)3 intermediate was leached with HNO3 at pH 6. The ion exchange process was used to extract and purify Ce, La and other rare earths from the leaching solution [2,3]. Inductively coupled plasma optical emission spectrometry (ICO-OES) and neutron activation analysis (NAA) are the equipment used for the determination of rare earths, uranium, thorium and other associated minerals in the sample during the monazite processing [4]. Although ICO-OES can be simultaneously analyzed rare earths with high sensitivity and more accuracy, it requires digesting of the ore in concentrated acid step and is also suitable for some low concentration rare earths [4,5]. For NAA, this technique suffers from a long irradiation times and long decay times [5]. X-ray fluorescence (XRF) is non-destructive technique for analysis of rare earths, uranium and thorium. It has been reported that this tool could be determined the rare earth, uranium and thorium concentrations in various samples such as mixed REO concentrates, CeO2, RE2O3 [6], thorium in the presence of uranium [7], monazite processing [8] and phosphate ore [9]. X-ray powder diffraction (XRD) has been applied for identification and quantification the mineralogy as well as crystalline phase structure and composition in various ores etc. monazite and phosphate rock [8,9]. In this work, the wavelength dispersive X-ray fluorescence (WD-XRF) and X-ray powder diffraction (XRD) techniques were developed to study the characterization of uranium, thorium and rare earths in Thai monazite ore processing samples. MATERIALS AND METHODS The samples used in this study were the Thai monazite ore, the RE(OH)3 intermediate, the U3O8, the ThO2, the La2O3 and CeO2 as obtained from the decomposition process of Thai monazite ore by alkali method. All samples were dried at 110 °C for 12 h and then grounded to form fine powder. The chemical and mineralogical analysis of the samples was carried out by using WD-XRF and XRD techniques. WD-XRF analysis: the sample was mixed with a reagent grade flux (mass ratio of lithium metaborate and lithium tetraborate, 1:4). The ratio of sample and fluxing agent was 1:9. Ammonium iodide as releasing agent was then added. The total amount of mixture was 6.9 g. The mixture was poured into a platinum crucible and fused at 1000 °C for 2 min using a fusion machine (Katanax K2classic automatic fluxer). The sample fused disc was analyzed for uranium, thorium and rare earth elements concentrations using a Bruker S8 Tiger WD-XRF spectrometer. XRD analysis: the XRD patterns of the samples were performed on a Bruker D8 ADVANCE diffractometer using Cu Kα radiation (λ = 1.5406 Å) operating at an accelerating voltage of 45 kV and a current of 40 mA. The patterns were recorded in the 2θ range of 10--90 ̊ with a 2θ step size of 0.039o and 177 sec/step. RESULTS AND DISCUSSION The monazite ore sample was ground to obtain 325 mesh before XRD and WD–XRF analysis. The XRD pattern of the sample showed that the ore consisted of monazite–Ce (Ce, La, Nd)PO4 with monoclinic structure. All diffraction peaks can be indexed according to the JCPDS card No. 00–046–1295 with lattice constants of a = 0.6811 nm, b = 0.7039 nm, c =0.6501 nm, α = γβ = 90 and β = 103.54. The major peaks were observed at 2θ = 21.63, 25.79, 26.95, 28.78, 29.8, 31.07 and 34.34. The average crystallite size of the sample of 38.52 nm was observed. The rare earths including CeO2 (30.74 wt%), La2O3 (11.07%), Nd2O3 (10.71wt%), Y2O3 (2.80 wt%), Pr6O11 (1.84 wt%), Gd2O3 (1.15 wt%), Dy2O3 (0.51 wt%) and Er2O3 (0.14 wt%), ThO2 (8.89 wt%) as well as UO2 (0.50 wt%) were detected by WD–XRF. For the RE(OH)3 intermediate sample, it has formed after the digestion of monazite ore by alkali method following the separation of thorium and uranium process. The XRD pattern of the sample indicated the presence of cubic of cerium and neodymium oxide with the standard card (JCPDS 00–028–0266). The characteristic diffraction peaks appeared at 2θ = 28.31, 32.67, 47.05, 55.88, 56.11, 68.67, 75.78 and 87.72 (a = b = c = 0.5458 nm and  α = β = γ = 90) with a small crystallite size of 8.13 nm. The concentrations of CeO2 (65.84 wt%), Nd2O3 (14.48 wt%), La2O3 (5.97%), Y2O3 (3.57 wt%), Pr6O11 (3.01 wt%), Gd2O3 (1.90 wt%) and Dy2O3 (0.84 wt%) were found. ThO2 and UO2 could not be detected by this WD–XRF technique. The U3O8 sample was obtained by the solvent extraction of Th and U cake with TBP/kerosene extractant. The obtained (NH4)2U2O7 was calcined at 900 oC to form the U3O8 cake. The XRD pattern of the sample exhibited predominantly peaks of uranium oxide at 2θ = 23.61, 24.97, 25.24, 27.69, 27.96, 34.65, 44.37 and 46.08 (JCPDS card No. 00–028–0164). The average crystallite size of the sample was 19.00 nm. The WD–XRF result showed that the sample composed of UO2 (87.77 wt%), ThO2 (6.21 wt%). The concentration of UO2 obtained by this WD–XRF agreed well with that determined by XRD technique (UO2 87.00%). After the separation of uranium, the TBP extraction process was used to purify Th and then the ThO2 cake sample was formed by NaOH precipitation. The sharp characteristic peaks of the sample located at 2θ = 27.65, 32.01, 45.85, 54.36, 57.01, 66.84, 73.76, 76.02 and 84.80 can be assigned to cubic phase of ThO2 which matched well with the standard data (JCPDS card No. 03–065–7222). The lattice parameters were a= b = c = 0.5596 nm and α = β = γ = 90 with the average crystallite size of 95.16 nm. The concentration of ThO2 in the sample was found to be 83.74 wt% with small amount of UO2 of 0.61 wt%. The CeO2 and La2O3 containing in the RE(OH)3 intermediate, were separated and purified by ion exchange process. For CeO2 sample, all of the diffraction peaks can be indexed to the face centered cubic phase of cerium oxide with lattice constant a= b = c = 0.5412 nm and α = β = γ = 90. The sharpness and high intensity of predominant peaks at 2θ = 28.51, 33.06, 47.44, 56.31, 59.03, 69.37, 76.68, 79.05 and 88.38 (JCPDS card No. 01–081–0792) indicated the well crystalline nature of the CeO2 sample. The average crystallite site of the sample was found to be 64.2 nm. The WD–XRF result indicated that the CeO2 sample contained a 99.47 wt% of pure CeO2 which matched well with that XRD result. In case of the La2O3 sample, a typical diffraction peaks of La2O3 appeared at 2θ = 27.34, 27.96, 31.62, 35.93, 39.51, 42.15, 48.65, 55.26, 64.00 and 69.56 (JCPDS card No. 01–076–0572), was observed. The characteristic peaks attributed to hexagonal with lattice parameters of a = b = 0.6523 nm, c = 0.3855 nm, α = γ = 90 and β = 120 and average crystallite site of 17.16 nm. The La2O3 sample analysed by WD–XRF composed of La2O3 (89.70 wt%) and CeO2 (8.15 wt%). CONCLUSION Monazite ore found in the tailing of tin from the south of Thailand has been used as source of rare earths, uranium and thorium. The decomposition process using alkali method, solvent extraction and ion exchange techniques were used for separating and purifying those elements. XRD and WD–XRF as fast, accurate and non-destructive methods were extremely useful for the determination of rare earths, uranium, thorium and associated mineral concentrations in the samples obtained during the process. The elemental compositions of all samples measured by WD–XRF were agreed well with that determined by XRD method. In addition, the concentration of uranium oxide in the U3O8 cake sample determined by WD–XRF (87.77 wt%) showed a very good agreement with that obtained by XRD method (87.00 wt%). The same phenomenon was observed for the CeO2 sample, the CeO2 concentrations of 99.47 wt% and 99.90 wt% were detected by WD–XRF and XRD, respectively. REFERENCES [1] INJAREAN, U., et al., Batch simulation of multistage countercurrent extraction of uranium in yellow cake from monazite ore processing with 5% TBP/kerosene, Ener. Proced. 56 (2014) 129–134. [2] RATTANAPHRA, D., et al., Purification process of lanthanum and neodymium from mixed rare earth, Proc. Pure Appl. Chem. Int. Conf. Thailand, (2013) 407–409. [3] PUSSADEE, C., et al., Purification process and characterization of cerium oxide from mixed rare earth, Proc. TIChE. Int. Conf. Thailand, (2012) 142–144. [4] BUSAMONGKOL, A., et al., Determination of rare earth elements in Thai monazite by inductively coupled plasma and nuclear analytical techniques, Country Report No. TH-071, IAEA, Vienna (2003). [5] ZAWISZA, B., et al., Determination of rare earth elements by spectroscopic techniques: a review, J. Anal. At. Spectrom. 26 (2011) 2373–2390. [6] WENQI, W., et al., Application of X–ray fluorescence analysis of rare earths in China, J. Rare Earths 28 (2010) 30–36. [7] TAAM, I., et al., Determination of thorium in the presence of uranium by wavelength dispersive X–ray fluorescence, Proc. Int. Nucl. Atlant. Conf. Brazil, (2007). [8] TAR, T.A., et al., Study on processing of rare earth oxide from monazite Mongmit Myitsone region, America. Scient. Res. J. Eng. Tech. Science. 27 (2017) 43–51. [9] ZHANG, Q., et al., Study on the rare earth containing phosphate rock in Guizhou and the way to concentrate phosphate and rare earth metal thereof, J. Powder Metall. Min. 3 (2014) 1–4.

Speaker: Dr Dussadee Rattanaphra (Thailand Institute of Nuclear Technology)

104 CONCENTRATION OF URANIUM FROM SOLUTIONS USING NANOMEMBRANES

INTRODUCTION Ensuring the effectiveness of the processes of natural uranium mining and processing is associated with the introduction of innovative methods and technologies that provide cost optimization and efficient use of resources, in particular, lower specific consumption rates of chemical reagents. Underground uranium leaching involves dissolving of the metal under the action of sulfuric acid at the site of the ore and subsequent extraction through the wells. Ground processing of the obtained productive solutions is carried out with the use of sorption technology. At the first stage uranium has sorbed on anion-exchange sorbents then desorption process has carried out with sulfuric solutions of ammonium nitrate. Obtained eluate has precipitated by hydrogen peroxide or sodium hydroxide solutions. For the selective uranium precipitation preliminary neutralization of excess acidity contained in eluate is required. This leads to a permanent loss of sulfuric acid and an increased consumption of sodium hydroxide. The actual task is to separate and return to the process the sulfuric acid contained in the eluate before the uranium precipitation. This problem can be solved by membrane separation and concentration processes. Relative simplicity of instrumentation, lack of the use of additional reagents, small volumes of liquid waste generated are the advantages of membrane processes. In addition, membrane processes have a number of undeniable advantages over other separation processes (rectification,extraction, adsorption, etc.):  continuity;  low energy costs;  convenience of combination with other technological processes;  soft technological conditions;  scalability. There are many membrane separation processes based on different principles or mechanisms applicable to the separation of objects with different sizes, from heterophase particles to molecules. The basis for separation during nanofiltration is the negative charge of the membrane surface. This makes it possible to retain multivalent anions as well as associated cations, to preserve electroneutrality. Positively charged ions, such as hydrogen, aluminum, sodium must pass through the membrane. Neutral molecules, as well as some cations having a large size, for example, uranium, will be retained by the membrane. In this connection prerequisites are created for the preliminary processing of eluate using membrane processes for the purpose of sulfuric acid separating and uranium concentrating. METHODS AND RESULTS A baromembrane nanofiltration method was chosen to optimize the composition of eluate (acidity reduce and increase uranium content). In this method the transfer of matter through the membrane occurs under the action of a pressure difference. A pilot installation which work is based on the action of the principle of tangential filtration was constructed. The main working element of the installation are membrane modules consisting of enclosures capable of withstanding pressures up to 70 bar, and directly of the membranes connected to each other. As a result of the solution passing through the installation, two constant fluxes are formed: a filtrate, also called permeate and a retentate, or a concentrate. To perform the tests, semipermeable (selective) membranes manufactured by DOW Company were chosen. In these membranes during the solutions flow motion under pressure, a positive transmembrane pressure is created across the surface of the membrane, which causes the passage of hydrogen protons and other components smaller than the pore size of the membrane through the membrane. To prevent nanomembranes clogging with mechanical suspensions located in eluate, a preliminary filtration of eluates through a fine filter with a pore size of 5 microns was envisaged in the technological scheme. Studies on the nanofiltration of eluate were carried out at an average pressure of 22 bar. The eluate with a uranium content of 37,21 g/dm3 and sulfuric acid of 23,73 g/dm3 was used as the basic solution. The basic solution was pumped by a low pressure pump to a fine filter, then a high pressure pump to the membrane module. Permeate and concentrate obtained with separation on the membrane module were taken from the installation to special tanks of the final product. The pressure at the outlet from the membrane module was 6 bar. The total capacity of the installation for permeate and concentrate was 250 l/h. At the same time the yield of permeate was 180 l/h, the concentrate yield was 70 l/h. The installation had worked for 720 hours in this mode. The average uranium content in the permeate obtained during the entire operation of installation was 2,32 g / dm3. The acid content in the permeate was on average 21,66 g / dm3. The average content of uranium in the obtained concentrate was 126,93 g / dm3, the acid content was 29,11 g / dm3. The experiment has showed that the maximum operating time of nanomembranes at the separation of eluate of the test compound is 64 hours. After this time it is necessary to rinse the membranes with process water for 10 minutes. After washing the membranes restore their throughput. The obtained concentrate was sent to peroxide precipitation. For comparison, uranium precipitation was also carried out from the initial eluate. Precipitation was carried out under the following conditions:  draining time of reagents is 30 minutes;  volume of eluate - 0,5 dm3;  excess of reagent-precipitator - from 0 to 100%;  precipitation time - 60 min;  neutralizing reagent - NaOH solution It was found that the permissible content of uranium in the mother solution (no more than 30 g/dm3) could be achieved with a 20% excess of H2O2. The efficiency of peroxide precipitation is higher the lower the salt composition of the processed eluate. The amount of uranium recovery (with other equal things) is significantly affected by the initial concentration of uranium in the desorbate. With an increase in the content of the target metal, the recovery rate increases. When uranium is precipitated from the concentrate obtained by nanofiltration, the specific rate of NaOH consumption for neutralization of excess acidity decreases in 2 times. This corresponds to a total saving of 0,35 kg of sodium hydroxide per 1 kg of uranium. CONCLUSION The conducted experiments of the eluate nanofiltration has showed the principal possibility of uranium and sulfuric acid separation. Nanofiltration of the eluate makes it possible to achieve an increase the uranium concentration of 4 times with a simultaneous decrease in the relative acid content by 63%. The extraction of uranium into the concentrate is 93,76%. Concentration of uranium with a simultaneous decrease in the excess acid content leads to an increase in the efficiency of peroxide precipitation and a decrease the specific consumption of sodium hydroxide.

Speaker: Ms Mariya Kopbayeva (Institute of High Technologies)

105 CONCEPTUAL MODEL OF THE FRACTURED AQUIFER OF THE URANIUM MINE IN CAETITÉ, BRAZIL: IMPLICATIONS FOR UNDERGROUND WATER FLOW

The studied area is the uraniferous district of Lagoa Real in Brazil. The region is set in a semiarid climate context, with hydric deficit along all months of the year and high aridity index. Groundwater represents the main supply source considering that most surface water sources are temporary and only exhibit flow in rainy periods. The main aquifer system present on the region is fractured, and the presence of groundwater flow occurs through the discontinuities of the rock considering that the rock mass corresponds to the set formed by the rock matrix and all its discontinuities (fractures, foliations and discordances). In this sense, the main purpose was to develop a conceptual model for the aquifer system, through the geotechnical characterization of discontinuities, once these structures allow the secondary porosity of the medium. Hydrochemical data hand out as complement for physical characterization for the behavioral interpretation of the aquifer. The aquifer system is unconfined, however, presents points of stagnation of flow forming compartments without communication with the surrounding areas. Results showed that discontinuity distribution were not a predominant factor to the concentrations homogenization of the chemical parameters. The composition of the rock was revealed as the most important factor.

Speaker: Ms Liliane Silva (National Security Cabinet - Federative Republic of Brazil)

106 Coordinated Research project on Uranium/Thorium Fuelled High Temperature Gas Cooled Reactor Applications for Energy Neutral and Sustainable Comprehensive Extraction and Mineral Product Development

Around the world the demand for mineral commodities is growing strongly and high-grade, easily extractable resources are being depleted. Thermal processes are often the most appropriate for production from low-grade and some unconventional mineral resources; these in turn depend on the availability of large amounts of energy. These thermal mineral extraction processes are usually cleaner and generate lower quantities of wastes than current chemical processes. The availability of affordable and responsibly-produced energy would, in many cases, also promote value addition and allow the production of higher end products, which would improve the overall economics of the project. Thermal processes using high temperature nuclear heat could be a more sustainable and environmentally friendly alternative to heat generated by other means and conventional chemical processes. Many mineral deposits contain low concentrations of uranium and thorium; these could be recovered and used as, or be equivalent of, fuel in the reactors. The IAEA’s Coordinated Research Project generates basic data on the availability and characteristics of various potentially-suitable mineral resources and process residues, and conducts conceptual and pre-feasibility studies on appropriate thermal processes in which thorium/uranium fuelled high temperature gas cooled reactors (HTGRs) provide the required energy.

Speaker: Mr Frederik Reitsma (International Atomic Energy Agency)

107 DETERMINATION OF URANIUM-BEARING SAMPLES IN TERMS OF POSSIBLE CONTAMINATION, ARIKLI URANIUM REGION, CANAKKALE, TURKEY

INTRODUCTION Radioactive mineralisation sites and related exploration activities threaten the living ecosystems of surrounding areas which is a current concern in many countries [1,2]. Natural and artificial factors provoke the dispersion of radioactive isotopes from the sites and increase the contamination in the impacted area [3,4]. It is observed that the isotopes may be liberated, transported and precipitated under certain oxidation conditions and can accumulate in different regions and this process even may lead to secondary mineralization under appropriate conditions. Over time, these accumulation and transport environments may act as secondary sources and damage human and environmental health [5,6,7]. Radioisotope distribution continuously vary among landscape components (e.g. rock, soil, groundwater and surface water) [3,8,9]. As an example, groundwater interacts with background rock, leaches radioisotopes and then influences the chemical composition of the surface water and soil [10] Sampling strategy is one of the most important issues in contamination research. Methods which are suitable for one environment may be quite inappropriate for another one. For example, the mechanisms of the formation of uranium deposits vary widely and hence the geochemical makeup of the deposits also vary [3]. Therefore, careful measurements and analyses are needed to understand the geological and physical structure of the area before cost-effective analyses. Generally, for the determination of the radioactive element distribution originating from an exploration site, the easiest and cheapest step is to carry out outdoor absorbed gamma dose measurements (OAGD). The distance between the measurement points should be adjusted according to the detector range and integration time. Based on the gamma measurement values, the target area can be restricted. Especially, if erosion is dominant in the area, drawing the borders along the hilltops, gives the advantage to understand the flow of elements. Primarily the catchments of the exploration sites should be investigated, but measurements should also be performed at neighbouring catchments in terms of comparisons of the results and possible contamination risk. For sampling design, the next step is geochemical analysis. Geochemical parameters such as pH, EC (electric conductivity), organic matter, carbonate and clay content, and oxidation state help to evaluate the migration characteristics. Proper GIS operations using all the multisource predictor maps such as lithology, topography, soil type, land cover, erosion, hydrology, flow accumulation, run-off etc. can significantly reduce the sample number. Statistical analyses such as homogeneity test of univariate distributions, bivariate scatter plots, and multivariate cluster analysis (CA) and, principal component analysis (PCA) are used to separate populations in the dataset that possibly indicate various geochemical processes. The case study reported in the present work develops an integrated methodology including geochemical, radiometric and GIS-based landscape analysis for the determination of uranium-bearing samples to assess the possible uranium-related contamination at Arıklı uranium mineralisation region. DESCRIPTION The restricted study area, after the OAGDR orientation measurements, is covering Arıklı (Turkey/Çanakkale/Ayvacık) uranium mineralisation site (Ayvacık-Çanakkale/Turkey) and its surroundings. Turkey General Directorate of Mineral Research and Exploration (MTA) Office determined radioactive anomalies by an airborne survey in 1959 in the area. In 1967 the field was surveyed by the help of exploration ditches and between 1968-1982 a total 56 uranium exploration drillings were carried out [11]. Although it had been reported that the area contained uranium-favourable regions, the last drilling programme (1982) was finalized due to the decision of the government about uneconomical reserves [12]. According to the geochemical analyses applied to the samples taken from rock dumps and exploration ditches, phosphate-uranium relationship and in some samples, thorium enrichment was detected. Although, based on these analyses, the area was considered to be a phosphate-favourable area, after detailed analyses, it was abandoned due to insufficient economic reserves, as well. Later on, as stated in the report of Gök (1978), magnesite lenses and radioactive minerals were also found in some parts of volcanic tuff levels in samples taken from the vicinities of Arıklı village and in 1980, MTA took two samples from the region and 1050 mg/kg and 1300 mg/kg uranium was detected by TAEK (Turkish Atomic Energy) laboratories [13, 14] By the help of the phosphate related studies on Arıklı tuffs (ignimbrite) performed by Çelik et al. (1999), Günaydın and Çolak (2009) and Günaydın (2017) it was concluded that uranium and phosphate enrichments were formed by the help of hydrothermal fluids and they were accumulated at fragmented fault zones [15,16,11]. Bayleyite [Mg2(UO2)(CO3)3.18H2O] and ningyoite [(U,Ca,Ce)2(PO4)2.1−2H2O] were defined as minerals of uranium in the area. During the studies, 1:5000 scale geological maps were prepared [11]. Based on the restrictions after outdoor gamma measurements, the final study area covers approximately 12 km2 at the south-east of Ayvacık town in Ayvalık İ17-d4 pedestal. The population of Arıklı village was is about 256 in 2000. Livestock, poultry and beekeeping are common in the village. The region is also very important for olive production. The region has own private drinking water source transferred from the Kaz mountains, but groundwater is also used as drinking water. Additionally, groundwater is also used for agriculture and animal husbandry in the region. Streams flow into the Edremit Gulf, but their water flows are intermittent during the year. The area contains deep valleys and narrow plains. Kocakaya Hill is the highest peak in the region with 742 m height. Olive trees grow at the southern coastline, pine forests on the north side and some short trees and bushes can also be found there. Significant faults developed in NE-SW and NW-SE directions. [17]. The study area consists of four main rock groups. These are Upper Cretaceous aged ophiolitic base rocks, volcanic units, lacustrine sediments and alluvial sediments; The Çetmi ophiolitic melange which is a complex rock group of split-volcanic lavas, pyroclastic rocks, limestone blocks shale and greywacke form the basement of the study area and are covered by volcanic and lacustrine sediments [18]. Neogene-aged lacustrine sediments are called Küçükkuyu formation [19]. The formation contains volcanic intercalations with conglomerate, sandstone, siltstone, claystone and marl. These levels are transverse to each other in lateral and vertical directions [20,21]. In the study area, the main unit is Arıklı tuff which consists of andesite/andesitic tuffs and andesitic agglomerates. Based on its SiO2 content, it has an acidic-moderate character and in terms of their chemical characteristics, they are rhyolite and rhyodacite [11]. Inside the tuffs, there are silicic and altered nodules of 2-7 cm radius, some of which have rings of iron-oxide bands. Uranium enrichment developed via Ca+2-U+4 ion exchange in the phosphate nodules found in the Arıklı volcanic [21]. MATERIALS AND METHODS Taking into consideration the studies made by MTA, at first OAGDR (Outdoor Absorbed Gamma Dose Rate) orientation measurements were performed in the presented survey covering Arıklı, Nusratlı, Ahmetçe, Hüseyinfakı, Demirciköy and Kayalar villages, approximately 50 km2. For the measurements, portable ESP-2 Na(I) probed Eberline gamma detector was used at 1 m above the ground level during 100 s for each measurement [22]. The measurements were planned according to the lithological units. The map of the OAGDR data was prepared by kriging geostatistical interpolation method applying with the Arc-GIS software. As a result, the study area was restricted into a 2,63 x 4,25 km rectangle (~11 km2) which includes the catchment area of Arıklı mineralisation site and the Arıklı village. The restricted area first was split into 500x500m grids then inside the catchment, they were minimised to 250x250m. From the corners of each square, OAGDR measurements were taken. Open exploration ditches were identified and their OAGDR measurements were taken, either. From the measurement points soil samples were collected. Before collecting the soil samples, the sampling points were cleared off from vegetation, root and stones then 250 g of material from the first 10 cm of the topsoil was packaged. Beach sediments were homogenised and representative 250 g samples were collected in plastic bags. All the samples were dried to remove the moisture under sunlight and then transported to laboratory. The samples were sieved in 1-mm mesh, packaged and labelled. For pH measurement 6 g sample was mixed with 15 mL distilled water and after 12 h waiting, measurements were taken. For calibration of the pH meter (Multi 340i and pH/Cond 340i Handheld Multimeter) pH 4.00, 7.00 and 9.00 buffer solutions were used. The same solution at the same time and with the same device but different probe was used for EC measurements with the same device [23]. For carbonate analysis, 3-10 g soil was mixed with 0.1 M HCL solution. The probe of the Scheibler calcimeter was filled with the HCL solution and after fixing into the polyethylene wide-mouth 250 ml tube, the solution was mixed into the samples and were shaken by magnetic stirrer. CO2 pressure was measured by the Scheibler calcimeter chamber filled with 0.1 M Sodium hydroxide solution. The results of the gas volume were converted to CaCO3% by calculations [24]. Barium chlorite method was used for cation exchange capacity analysis (CEC). 4 g sample was mixed 0.1 M BaCl2 solution and buffered up to pH 8.0 with tetraethyl ammonium (TEA). After stirring by shaker 2 hours at 480 rpm the solution was filtered into centrifuge tubes and centrifuged. Finally, Ba2+ content is measured by ICP-OES [25]. On account of topographic analyses, run-off, slope-break and watershed models were derived from Digital Elevation Model (DEM) for 5x5m grid cells (Jordan, 2011). Drainage map and land cover map derived from topographic map using Arc-GIS software. All the multisource predictor maps were superimposed by using GIS operations using Surfer Software Homogeneity test of univariate distributions, bivariate scatter plots, and multivariate cluster analysis (CA) and, principal component analysis (PCA) were used for statistical analysis. RESULTS In the area, the highest outdoor gamma levels were detected at Karakisla region. In the study area, other anomalous measurement levels were found in the exploration ditches on Feyzullah Hill. At both sites, the ditches were still open and the maximal depth reached even 5 m. It is advised to close the ditches and check the radon emission of the sites. Since the area was under the effect of slope driven soil erosion, the OAGDR measurements were more correlating with topographical units than with the lithological units. The gamma levels at the alluvial accumulating flat bottoms of valleys were also higher than the background level due to the erosion effect and hills acted as physical barriers to prevent the dispersion of the radioactive contaminants from the catchment. According to the results of soil chemical analyses, higher values of EC and CEC measurements were driven by topographical and hydrologic barriers. For example, in the alluvial accumulative bottoms of valleys and along the meanders of stream branches, where water flow is slower, deposition took place providing higher values of EC and CEC. Regarding pH and carbonate measurements, their results correlated to each other and had the highest values in the beach sample. CONCLUSION Although there are numerous in situ geogenic radioactivity determination studies, this interdisciplinary developed methodology helps to analyse the behaviour of uranium distribution originating from Arıklı mineralisation site. It determines the geochemical, topographic units and proves their control mechanisms on the distribution. REFERENCES [1] INTERNATIONAL ATOMIC ENERGY AGENCY, Management of Radioactive Waste from the Mining and Milling of Ores, Safety Standard Series No. WS-G, IAEA, Vienna (2002). [2] INTERNATIONAL ATOMIC ENERGY AGENCY, Occupational Radiation Protection in the Mining and Processing of Raw Materials, Safety Standards Series No. RS-G-1.6, IAEA, Vienna (2004). [3] INTERNATIONAL ATOMIC ENERGY AGENCY, World Distribution of Uranium Deposits (UDEPO) with Uranium Deposits Classification, IAEA-TECHDOC-1629, IAEA, Vienna (2009). [4] CARVALHO, F.P., “Environmental radioactive impact associated to uranium production”, Am J. Environ Sci. Vol.7, Issue 6, (2011), 547–553. [5] FAIRBRIDGE, R, W., “The encyclopedia of geochemistry and environmental sciences”, Van Nostrand Reinhold Co, New York, (1972). [6] READ, D., et al., “Secondary uranium mineralization in Southern Finland and its relationship to recent glacial events”, Global and Planetary Change, Volume 60, Issues 3–4, (2008), 235-249. [7] DUTOVA, E. M., et al., “Modelling of the dissolution and reprecipitation of uranium under oxidising conditions in the zone of shallow groundwater circulation”, Journal of Environmental Radioactivity, Volumes 178–179, (2017), 63-76. [8] PLANT, J.A.,SAUNDERS, A. D.,“The radioactive earth”, Radiat.Prot. Dosim,68, (1996), 25-36 [9] LIU, G. S., “Soil physical and chemical analysis and description of soil profiles (in Chinese)", Chinese Standard Press, Beijing, 1996 [10] ENGELEN, G.B., KLOOSTERMAN, E.H, “Hydrological systems analysis: Methods and applications”, Water Science and Technology Library 20, Kluwer Academic Publisher, (1996). [11] GÜNAYDIN, A., “Arıklı ve Nusratlı Köyleri (Ayvacık-Çanakkale) yumrulu-fosfat ve fay kontrollü hidrotermal-fosfat cevherleşmelerinin jeolojisi ve jeokimyası”, Maden Tetkik ve Arama Dergisi, 155, (2017). [12] AKGÜNLÜ, H., SAĞLAM, R.,“Çanakkale-Ayvacık-Arıklı Köyü çevresindeki uranyum cevherleşmesi”, MTA Genel Müdürlüğü Rapor. No:542, (1983). [13] GÖK, S., Türkiye neojen formasyonlarının ekonomik jeolojisi, Maden Teknik ve Arama Enstitüsü, Jeoloji Mühendisliği, Şubat (1978), [14] ÇEKMECE NÜKLEER ARAŞTIRMA ve EĞİTİM MERKEZİ, “İlerleme raporu”,ÇNAEM-R-211, (1980). [15] ÇELİK, E., AYOK, F., DEMİR, N., “Ayvacık-Küçükkuyu (Çanakkale İli) Bölgesi fosfat cevherleşmesi maden jeolojisi raporu”, Maden Tetkik ve Arama Genel müdürlüğü-Balıkesir Bölge Müd. Arşivi Rap. No:891, (1999). [16] GÜNAYDIN, A.B., ÇOLAK, T, “Arıklı-Nusratlı Köyleri Ayvacık-Çanakkale fosfat sahası maden jeolojisi raporu”, Maden Tetkik ve Arama Genel Müdürlüğü, Derleme No:11434, Ankara (2009). [17] T:C ÇANAKKALE VALİLİĞİ İL ÇEVRE VE ORMAN MÜDÜRLÜĞÜ, “Çanakkale ili çevre durum raporu 2006-2007”. [18] OKAY, A.İ., SİYAKO, M., BÜRKAN, K.A. “Biga yarımadasının jeolojisi ve tektonik evrimi”, Türkiye Petrol Jeologları Derneği Bülteni, (1990), 83– 121. [19] ÇİFTÇİ, N.B.,TEMEL, R.O., TERZİOĞLU,.M.N.,“Neogene stratigraphy and hydrocarbon systematics around Edremit Bay”,Assoc. of Turkish Petroleum Geologists Bull.,16(1), (2004),81-104. [20] SAĞDIK,U.,GÖNEN,N., “Çanakkale-Ayvacık Küçükkuyu uranyumlu fosfat cevherlerinin laboratuar çapta ön teknolojik deneyleri”, MTA Rap.No:278, Ankara (1981). [21] ÖZEN, S., GÖNCÜOĞLU, M.C., “Origin of analcime in the Neogene Arikli Tuff, Biga Peninsula, NW Turkey”, N.Jb.Miner.Abh,189/1, (2011),21-34 [22] JUSTO, J., HAMZA, V. M., LAMEGO, F. F., FILHO, S.,“Mobility of radionuclides and rare earth elements in the coastal area of Rio de Janeiro : Implications for Monazite deposits in Offshore”, Areas. J. Earth Sci. Geotech. Eng., 3(4),(2013) 201–224. [23] BLACK, C.A.,“Methods of soil analysis”, Agronomy Series 9, ASA, Part 2, Madison,(1965), p.914. [24] HUNGARIAN STANDARTS, “Laboratory İnvestigations of some chemical characteristics of soil”, Number of the standart: MSZ-08 02026/2-78. [25] HENDERSHOT, W H., DUQUETTE, M., cA Simple Barium Chloride Method for Determining Cation Exchange Capacity and Exchangeable Cations”, Soil Science Society of America Journal 50(3), (1986)., [26] JORDAN, G.,.,& ANDREA, S., “Geochemical Landscape Analysis: Development and Application to the Risk Assessment of Acid Mine Drainage. A Case Study in Central Sweden”, Landscape Research,Vol. 36, No.2, (2011), 231-261.

Speaker: Ms Gülcan Top Top (ITU Eurasia Institute of Earth Sciences/Istanbul/Turkey)

108 Effective and environmentally compliant in-situ recovery of sedimentary-hosted uranium (poster)

This poster is the companion to the oral paper (Contribution 219) that reviews recent advancements in Development of in-situ recovery (ISR) projects for uranium including  dedicated exploration/delineation methods and field tests for gathering deter-mining data,  efficient lab tests and assays of core samples, including up-scaling methodolo-gy applied to (1D) column leach tests for a reliable feasibility study of (3D) field ISR, Planning and optimization of ISR processing comprising  wellfield hydrology,  leaching chemistry,  monitoring and process control,  economics,  environmental compliance, Post-mining measures for ISR aquifer restauration in accordance to regulatory re-quirements including  conceptual methodology (combining test procedures and model predictions) for ISR project development and permit procedure,  monitoring and optimization. The effective and environmentally compliant ISR of uranium will be demonstrated for recent ISR projects operated by Heathgate Resources in the Frome Basin, South Australia.

Speaker: Dr Horst Maerten (Heathgate Resources Pty Ltd)

109 ENVIRONMENTAL FACTORS CONTROL AT SIERRA PINTADA, ARGENTINA: WATER QUALITY

INTRODUCTION The Sierra Pintada uranium mine is located in Mendoza Province, Argentine, 38 km. west from San Rafael and 240 km. south from Mendoza city. It was in production from 1975 to 1995 when the operations were stopped owing to economic reasons. Under the open-pit extraction system, 1,600 tons of uranium ore were extracted and treated by acid leaching and ion exchange columns with a nominal capacity of 120 tU / year, and more than 6.000 tons of uranium remain to be extracted. The CMFSR (San Rafael Manufacturing Mining Complex, according to its initials in Spanish) supplied for 22 years the whole uranium required by power plants for nuclear power production and research reactors and production of radioisotopes in Argentina. Currently, the activities carried out at the site are maintenance, monitoring and environmental management. At this moment, the treatment of pit water and the management of solid waste disposed in the complex is in the stage of environmental impact assessment. Soon it will begin to define the closure of the El Gaucho open pit, one of the four pit in which the mining operation was completed and still remains open pending the restoration The area where most of the facilities of the CMFSR are located is in the basin of the El Tigre brook, which crosses the mineralized zone and flows into the Diamante River, the main water course that feeds the irrigation network of the San Rafael Department. Due to the El Tigre stream originally passed directly over the mineralized zone, a deviation of its natural course was made previously to the mining operation stage, preventing the water from entering one of the open pits with a high uranium content. The importance of the Diamante River as a water resource in the south of the Mendoza province is given by being the main supplier of water for irrigation in the city of San Rafael and its surroundings, where economic activities related to agriculture are carried out, with special emphasis on the fruit and viticulture production [1]. This area is characterized by being a semi-desert zone, which thanks to the irrigation supplied by this river, is transformed into a productive agricultural area. CNEA's (Atomic Energy National Commission, by its initials in Spanish) commitment to maintain and constantly improve its relationship with the environment according its environmental policy, ensuring that environmental factors, specially water courses are not affected by the activities developed in the mining complex, has led to the development of an extensive monitoring plan to evaluate the quality of the water resource. In the same way, the concern of the population near the site turns into strict controls of the water factor by the control organisms: the DGI (Irrigation General Department, by its initials in Spanish) and the ARN (Nuclear Regulatory Authority, by its initials in Spanish), the former provincial and the latter national. MONITORING PLANS From the very beginning of the activities developed in the Sierra Pintada uranium deposit, the controls of the different environmental variables were carried out, with special emphasis on the water resource. CNEA has a wide network of water monitoring, internal and external to the mining complex. The quality of this resource is verified in the environmental laboratory located in the CMFSR, wich is certified by the Argentine Accreditation Organism for the technique of uranium determination in samples of surface and underground water. The main objective of the water monitoring plan is to analyze the temporal and spatial evolution of the parameters and to have data available to detect possible anomalies or incidents and, where appropriate, evaluate them and make evolutionary predictions. The current network includes 45 points for groundwater, of which 29 are internal wells to the deposit area, and 32 points for surface water, of which 17 are internal, the rest are outside the boundaries of the Complex in areas of interest for nearby populations. The regularity of the sampling in each of these points, (monthly, bimonthly, quarterly or biannually) according to the needs of the site, was defined from the analysis of the seasonal variation, or not, of the normal behavior, after more than 40 years of compilation of data and experiences. On average about fifty different samples are analyzed monthly, which are studied for determination of physicochemical parameters (electrical conductivity, total dissolved solids, acidity, temperature), anions (chlorides, nitrates, sulfates, carbonates, bicarbonate, hydroxide), cations (ammonium, sodium, potassium, calcium, magnesium, lead, chromium, arsenic, mercury) and radiological parameters (uranium and radio-222). Special emphasis is placed on 8 control points measured monthly, 4 of surface water and 4 of groundwater, which can give an environmental diagnosis of the situation of water quality in the area. These points are strategically located upstream and downstream of the Complex, and allow to correlate the contribution of the deposit to the values of uranium, since the water courses pass through a highly mineralized zone. Regarding to surface water, the most significant control points are upstream and downstream of the CMFSR in both El Tigre and Diamante streams. This allows to know, if exists, the variation in uranium values with that the mineralized zone contributes to the modification of water quality. Both the Mining Code (National Law 24.585) and the Provincial Law 5961, Decree 820/2006 establish a limit of 100 μgU/l as the permitted limit in water for human consumption. The same maximum limit is allowed for the discharge of liquids to receiving bodies according to Resolution number 647/00 of the General Irrigation Department. In the case of El Tigre brook, which has an average flow of 0.16 m3/s, before entering the mineralized zone, the current brings on average 3.94 μgU/l and leaves it with an average of 12.31 μgU/l, this means an increase of more than 200%. As to the Diamante River, which has an average flow of 28.25 m3/s, upstream of the mouth of the El Tigre stream, it brings on average 1.57 μgU/l and waters below it with an average of 2.028 μgU/l, this means an increase of 30%, which is contributed by the brook. Regarding to groundwater, the most significant control points are two upstream and two downstream of the CMFSR, strategically located according to the direction of groundwater flow. The average values are around 15 μgU/l. The analyses are carried out in the environmental laboratory of the Complex, since it has technology to fulfill studies. It is equipped with an atomic absorption spectrophotometer for the determination of metallic elements and an ion chromatograph for the determination of anions. The laboratory can provide the analytical service for environmental samples, not only of ground and surface water, but also of sediments. In the year 2014 the laboratory was able to accredit the laser fluorimetric determination of uranium in water technique, through the OAA (Argentine Accreditation Organization, according to its initials in Spanish), since it meets high quality standards. It is important to mention that there are no others laboratories with this high degree of quality in the nearby, including the laboratories from the control organisms. With respect to the air factor, radon levels are monitored periodically in both the CMFSR area and nearby populations. A study is currently underway to model the transport of particulate matter in the atmosphere to implement a new air quality monitoring plan. CONTROL ORGANISMS Due to the concern of the population of the area adjacent to the Mining Complex, and the importance of the Diamante River for the area of influence of the CNEA facilities, the control authorities carries out periodic checks on the activities developed in the facilities and their impact on the environment. On the one hand, the General Department of Irrigation (DGI), through the Sub Delegation of the Diamante River, takes samples of water, which are analyzed by the National University of Cuyo. The DGI takes the samples at the exit of the industrialized zone for the El Tigre brook and downstream from the mouth of the same in the Diamante River. The average values of uranium content are 16.62 μgU/l and 1.74 μgU/l respectively, which are concordant with those measured by CNEA. In all the measurements made by this control body, the measured values are lower than the limits allowed by Resolution number 647/00. At a national level, the control is carried out by the ARN (Nuclear Regulatory Authority, according to its initials in Spanish), taking samples of both air (to control the levels of Radon gas) and surface water with an annual periodicity. The ARN has approved the water and sediment monitoring plans and analyzes both the results of its monitoring and those reported monthly by CNEA, submitting quarterly reports that conclude, until now, that the levels of uranium in the water courses surrounding the deposit are at normal levels, and below the allowed limits. This corroborates CNEA's commitment to the environmental policy on the site. The results of the analyzes implemented by the ARN on the channel of the El Tigre brook give average values of 3.9 μgU/l waters below the mineralized zone and 13.3 μgU/l upstream of the same, with registered maximum values of 6.3 ± 0.3 μgU/l and 29.0 ± 3.5 μgU/l respectively. While in the Diamante River the average values measured by this control organism are 1.2 μgU/l upstream from the mouth of the El Tigre stream and 1.4 μgU/l downstream, with historical maximums of 3.0 ± 0.7 μgU/l 2.9 ± 0.5 μgU/l respectively [2]. The ARN concludes in its reports that the values reported by the CNEA are compatible with the results of the routine monitoring carried out by the control organism and that, on the other hand, they are lower than the guideline established by the World Health Organization for drinking water of 30 μgU/l. CONCLUSIONS During the productive and the subsequent stages, no values were recorded above those allowed in the water courses of the El Tigre stream and the Diamante River, demonstrated not only by the own monitoring, but also by those carried out by the Irrigation General Department and the Nuclear Regulatory Authority. Over 40 years of CNEA activities in the area, with almost 20 years using sulfuric acid for the process of treating the minerals, there has been no alteration in the quality of the surface or underground water, since the beginning of the production activities of uranium concentrates in 1979, suitable methodologies were used for handling of acid solutions and for the management of process effluents. In all these time, CNEA maintains its commitment to the care of the environment, through the implementation of its environmental policy and putting into practice the concept of continuous improvement to ensure sustainable environmental management. REFERENCES [1] IRRIGATION GENERAL DEPARTMENT – MENDOZA PROVINCE, Aquabook, 2016, http://aquabook.agua.gob.ar [2] NUCLEAR REGULATORY AUTHORITY – SCA Nº09/17. Evaluation of the monthly reports of control points of surface and groundwater of the CMFSR, corresponding to the third quarter of 2016.

Speaker: Ms Marisa Arrondo (Atomic Energy National Commission)

110 Evaluation of the opportunity of production of uranium from phosphorite ore

INTRODUCTION The bulk of the unconventional uranium resources worldwide is associated with phosphorite ores. Despite the ongoing depression in the world uranium markets, intense research is underway in various countries with an objective of developing cost-effective ways of uranium recovery from non-conventional resources. The world phosphorous pentoxide (Р2О5) per year is about 50 Mt, including 9,5 Mt in North America, 9,4 Mt in Africa and 19,2 Mt in Asia. Up to 15 400 tU is contained in phosphorite ores mined worldwide each year, , while practically no uranium production has been reported. The value of uranium produced as a minor by-product during the phosphate fertilizer production is negligible when compared to value of the main product (phosphate fertilizers). Hence, the phosphate fertilizers market acts as a determining factor of how much uranium contained in the phosphate resources can be produced, and of its production cost parameters which are closely tied to the fertilizer production economy. DESCRIPTION According to the traditional technology, uranium is recovered from wet-process phosphoric acid using SX-based flowcharts, with octylpyrophosphoric acid (OPPA), di(2-ethylhexyl)phosphoric acid coupled with trioctylphosphinic oxide (DHEPA–TOPO), and octylphenylphosphoric acid (OPAP) used as extractants. The preliminary reduction of U(VI) to U(IV) is traditionally performed by adding iron powder (specific consumption of the iron powder being 8 kg/m3 of the source solution). In 2009, Urtek LLC developed an alternative uranium recovery technology from phosphorites named PhosEnergy and successively piloted it in Australia and the US. The novel technology features ordinary IX sorption of uranium from the wet-process phosphoric acid followed by its desorption and yellowcake production using traditional methods. Wet-process phosphoric acid (20 – 40 % Н3РО4) coming directly from the phosphorite sulfuric acid treatment is used as the uranium source for the PhosEnergy process. The uranium sorption is combined with its oxidation from U(IV) to U(VI). The phosphoric acid, thus purified of uranium, is then returned to the main process stream. The PhosEnergy process can be essentially described as the decontamination of the wet-process phosphoric acid of U и V without any waste or refuse forming. In the former USSR lean complex phosphate-type ores of Melovoye and Tasmurun deposits were mined for uranium. The ores of those deposits are represented by exotic uranium-rare metal-phosphate-containing bone detritus hosted by Maikop (Oligocenic – Early Miocenic) clays originating from outer deep sea depressions of the vast marine paleobasin of Eastern Paratetis. Skeletal detritus of various marine paleofauna in which the original bone tissue was replaced by francolite – a phosphate mineral – is uniformly distributed throughout the ore mass. Both U and REEs are contained in the crystallic structure of francolite partially replacing calcium ions of the lattice, with the other valuable elements concentrated in pyrite also contained in the ores. The yttrium-group REE grade in the ores is uniquely high, totalling about 30 – 35 % of the overall REE grade. The uranium reserves of Melovoye deposit – the largest ore deposit of the Transcaspian uranium region (Kazakhstan) – were put at 44 000 tU. The uranium recovery from the lean ores (<0,05 % U) was conducted by means of the hydraulic separation of the bone concentrate and the subsequent production of phosphate fertilisers from it during which process not only uranium but also valuable minor by-products were recovered (thorium, REE, scandium, sulfur) [3]. The above-mentioned francolite concentrate produced by the hydraulic separation pre-concentration process consisted mainly of francolite with minor admixture of residual clay and pyrite. On the average, the concentrate contained ca. 25% Р2О5, up to 1% Ln2О3, 0,2% U and up to 0,04 % Sc. The dissolution of the concentrate was performed by using sulfuric acid or a sulfuric acid-nitric acid mix taken stoichiometrically against the CaO contents in the concentrate [1]. The recovery of uranium from the resulting acid digestion solutions was conducted via SX with the final product being U3O8. During the SX process, iron and scandium are co-extracted into the organic phase while both phosphorus and REE remained in the raffinate. Following the stripping of uranium from the organic phase, the stripping of scandium was made with 99,9 % Sc2O3 finally produced as a by-product [1, 2]. Following the recovery of uranium and the valuable by-products the acid technology solutions containing both phosphate and the residual sulfuric acid were further treated to produce a granulated complex ammophos-type fertiliser containing in excess of 50 % of N and P2O5. The fertiliser production process consisted of the ammonisation of the source solution followed by further concentration for which countercurrent multiple-effect evaporation scheme was employed. The resulting concentrated slurry was then granulated, dried, chipped and classified before packaging and shipping [1]. The final products of the ore processing, along with the fertilisers, were U3О8, REE oxides and Sc2O3. The total percentage recovery of the target elements stood as follows: U - 93%, REE - 54%, Sc - 70%, Р2О5 - 85,5% from the respective source ore grades. The technology described above was implemented in 1969 at Almaz Production Association (Lermontov town) and had been used with some minor adjustments until 1991. The processing of the ore concentrates sourced from Melovoye deposit had been conducted at a plant in Dneprodzerzhinsk until 1989. The Yergeninsky uranium ore district situated in the Republic of Kalmykia is a Russian Federation analog of Melovoye deposit. It comprises 13 uranium deposits hosted in Oligocenic to Early Miocenic clay sediments of the Maikop series, featuring the above-mentioned complex uranium-phosphate-rare earth ores. The resource estimate for these as represented by the author calculations is 59 000 tU, 84 620 t P and 260 000 t REE. The Shargadyk deposit is the most extensively studied one of the Yergeninsky ore district. The resources of the deposit to be commercialized are uranium, phosphates and REE. The main ore constituent is fossilized bone detritus (15 – 45 % of the bulk ore) which contains the uranium and the REE resources. The detritus is associated with varying proportions of minor ferric sulfide, clay and carbonate constituents. It is essentially a calcium phosphate-based mineral matter mineralogically very similar to hydroxylised carbonated fluorapatite, containing some minor organic impurities. In 2015 – 2016, a pilot plant run was conducted at the Shargadyk deposit to test the possibility of the target metal recovery from the ores by heap leaching. The sulfuric acid solution leaching of the agglomerated ore was successfully tested. The source ore was crushed to 100 % – 20 mm and then agglomerated before the leaching. The resulting ore agglomerate was placed into percolation columns measuring 1 m in diameter and 5 m in height. During the ensuing sulfuric acid percolation leaching U, REE, Ni, Co along with P2O5 became dissolved for subsequent separation and recovery of individual products from the resulting solutions using ion exchange sorption (IX) and selective precipitation. The results obtained during the pilot plant run were a sufficient ground to recommend the heap leach processing of Shargadyk deposit ores occurring at the depth of up to 120 m., which can easily be mined using the open-pit method. The prospective process flowchart tested and streamlined during the pilot plant operation comprises the following stages and operations: 1. Ore preparation (mining, crushing, agglomeration, heap stacking): • Ore delivery to the heap leach site using dump trucks combined with the simultaneous transporting of the leached ore for dumping to old excavated parts of the open pit (up to 1500 t/day; • The ore crushing to 100 % – 20 mm (up to 100 t/hr); • The agglomeration of the crushed ore with concentrated sulfuric acid and sodium silicate to be added into the process. The agglomerate is to be produced in a pipe-type agglomerator. The ore throughput rate: up to 100t/hr; • The stacking and formation of the ore heaps using a heap stacker with the subsequent pipelining at the rate of one heap (84 000 t of the agglomerated ore) every 2 months (up to 1500 t ore per day). 2. The heap leaching of the ore heaps comprising the following operations: • The three-stage heap leaching at the rate of 6 ore heaps per annum (84 000 t of the agglomerated ore each). Two ore heaps are to be leached at a time to produce the heap leach solutions at the mean rate of 230 m3/hr with the collection of the drainage into the collector ponds. • The heap leach solutions are to be collected into 5 collector ponds as follows: 2 individual collector ponds No.1 and 2 (V = 25 000 m3 each) are to receive Stage 1 heap leach solutions (one to serve as a drainage reception unit, the other – as an evaporation pond). Collector pond No.3 (V = 5 000 m3) is to receive Stage 2 heap leach solutions, collector pond No.4 (V = 5 000 m3) is to receive Stage 3 heap leach solutions . One collector pond (V = 10 000 m3) is to be used for collecting the barren solutions to be pumped back to the irrigation. 3.The pregnant solution processing. • The IX sorption of nickel and cobalt to Lewatit TP 207 ionite to produce the Ni-Co concentrate. • The IX sorption of uranium to Lewatit K 1000 ionite to produce the U concentrate. • Adding magnesia (MgO) to the pregnant solution from the above operation to produce three separate phosphate precipitates of Fe, REE and Mg. • The sintering of the iron and REE phosphate products (10 t/hr) with sodium carbonate (5 t/hr) in a natural gas-heated tube kiln at 7000С. • Hot water leaching of sodium phosphate from the sintering product followed by the precipitation of secondary magnesium phosphate with sodium sulfate solution as a by-product. • The addition of sulfuric acid solution to the precipitates of the primary and secondary magnesium phosphate to produce a solution containing phosphoric acid and magnesium sulfate. • Adding lime to the above solution to produce a superphosphate precipitate and a magnesium sulfate solution. The rinsed residue of the hot water leaching of sodium phosphate from the sintering product is to be leached with 50 g/l H2SO4 for REE; the solution is to be treated with oxalic acid to produce the REE oxalate concentrate containing ca. 50% REE (3 kg of the concentrate/t ore); the oxalic acid leaching residue is then to be calcined to produce ferric cake (43 kg of the cake/t ore), containing 180 g/t Sc and 45% Fe2О3. • The evaporation of the post-precipitation solutions to produce magnesium sulfate and sodium sulfate products (5 t/hr each) by crystallization. The marketable products of the project are: superphosphate (P2O5 grade 27 %, according to Russian technical specifications (ТУ 2182-003-56937109-2002), uranium concentrate (ammonium polyuranate, grade no less than 60 % U according to Russian technical specifications ТУ – 95.2822.2002), a 50 % nickel-cobalt hydroxide mix concentrate (Ni – 37 %, Co – 13 %), a mixed hydroxide-oxalate REE concentrate, containing ca. 50 % REE+Y. Marketable side products obtained during the utilisation of the leaching chemicals are sodium sulfate. technical grade (grade 2 according to Russian Federation state standard GOST 6318-77), magnesium sulfate heptahydrate (GOST 4523-77), construction-grade sand (GOST 8736-2014). The summary recovery rates for the key elements have been confirmed to be as follows: U – 84 %, Ni – 76 %, Co – 61 %, ∑ REE+Y - 63 %, P2O5 – 77 %, with the respective average content values in the dewatered source ore: U – 0,035 %, Ni – 0,05 %, Co – 0,02 %, ∑ REE+Y - 0,28 %, P2O5 – 11 %. The solid wastes of the project are ore processing tailings (mainly phosphogypsum), which are to be used as a backfill for the ore pit upon depletion, and the ferric residue containing 180 g/t Sc to be stored on-site for the recovery of scandium in the future. The value breakdown for the final products of the proposed heap leach plant looks as follows: superphosphate (53 %), followed by uranium concentrate (17,6 %), sodium sulfate (10,8 %) and the REE concentrate (9,6 %). DISCUSSION AND CONCLUSION The feasibility analysis was calculated proceeding from the discount rates set at 10 % and 15 %. The ore resources of the projected plant are sufficient for the 39 years of operation. The planning horizon used was assumed to equal 17 years. The feasibility analysis conducted backs up the potential commercial profitability of the development and exploitation of the Shargadyk deposit resources. In case the discount rate is set at 10 %, the NPV (net present value) is to total RUR 2661,4 million, the yield index – 1,2, the internal rate of return (IRR) stands at 14,4 %, the discounted payback period is 9,5 years while the discounted budget efficiency totals RUR 4607,1 million. The main conclusions from the above pilot plant test results: – In the market scenario, the recovery of uranium and the associated metals from Shargadyk complex phosphate ore deposit will be considered only when it is economically viable to do so. – The development of the Shargadyk deposit of complex uranium-phosphate-rare earth ores looks commercially profitable. The development project displays fairly high commercial and internal financial efficiency values in case the discount rate stands at 10%, yet the efficiency looks to be problematic in case the discount rate of 15 % is adopted. REFERENCES [1]. Гидрометаллургическая переработка уранорудного сырья. Под ред. Д.И. Скороварова/ М.: Атомиздат, 1979. 280 с. [2]. Никонов В.И., Смирнов К.М., Меньшиков Ю.А., Крылова О.К., Маликов В.А. Разработка технологических решений для переработки уранофосфорных руд/ В сб.: ВНИИХТ-60 лет. Под ред. Г.А. Сарычева. М.: ООО «Леонардо-Дизайн», 2011. С. 145-149.

Speaker: Mr Grigory Mashkovtsev (All-Russian Scientific-Research Institute of Mineral Resources)

111 GEOCHEMICAL AND MINERALOGICAL CHARACTERIZATION OF THE URANIFEROUS PHOSPHATE ROCKS OF THE NAVAY FORMATION, TÁCHIRA STATE, VENEZUELA

INTRODUCTION Through the CRP IAEA T11007 a geochemical and mineralogical characterization study of the uraniferous phosphate rocks of the Navay Formation, Táchira state, Venezuela. Phosphates deposit associated with sandstones in the top levels of the Navay Fm. (Upper Cretaceous) in southwest of Táchira state, Venezuela, was discovered in early 1978 by radiometric surveys, conducted by Ministry of Energy and Mines by The National Commission of Nuclear Affair (CONAN). This consists of siliceous shales, calcareous shales, uraniferous phosphatic sandstones and, cherts (“ftanites”) [1]. To date there have been studies on the feasibility of exploiting to produce phosphate fertilizers. There have been no studies on uranium mining. METHODS AND RESULTS Mineralogical analysis. Petrographic and mineralogical analyzes by X Ray Diffraction (XRD) it was obtained that the main minerals that make are fluorapatite/chlorapatite (Ca5(PO4)3(F,Cl), collophane or carbonate fluorapatite which is a compositional variant of apatite (Ca5(PO4,CO3)F), uranospathite (Al1-x[ ]x[(UO2)(PO4)]2(H2O)20+3xF1-3x), quartz (SiO2) (4 – 88 %), calcite (CaCO3) (10 – 35 %), montmorillonite ((Na,Ca)0,3(Al,Mg)2Si4O10(OH)2) (maximum 6 %), and, microcline (KAlSi3O8) (maximum 1,43 % %) mainly. The mineralogical studies show the uranium to be present in the following forms: • Fluorapatite – carbonate fluorapatite (28-75%). • Uranospathite (2-3%). Chemical analysis. Chemical analysis was done by several techniques: portable X Ray Fluorescence (pXRF), Total Reflection X-Ray Fluorescence (TRXRF) and, Inductively Coupled Plasma – Atomic Emission Spectroscopy (ICP AES). According to this the background of the concentration of U is 102 ppm, reaching a maximum value of 160 ppm in a calcareous phosphatic sandstone, what is within the average range of U in marine phosphate rocks (50-300 ppm U) [2]. Sub anomalous values were determined statistically Cd (82 ppm), Cu (261 ppm), Zn (268 ppm), Sr (1832 ppm), Zr (510 ppm) and, anomalous values of Cr (1653 ppm). In addition, maximum values of majority, minority and trace elements were detected: MgO (12.40 %), Al2O3 (9.60 %), K2O (3.07 %), Fe2O3 (1.25 %), MnO (0.05 %), TiO2 (0.35 %), S (1.31 %), Cl (1.07 %), V (82 ppm), Ni (2083 ppm), Pb (86 ppm), Co (199 ppm) and, Rb (91 ppm). According to the chemical composition of the samples, most correspond to phosphate rocks (median 17.25 % and maximum 24.81 % of P2O5), quartz sandstones (median 25.60 % and maximum 88.70 % of SiO2) and phosphate limestones (median 27.88 % and maximum 70.40 % of CaO) [3]. Gamma Spectrometry. Gamma spectrometry analysis was also done on several samples of the deposit, in which 226Ra was detected, which may be present in the apatite either replacing the Ca2+ (geochemical affinity) or by the radioactive decay of the 238U series. Other isotopes of this decay series were detected (214Pb and 214Bi). DISCUSSION AND CONCLUSION Mineralogy composition. Fluorapatite has been identified as the main phosphate mineral, which in some cases contains carbonate in its structure (CO32-), which is common in this group of minerals where carbonate ions can replace phosphate ions (PO43-) [4]. The U is hosted in the apatite because the U4+ (ionic radio 0.97 Å) can replace the Ca2+ (ionic radio 0.99 Å) [5]. The presence of uranospathite has been detected by XRD, which is a secondary phosphate of Al and U belonging to the autunite group formed as a result of the weathering of primary phosphates in humid environments [6]. The presence of autunite and wavelite is not ruled out, which have been identified in samples from La Lucha River in Táchira state [1]. The mineralogy is typical of marine phosphatic deposits. Some samples in thin sections were studied by petrography, where they determined that the samples correspond to sandstones phosphatizing, limestones phosphatizing and micritization of peloids. The fossil Orthokarstenia ewaldi of lower Cretaceous period Maastrichtian age, which indicates a shallow marine environment, was identified by means of petrographic analysis, it is a foraminifera associated with this type of environment [7-8]. The Navay deposit is sandy phosphorites type, formed during the lower Cretacic, probably by currents upwelling, which produced the deposit of these sediments. Constitute a lithological facies deposited in shallow waters while cutting lines and is locally Campanian-Maastrichtian age [9]. The Navay Formation is a lateral equivalent of the La Luna Fm. in western Venezuela, which contains black phosphorites and black shales hydrocarbon-generating [10]. Chemical composition. The chemical analyzes it was obtained that the U and Ca correlates with the P, indicating that the mineral that host is the apatite. There are strong correlations between P - Y (0.72) which may indicate the presence of yttrium in the mineral phosphates, Ca - Mg (calcite), Ca - Sr (substitution of Sr2+ by Ca2+), Si with Al and K (silicates as microcline and clays such as montmorillonite), Fe -S (possibly forming sulphides), Fe-V (associated in detrital oxides and/or in organic matter), S - V (possibly in organic matter), U with V and Ni ( probably associated with organic matter, as well as the strong V - Ni correlation, which may be geochemically associated with porphyrins [11-12]. In several samples yttrium (Y) was detected, which is associated with phosphates, this may be due to ionic substitutions of Y3+ (ionic radio 0,93 Å) in the structure of the apatite by Ca2+ (ionic radio 0,99 Å). It is recommended to perform REE analysis using ICP-MS or another analytical technique, since they could not be detected using the techniques used in this research. The REE can be included in the phosphate minerals, due to their geochemical affinity [2]. By calculating elementary relationships V/Cr - V/V+Ni V/Ni, Navay sediments were deposited under oxic conditions, without replacement, using the Ni/Co ratio, several samples indicate that these sediments were deposited under sub-oxic to anoxic conditions [13-14]. This difference may be due to the fact that there were redox changes during sedimentation, as a result of upwelling currents that brought oxygen-poor water from the bottom to the surface. On the other hand, there may be remobilization, that is, secondary dispersion of several of these elements are redox sensitive and under oxidative conditions by weathering, they have been oxidized and/or dispersed in the deposit. Gamma spectrometry analysis. According to the analysis of gamma spectrometry of surface samples and cores, a concentration of average activity of 226Ra of 2100 Bq/kg was detected, in addition to other isotopes of the decay series of 238U were detected. The 226Ra was measured (by the 214Pb and 214Bi measure) and 234Th directly through issuance of 63 keV. The low contrast concentrations activity of the isotope 232Th series and 40K not detected by this technique. This implies that there are low concentrations of thorium in the deposit, what corresponds to geochemical environments of this type, in which the U is mobilized as U6+ (uranyl ion UO22+), fixed in the apatite as U4+ under reducing conditions, while the Th4+ is immobile in superficial environments, for which its concentration is low in this type of deposits. By the analysis of gamma spectrometry 226Ra was detected, as well as other isotopes of the decay series of the 238U, however, no isotopes of the 232Th or 40K series were detected. Conclusions. The mineralogy of Navay Fm. is typical of marine phosphatic deposits with fluorapatite/chlorapatite, collophane or carbonate fluorapatite which is a compositional variant of apatite (Ca5(PO4,CO3)F), uranospathite, quartz and, calcite mainly. The presence of autunite and wavelite is not ruled out, which have been identified in samples from La Lucha River in Táchira state, in outcrop Navay Fm. The mineralogical studies show the uranium to be present in the following forms: apatite (28-75%) and, uranospathite (2-3%). The fossil Orthokarstenia ewaldi of lower Cretaceous period Maastrichtian age, which indicates a shallow marine environment, was identified by means of petrographic analysis According to chemical analysis the background of the concentration of U is 102 ppm, reaching a maximum value of 160 ppm in a calcareous phosphatic sandstone, so it can be considered a deposit of uranium as unconventional according to the U grade. Statistically sub anomalous values were determined Cd (82 ppm), Cu (261 ppm), Zn (268 ppm), Sr (1832 ppm), Zr (510 ppm) and, anomalous values of Cr (1653 ppm), these are considered elements of interest because of their association geochemical with uranium and phosphates. In several samples yttrium (Y) was detected (Y max. 144 ppm), which is associated with phosphates, it is recommended to perform REE analysis using ICP-MS or another analytical technique, since they could not be detected using the techniques used in this research. By calculating elementary relationships V/Cr - V/V+Ni V/Ni, Navay sediments were deposited under oxic conditions, but using the Ni/Co ratio, several samples indicate that these sediments were deposited under sub-oxic to anoxic conditions, this difference may be due to the fact that there were redox changes during sedimentation, as a result of upwelling currents that brought oxygen-poor water from the bottom to the surface. REFERENCES [1] CÁRDENAS, H., Historia de Caso: El descubrimiento e Investigaciones preliminares de los Fosfatos Uraníferos asociados a las Formaciones Navay-Burgüita, sectores Las Tapas–La Lucha-Fila El Toro, Parroquia San Joaquín de Navay, Municipio Libertador, Estado Táchira. Período 1978-1979, Petroquímica de Venezuela S. A. (PEQUIVEN) (unpublished report) (2007) 1-27 (in spanish). [2] CUNEY, M., KYSER, K., Recent and not-so-recent developments in uranium deposits and implications for exploration, Short Course Series, Mineralogical Association of Canada, Quebec City, Quebec 39 (2008) 1-259. [3] BOGGS, S., Petrology of Sedimentray Rocks, 2nd Ed, Cambridge University Press (2009) 1-612. [4] KNUDSEN, A., GUNTER, M., Sedimentary Phosphorites – An Example: Phosphoria Formation, Southeastern Idaho, U.S.A., Reviews in Mineralogy and Geochemistry 48 1 (2002) 363. [5] BRUNETON, P., CUNEY, M., Geology of uranium deposits, Uranium for Nuclear Power, Resources, Mining and Transformation to Fuel 1 (2016) 11. [6] LOCOCK, A., et al., The structure and composition of uranospathite, Al1–x_x[(UO2)(PO4)]2(H2O)20+3xF1–3x, 0 < x < 0.33, a non-centrosymmetric fluorine-bearing mineral of the autunite group, and of a related synthetic lower hydrate, Al0.67_0.33[(UO2)(PO4)]2(H2O)15.5, The Canadian Mineralogist 43 (2005) 989. [7] CRUZ, L., et al., Caracterización físico química, taxonomía y ecología de orthokarstenia ewaldi (foraminiferida: siphogenerinoididae) de la Formación Los Pinos (cretácico: maastrichtiano) de Samacá (Boyacá, Colombia), Boletín de Geología 33 2 (2011) 95 (in spanish). [8] PARRA, M., et al., Late Cretaceous Anoxia and Lateral Microfacies Changes in the Tres Esquinas Member, La Luna Formation, Western Venezuela, Palaios 18 4-5 (2003) 321. [9] KISER, G., Review of the Cretaceous stratigraphy of the Barinas mountain front, Boletin A.V. G. M. P. 11 (1961) 335. [10] APPLETON, J, D., NOTHOLT, A, J, G., Local phosphate resources for sustainable development in central and south America, Economic Minerals and Geochemical Baseline Program, Report CR/02/122/N, British Geological Survey, Natural Environment Research Council, Keyworth, Nottingham (2002) 1-102. [11] GAO, Y, Y., et al., Vanadium: Global (bio) geochemistry, Chemical Geology 417 (2014) 68. [12] HUANG, J, H., et al., Distribution of Nickel and Vanadium in Venezuelan Crude Oil, Petroleum Science and Technology 31 (2013) 509. [13] SÁEZ, R., et al., Black shales and massive sulphide deposits: causal or casual relationships? Insights from Rammelsberg, Tharsis, and Draa Sfar, Miner Deposita 46 (2011) 585. [14] JONES, B., MANNING, D., Comparison of geochemical indices used for the interpretation of paleoredox conditions in ancient mudstones, Chemical Geology 111 (1994) 111.

Speaker: Mr John Manrique (Universidad Técnica Particular de Loja)

112 Geochemical and mineralogical studies of uranium potential of the late Devonian to early Carboniferous Takoradi Black Shale, Sekondian Group, Ghana

Geochemical and mineralogical studies were carried out on the Late Devonian to early Carboniferous Takoradi Shale Formation (TSF) of Sekondian Group, Ghana to investigate its potential to host uranium, thorium and other trace elements. The TSF is typically composed of hard, compact, black/dark grey fissile shale/sandy shale, rich in organic matter, and its upper part is characterised by inclusions of large discoidal siderite nodules. Mineralogical studies of the shales were performed by powder X-ray diffraction. The main mineral phases identified include quartz, vermiculite, zeolite and other clay minerals as well as uranium oxide and uranyl-oxide minerals. Whole-rock geochemical analysis of 19 representative black shale samples by ICP-MS has revealed Th and U concentrations of 18.05–22.06 ppm and 6.89–8.99 ppm, respectively. Thorium, Zr, Nb, Ta, V, La, total REEs and Ti which are typically enriched in uraniferous black shales are also enriched in the Takoradi Shales relative to Post-Archean Average Australian Shale. Uranium shows strong positive correlation with compatible trace elements such as Cr, V, Zr and Ni. Further studies will be conducted to confirm these elemental associations and the low uranium potential of the Takoradi Shale Formation.

Speaker: Samuel Boakye Dampare (School of Nuclear and Allied Sciences, University of Ghana - Atomic, Kwabenya, Accra, Ghana)

113 Geological and geochemical characteristics of the Jiling Na-metasomatism uranium deposit, Gansu, China.

The metasomatite-related uranium deposit hosts the second largest uranium resource repository in all deposit types. It widespread distributes in Australia, Brazil, Russian, and Ukraine, but rarely presents in China. The Na-metasomatism-related uranium deposit in the Jiling area, northwest China was selected to investigate the genesis. The petrology indicates that late-magmatic albitization was followed by chlorite alteration of biotite and feldspar. The major uranium minerals are uraninite and brannerite. A large amount of uranium minerals occur in fractures in the newly formed albite and chlorite, indicating the main mineralization stage occurred later than albitization and chloritization. The geochemistry reveals that the Jiling granitoids belong to A-type granitoids and generated by mingling between the crust- and mantle-derived magmas. The high Th/U ratios (2.76 to 10.63) of the Jiling granitoids can provide uranium for mineralization. Compared to the fresh granitoids, the mineralized granitoids display high Na, U, low K, Si contents, and LREE/HREE ratios. H, O, and C isotope reveal that the CO2 originated from the mantle, and H2O in hydrothermal fluid from mixing between magmatic hydrothermal and meteoric water. Pb isotope reveals that the uranium may derive from the host granitoids.

Speaker: Dr Kai-Xing Wang (East China University of Technology)

114 Geological samples pinpoint for nuclear forensics examination in Thailand

INTRODUCTION Nuclear forensics laboratory was established in 2013 at Office of Atoms for Peace (OAP), Ministry of Science and Technology, Thailand [1]. One of the purposes is to collect the data of uranium and thorium resources in Thailand. Thus, we signed up Memorandum of Understand (MOU) among Department of mineral resources (DMR), Ministry of Natural Resources and Environment and Thailand Institute of Nuclear Technology (TINT), Ministry of Science and Technology. The purposes of the MOU are incorporate and information sharing about rare-earth elements (REE), Naturally Occurring Radioactive Material (NORM); knowledge management for mineral resources; NORM monitoring; develop national nuclear forensics database ; and develop REE and nuclear materials determination techniques [2]. Uranium (U), thorium (Th) and other rare-earth elements (REE) which are occurred with monazite ore, was surveyed by DMR. The results show that U, Th and REE are mutually associated with Tin and wolfram minerals, while REE occurs in the form of phosphate mineral. In early 1970’s, the geologist discovered of REE and other heavy minerals in significant amount as secondary deposits and alluvial with tin deposits in southern part of Thailand [3]. In 1980’s DMR corporated with Japan International Cooperation Agency (JICA) examined REE mineral deposits in northern part of Thailand. The highest REE contents which found in the southern part of Thailand which contents 0.092% [4]. In 2014, Kritsananuwat, R., et al. studied for the amount of REE, Th and U concentration in marine sediments along the Gulf of Thailand, they found the group of correlation between the source and type of elements [5]. In the present, there are several techniques to identify the major and trace element in geological samples. The data from many analytical methods can be used for nuclear forensics aspect. It is meant that scientists look after the nuclear forensics signatures from geological samples. Nuclear forensics is the procedure for determine the origin of radioactive materials, nuclear materials and contaminated evidences. Nuclear forensic laboratory can afford the analysis samples in order to identify material types, manufacturing company, and fabrication process in terms of support the investigation. [6]. Mary Kathleen mine, uranium mine in Australia, is a classical case study for combined nuclear forensics capabilities with mining resources [7]. This study compared the uranium and other trace elements concentration with the several sources, by using 13 characterization techniques. DESCRIPTION DMR collected geological samples from the Southern part of Thailand. After Nuclear Forensic Laboratory received 150 grinded geological samples from DMR. The samples were labeled, dried in an oven at 110 C for 3 hours, grinded, then they were keep in desiccators and room temperature. Nuclear forensics scientists examined the samples by using non-destructive analysis (NDA) and destructive analysis techniques. Characterization of samples The samples have 3 colors: light gray, brown and red. The samples were well-mixed or homogenized. We found that samples in the same area would be in the difference colors. For NDA techniques, we used 4 techniques: • Scanning Electron Microscope with Energy Dispersive Spectrometry (SEM/EDS) from Vega3 LMU (TESCAN, Brno Czech Republic) was examined surface and microstructure [5] of soil samples for magnification 13x up to 1,000,000x. We found that the heavy elements especially uranium, thorium and REE will be brighter than the other elements in back-scattering mode. Thus, SEM would be used to examine in geological samples which they have small amount of signature elements. • X-ray diffraction (XRD) with D2 Phaser (Bruker AXS GmbH, Germany) was used to study the crystal structures. We found 2 major crystal structures: quartz (SiO2) and microcline (KAlSi2O3) that have Silicon dioxide (SiO2) or quartz, Aluminium oxide (Al2O3) component. • X-ray fluorescence (XRF) by S1 TITAN (Bruker AXS GmbH, Germany) was identified the major elements in samples. Silicon dioxide (SiO2), Aluminium oxide (Al2O3) and Iron oxide (Fe2O3) are the major component of samples, respectively. • High Purity Germanium detector (HPGe) for Gamma Spectrometry (ORTEC Gem Series, USA) was used to measured radioactive material in samples. The samples were packed in wide-mouth bottle, around 150 grams per samples. The measurement time was 10,000 second per sample. We found natural radioactivity in samples such as potassium-40, thorium-232 and uranium-238. The variation of radionuclide components in the sample would be determined the distribution of geological source [8]. For DA method, we used Inductively Coupled Plasma – Mass Spectrometry (ICP-MS) from Agilent 7700x (Agilent, Japan). The samples were prepared to be a solution by using fluxer (K1 Prime Katanax, inc., Canada) which added some lithium borate fluxes. Then, the samples were determined major elements and trace elements (detection limit in part per billion) which were supported for nuclear forensics investigation. Because it is an accuracy techniques and it can be segregated small amount concentrations which gives information of the mining and/or rare earth ore processing [9]. DISCUSSION AND CONCLUSION The amount of several elements in geological samples can be identified source of origin. In this study, we found that the trace elements and REE are the signature of samples. The XRD spectra show that they would be quartz and microcline. Due to the samples are from many provinces in southern part of Thailand. It can be assumed that we can use the mineral resources (included uranium, thorium, REE and other trace elements) as the one of the nuclear forensics database in order to pinpoint the global positioning system (GPS) and compare to unknown sample location. The authors are thankful to Department of Mineral Resources and Thailand Institute of Nuclear Technology for their support of samples and data analysis record. We would like to give thanks for CBRN Centres of Excellence, Joint Research Centre Institute of Transuranium Elements for Project 30: Network of Excellence for Nuclear Forensics in South East Asia Region for supporting the SEM/EDX instrument. REFERENCES [1] CBRN Centres of Excellence Newsletter ISSN 1977-2742 (online), European Union, Volume 6 -June 2013, 16. [2] Memorandum of Understand for information sharing about rare-earth elements and radioactive materials between Department of mineral resources (DMR), Ministry of Natural Resources and Environment, Thailand Institute of Nuclear Technology (TINT), Ministry of Science and Technology and Office of Atoms for Peace (OAP), Ministry of Science and Technology, Thailand, 20 February 2017 (Thai language) 4 pages. [3] Charusiri, P., Sutthirat, C., and Daorerk, V., “Introduction to Rare – Earth Metal Resources in Thailand”, ICMR 2009 Keynote Session A1-3, 73-78. [4] Kritsananuwat, R., et al., “Distribution of rare earth elements, thorium and uranium in Gulf of Thailand’s sediments”, (Environmental Earth Sciences, September 2014). [5] INTERNATIONAL ATOMIC ENERGY AGENCY, Implementing Guide IAEA Nuclear Security Series No. 2-G (Rev. 1) Nuclear Forensics in Support of Investigations, IAEA, Vienna (2015). [6] Keegan, E. et. All., “Nuclear forensic analysis of an unknown uranium ore concentrate sample seized in a criminal investigation in Australia”, Forensic Science International, 240 (2014) 111-121. [7] Kritsananuwat, R., et al., “Natural radioactivity survey on soils originated from southern part of Thailand as potential sites for nuclear power plants from radiological viewpoint and risk assessment”, Journal of Radioanalytical and Nuclear Chemistry”, 302 (2) (2015) 487-499. [8] SGS MONGOLIA, Rare earth ore processing, SGS Minerals Services – T3 SGS 302, 10-2013. [9] DEPARTMENT OF MINERAL RESOURCES, Map of mineral deposit in Thailand: Mineral deposit and mineral resources in Thailand No.1, 2000, ISBN: 974-7733-35-8.

Speaker: Ms Kalaya Changkrueng (Office of Atoms for Peace)

115 GEOLOGY, MINERALOGY AND PETROGRAPHY OF ROCKS WITH RADIOACTIVE ELEMENT MINERALIZATION IN ANOMALY 6 OF THE KHOSHUMI AREA, ISLAMIC REPUBLIC OF IRAN

Khoshumi area is located in the Yazd province. It's part of the central Iran zone. The oldest rocks in this area are gneiss, micaschist and amphibolite. Based on microscopic studies, radioactive mineralization is relevant to gneiss and pegmatites. The main minerals in the gneiss are felsic minerals, biotite and amphibole. Pegmatitic rocks has mainly quartz, albite and pertite.Major alterations are potassic, sodic, siliceous and carbonate. Main mineralization is consist of three categories: REE minerals, radioactive and inactive minerals. The first category is includes zircon, zirconolite and etc. Radioactive minerals are Pitch-blend and uranium silicates such as coffnite. In the specimens, pitch-blend and uranium silicates hase granular texture, and aggregational to spheroial textures. Also, inactive minerals are a set of iron and titanium-bearing minerals. Mineralization in the Khoshumi area is related to pegmatitic and hydrothermal phases. These Phases are associated with enrichment in the REE, U, Cu, Mo, Ni and Th in some areas. In the Pegmatitic phase, enrichment of U and REE is occurred in zircon and allanite. Hydrothermal mineralization led to formation of minerals like pitch-blend and arsenopyrite. In the final stage.

Speaker: Dr Jalil Iranmanesh (Atomic Energy Organization of Iran)

116 HYDROMETALLURGICAL TESTS FOR VANADIUM EXTRACTION FROM BLACK LIMESTONES FROM PUYANGO SECTOR, LOJA PROVINCE, ECUADOR

INTRODUCTION The following study is directed to the vanadium hydrometallurgy, a trace element distributed throughout the earth's crust with great commercial and economic importance, used in the steel industry forming alloys with titanium (for aerospace applications) and iron in order to improve its mechanical properties such as hardness, resistance to fatigue and stress [1], in addition to its use as a catalyst in the form of vanadium pentaoxide, in the manufacture of sulfuric acid, replacing platinum and in the production of batteries (for example in Li3V2 (PO4)3 in batteries for electric cars) [2]. In the Puyango sector, Ecuador, geochemical anomalies of vanadium and uranium have been detected in samples of black bituminous limestones, with about 1.6% of V2O5. However, when starting from samples of a material different from that used in other countries, it is necessary to carry out a more specific study of the characterization (physical, chemical and mineralogical) of the samples, allowing to determine, analyze and obtain the necessary information of the composition of them, in addition to identifying the mineral phases to which vanadium is associated to carry out the hydrometallurgical tests using the acids necessary for the extraction thereof. METHODS AND RESULTS Preparation of the sample The sample was set to a series of processes of particle size reduction, starting with a primary fragmentation of the material into more manageable pieces and subsequent drying. Then a crushing was performed in a jaw crusher, until the material has a grain size of 2 mm. After this a homogenization was performed to obtain a representative sample, the technique of quartering (with device and manual) was used, from which 100 g of sample was taken and weighed to be pulverized in a disc mill, under operating conditions of three minutes and 700 rpm. The powdered has a D80 of mesh 200 (0.075 mm), granulometry used in the process. Determination of head grade of V2O5. A preliminary chemical analysis of the different samples collected in the sector was carried out to determine the percentage of V2O5 present in them, using portable X Ray Fluorescence (pXRF). From this sample, the highest percentage obtained was 1.6% of V2O5, which was used for subsequent processes. Mineralogical characterization. The mineralogical analysis was carried out through X Ray Diffraction (XRD) where the sample presented the following mineralogical composition: calcite (79%), quartz (15%), uranospatite (3%), apatite (1%), sherwoodite (1 %), and minor amounts (<1%) of illite, biotite, kaolinite, rossite and ronneburgite. Occurrence state of vanadium. Operating conditions were set such as the leaching time comprised in three hours, the solid/liquid ratio of 1:10, granulometry of 0.075 mm, conditions taken from other hydrometallurgical tests of vanadium [3,4,5]. For the agitation speed, 300 revolutions per minute were set, since in previous tests it was verified that at the speed of 200 rpm there was no longer any dependence between the agitation speed and the percentage of leaching [6]. Leaching with distilled water. 10 g of powdered sample were weighed in a beaker (in triplicate). To these samples were added 100 ml of distilled water and they were brought to constant agitation for a period of three hours at an agitation speed of 300 rpm, in this way all the material has contact with the water and the leaching is carried out [3]. For this procedure, the operating variables were the leaching temperatures of 35, 48 and 61˚C, which were fixed experimentally. After the leaching time the mixtures were allowed to settle for 10 minutes, the liquid was taken to centrifugation to completely separate it from the solid, a process that was carried out at 7830 rpm for a lapse of 15 minutes. The remaining solid was dried in an oven at 105 ˚C for 12 hours, this tail was finally analyzed by pXFR. To calculate the percentage of leaching, the percentage of V2O5 present in the head grade of the sample minus the percentage of V2O5 in the solid (leaching tail) result was taken as percentage, being the initial concentration of V2O5 100% vanadium present. In the sample used, a 6.25% leaching of V2O5 with distilled water was registered, a value that denoted the presence of vanadium (V) slightly absorbed in the surface of organic matter and detrital minerals. [3]. Leaching with hydrochloric acid (HCl). For this process, 5 g of pulverized sample were weighed in four beakers and the initial operating conditions were kept fixed, in addition to the leaching temperature, which was maintained at 25˚C to evaluate the action of the acid alone. on the sample, without the intervention of the temperature [3]. The operation variable was the concentration of hydrochloric acid. To each glass was added 50 ml of HCl of different concentration: 15%; 21%; 27% and 32%. These concentrations were established establishing a range of four percentages comprised within the highest concentration available in the laboratory, which was 32%. Once the time of three hours of leaching had passed, the mixture was allowed to settle, the liquid part was brought to centrifugation and the remaining solid was dried on a heating plate at a temperature of 150 ° C. For the reading of the resulting solid the pXRF equipment was used, by subtraction with respect to the initial concentration of V2O5 the percentage of leaching with HCl was obtained. To this result the percentage of V2O5 leached with distilled water was subtracted to obtain the percentage of vanadium (V) strongly absorbed in the surface of the organic matter and the detrital minerals that was of 43.11% of the sample used for the process [3]. Leaching with sulfuric acid (H2SO4). Finally, leaching was carried out with different concentrations of sulfuric acid, which was used due to the universal use for the leaching of vanadium in other projects consulted, in addition to the low percentage of aluminosilicates, which is why HF was not used [6]. As in the previous leaching, factors such as agitation speed, leaching time, solid / liquid ratio and temperature of 25˚C were kept constant. Four beakers of precipitation were prepared, where 5 g of pulverized sample was weighed in each one and 50 ml of sulfuric acid were added at different concentrations: 7%; 15%; 25% and 35%. As with HCl, it was decided to set these concentrations based on the highest available concentration of sulfuric acid. Leaching was carried out with higher concentrations of sulfuric acid (50% and 75%) but no better results were recorded than those previously obtained at lower concentrations. After three hours of leaching, the samples were allowed to settle and then the solid phase was separated from the liquid phase. The liquid was taken to centrifuge, where speed and time parameters of 7830 rpm and 15 minutes were set, respectively. The resulting solid was dried on a heating plate at 150 ° C, and analyzed by pXRF. The percentage of V2O5 leached with sulfuric acid was calculated with respect to the concentration of V2O5 present in the head grade, which in turn was subtracted the sum of the percentage of vanadium leached with distilled water plus the leaching with HCl to thus calculate the percentage shared between vanadium in state (V), which is strongly absorbed in the surface, and vanadium (IV) that is strongly linked to organic matter [3], which was 33.13%. When adding the three percentages of leaching (H2O + HCl + H2SO4) it is assumed to obtain the percentage of total vanadium leaching in state (IV) and (V), which when subtracted from 100% of the head law, results in a 17.5% of vanadium existing in state (III), the same that is unable to be leached with the use of acids [4]. Hydrometallurgical tests of vanadium. Variables such as the choice of leaching acid, the optimum concentration of this medium, the ideal temperature at which to carry out the process and whether the oxidation of the sample is significant before and after being attacked by the selected medium were involved in this trial. Choice and determination of the concentration of the leaching medium. As a result of the vanadium speciation, the leaching percentage information was used with each of the media, and leaching was carried out with nitric acid at different concentrations, where there was no satisfactory leaching, leaving the highest percentage of vanadium in the solid (tailings), so it was determined as the best means of leaching, the sulfuric acid at the concentration of 15%, denoting the percentage of leaching yield of 82.5%. Variation of temperature. The operating conditions verified in the previous tests were fixed, the sulfuric acid was selected as a leaching agent at a concentration of 15%. The variable of this test was the temperature, which was established at 25˚C, 37˚C, 50˚C and 75˚C, temperatures set experimentally, since above this range (as used in other methodologies [1,6,7] there was no adequate separation between the solid residue and the leachate, due to the high viscosity of the mixture. Like the previous experimental processes, the mixture was left to settle for a lapse of 10 minutes and for its subsequent centrifugation at 7830 rpm for 15 minutes, after this time the solid was separated from the leachate. The solid was dried on the heating plate at 150 ° C and analyzed by pXRF, which showed inferior results to those obtained at 25 ° C. Oxidation of vanadium (III) The solid residue, product of the leaching at 25˚C with 15% H2SO4, was used as starting material for the oxidation process. It started with the division into three equal parts of the solid waste and according to its weighing, the volume of the hydrogen peroxide solutions of 10 volumes (3% concentration) was added, in concentrations of 10, 20 and 30 g / L [7, 8] to maintain the solid / liquid ratio of 1:10. The agitation time and speed of 3 hours and 300 rpm, respectively and 25 ° C of temperature, were maintained. Once oxidized the material was left to rest for 10 minutes and the liquid was centrifuged at 7830 rpm and 15 minutes, then the solid was allowed to dry at room temperature (inclemency), spread on a glass watch. With the help of a spatula the solid was removed and measured with the use of pXRF, the result was maintained, so there was no loss of vanadium in this process. Second leaching. Each solid residue resulting from the oxidation was weighed and according to this the volumen of the acid was added, to maintain the solid / liquid ratio of 1:10, in addition to the other operating conditions. The medium used for the second leaching was sulfuric acid at a concentration of 15%. Optimal conditions according to previous tests. Once the leaching time was over, which was three hours, the solid was allowed to settle and again centrifuged at the same conditions and the solid was dried on a heating plate at 150 ˚C, the same as measured by pXRF and finally it was determined that the concentration of hydrogen peroxide required to achieve the highest oxidation of the vanadium in state (III) was 20 g / L. Subsequently, the percentage of the total vanadium yield of the leaching process that was 96.95% was calculated. DISCUSSION AND CONCLUSIONS In the case of the selected bituminous black limestone sample, vanadium is found mostly in state (V) approximately 43.12%, occurring in minerals such as sherwoodite and, to a lesser extent, in minerals such as ronneburgite and rossite, notwithstanding a percentage notable (33.13%) is found as vanadium (IV), which is strongly bound to organic matter and 17.5% vanadium (III) which can be found in the illite, replacing Al. Due to its leaching action, sulfuric acid was taken into account as a means for leaching, giving approximate percentages of 82.5% in the first process. When carrying out the oxidation of vanadium (III) to vanadium (IV) or (V), it could be leached, increasing the yield of the process to 96.95%, which is why the oxidation process, with H2O2 as an oxidizing agent , must be taken into account to obtain an efficient process. Conclusions The best leaching agent was H2SO4 at a concentration of 15%, using operating conditions such as temperature of 25 ˚C, solid / liquid ratio 1:10, time and rate of leaching agitation of 3 hours and 300 rpm, respectively. Vanadium (III) can not be leached by acids (with the exception of HF), like the other states (IV and V), reason why oxidation is an indispensable process for the increase of the total yield, where the best concentration experienced it was 20 g / L of H2O2 (10 volumes), this procedure being very useful, since there is no greater economic demand due to the low prices of hydrogen peroxide. REFERENCES [1] LI, M., et al., Acid leaching of black shale for the extration of vanadium, International Journal of Mineral Processing 95 (2010) 62. [2] POHL, W., Economic Geology, Principles and Practice, Wiley-blackwell, Oxford (2011) 183-185 and 306. [3] ZHANG, Y., et al., The ocurrence state of vanadium in the black shale-hosted vanadium deposits in Shangling of Guangxi Province, China, Chinese Journal of Geochemistry 34 (4) (2015) 484. [4] LI, C., et al., Recovery of vanadium from black shale, Transactions of Nonferrous Metals Society of China 20 (2010) 127. [5] TESSIER, A., et al,, Sequential Extraction Procedure for the Speciation of Particulate Trace Metals, Analytical Chemistry 51 (7) (1979) 844. [6] LI, M., et al., Kinetics of vanadium dissolution from black shale in pressure acid leaching, Hydrometallurgy 104 (2010) 193. [7] Barrera, A., Recuperación de níquel, vanadio y molibdeno del catalizador agotado de la unidad de craqueo catalítico fluidizado (FCC), Engineering Thesis, Escuela Politécnica Nacional, Quito (2015) (in Spanish) [8] KHORFAN, S., et al., Recovery of vanadium pentoxide from spent catalyst used in the manufacture of sulfuric acid, Periodica Polytechnica Ser. Chem. Eng. 45 (2001) 131.

Speaker: Ms Erika Calderón (Universidad Técnica Particular de Loja)

117 IAEA Coordinated Research Project: Geochemical and Mineralogical Characterization of Uranium and Thorium Deposits

In the last decade there have been a multitude of new methodologies and techniques which have been developed in the mineral sector but these have, for the most part, not been applied to uranium and thorium resources. The main objective of this coordinated research project is to undertake geochemical and mineralogical studies of mineralised samples and apply this to understanding the genesis of uranium and thorium deposits and geochemical and mineralogical constraints on mineralization processes. This new knowledge and experience will assist in exploration for uranium and thorium and defining resources. The project involves thirteen Member States including Argentina, Canada, China, Egypt, Ghana, Iran, France, Kenya, Madagascar, Mongolia, Philippines, Ukraine, and Venezuela.

Speaker: Dr ADRIENNE HANLY (IAEA)

118 INDOOR RADON LEVELS IN GACHIN (ISLAMIC REPUBLIC OF IRAN)

Indoor radon gas (222Rn) has been recognized as one of the causes of lung cancer. Considering the risk, the measurement of its indoor concentration is therefore considered necessary. The Gachin region is located in the vicinity of the city of Bandar Abbas, Islamic Republic of Iran, and is an interesting area owing to traces of naturally occurring uranium. This study was conducted to determine radon concentrations in Gachin houses. In this study, 100 radon passive dosimeters (CR-39) were left on different floors of houses constructed with different materials, such as cement, fired brick and clay as raw brick, at every floor, for 6 months. The electrochemical etching method was applied to detect alpha tracks on the dosimeters, and based on number of these tracks, the corresponding radon concentration was determined. This study showed that the average radon concentration was 39 Bq/m3 in the houses. On different floors and according to the construction material used, the average effective dose equivalent of lung tissue was 0.97 mSv/year. On the basis of these results, it can he concluded that the indoor radon levels in Gachin houses are within an acceptable range.

Speakers: Dr Gholamhassan Haddadi (Paramedical School, Shiraz University of Medical Sdiences), Mr Mohammadbagher Haddadi (Avesina Hospital, Shiraz University of Medical Sciences)

119 INNOVATIVE INTELLECTUAL MANAGEMENT TECHNOLOGY OF URANIUM MINING BY THE ISL METHOD

INTRODUCTION In recent decades, there has been an intensive expansion of the information technology application in mining. From the tool of geometrical modeling of deposits and calculation of reserves they have turned into a tool of mining optimization and enterprise management. This is due to the multidimensionality and multivariance of the mining tasks, the need to make the right investment, design and management decisions under numerous constraints, risks and uncertainties. At present, the information technologies are applied to problems of geological and hydrogeological modeling, designing mining enterprises and their feasibility studies, production scheduling, assessment of geoecological consequences, transportation, etc. Mining companies implement complex information systems that are constantly used by engineering and technical services for monitoring mining operations, preparing reports, analyzing and optimizing of the deposit development, operational and strategic managing a mining company. However, the use of information systems designed for traditional mining methods is difficult for the development of infiltration uranium deposits by in situ leaching (ISL) process. Since ISL process does not involve ore excavation, it is based on a useful component transfer to a solution and surfacing from production horizon by means of a technological wells system. In connection with this, Seversk Technological Institute of the NRNU "MEPhI" has developed a specialized software package for informational support of the uranium mining by the ISL method [1-6]. The coordinated work of the information systems of the software package makes it possible to implement the intellectual technology for managing the uranium deposit development by the ISL process. The intellectual technology is based on a comprehensive analysis of geological and geotechnological data at all stages of the enterprise's life cycle, multivariate geological, geotechnological, technical-economic modeling of the operating procedures, application of intelligent expert systems for decision support. The present report is devoted to the systems of the software package and its application for increasing the uranium mining efficiency by the ISL method.The use of information systems designed for traditional mining methods for the development of infiltration uranium deposits by in situ leaching (ISL) process is difficult. Since ISL process does not involve excavation of ore, it is based on a useful component transfer to a solution and surfacing from production horizon using a system of technological wells. In connection with this, the Seversky Technological Institute of the NNIU "MEPhI" has developed a specialized software package for informational support of the uranium mining by the ISL method [1-6]. The coordinated work of the information systems of the software package makes it possible to implement the intellectual technology for managing of the uranium deposit development by the ISL process. The intellectual technology is based on a comprehensive analysis of geological and geotechnological data at all stages of the enterprise's life cycle, multivariate geological, geotechnological, technical-economic modeling of the operating procedures, application of intelligent expert systems for decision support . The present report is devoted to the systems of the software package and its application for increasing of the uranium mining efficiency by the ISL method. METHODS AND RESULTS The software package consists of seven interconnected information systems: mining-geological, technological, geotechnological modeling, geoinformation expert-analytical, technical-economic, computer-aided design, mining planning. In addition, the software package includes a data warehouse that provides consistent storage of the information of any information system. The program code is developed in the programming language C ++ using the object-oriented approach. The operation of the software package is based on client-server technology. The interaction of client programs with the data store is performed by means of SQL queries. Mining and geological information system (MGIS) allows to collect, process primary geological data, create two and three-dimensional geological and mathematical models of the productive horizon, to calculate uranium reserves and other geotechnological indicators of geological and operational units in various ways, and also visualize information on the production horizon condition by means of geological columns, sections, maps, etc. [2]. The entire amount of geological information received during the MGIS operation is stored in the geological data base included in the data warehouse of the software package. In addition to storage, the geological data base ensures the integrity and consistency of various information types. The technological information system (TIS) is designed to form a model of the structure of the geotechnological enterprise mining complex (MC), to collect and handle technological data on the operation process, to coordinate data and prepare reports on the MC operation [3, 4]. The model of the MC structure includes a set of technological objects models and relations between them. TIS allows you to import geological data related to on technological wells and production units from the geological database, to create and edit the process object models, to define assign their relationships, to carry out the expert assessment of the data to identify any contradictions and logical errors, and to visualize the model in the form of plans, structured lists and tables. Collection of primary actual data on the process parameters and the condition of MC objects is performed from various sources using client programs. On the base of the MC structure model and the agreed data coordinated, the values of geotechnological indicators of the operational units are determined, and shifts, daily and monthly technical reports are formed. The initial data and the MC structure model are stored in the database of technological data, taking into account all the interrelations, which ensures their integrity and consistency. The geotechnological modeling system (GMS) makes it possible to carry out simulation of the underground uranium ISL process and the pollutants migration within groundwater [5]. The calculations are performed on the basis of the geological and mathematical model of the productive horizon and the digital model of the mining complex imported from geological and technological data bases, correspondingly. Geotechnological simulation is based on a mathematical model of a multicomponent non-equilibrium filtration of reacting solutions. The hydrodynamic part of the model includes calculating the distribution of underground water heads, the filtration velocity, the convective mass transfer and hydrodynamic dispersion. In the physical-chemical part, homogeneous and heterogeneous processes occurring at ISL in the system of working solution - groundwater - the host rock (acid-base and redox processes, complexation, etc.) are considered. Geoinformation expert-analytical system (GEAS) is used to optimize the operating modes of technological objects, to evaluate and analyze the efficiency of the geotechnological process. GEAS allows to visualize the entire amount of information about the MC operation, stored in the data warehouse. All MC objects are displayed on the interactive plan for the date specified by the user. For any MC object, it is possible to obtain all the information available from the data warehouse in the form of graphs, tables, maps of geological columns, sections, etc. In addition, the simulation results of the productive horizon condition, performed by the GMA, can be shown on the plan. The system has built-in tools for investigating correlations between geological, geotechnological parameters and indicators for different MC of objects. With the help of the GEAS, it is possible to analyze the hydrodynamic flows in the productive horizon and optimize them, in order to improve the quality of the productive solutions and reduce the reagents expenditures during the ISL process. The technical-economic system (TES) includes an economic-mathematical model for calculating the economic performance of the operation units. The model describes capital costs and operating costs for the construction and development of units. On the basis of the economic-mathematical model, the uranium mining unit base cost and other economic indicators of unit development can be calculated. The computer-aided design (CAD) system is used to design and optimize the system of uranium deposit development [6]. The initial datum for the design is the geological and mathematical model of the deposit. The design of the mining development pattern can be carried out in automatic or manual mode. In automatic mode, the pattern of holes is designed using the specially developed algorithms. Algorithms make it possible to create in-line and cellular mesh patterns adapted to the deposit morphology. The optimization of the hole patterns is carried out by searching for the extremum of objective functions by the gradient descent method. The objective functions are: time, the ratio of L/S (the ratio of the volume of working solutions to the solid lode rock mass) for a given degree of unit development, the formation exposure degree, the uranium mining unit cost, and also their combination. The mining planning system (MPS) is used to predict the performance of existing and planned operational unit and to form the mining plans of an enterprise on the basis of the predicted data, which guarantee the planned production level of the uranium mining. The system operation is based on multifactorial statistical models of the operational units productivity. The input data for making mining plans are the geological and technological parameters of the planned operation units and geotechnological retrospective data of the operating units. DISCUSSION AND CONCLUSIONS The software package is applied practically at all stages of the mining enterprise life cycle. At the stage of exploration work, the geological data obtained during the core survey and geophysical studies of the wells are collected with the help of MGIS. Based on the received information, a digital model of the productive horizon is constructed, and the geotechnological parameters of the geological units are calculated. The deposit estimation and the feasibility study are carried out on the basis of the digital model of the deposit created at the previous stage. The optimal parameters of the field development system (the distances between the technological wells, the distances between the row wells, etc.) are determined by carrying out a series of geotechnological modeling using GMS. The modeling parameters are determined on the base of the results of laboratory studies, geotechnological investigation and pilot-industrial geotechnological test work at the field. With the help of the MPS, the prediction of geotechnological indicators of the operation units development is carried out (production rate, uranium content in productive solutions, specific acid consumption, etc.) based on a certain set of geological and geotechnological parameters (ore mass, metal content in the rock, well production, acid concentration in working solutions, etc.). On the basis of medium and long-term prediction, the mining plans of the enterprise, which provide planned production level, are carried out. Based on the results obtained, using the TES, the analysis and evaluation of the technical and economic performance of the enterprise are carried out, which are used to prepare the feasibility study for the enterprise construction. Design of operational units is carried out using CAD, GMS and GEAS. Based on the geologic-mathematical model of productive horizon, an adapted well pattern is created and a unit design is formed. For the proposed draft operational units, multivariate geotechnological modeling is carried out, the cost price of uranium mining and other economic indicators for different variants of the unit development are calculated. Based on the results obtained, the best unit design is selected, which is the most appropriate for the tasks facing the enterprise. At the stage of field development with the help of TIS, a digital MC model is created and maintained, the coordinated values of geotechnological indicators are calculated, and shift, daily and monthly reports on the enterprise work are prepared. GMS is used for epignostic and predictive geotechnological simulations to determine the current state of the productive horizon, to optimize the ISL processing of technological units, short-term development planning of the deposit development, to predict the propagation of the technological solutions within aquifer. The modeling parameters are constantly adjusted by comparing data of the MC control and the productive horizon state monitoring with the results of epignostic geotechnological simulations. Based on the results of the epignostic simulations, the unit part are identified where the ISL process is not effective enough and proposals are being prepared to change the operating modes of the technological wells. The verification of the proposals effectiveness is carried out by means of multivariate modeling. With the help of the GEAS, the analysis and assessment of the efficiency of individual operational units and the enterprise as a whole, preparation of proposals for uranium extraction intensification and reducing of the reagents consumption are carried out. The analysis of geological data for wells and sections is carried out using MGIS. The MPS is used for multifactor analysis and prediction of geotechnological indicators of unit development. The TES is used for calculating the economic performance of the MC (the cost of operational uranium mining, capital and operating costs, the cost changes dynamics with time, etc.) and the selection of the most effective operating modes for the operational units. At the stage of the completion of the field development, the software package is used to determine the optimal procedure for decommissioning technological cells and units, to prepare activities for the additional recovery of uranium from the cranch, to forecast and assess the geoecological consequences of the ISL process, to determine the duration and depth of groundwater self-purification, and to prepare the aquifers plan recultivation. The advantages of the developed software package are: modular architecture, scalability and the possibility of development; optimal database structure, ensuring the integrity and consistency of information; availability of mechanisms for integration with existing information systems at the enterprise; the inclusion of new modern decision support tools; compliance with information security requirements. The use of the software package for managing the field development makes it possible to create an integrated information and production environment for a mining enterprise; it also provides consolidation of information for the purposes of operational management, production accounting, planning and forecasting; increases the productivity of and technical, engineering and administrative personnel (automation of data processing and preparation of reporting documents, efficiency and availability of any information at various levels, etc.); improves the quality of management decisions (completeness, accuracy, reliability and relevance of data, automated analysis of sizable data, support for decision-making, etc.). All these contribute to the increasing of the field development efficiency and reducing the cost of mining uranium, by choosing the optimal development systems, monitoring technological regimes and optimizing the ISL process. An important factor in the effectiveness of the software package application is the completeness of the line of software products that provide solving the tasks facing an enterprise for the entire life cycle, from exploration to the completion. Joint application of various systems of the software package gives a synergetic effect and allows us to talk about the creation of an intelligent technology for geotechnological enterprise managment based on a comprehensive analysis of geological and geotechnological data, multi-variant modeling of the geotechnological process, and the use of intelligent systems to support decision-making. REFERENCES [1] NOSKOV, M.D., et al., Software package for managing of the uranium mining by the ISL method, Vestnik of the National Research Nuclear University "MEPhI" 39 (2013) 95(in Russian). [2] ISTOMIN, A.D., et al., Application of the geological geoinformation system to geological exploration of the infiltration uranium deposit, Prospect and Protection of Mineral Resources 8 (2011) 6 (in Russian). [3] ISTOMIN, A.D., et al., Information support system for uranium mining managing by the ISL method, Automation in Industry 1 (2011) 5 (in Russian). [4] ISTOMIN, A.D., et al., Technological information system for control and management of the uranium mining enterprise by underground leaching, Non-Ferrous Metals 1 (2012) 16 (in Russian). [5] NOSKOV, M.D., et al., Application of mathematical modeling for the solution of geotechnological and ecological problems of the uranium mining by the ISL method, Mining Information-Analytical Bulletin 7 (2012) 361 (in Russian). [6] GUTSUL, M.V., et al., Computer-aided design system of the operational unit at uranium mining by the ISL method, Izvestiya VUZ. Fizika. 58 (2017) 123 (in Russian).

Speaker: Prof. Mikhail Noskov (Seversk Technological Institute of NRNU MEPHI)

120 INVESTIGATION OF U-238 AND Th-232 IN FINGERNAILS, TOTAL BLOOD AND DRINKING WATER AMONG WELL USERS IN KADUGLI TOWN, A HIGH NATURAL BACKGROUND RADIATION AREA IN SUDAN

Sudan Atomic Energy Commission (SAEC) has an ongoing national programme for monitoring radioactivity in Sudanese environment to establish a baseline data as a useful reference for radiation protection in Sudan. Nuba mountains, south-west of Sudan has been detected as a region with the highest radioactivity from natural background. This elevated natural radiation is attributed to the high concentration of 238U, and 232Th series, and 40K in the geological formation. Mining activities (uranium and gold) might take place soon, which will increase radiation hazard to the public. Our aim is to investigate the distribution of 238U and 232Th in fingernails and whole blood in relation to its intake via drinking water by Nuba people who live in that area. Water, fingernails, and blood samples were analysed for 238U and 232Th using ICP-MS. Results of some water supplies revealed uranium concentrations higher than the WHO guidance level (15 µg/L) for drinking water. Analysis of body tissues showed that both 238U and 232Th were better reflected in fingernails than in blood, and thus may serve as biomonitors for uranium and thorium intake in that area. The generated data is a valuable baseline for the decision makers before mining activities begin.

Speaker: Dr Alfatih Osman (Sudan Atomic Energy Commission (SAEC), Al-Gamaa Str.2, 11111 Khartoum, Sudan)

121 NEW STUDIES OF URANIUM DEPOSITS RELATED TO GRANITES IN ARGENTINA

INTRODUCTION At present, the National Atomic Energy Commission of Argentina (CNEA), in cooperation with the National University of Cordoba (UNC), is carrying out the project “Geochemical and Mineralogical Characterization of Uranium and Thorium Deposits” in the framework of the IAEA Coordinated Research Project (CRP), which is "Geochemical and Mineralogical Characterization of Uranium and Thorium Deposits". This paper briefly describes the specific objectives and activities in progress of this research project which has been underway since 2015 [1]. This project aims to focus their studies to characterize the Devonian to Lower Carboniferous magmatic and hydrothermal systems related to granitoids of Pampean Ranges and relate these processes to uranium metallogeny. Therefore, several metallogenetic studies have been carried out in order to improve the geological, structural, geochemical and mineralogical characterization of uranium deposits related to granites to define: felsic igneous rocks that have played the most relevant role as uranium sources; successive fractionation in the different magmatic complexes; relations between magmatic uranium enrichment and hydrothermal deposits; alteration and uranium mobility. DESCRIPTION AND RESULTS The scientific scope of this paper is specifically covers four mineralizations where granite-related (endogranitic) have been described: Sala Grande, Don Alberto and Los Riojanos enclosed in the Achala Batholith and La Estela located in Cerro Áspero – Alpa Corral Batholith [2] [3]. Petrographic data were obtained from observations of polished thin sections using conventional transmitted and reflected light microscopy. Appropriate unaltered mineral areas suitable for laser ablation analysis were selected using a CAMECA SX100 electron microprobe (EMP). Major and trace elements (U, Pb, Th, Ca,Si, Al, Ti, Fe, Mn, V, Na, Nb, La and Y) were obtained by the EMP method, while Rare Earth Element (REE) and a series of trace element contents of uranium oxides were determined using laser ablation inductively coupled plasma mass spectrometry (LAICPMS). These studies were carried out at the facilities of the Nancy University [4][5]. Don Alberto, Sala Grande and Los Riojanos sites are located in the peraluminous S-type Achala batholith (ca. 2500 km2), which belong to the Cordoba Pampean Ranges. This is composed by several magmatic suites and numerous facies, where two-mica monzogranites are by far the most largely exposed lithologies and muscovite leuco-monzogranite is the most evolved rock that occurs as marginal plutons or facies [6][7]. In Don Alberto site uranium mineralization is hosted in dark gray, coarse grained biotitic gneiss, weakly foliated, intruded by a porphyritic two mica granite. Microtexture is predominantly granoblastic, with few biotite-sillimanite rich domains. It shows polygonal aggregates of quartz, plagioclase and cordierite (pinnite replacing cordierite). Accessories minerals are apatite, zircon and opaque minerals (uraninite, ilmenite and rutile). The cordierite shows two textural varieties: idioblastic poiquilitic and xenoblastic highly poiquilitic with biotite, zircon, apatite and euhedral uraninite crystals inclusions. The uraninite shows concentric radioactive disintegration halos of yellowish and brown tones and marked radial fracture. Uranium oxides from the two samples analysed of Don Alberto are present as euhedral uraninite grains with significant Th content (about 1 wt % ThO2) which indicates a high temperature origin. They have between 2.7 and 3.8 wt% PbO corresponding to chemical ages comprised between 255 and 325 Ma. Their Yttrium content is not significantly enriched (0.07 to 1 wt% Y2O3), but the highest value correspond to an altered U-oxide (characterized by the lowest UO2: 86.2 wt% and PbO: 0.1 wt% contents, and the highest SiO2: 7.58 wt% and CaO: 3.18 wt% contents, compared to the other analytical points). The global fractionation of the REE patterns and the high REE contents of the U-oxides from the two samples of Don Alberto are identical. Only one analysis has slightly lower REE contents. These patterns are similar to those found for magmatic uraninite at Rössing deposit in Namibia, but with lower total REE contents [8]. The other trace element patterns of these U-oxides are also similar, with significant enrichment in W, Zr and Mn and more limited enrichments in B, As, W, except two samples which are not enriched in Mo, W and Ti. They are boh very poor in Nb. In Sala Grande site uraniferous mineralization is located in the subhorizontal contact between the biotitic (± sillimanitic) gneiss and the intrusive granitic surface. The metamorphic rock lies as a roof pendant affected by contact metamorphic process developing a compact hornfels rock in hornblende facies [9]. The intrusive facies in this site is a porphiryc, two micas coarse grained, granite. Microtexture shows a spaced foliation; cleavage domains consist mainly of biotite-sillimanite and microlithons composed by quartz, relict andalusite, cordierite and scarce plagioclase. Second andalusite blastesis is poiquilitic with inclusions of biotite, apatite and fibrolite. It presents hex-shaped uraninite inclusions with marked radiohalos that may be partially altered to oxidized uranium minerals, probably corresponding to uranophane. Other accessory minerals are: monazite, zircon, fluorite and manganese rich ilmenite. Uranium oxides from Sala Grande are similar to the ones of Don Alberto, with a ThO2 content of about 1% indicating high temperature uraninite. Their REE patterns are also identical to the non-altered uranium-oxides from the Don Alberto mineralization, suggesting a similar origin for the two occurrences. The trace elements pattern is also very similar to those of Don Alberto, indication similar environment and formation processes. In Los Riojanos, main lithologies in this site are an equigranular reddish fine grained muscovite leucogranite and fine grained porphyric granite. The first facies has monzogranitic modal composition with albitic plagioclase (An05-An10) and shows intergrowth of quartz and antiperthite textures. Biotite has been totally muscovitized, being the last one relatively abundant. Accessory minerals are apatite, zircon, monacite and rutile. The porphyric granite is monzogranitic but this composition may by locally modified by post magmatic hydrothermal processes. The accessory minerals are apatite, zircon, rutile, titanomagnetite, fluorite and tourmaline. The main uranium mineralization is hosted in a cataclastic belt affecting the equigranular granite. This cataclasites are formed by a recrystallized fine grain granitic matrix and also low temperature hydrothermal quartz [10]. The sample corresponds to a drill core of 44 meters deep. The uranium is located in a 0.5 mm vein, associated with pyrite and quartz. This vein present "in mortar" texture formed by crushed and recrystallized quartz. Both, the vein and small cavities are filling with pyrite and sooty pitchblende. Uranium oxides from Los Riojanos have no detectable Th-content; significant yttrium (0.47 to 1.01 wt % Y2O3) and calcium (3.49 to 4.46 wt% CaO) with low to moderate silica contents (1.7 to 3.21 wt %), indicating a low temperature hydrothermal origin. La Estela mine, with estimated resources of 1500 tU at 0.07%U, is located in calc-alkaline high K Cerro Áspero – Alpa Corral batholith (ca. 440 km2) which belongs to Comechingones Range [11]. The main internal facies is represented by coarse-grained biotite monzogranites. The border facies is made of two mica or muscovite leucogranites, whose compositions range from monzogranites to alkali-feldespatic granites [12]. In this deposit, fluorite is spatially associated with pitchblende and other hexavalent uranium minerals (uranophane, metaautunite). This granite has primary magmatic foliation which would control the movement of younger hydrothermal system generating intense E-W brecciation of surrounding granitic rocks. The breccia is poly-episodic showing fractures filled with black fluorite (antozonite) associated with pitchblende and pyrite [13]. Uranium mineralization has a completely different composition compared to Don Alberto and Sala Grande ones. La Estela deposit does not have detectable Th and yttrium contents, and shows relatively high Si (14.82 and 15.47 wt% SiO2) and Ca concentrations (6.91 and 6.67 wt% Ca) corresponding to a coffinite type composition. Their REE patterns are similar to deposits associated to granites, but with an important Ce positive anomaly and a very high abundance in total REE. Their trace element patterns are characterized by a very high abundance of elements associated with hydrothermal granite related deposits such as B, As, Mo, W, Mn, as well as less mobile elements as Ti, Nb and Zr. DISCUSION AND CONCLUSION The interpretation of different REE and other elements patterns [14] allowed improving the metallogenic knowledge of uranium deposits related to granites which would aid in turn to adjust the exploration guides to be applied. Finally, it can be pointed out that granites play an important role both as uranium source and hosting diverse types of uranium mineralization. Besides, it is thought that, at the existing level of knowledge, there are prospects to develop new uranium resources related to granites in Argentina. This contribution is a summary of several studies that were conducted by the National Atomic Energy Commission (Argentina), the University of Nancy (France), the International Atomic Energy Agency and the National University of Cordoba. The authors are grateful to many institutions for allowing the information to be assessed and presented here. REFERENCES [1] ÁLVAREZ, J., LOPEZ, L., Annual Progress Reports for Contracts under the Coordinated Research Activities. Assessment of the uranium potential of phosphate rocks and testing low-grade phosphate ores extraction, IAEA internal report, unpublished (2016-2017). [2] CUNEY, M., GAGNY, C., The uranium potential of the Achala batholith (Argentina). Proposed exploration strategy, IAEA internal report, unpublished (1994). [3] ZARCO, J., "Estudio de los controles estructurales y magmáticos de indicios intragraníticos del batolito de Achala (Córdoba)", Comisión Nacional de Energía Atómica report, unpublished (2005). [4] CUNEY, M., MERCADIER, J., Report on the geochemistry of the U oxides from different Uranium deposits from Argentina, University of Nancy – CREGU internal report, unpublished (2017). [5] LACH, P., MERCADIER, J., DUBESSY, J., BOIRON, M.-C., CUNEY, M., In-situ quantitative measurement of rare earth elements in uranium oxides by laser ablation inductively coupled plasma-mass spectrometry, Geostand. Geoanal. Res. 37, 1–20 (2013) http://dx.doi.org/10.1111/ j.1751-908X.2012.00161.x. [6] CUNEY M., LEROY J., VALDIVIEZO A., DAZIANO C., GAMBA M., ZARCO J., MORELLO O., NINCI., MOLINA P., Geochemistry of the uranium mineralized Acahal complex, Argentina: comparison with hercynian peraluminous leucogranites of western Europe, IAEA Technical Meeting on Metallogenesis of uranium deposits, Proceedings, Vienna (1987). [7] DEMANGE, M., ALVAREZ, J. O., LOPEZ, L. Y ZARCO, J. L., The Achala Batholith (Córdoba, Argentina): a composite intrusion made of five independent magmatic suites. Magmatic evolution and deuteric alteration, Journal of South American Earth Sciences, 9(1-2): 11-25 (1996). [8] MERCADIER, J., CUNEY, M., LACH, P., BOIRON, M.-C., BONHOURE, J., RICHARD, A., LEISEN, M., KISTER, P., Origin of uranium deposits revealed by their rare earth element signature, Terra Nova 23, 264–269 (2011). [9] LIRA, R., Un nuevo modelo metalogenético uranífero en el basamento cristalino de las sierras Pampeanas: uranio en metamorfitas de contacto (batolito de Achala, Provincia de Córdoba), Boletín de la Asociación Geológica de Córdoba 7: 438–451 (1985). [10] LIRA, R., Manifestación nuclear “Los Riojanos”. Estudio mineralógico de testigos de perforación, sondeo L.R. ex-15. National Atomic Energy Commission (CNEA) internal report, 4 p., Córdoba, unpublished (1983). [11] BLASÓN, R., Yacimiento La Estela, distrito uranífero Comechingones, San Luis. En: Recursos Minerales de la República Argentina (Ed. E.O. Zappetini), Instituto de Geología y Recursos Minerales SEGEMAR, Anales 35: 621-624, Buenos Aires (1999). [12] PINOTTI, L., CONIGLIO, J., ESPARZA, A., D ́ERAMO F. Y LLAMBÍAS, E., Nearly circular plutons emplaced by stoping at high crust level. Cerro Áspero Batholith. Sierras Pampeanas de Córdoba, Argentina, Journal of South American Earth Sciences 15: 251-265 (2002). [13] CONIGLIO, J.E., Evolución petrológica y metalogenética del batolito Cerro Áspero en relación con el ciclo geoquímico endógeno del flúor, Sierra de Comechingones, Córdoba, Argentina. PhD, Universidad Nacional de Río Cuarto, 163 p, unpublished (2006). [14] LACH, P., Signature géochimique des éléments des terres rares dans les oxydes d'uranium et minéraux associés dans les gisements d'uranium: analyse par ablation laser couplée à l'ICP-MS et étude géochronologique, PhD Dissertation, Université de Lorraine, France, 293 pp., unpublished (2012).

Speakers: Mr Juan Alvarez (CNEA), Mr LUIS LOPEZ (CNEA (Argentina))

122 Organic Solvent Extraction of Uranium from Alkaline Nuclear Waste

During the dissolution process of the irradiated uranium target plates, the uranium and some fission products are precipitated as mixed hydrated oxides to form the residue. The same residue is commercially valuable, as a feed stock for recovering and purifying uranium from the other fission products and trans-uranium elements. PUREX (Plutonium Uranium Redox Extraction) is a worldwide known technique for the extraction of uranium using the conventional acid route. However, during the PUREX extraction of uranium, plutonium and thorium are also extracted in this process. In addition, there are proliferation issues, which make the PUREX process not favorable. The aim of this research was to evaluate organic extraction ligands that can operate in alkaline media to remove uranium from the nuclear waste and the objective was to characterize the most effective organic solvent for extracting uranium only, from alkaline media. Uranium oxide was dissolved in sodium carbonate solution to form the uranium tri-carbonate aqueous feed solution. 5% (v/v) Aliquat 336 in either xylene or toluene was used as the organic extractant. The samples were analyzed using the VARIAN CARY 100 UV-VIS Spectrometer set at 450 nm, at an optimum solution pH of 12. The results from this work indicate that Aliquat 336 in Xylene has a less effective extraction percentage of 72% for uranium within the time of 60 minutes, if extraction is performed immediately after the preparation of the uranium feed solution. Toluene extracted 82% of the uranium from the feed solution after 30 minutes. However Toluene showed a decrease in extraction capability to 76% after 60 minutes. Plutonium and thorium were not detected in the final uranium product, indicating that the organic solvent alkaline extraction method could be a valuable technique in uranium processing.

Speaker: Prof. Manny Mathuthu (North West University)

123 Perspectives of Phosphate - Uranium Comprehensive Extraction Projects in Argentina

INTRODUCTION Systematic prospecting studies of phosphates in sedimentary basins were carried out during the 1970s by the Argentine Geological Mining Survey (SEGEMAR). This program delineated eighteen areas in several marine basins with phosphate potential, occupying a total area of about 640,000 km2 [1]. In the mid-80s, a research group of the Department of Geology of the University of Buenos Aires (UBA), faced the study of new areas for the prospection of phosphates, which currently continues, focused on the genesis and sedimentation environment of phosphate deposits in different basins. New data, together with published information about phosphates have been compiled, and principal phosphate occurrences and their correlation with the global phosphogenetic events have been defined (Cambrian, Ordovician, Jurassic-Cretaceous, Cretaceous-Paleocene, Miocene and Modern) [2]. At present, the National Atomic Energy Commission of Argentina (CNEA) and the UBA, in cooperation with the National University of Salta (UNSa), are carrying out the project “Assessment of the uranium potential of phosphate rocks and testing low-grade phosphate ores extraction” in the framework of the IAEA Coordinated Research Project (CRP), which is "Uranium-Thorium fuelled High-Temperature Gas-cooled Reactor (HTGR) applications for energy neutral sustainable comprehensive extraction and mineral product development". This paper briefly describes the specific objectives and activities in progress of this research project which has been underway since 2015 [3]. DESCRIPTION In Argentina, all of the uranium identified and undiscovered resources belong to conventional sources, and the purpose of the aforementioned RC is to assess the unconventional uranium (Th, REE) resources related to phosphate rocks. The project also pursues the aim of better understanding how thermal extraction can be used to beneficiate and process low-grade phosphates from Argentinean sedimentary basins. This would help to increase the socio-economic viability and technical feasibility to set up productive projects in the long term. The research project involves studies in three sedimentary basins (Ordovician North-Western Basin, Upper Jurassic – Lower Cretaceous Neuquen Basin, and Paleocene - Miocene Patagonia Basin), where low-grade phosphate mineralization and uranium anomalies (up to 135 ppm U) have been detected. Exploration and beneficiation/extraction studies are being conducted, which would allow an evaluation of the economic potential of the study areas. During the first year of the project studies have focused on the geological and geochemical characterization of phosphate rocks of the Ordovician North-Western basin. After completion of the evaluation of available information, Mojotoro Range (Salta Province) and Tilcara Range (Jujuy Province) sites, which are located approximately 1500 km away from Buenos Aires city, were selected for specific studies. Two field missions for geological characterization, sampling and ground gamma-ray spectrometry surveying have been carried out. In total, nine stations were set up, where geological studies and collection of 10-kg samples of phosphatic rocks, including all of the mineralized levels and the barren material as a background, were implemented. These Ordovician phosphate deposits show a temporal and a spatial distribution of phosphate-bioclastic accumulations linked to the paleogeographic basin evolution and mineralization is made of discontinuous lenses from 10 to 60 cm thick of lingula-bearing coquinas outcropping in studied areas. These phosphatic levels are intercalated in Tremadocian shales, Tremadocian-Floian shales and mudstones, Dapingian-Darriwilian quartz sandstones and Darriwilian-Sandbian shales, and limestones. Phosphatic inarticulate brachiopoda fragments are concentrated in the lower part of the laminated fine quartz sandstone, assigned these deposits to tempestites accumulated in lower to middle shoreface coastal marine environments. The grade varies between 5 to 7 per cent P2O5. There is a positive correlation between phosphorus and U, Th and rare earth elements (REE). According to their P2O5 contents the analyzed samples are classified as: Phosphorites (19 and 21 per cent P2O5), phosphate rock (8 - 18 per cent P2O5) and slightly phosphatic rocks (<8 per cent P2O5). By comparing date from mineralized and barren material, preliminary studies indicate that all samples exhibit significant enrichment in Y, Sr, La, Yb, U, Th, Pb, Zr and REE, which encourage further comprehensive extraction tests [4]. During the second year tasks have been addressed to the Upper Jurassic - Lower Cretaceous Neuquen basin. After completion of the evaluation of geological, geochemical and gamma-ray spectrometry available information, two areas were selected for specific studies: "Cerro Salado" and "Vaca Muerta", which are located in the Neuquen province, approximately 1300 km away from Buenos Aires city. Therefore, at this basin, a field mission for sampling and ground gamma-ray spectrometry surveying has been carried out including a total of ten stations where geological studies and collection of 10-kg samples of phosphatic rocks for mineralogical, chemical and extraction studies were implemented. P2O5 content is between 3 to 4.5 per cent and U varies from 3.5 to 5.5 ppm [5]. The Quintuco Formation is 218 m thick and hosts phosphate mineralization. The phosphatic beds are wackestones, bioclastic rudstones and hybrid sandstones forming condensed beds with variable mechanical reworking and are grouped into four phosphatic intervals. Phosphatic particles are mainly nodules and subordinated, partially or totally phosphatized shells. It is though that the phosphogenesis took place during sea high stands and low clastic sedimentation rates, and then reworking by waves and currents and concentration of phosphatic particles occurred during periods of sea-level rise and fall [6]. During the third year of the RC, field work and laboratory studies are focused on Cenozoic marine section cropping out near Gaiman (Chubut Province, SE Argentina approximately 1400 km away from Buenos Aires city), which shows that most of the succession was deposited in a shallow, storm-dominated marine environment. Flat-lying Miocene rocks exhibit a 200 m thick column composed of a coarsening upwards succession of mudstones, fine tuffs, sandstones and coquinas, rich in phosphatic concretions, ray teeth, shark teeth and bones from marine vertebrates. Phosphatic strata are related to: a) in situ concretions developed within transgressive-early highstand system tracts, and b) reworked and winnowed lags associated with transgressive surfaces which display a concentration of phosphatic concretions, ooids, vertebrate bones, teeth and shells. P2O5 content in concretions is between 15.61 to 28.97 per cent and U varies from 46 to 135 ppm. Phosphogenesis would have taken place after cold and corrosive water, probably similar to the present Antarctic Intermediate Water (AAIW), flooded the continental shelf and mixed with warmer surficial waters. The development of the phosphorites would have occurred at times of global climatic transition and increased oceanic circulation, probably during the Late Oligocene–Early Miocene [7]. DISCUSSION AND CONCLUSION It could be pointed out that to date economical phosphate deposits have not been found nor has production been carried out in Argentina. Phosphate identified resources, which belong to restricted sites of Northwest and Neuquen Basins, have been evaluated at 1 M t of P2O5 with grades ranging from 2.5 to 6.3 per cent P2O5 [8]. However, the existence of favorable basins and different mineralization models suggest promising conditions to set up new projects to develop the phosphate potential in the country, taking into consideration the perspective of uranium recovery from this unconventional source of nuclear raw material. At the current level of knowledge, uranium quantities linked to phosphates are evaluated in the United Nations Framework Classification for Resources (UNFC) scheme as "Additional Quantities In Place Associated with Potential Deposits", where a portion of these quantities may become recoverable in the future [9]. The IAEA project CRP on neutral uses of HTGRs would allow accounting for a better understanding about heat processing of low-grade phosphates. This process would aid to increase the socio-economic viability and technical feasibility to set up productive projects in the long term by providing positive implications regarding food and energy security. This contribution is a summary of several studies that were conducted by the National Atomic Energy Commission of Argentina, the University of Buenos Aires, the International Atomic Energy Agency, the National University of Salta and the Argentine Geological Mining Survey. The authors are grateful to many institutions for allowing the information to be assessed and presented here. REFERENCES [1] LEANZA, H., SPIEGELMAN, A., HUGO, C., MASTANDREA, O., OBLITAS, C., Phanerozoic Sedimentary Phosphatic rocks of Argentina, In: Phosphate rocks resources, Eds. Notholt, J., Sheldon, R., Davidson, D., 2 (24):147-158, Cambridge (1989). [2] CASTRO, L.N., SCASSO, R., MOYA M.C, Phosphate deposits in Argentina: State of the art, COVAPHOS III The third international conference on the valorization of phosphates and phosphorus compounds: Phosphate Fundamentals, Processes and Technologies in a Changing World, Marrakech, Marruecos, Po1-05 (2009). [3] LOPEZ, L., Annual Progress Reports for Contracts under the Coordinated Research Activities. Assessment of the uranium potential of phosphate rocks and testing low-grade phosphate ores extraction, IAEA internal report, unpublished (2016-2017). [4]MOYA, M.C., SCASSO, R.A., CASTRO, L.N., FAZIO, A.M, Los fosfatos en el Ordovícico del Norte Argentino, In: Marquillas, R. A., Sánchez, M.C., Salfity, J.A. (Eds.), Aportes sedimentológicos a la geología del noroeste argentino, Relatorio 13° Reunión Argentina de Sedimentología, pp. 145-167 (2012). [5] CASTRO, L. N., SCASSO, R.A, FAZIO A.M., Fosfogénesis y geoquímica de tierras raras en niveles fosfáticos la Formación Quintuco, área Cerro Salado, provincia del Neuquén XIX Congreso Geológico Argentina, Córdoba, Actas en CD (2014). [6] MEDINA, R.A SCASSO R.A., MEDINA, F.A., Geología y estratigrafía de los bancos fosfáticos del Cretácico Inferior en el área del cerro Salado, Cuenca Neuquina, Argentina, Revista de la Asociación, Argentina, 73 (4): 520-537 (2016). [7] SCASSO, R.A., CASTRO, L. N., Cenozoic phosphatic deposits in North Patagonia, Argentina. Phosphogeneis, sequence-stratigraphic and paleoceanographic meaning, Journal of South America Earth Science, 12:471-487, Elservier (1999). [8] SERVICIO GEOLÓGICO MINERO ARGENTINO, Zappettini (Ed.), Recursos Minerales de la República Argentina, Anales Nº 35 SEGEMAR (1999). [9] UNITED NATIONS ECONOMIC COMMISSION FOR EUROPE, Guidelines for Application of the United Nations Framework Classification for Fossil Energy and Mineral Reserves and Resources 2009 for Uranium and Thorium Resources, ECE ENERGY SERIES No. 55 (2017) http://www.unece.org/fileadmin/DAM/energy/se/pdfs/comm24/ECE.ENERGY.2015.7_e.pd

Speaker: Mr Luis López (CNEA, Argentina)

124 Possibility of Uranium industry wastes reprocessing in Tajikistan

Total amount of wastes in tailings of former uranium industry in Republic of Tajikistan is approximately 55 million tons. Summary activity of wastes according to different assessments is from 6.5 till 7.7 thousands Curie. Dump fields basically are not arranged, their amount and area are not exactly determined. Practically all tailings and dump fields are subject to erosion processes and drained by underground waters to adjoining creeks and river network. The surface of tailings, especially those which doesn’t have protective coverage or subject to destructive effect of natural factors or digging animals are presenting threat for considerable dispersion of contaminated substances and residues of tailings beyond of their initial localization. Uranium ores reprocessing methods are known which allows extracting of uranium oxide from barren ores. However, these methods require preliminary preparation of the ore, grinding and in addition are contaminating the environment. We propose the diagram of uranium ores reprocessing with the purpose of raw material base extension, production of uranium oxide from uranium industry wastes with uranium content from 0,03 up to 0,3 mass per cent. Final product is uranium oxide containing 75% of U3O8. Product output is from 90 to 99 per cent.

Speaker: Prof. Ulmas Mirsaidov (Nuclear and Radiation Safety Agency)

125 Radioactivity monitoring and environmental restoration of a legacy mine and milling site

A former radium and uranium producing mine at Forte Velho, Guarda, Portugal, was in activity during the 40s-60s last century. After mine closure, waste piles remained uncovered for decades, until a radiological assessment of the site attracted attention to elevated ambient radiation doses. An aerial radiation dose rate survey was carried out using a detector mounted on a drone and also at ground level. Ambient radiation dose rates attained 9.5 µSv/h on waste piles. As waste piles were on the mountain slope, the site was a source of contaminated materials and leaching gradually transported down the slope with surface runoff. Natural vegetation covered the waste piles and radionuclides were analyzed in herbaceous plants and pine trees. Results showed that uranium daughters were easily transferred to plants. Remediation action was taken in 2015.After the clean-up of Forte Velho mine site, a clean soil layer and plants were introduced. A post-remediation radiation survey of the Forte Velho site was made and confirmed suitable abatement of ambient radiation doses and conformity with basic safety standards and remediation goals.

Speaker: Prof. Fernando P. Carvalho (Instituto Superior Técnico/Laboratório de Protecção e Segurança Radiológica,)

126 Recovery of uranium and accompanying metals from the secondary raw materials

In the last years the interest of uranium recovery from secondary sources is growing. In Poland, the advanced studying concerning the possibility of uranium obtaining form domestic resources and also secondary resources such as phosphates rocks and industrial wastes: flotation tailings from copper industry and phosphogypsum, is performed . There are two main reasons for these kind of studies: - recovery of heavy metals form the industrial wastes is important to the society, industry and environment - the selective separation of uranium is a very important in the context of energy production and treatment of nuclear wastes The solid materials were leached with using acids or alkaline solutions in stationary reactors or with perolactive leaching. The obtained liquors were separated from solid residue and then were purified by liquid-liquid extraction or ion exchange chromatography. Acknowledgement: The studies were supported by the financial resources for science in the years 2017-2018 granted for the implementation of the international project co-financed 3643/IAEA/16/2017/0, IAEA Research Contract No: 18542

Speaker: Dr Katarzyna Kiegiel (Institute of Nuclear Chemistry and Technology)

127 Recovery of Uranium from Seawater by Polymeric Adsorbent Systems

In order to maintain a sustainable reserve of nuclear fuels for the nuclear power industry, tremendous research efforts have been devoted to the development of advanced adsorbent materials for extracting uranium from seawater. Uranium exists uniformly in the world’s oceans in the form of a tricarbonate complex at a concentration of 3.3 μg L−1. Adsorbents which have been developed include inorganic adsorbents, which showed poor selectivity and low capacity, to the most recent polyethylene-fiber-based sorbents containing amidoxime–carboxylic acid copolymers. This presentation will focus on the development and performance of three classes of advanced adsorbents developed as a part of the integrated research effort overseen by the U.S. Department of Energy Office of Nuclear Energy to reduce the technology cost of extracting uranium from seawater: (1) high-surface area polymer fiber adsorbents based on radiation-induced grafting, (2) polymer fiber adsorbents derived from atom-transfer radical polymerization (ATRP), and (3) surface-functionalized polyacrylonitrile fiber adsorbents. The pros, cons, and cost of each technology will be discussed along the recent developments on improving the capacity and the uranium to vanadium selectivity. The potential for these adsorbent to be used in other applications, such as cleanup of heavy metals in mine tailing, will be discussed.

Speaker: Mr Sheng Dai (Oak Ridge National Laboratory)

128 Remote Sensing Identification of Uranium Exploration Targets - Laguna Sirven Project, Santa Cruz, Argentina

1. Introduction The Laguna Sirven uranium-vanadium deposit belongs to the surficial geological type. The presence of uranium minerals, mainly carnotite, has been detected between 0.5 to 3 m depths, within the calcrete level which serves as cement to a polimictic matrix. Uranium target areas were identified by means of the processing and interpretation of multispectral satellite imagery and SRTM data. LandSat 7 ETM+ and ASTER generated products indicated mainly two types of non-pedogenic mineral patterns related to the precipitation of uranium and vanadium minerals, showing two different depositional pathways, one related to carbonate minerals and another to sulfate minerals. The present contribution briefly describes the methodology and results of the application of remote sensing techniques for the identification of uranium exploration targets in this type of geological model. Laguna Sirven corresponds to a sedimentary deposit formed by rich uranium precipitations at the water table interface, creating calcretes of a large extent and typically tabular form. In most of these deposits, uranium comes from the weathering of volcanic rocks, which could be secondary uranium deposits. Uranium solubility is closely linked to oxidation potential, whereby under oxidizing conditions uranium is found as U6+ cation, highly soluble and therefore very mobile. However, in a reducing environment, the U6+ ion is converted into the insoluble form U4+. Thus, the uranium in solution flows through permeable strata until it meets reducing conditions and precipitates, such as the sediments of the Deseado River [1]. As previously studied, soils are important fixing materials due to the content of clay minerals, organic matter, iron hydroxides, manganese or aluminum hydroxides [2]. 2. Methodology & Results The rationale behind the application of this technology in the identification of uranium exploration is that the migration of minerals to the subsurface can generate local anomalous areas, which are characterized by reduction conditions that facilitate the development of a variety of chemical and mineralogical changes that can be detected through remote sensing techniques. Possible alterations include bleaching, the development of iron and clay minerals, the formation of carbonates and geo-botanical anomalies, among others. Thus, the analysis of the presence and abundance of such minerals and soil chemical anomalies combined with a comprehensive study of the structural geology and geomorphology of the area facilitates the identification of uranium mineralized potential target areas. The remote sensing study comprised different phases. Prospective areas are identified after the careful selection of imagery data during the acquisition phase and the later effective preparation, processing and interpretation of such spectral data. First, LandSat-7 ETM+ and ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) multispectral imagery and SRTM data was acquired, with the following spatial and spectral resolutions: LandSat 7 ETM+: Spatial Resolution: 15, 30, 60 meters. Spectral Resolution: Seven (7) bands, ranging from 0.45 to 12.50 nm, (Visible, Near Infrared, Short Wave IR and Thermal IR). ASTER: Spatial Resolution: 15, 30, 90 meters. Spectral Resolution: Fourteen (14) bands, ranging from 0.50 to 11.40 nm, (Visible, Near Infrared, Short Wave IR and Thermal IR). SRTM: Spatial Resolution: 90 meters. Frequency: 5.3- 9.3 GHz Atmospheric, radiometric and geometric corrections were applied to this data in a preliminary processing stage. Upon such corrections, imagery was georeferenced according to the POSGAR 1994, Faja 2 System. In this stage, ASTER´s thermal IR data was converted to superficial emissivity values by means of the normalization values taken from global maps with surface properties generated by various international research programs. Later data processing included spectral enhancements through the application of a series of digital filters and the application of band ratioing and statistical analysis procedures, such as principal components. Band ratioing is a very fast and effective method to obtain information about the Earth’s surface components from LandSat ETM+ and ASTER multispectral imagery. These ratios are simple mathematical relationships between values of two specific selected bands. The principal component analysis or rotation is a mathematical process originally designed to evaluate the spectral correlation between bands. By means of this process, the highly correlated data present in LandSat-7 ETM+ or ASTER bands is comprised into fewer bands using statistical algorithms. In the resulting set, the bands are non-correlated, and its reduced dimensionality allows the extraction of more information from it. A suite of abundance mineral maps was created through the combination of several ratios that enhanced the presence of Al-OH and Mg-OH associated with clays and other hydroxyl minerals as well as other ratios that showed the presence of carbonates and iron oxide and hydroxide rich sediments. These mineral indexes have the advantage of normalizing spectral data, reducing the effect on the ground variations and the illumination differences [3]. The interpretation stage showed that both the Gypsum and the Carbonate Indexes proved to be the most useful tools within the generated products in the identification of uranium targets in the project. The analysis of such mineral indexes indicated that the NW sector of the project is characterized by a suite of carbonate minerals while the SE section showed a large abundance of sulfate minerals. It is understood that this difference in exploration indicators was essentially due to the difference of the chemistry of the fluids from which mineralization was formed. Both high non-pedogenic carbonate and sulfate areas have a wide superficial extension and correlate with the known uranium anomalies found in the Laguna Sirven plateau. Such preliminary model was validated by means of ground gamma-ray spectrometry and soil geochemistry surveys recently performed [1]. 3. Conclusions Two prospective uranium exploration targets were identified within the project after the careful selection of remote sensing data during the acquisition phase and the later preparation, processing and interpretation of such spectral data. The analysis of the presence and abundance of sulfate and carbonate related minerals indicated by both the Gypsum and the Carbonate Indexes proved to be a very useful tool to identify uranium targets in this calcrete-type deposit. 4. References [1] BERG, Talía C., ECHEVARRIA, Pablo J. y Guillermo E. RE KÜHL. Uranium exploration through the integration of Multispectral Imagery, Radar and Field Radiometry at the Laguna Sirven Project, Province of Santa Cruz. Serie Correlación Geológica - 33 (1 - 2): 129 – 142 (2017). [2] CORDANI, U. G.. Evolución tectónica de la corteza continental de Sudamérica y su importancia en la caracterización de provincias uraníferas. Uranium deposits in Latin America: Geology and exploration, 3-2 (1981). [3] NINOMIYA, Y.. Lithologic Mapping with Multispectral ASTER TIR and SWIR Data. SPIE Proceedings, 5234: 180-190 (2004).

Speaker: Ms Talia Berg (Hytec Alto Americas)

129 Removal of Uranium and Thorium from Uranium and Rare Earth ores Processing - Case study of QA/QC on environmental analysis

The removal of uranium and thorium from unconventional mining ores such as graphite, phosphate, or beach-sands have been carried out for decades. During processing the ore for getting the main products, the mining tailing contains considerable amounts of radioactive elements such as uranium and thorium, which would be accumulated at some storage (in beach sand exploitation) or just released at the site (as NORM /TENORM waste from phosphate or graphite product). The study on these deposits became more intensive to assure the safe environment. Several research projects have then been set up for the recovery of by-products including uranium and/or thorium. Furthermore, a small amount of these accompanied elements as impurities in the mineral products or rare earth raw compounds should be controlled for exporting or for further processing. The QA/QC on analysis of these element would thus be posed. XRF and other analytical techniques have been studied for supplying the demands from research projects. The use of CRMs and secondary standards for QC contribute to reliable and unbiased results and narrow uncertainties. Analytical results of samples and of various reference materials are presented and discussed with focusing on concentration range, matrix compositions, and determination limits.

Speaker: Dr Thi Kim Dung Nguyen (ITRRE, VINATOM)

130 TAILINGS AND WASTE MANAGEMENT AT THE KENTICHA TANTALUM MINE SITE

Tantalum mining is a big source of radioactive waste in Ethiopia with U-238, Th-232 and K-40 average concentration in the solid waste of 110, 15 and 0.6 kBq/kg respectively. It is clear that nations cannot reduce pollution from waste by reducing the nation’s growth. This, economic growth should be developed in a sustainable way. The generation of radioactive waste due to tantalum mining in the country need to be regulated and managed in an efficient manner in order to comply with the health, environmental and safety regulations. The regulations are enforced in order to avoid hazardous radiation exposures to workers in the industry, public in general and protect the environment we live in. The regulatory body emplace an extensive radiological monitoring programme at the Kenticha mines sites and tailings dam to measure the radiation exposure of people living close to the mine with measuring radionuclides dispersed by the surface water, groundwater and atmospheric pathways in collecting water sample tests from effluent, soil and cereals from the environment and converts these measurement into radiation exposure estimates and the annual radiation dose estimates have been lower than the public dose limit, 1 mSv per annum.

Speaker: Eshetu Tilahun Zege (Ethiopia Radiation Protection Authority)

131 TECHNOLOGICAL UPGRADING BY RECYCLING EFFLUENTS GENERATED AT A URANIUM METAL PRODUCTION PLANT, INDIA

Uranium production plant of India has been assigned to produce uranium metal for different important requirements of nation. In the plant, di-uranates / other oxides are processed through several unit operations to produce uranium metal where three process effluents are generated in tonnage quantity. Among the three effluents, two are nitrate bearing radioactive wastes [Effluents (N)] and another is fluoride bearing radioactive effluent [Effluent (F)]. With time, waste disposal norms and regulations are becoming more stringent. In response to the stipulation, efforts have been put to develop suitable methodology for recycling the wastes and also for polishing the generated wastes making suitable for disposal. Suitable technologies have been developed to treat and recycle the effluents (N) and reduction of waste generation has been demonstrated for reuse in the same plant.Developed technology has been utilised to treat the fluoride effluent (F) and zero discharge principle has been achieved. Developmental study describing treatment and recycle of ammonium nitrate waste generated in ammonium diuranate precipitation process is challenging. This presentation will describe the insight of these developmental studies and also demonstrate up-gradation of uranium metal production technology of India with waste recycle schemes.

Speaker: Dr Santosh Kumar Satpati (Bhabha Atomic Research Centre, Mumbai, India)

132 THE EXTRACTION OF URANIUM FROM SALT LAKES IN CHINA

INTRODUCTION Uranium is one of the primary fuel sources for nuclear power generation, making it an element with considerable technological importance. The available energy of 1 kg uranium is equivalent to that of 2050 tons coal. Along with environmental concerns will undoubtedly increase, nuclear energy is prior to be chosen for development because of its cleanliness and high-efficiency. The terrestrial uranium resources are finite and odds and a few countries have major resource mostly in the world. It is reported that the uranium reserves was about 5 million tons when the exploitation cost was under 130 dollars per kilogram. The economical uranium reserves will be exhausted in the next several decades according to current consumption and development. Uranium resources are broadly classified as either conventional or nonconventional resources. Nonconventional resources are very low-grade resources and those from which uranium is only recoverable as a minor by-product. Uranium is therefore a secondary product and its recovery is not subjected to most of extraction costs. The exploitation of nonconventional resources is an inevitable choice for long-term development. The high-salt and low-uranium aqua-systems such as seawater or salt lake are one of the important nonconventional resources. The total amount of uranium in seawater is about 4.5 billion tons, one thousand times of the amount of uranium in terrestrial ores. We planed to uranium extraction from seawater taking the extraction of uranium from salt lakes as cut-in point. The technical deposit will be accumulated which promoting extraction uranium from seawater forward. DESCRIPTION 1. Uranium Resource of Salt Lakes in China There are many salt lakes in the west provinces of China such as Qinghai, Tibet, Inner-Mongolia, Sinkiang, and so on. Some of the salt lakes are uranous. The uranium bearing salt lakes distribute in five regions which are Tibet region, Qinghai region, Sinkiang region, Inner-Mongolia region, and east halite region from southwest to northeast. The boundary of different regions are mountain chains which starting from Himalayas and Kunlun mountains, to Altun-Qilian-Liupan mountains and to northeast Helan and Taihang mountains, ending at Greater Khingan mountains[1]. Uranium resources of salt lakes were estimated by volume measure. Based on the quantity and the known uranium gross of salt lakes, the potential uranium resource was calculated about 80 thousand tons. In view of unknown uranium gross of salt lakes, the total uranium resource of salt lakes is abundant. 2. Certain Uranium Bearing Salt Lake in Tibet Certain uranium bearing salt lake lies in the north of Tibet province where the climate is low precipitation, high evaporation and drought area. The water of the salt lake is achromatous, salty and little basified and the location is on the northwest of Gandise tectonic belt. The surface altitude of the lake is 4500 m, and the area is 252 km2. The best depth of the lake is 36m, and pH value of the water is 9.52, whose mineralization degree of is 20.35 g/L[2]. Uranium concentrations of the salt lake are around 260~324 μg/L and the average value is 289 μg/L. Uranium concentrations near the shores are higher than that of being river supplies and the deep higher than the upper. Uranium concentrations on the surface of the lake are diverse in the range of 264~324 μg/L because of river supplies and wind powers and the average value is 285 μg/L. 3. Synthesis of Functional Materials for Uranium Extraction from Salt Lakes The different methods such as solvent extraction, ion exchange, flotation, biomass collection, adsorption, and precipitation and so on can be used to extract uranium from seawater or salt lake, among which the adsorption is studied more and more feasible way to develop in application. To choose which kind of material is the key to adsorption method. It is important to prepare favorable materials for uranium extraction from salt lakes. According to the literature[3], the salophen(SLP) was immobilized on the surface of silica gel particles and used as the solid phase receptor for quantitatively analyzing uranium. Under optimal conditions, the linear range for the detection of uranium is 0.5~30.0 ng/mL with a detection limit of 0.2 ng/mL. It is obvious that SLP is selective interaction with uranium to form complex in the very dilute solution. Hereby, the route was designed and actualized, which SLP was grafted to styrene- divinylbenzene(ST-DVB) copolymer microspheres. Characterization. The infrared spectra of SLP functional material and amic microsphere were recorded with KBr pellet method. The element analyses of SLP functional material and amic microsphere were recorded by EL-2 type instrument. Uranium capacity. In the experiment, 1.0 g of SLP functional material was added into 100 L simulative salt lake solution which multi-ion solution containing uranyl ion as well as competingions(U 0.34 mg/L，K+ 0.55 g/L，Na+ 7.98 g/L，Mg2+ 0.13 g/L，Ca2+ 3.40 mg/L，Cl- 1.26 g/L，SO42- 6.28 g/L，CO32- 5.03 g/L，HCO3- 1.02 g/L，pH=9.5). After 30d, the uranium capacity of material was calculated, 1.17 mgU/g, by the way of cineration and lixiviation. 4. Spot Uranium Sorption Experiments of Materials Spot uranium sorption experiments of materials were located at above-mentioned salt lake in Tibet. The materials were tied underwater onto the simple equipment which was set in the centre of the lake. After 3 months, the equipment was fished out. A thick yellow matter was found on the equipment except for little mud. 5. Melioration of Functional Materials Identification of adhesion matter at spot. As shown above, a thick yellow matter was found on the equipment and materials, which blocks the adsorption pores on materials and debases uranium capabilities. What is the yellow matter? The yellow adhesion matter was identified by polar microscope. The monadic images were presented in the photographs, and diatom fronds were confirmed through investigation and contrast. Isothiazolinone（MIT）compounds are germicides used widely, which can restrain the growths of bacteria, mildews and algae effectively. Hereby, the route was designed and actualized, which MIT was grafted to ST-DVB copolymer microspheres. The infrared spectra of SLP functional material and amic microsphere were recorded with KBr pellet method. Uranium capacity. In the experiment, 1.0 g of MIT functional material was added into 100L simulative salt lake solution as above. Anti-bioadhering ability of MIT functional material. The living surroundings of algae are similar to that of bacteria, which can grow and propagate in salt solutions. The anti-bioadhering ability of MIT functional material was tested with germcultures in indoor experimentation, and SLP functional material was used in contrast. MIT and SLP functional materials were put into incubators at 30℃for germiculture(①The bacteria was thiobacillus ferrooxidans, and the substrate composition was including of 3.0 g (NH4)2SO4, 0.5 g K2HPO4, 0.1 g KCl, 1.0 g MgSO4·7H2O, 44.4 g FeSO4·7H2O, 1000 mL deionized water, pH=2.0；②The bacteria was sulfate-reducing bacteria, and the substrate composition was including of 5mL sodium lactate, 1 mL yeast extract, 0.2 g (NH4)2Fe(SO4)2·6H2O, 0.01 g KH2PO4, 0.2 g MgSO4·7H2O, 2.0 g NaCl, 7.2 g Na2SO4, 1000 mL deionized water, pH=7.0). After 7 d, the materials were taken out and observed by microscope. DISCUSSION AND CONCLUSION As a whole about uranium resource of salt lakes in China, the regions of higher uranium concentrations are near the shores in the directions of south and northwest, and the uranium concentration in the center of the lake is even. Uranium content of the surface below 18m either in the horizontal level or on the vertical section in the lake change little in the condition of wind powers possibly. Certain uranium bearing salt lake in Tibet is carbonate-type and the water gross is at least 5.0 billion cubes as calculated In the part of characteristic and batch sorption experiments of SLP functional material, the IR spectrum of SLP functional materials shows that the new frequencies appearing at 1618cm-1 belong to C=N stretching vibration in SLP. The C, H, N contents of SLP functional material decrease, while O, Cl contents accordingly increase compared with that of amic microsphere. The result indicates SLP was grafted to ST-DVB copolymer successfully. The SLP functional content was 2.23 mmol/g calculated. The result suggests that the graft reaction was successful. While, the sorption amount increases drastically with the increase of pH values which indicates that SLP functional material has high capacities in alkaline solutions. The uranium desorption rate of SLP functional material≥98% when 20 g/L Na2CO3+60 g/L NaHCO3 was used as desorption agent. In the spot uranium sorption experiments of SLP Materials, the materials were retrieved then washed by distilled water. The uranium adsorption capacities of materials were calculated by the way of cineration and lixiviation. SLP functional material is more selective adsorption of uranium, whose uranium capacity is up to 2.53 mgU/g. In addition, the uranium adsorption capacities of several materials in simulative solutions were higher than that in salt lake. The reason possibly is, on one hand, the simulative solutions are not balance states including kinetic and thermodynamic factors. On the other hand, the complexes of MgUO2(CO3)32- and Ca2UO2(CO3)3 interfere with adsorption courses of materials in solutions[4]. The bioadhering phenomena happened during spot experiments, the analogous instances for the uranium extraction from seawater at spot in Japan, America and China. It is a difficult problem to overcome bioadhering for the extraction of uranium from seawater or salt lake. The concept of anti-bioadhering materials for the extraction of uranium was presented firstly. Anti-bioadhering materials for the extraction of uranium is defined as, “a functional material can adsorb and enrich uranium selectively, which reduce or avoid bioadhering simultaneity in natural uranous water.” In the part of characteristic and batch sorption experiments of anti-bioadhering materials, the IR spectrum of MIT functional materials shows that the new frequencies appearing at 1646 cm-1 belong to C=N stretching vibration in MIT. The result suggests that the graft reaction was successful. After 30 d during spot uranium sorption experiments, the uranium capacity of material was calculated, 1.36 mgU/g, by the way of cineration and lixiviation, which was higher than that of SLP functional material. It was found that MIT functional material was of anti-bioadhering property remarkably. Anti-bioadhering mechanism of MIT functional material was present. MIT functional groups interfere with the phosphorylation of adhesion kinases partially. Certain bond of the adhesion kinase is the most sensitive part, where cells begin to be stopped breathing. The microbes can not attach anything and breed consequently. REFERENCES [1] Chen N, Niu Y, Chen S, et al. Strategic reaearch on extraction uranium from seawater or salt water lake. Consulting report of Chinese Academy of Engineering (2016). [2] Hao W, Chen S, Ren Y, et al. Study on extraction technology of uranium from salt water lake and resource investigation and evaluation. Uranium geology scientific research report (2015). [3] Wu M, Liao L, Zhao M, et al. Separation and determination of trace uranium using a double-receptor sandwich supramolecule method based on immobilized salophen and fluorescence labeled oligonucleotide[J]. Analytica Chimica Acta(2012), 729: 80–84. [4] Endrizzi F, Rao L. Chemical speciation of Uranium(VI) in marine environments: Complexation of Calcium and Magnesium ions with [(UO2)(CO3)3]4- and the effecton the extraction of Uranium from seawate[J]. Chemistry A European Journal(2014), 20: 14499–14506.

Speaker: Prof. Yuqing Niu (Beijing Research Institute of Chemical Engineering and Metallurgy, CNNC)

133 The Test of new UAV Gamma-ray Spectrometer at a Real Uranium Anomaly

INTRODUCTION Localization of size-limited gamma-ray objects plays a fundamental role in uranium prospecting and environmental studies. Unmanned Aerial Vehicle (UAV) mini-airborne measurements have been applied for many environmental issues, including radiation protection and nuclear accident monitoring [1-6]. The instrument reported by Sanada and Tori [5] was based on LaBr3:Ce scintillator, which is not appropriate for measurement of natural radiation due to the inherent contamination of the crystal by 138La. Instruments employed by MacFarlane et al. [1], Martin et al. [2-4] and Falciglia et al. [6] have very good energy resolution, but they are not suitable for radioactive ore prospecting due to their small volume and insufficient sensitivity for the not very intense natural radiometric anomalies. The instrument suitable for prospecting of radioactive geological objects and used in this project was the Georadis D-230A, a newly developed gamma-ray spectrometer specially designed for UAV and equipped with two BGO scintillation detectors. The objective was to assess this equipment for localization of a size limited U mineralization. The possibility of anomaly detection depends on its size, shape and gamma-ray intensity and on the instrument sensitivity, flight speed and flight altitude [7]. The mini-airborne gamma-ray spectrometer Georadis D 230A, having two 51 mm × 51 mm BGO scintillation crystals, provides the sensitivity of 0.55 cps (counts per second) per 1 ppm eU on the ground. The sensitivity of a standard 76 mm ×76 mm NaI(Tl) scintillation detector is approximately 0.33 cps per 1 ppm eU [8]. The sensitivity of Georadis D-230A is about 300 times greater than the sensitivity of the 1 cm3 CZT detector, which was used for many previous UAV surveys in environmental applications [1-4]. METHODS A uranium mineralization near the village of Třebsko, five km to the south from the town of Příbram, Central Bohemia, Czech Republic, served as a test site for the performance of the Georadis D-230A gamma-ray spectrometer. The spectrometer was attached to a powerful hexacopter. The radiation anomaly at the test site is related to an outcropping U mineralized vein. Concentrations of radionuclides at the anomaly were assessed by a detail ground measurement with a portable gamma-ray spectrometer GS-256 equipped with a 76×76 mm NaI(Tl) scintillation detector. Calibration of the GS 256 spectrometer was performed at the calibration facility in the Czech Republic, in conformity with the standard procedures as recommended by the IAEA [8]. Registered field data were interpolated by the kriging method and the U contour map of the anomaly was compiled. The hexacopter by Robodrone Industries (Czech Republic), type Kingfisher, was used as an airborne platform. It was a powerful hexacopter with up to 5 kg payload capacity, dimensions 120×140×22 cm, maximal endurance 45 min., endurance with attached 4 kg instrument was 16 min, maximal speed was 70 km/h and wind resistance 10 m/s [9]. The navigation could be manual or autonomous. The autonomous mission was specified by waypoints given by GPS coordinates and the flight altitude as the third coordinate. The system measures the altitude by a barometric pressure sensor MS5611-01BA03 [10]. The atmospheric pressure altimeter is calibrated to zero height on the ground before each flight. Mini-airborne 1024 channel gamma-ray spectrometer Georadis D 230A (Czech Republic) with two Bismuth Germanium Oxygen (BGO) scintillation detectors of the volume 103 cm3 each has an automatic spectrum stabilization using energy lines of natural radionuclides. The instrument energy resolution 13.6 % at 662 keV was determined experimentally. The instrument weight was approximately 4 kg including rechargeable battery and dural holder fixing the instrument under aircraft. Mini-airborne measurement was carried out on three 100-m-long parallel lines NW – SE perpendicular to the longer axis of the anomaly (NE – SW). The separation between profiles was 10 m. The data recording time interval was 1 second. Each of the three profiles was flown at eight altitudes from 5 m to 40 m above the ground with the vertical step of 5 m. Flight velocity was 1 m/s. The navigation was performed in the autonomous GPS flight mode. The result of flight operation were 1s interval 1024 channel gamma-ray spectra, which were processed to U concentration and TC count rate. RESULTS AND DISCUSSION The resulting U contour map obtained from the ground assaying shows the size of the anomaly approximately 80 m by 40 m with average U concentration of 25 ppm eU, which locally attains 700 ppm eU. The results show the significant dependence of the recorded anomalous gamma-ray field converted to TC data and apparent U concentrations on the flight altitude. The anomaly was recognized at all profiles and flight altitudes. Recorded maxima of count rates exceed the N + 3S level [8] at all cases. A comparison between sensitivities and data quality of a standard airborne survey and the mini-airborne survey is illustrative. Grasty and Minty [11] reported U sensitivity of an airborne spectrometer at 80 m flight altitude approximately as 8 cps per 1 ppm eU. The flight speed of the aircraft is about 50-60 m/s for fixed-wing surveys [8]. The Georadis D-230A has U sensitivity on the ground 0.55 cps per 1 ppm eU. Uranium sensitivity at the altitude of 40 m is approximately 50% of the sensitivity on the ground [11, 13], which means about 0.25 cps per 1 ppm eU. Flight speed of the UAV multicopter can be slowed down to 1 m/s. Theoretically, a standards airborne survey at flight altitude of 80 m over 100 m long profile with unit uranium concentration 1 ppm U will generate in U energy window 16 counts while for the Georadis D-230A at a flight altitude of 40 m and attainable speed 1 m/s 25 counts will be recorded. It is obvious that UAV mini-airborne survey can, due to low speed and lower flight altitude, collect data with comparable quality, on a detailed scale, as standard airborne survey. CONCLUSION The presented issue deals with the methodology and potential of mini-airborne gamma-ray spectrometric survey for radioactive ore prospecting using unmanned aerial vehicles. The research has shown real operational possibilities of the tested mini-airborne system with a progressive BGO gamma-ray spectrometer with relatively large volume detector. Experimental measurement profiles over a size limited U anomaly at flight altitudes from 5 m to 40 m showed the rapid decrease of the gamma-ray field with increasing flight altitude. Flight altitude is an important setting for mini-airborne survey. Based on our results, the flight altitude for mini-airborne surveys can be up to 40 m and take into account all important conditions like size and intensity of an assumed anomaly, detector sensitivity, flight speed and vegetation character. A detailed ground gamma-ray spectrometry investigation of the U anomaly enabled analysis and comparison with airborne data. A small UAV can fly at low altitudes and enables detection of size-limited radiation objects which are undetectable by conventional airborne gamma-ray spectrometry at standard flight altitude of about 80 m. In this sense UAV systems fill a gap in technical possibilities between ground and conventional airborne measurement. The UAV mini-airborne instrument can collect the same number of counts per unit distance on a profile as a standard airborne survey, due to low speed and lower flight altitude. The main limitations of mini-airborne gamma-ray spectrometry are short operational time and slow survey speed causing the method to be not applicable for regional surveys. The authors would like to thank the International Atomic Energy Agency for funding the project. The IAEA contributed to the research under the Research Contract No 19036. The technical support for field experiments was generously provided by Georadis s.r.o. and National Radiation Protection Institute of the Czech Republic. REFERENCES [1] MacFarlane, J.W., Payton, O.D., Keatley, A.C., Scott, G.P.T., Pullin, H., Crane, R.A., Smilion, M., Popescu, I., Curlea, V., Scott, T.B., 2014. Lightweight aerial vehicles for monitoring, assessment and mapping of radiation anomalies. J. Environ. Radioact. 136, 127 – 130. http://dx.doi.org/10.1016/j.jenvrad.2014.05.008. [2] Martin, P.G., Payton, O.D., Fardoulis, J.S., Richards, D.A., Scott, T.B., 2015a. The use of unmanned aerial systems for the mapping of legacy uranium mines. J. Environ. Radioact. 143, 135 – 140. http://dx.doi.org/10.1016/j.jenvrad.2015.02.004. [3] Martin, P.G., Payton, O.D., Fardoulis, J.S., Richards, D.A., Yamashiki, Y., Scott, T.B., 2015b. Low altitude unmanned aerial vehicle for characterising remediation effectiveness following the FDNPP accident. J. Environ. Radioact. 151, 58 – 63. http://dx.doi.org/10.1016/j.jenvrad.2015.09.007 [4] Martin, P.G., Moore, J., Fardoulis, J.S., Payton, O.D., Scott, T.B., 2016. Radiological Assessment on Interest Areas on the Sellafield Nuclear Site via Unmanned Aerial Vehicle. Remote Sensing 8(11), 913. http://www.mdpi.com/2072-4292/8/11/913 [5] Sanada, Y., Torii, T., 2014. Aerial radiation monitoring around the Fukushima Dai-ichi Nuclear Power Plant using an unmanned helicopter. J. Environ. Radioact. 139, 294-299. http://dx.doi.org/10.1016/j.jenvrad.2014.06.027 [6] Falciglia, P.P., Biondi, L., Catalano, R., Immé, G., Romano, S., Vagliasindy, F.G.A., 2017. Preliminary investigation for quali-quantitative characterization of soils contaminated with 241Am and 152Eu by low-altitude unmanned aerial vehicles (UAVs) equipped with small size γ-ray spectrometer: detection efficiency and minimum detectable activity (MDA) concentration assessment.J Soils Sediments.https://doi.org/10.1007/s11368-017-1720-6 [7] Mareš, S., Gruntorád, J., Hrách, S., Karous, M., Marek, F., Matolín, M., Skopec, J., Válek, R. (1984): Introduction to Applied Geophysics. D. Riedel Publishing Company, Dordrecht and SNTL, Prague. [8] IAEA, 2003. Guidelines for Radioelement Mapping Using Gamma Ray Spectrometry Data. IAEA-TECDOC-1363, IAEA, Vienna [9] Robodrone Industries, 2017. Product specification, website https://www.robodrone.com/kingfisher (accessed on 09.09.2017). [10] TE Connectivity, 2017. MS5611-01BA03 Barometric Pressure Sensor documentation, websitehttp://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=MS5611-01BA03&DocType=Data+Sheet&DocLang=English [11] Grasty, R.L., Minty, B.R.S., 1995. A guide to the technical specifications for airborne gamma-ray surveys. Australian Geological Survey Organisation, Record 1995/60. [12] IAEA, 1991. Airborne Gamma Ray Spectrometer Surveying. IAEA TRS No. 323, IAEA, Vienna. [13] IAEA, 2013. Advances in Airborne and Ground Geophysical Methods for Uranium Exploration. IAEA NUCLEAR ENERGY SERIES No. NF-T-1.5, IAEA, Vienna

Speaker: Mr Ondrej Šálek (Charles University)

134 The Мining Sector Capacity Improvement in the Kуrgуz Republic through building effective cooperation among governments, mining companies and local communities

INTRODUCTION Mining practices began as early as the 19th century in the Kyrgyz Republic. In 1890, coal mining started in Naryn, followed by the Kok-Zhangak mine in 1896 and the Kyzyl-Kiya Suluktinskoye mines in 1898 [1]. The Kyrgyz Republic greatly contributed to the mining industry of the Soviet Union. In the history of the development of the atomic industry and energy of the USSR (Union of Soviet Socialist Republics), Kyrgyz uranium deposits played a very significant role, and the first Soviet radium was mined at the Tyu-Muyun field in the south of the Kyrgyz Republic. The first uranium ore was mined in 1946 at the Gylish uranium-coal deposit. At some point, the total extraction of minerals in the Kyrgyz Republic reached 15-18% of the total production of the Soviet Union, including 40-100% of mercury, 100% of antimony, 30% of rare earth metals and 15% of uranium [2]. The mining industry is the basis of industrial production in Kyrgyzstan. It is of great importance in the development of the economy. In 2013 the share of the mining industry in GDP was 10.1% with 47.1% of the total exports and 16.8% of tax revenues [3]. The share of foreign direct investment in 2014 was about US$113 million, which accounted for 26% of the investment in fixed assets in the mining industry [4]. At present, there are substantial deposits of gold, uranium, antimony, mercury, tin, molybdenum, coal and brown coal, oil and gas, non-metallic minerals, groundwater, and other types of minerals. So, according to the State balance of mineral resources of the Kyrgyz Republic as of January 1, 2017, there are 3555 tons of uranium. Development of mineral resources is a necessary condition for the successful development of the economy of the Kyrgyz Republic and for remote mountainous areas is often the only possible way of improving the social welfare of the population. However, further development in the mining sector has been derailed by various problems and challenges. One of the major problems in recent years, the Kyrgyz Republic has experienced serious conflicts between mining companies and local communities. Many investors attribute the cause to the weak law enforcement mechanism of the Kyrgyz Republic in handling conflicts with the local population. This claim is partly correct. From 2005 to 2010, for example, opposition forces against mining took advantage of political instability and increased the number of confrontations with authorities [5]. DESCRIPTION There are various causes of mining conflicts, such as environmental problems, socio- economic disparities, and health-related concerns and cultural misunderstandings. So far, the main cause of conflicts over the mining industry in the world is environmental issues. According to the EJOLT report [6], all 24 analyzed mining conflicts were partly caused by environmental concerns, including water issues. During the period between 2012 and 2013, conflicts increased between the local population and mining companies. According to several researches [7], main causes of these conflicts were attributed to (1) environmental problems, (2) distrust to mining companies, (3) distrust to government bodies, (4) social problems, (5) inadequate information from companies and government bodies about the proposed mining operations, and (6) lack of dialogue between stakeholders. One of the main concerns of local people was the negative impact of mining on the environment. In the Republic there are still uranium tailings, which have been left after the exploitation of various deposits during the Soviet period. According to the State Cadaster on the mining waste, there are 92 tailings and mountain dumps located in the Country. Among these tailings, 28 are radioactive and 5 are toxic. Also, 25 tailings are radioactive mountain dumps [8]. Local people near former mines worried about water and air pollution, the destruction and degradation of pastures and agricultural lands, negative impacts on crops and livestock, and damages to infrastructure and roads [9]. Opposing local communities often systematically obstructed mining preparation and operation activities by blocking access roads and engaging in violent direct actions again mining companies [10]. Some of the protestors demanded investors and government officials to recognize community’s right to receiving some part of mining benefits. Some others demanded to have sufficient information about the impact of mining on local ecosystems. Many herders and others were afraid of irreversible damage on grazing areas or other local livelihood activities. Some conflicts between local communities and mining companies (e.g., Solton-Sary gold mine) intensified and company representatives were forced to leave the fields for their own safety [5] as some protestors’ demands included the complete cessation of the miningwork and the termination of licenses [5]. To illustrate the scale and scale of conflicts in the mine in the country, one incident can be considered, which occurred in 1998 at the Kumtor mine. To date, the Kumtor area has nation’s largest gold ore deposit. Kumtor's contribution to GDP ranged from 6.8 % in 2009 to 9.4 % in 2013. Its industrial output reached 48.6 %. exports (41.2 %). The Kumtor Gold Company, which has financed the mining operation, is one of the largest investors in the Kyrgyz Republic. Its share in total capital investments of the country in 2012 was 15.6 %. Share in total gross FDI in 2011 was 51 % [11]. The rapid expansion of this mine resulted into the environmental disaster at the mine site. It made a huge impact on subsequent conflicts [9]. METHODOLOGY The research was based on the qualitative research method including a literature review documents, policy documents, statistical information, scientific publications, reports and web pages from non-governmental organizations. The literature review was aimed at studying the nature of conflicts in the mines in the Kyrgyz Republic and around the world between local communities and mining companies through comparative analysis and the search for positive experience in the prevention and resolution of conflicts in various countries of the world. DISCUSSION AND CONCLUSION This research has attempted to understand mining conflicts in the Kyrgyz Republic and around the world through comparative analysis. Its findings show that the main causes of these conflicts were environmental problems, socio-cultural misunderstanding, socio-economic conditions, mistrust and lack of dialogue among stakeholders. It examined good practices to prevent and resolve mining conflicts in different countries. It found that some Canadian mining companies worked closely with the local population in the early stages of the project. This public engagement from the initial stage resulted into its own benefits and the improved living standard of local people as well as improved environmental conservation status [12]. The cases in Canada demonstrate that the earlier the mining company begins to interact with local communities, the better for all stakeholders. The early participation of the community gave it an opportunity to learn more about local community's concerns for the environment and their socio-economic well-beings. And those Canadian companies largely responded to the needs in a timely manner. In Canada, conflict resolution and prevention measures involve research institutions and universities that upon request conduct specific researches. This Canadian experience provides some useful insights in improving the practice of mining companies in the Kyrgyz Republic. After independence, in order to improve the investment attractiveness and transition from a planned economy to a market economy, the Government of the Kyrgyz Republic has made several attempts to change the shortcomings of the regulatory system of the mining industry and to weaken the administrative control. In order to invite more foreign investments and effectively develop mineral resources, the State Agency for Geology and Mineral Resources began reforming subsoil use policies. As a result, a new law on the subsoil was adopted on August 9, 2012. This law, which is currently in force, (1) establishes the ownership of subsoil and mineral resources; (2) identifies the powers of state administrations, local governments, and other subsoil use regimes; and (3) establishes types of licenses and the procedure for issuing, renewing and terminating licenses [13]. In recent years, the State Committee for Industry, Energy and Subsoil Use has been working hard to reduce conflicts between mining companies. In recent years, the State Committee for Industry, Energy and Subsoil Use has conducted a number of field visits to mining areas and explained local people about the activities of the mining industry. It has held training seminars, conferences with the participation of governments, local self-government bodies, mining companies and local communities. As a result, the number of conflicts has decreased according to my interview with the State Committee chairman D. Zilaliev on May 26, 2017. He also noted that local self-government bodies began to provide assistance in resolving conflicts [14]. This means that the close interactions among government officials, mining companies and the local community can reduce conflicts. In my opinion, the problem of conflicts in the mining industry can never be solved for good. However, it is possible to reduce or minimize them. Experience shows that the resolution of conflicts by the state force does not resolve conflicts. This oppressive action sometimes exacerbates conflicts instead [15]. In resolving or preventing mining conflicts, the state can act as an intermediary, as it is interested in business development, local citizens’ social and economic development, and the minimization of the negative environmental impacts. REFERENCES [1] DJUNUSHALIEVA G., “Becoming of mining industry of Kyrgyzstan”, №1 (120) Kyrgyz Russian Slavic University № 21, (2012). Retrieved on March 1, 2017, from http://khaydarkan.su/arhivy_foto/stanovlenie_gornoy_promyshlennosti/stanovlenie- gornodobyvayuschey-promyshlennosti-v-kyrgyzstane.pdf. [2] BOGDETSKY V., IBRAEV K., ABDYRAKHMANOVA J., “Mining industry as a source of economic growth, developed under Project Implementation Unit of World Bank IDF Grant for Building Capacity in Governance and Revenues Streams Management for Mining and Natural Recourses,” (2005). Retrieved on March 1, 2017, http://siteresources.worldbank.org/INTOGMC/Resources/3360991156955107170/miningsou rceeconomicgrowth.pdf. [3] EXTRACTIVE INDUSTRIES TRANSPARENCY INITIATIVE, “EITI Report of Kyrgyz Republic for 2013 – 2014.” Bishkek, (2015). Retrieved March 3, 2017, from https://eiti.org/sites/default/files/documents/2013- 2014_kyrgyz_republic_eiti_report_en.pdf. [4] NATIONAL STATISTICAL COMMITTEE OF THE KYRGYZ REPUBLIC, “Investments in the Kyrgyz Republic 2010-2014.” (in Russian) Table I.2.5, (2015). Retrieved on March 3, 2017, from http://www.stat.kg/media/publicationarchive/1e3c3994- 8277-4c1f-899e-1867a8cc6a77.xls. [5] ZOÏ ENVIRONMENT NETWORK, UNIVERSITY OF EASTERN FINLAND, GAIA GROUP OY, “Toolkit Companion with Case Studies - Mining, development and environment in Central Asia,” (2012). Retrieved on February 21, 2017, from http://www.zoinet.org/web/sites/default/files/publications/companion_ENG.pdf. [6] THE ENVIRONMENTAL JUSTICE ORGANISATIONS, LIABILITIES AND TRADE, “Mining conflicts around the world. Common grounds from an Environmental Justice perspective”, (2012). Retrieved on March 5, 2017, from https:///C:/Users/www/Downloads/metis_183590.pdf. [7] MINISTRY OF ECONOMY OF THE KYRGYZ REPUBLIC, “Draft medium-term and long-term development strategy for the mining industry of the Kyrgyz Republic.” (in Russian), (2014). Retrieved on March 1, 2017, from http://www.mineconom.gov.kg/images/projects/files/125_1399444897.pdf. [8] MINISTRY OF EMERGENCY SITUATIONS OF THE KYRGYZ REPUBLIC, “Historical reference” on March 7, (2017). Retrieved on XXXX from Ministry of Emergency Situations http://mes.kg/en/about/subordinate/ARB-en/istoriya-ARB-en/. [9] EFCA, OXUS INTERNATIONAL, AND USAID, “Extracting Sentiments: The Effect of Mining Exploration and Extraction on Eight Comminutes in the Kyrgyz Republic,” (2012). Retrieved on March 15, 2017, from https://issuu.com/efca/docs/extracting_sentiments_the_effect_of. [10] WORLD BANK, “Kyrgyz Republic: Mining Industry Needs Assessment.” Горной Отрасли Требуется Оценка (in Russian), Bishkek, (2013). Retrieved on April 28, 2017 from http://documents.worldbank.org/curated/en/687851468047369947/text/876860WP0P13310t0 0000date0june02013.txt. [11] MOGILEVSKII,R., ABDRAZAKOVA, N., CHALBASOVA S., “The Impact of Kumtor Gold Mine on the Economic and Social Development of the Kyrgyz Republic.” University of Central Asia, (2015). Retrieved April 10, 2017, from http://www.ucentralasia.org/Content/Downloads/UCA- IPPA-WP32-Kumtor-Eng.pdf. [12] GOVERNMENT OF CANADA, “Stakeholder Engagement, Good Practices in Community Engagement and Readiness Compendium of Case Studies from Canada’s Minerals and Metals Sector, (2016). Retrieved on May 19, 2017, from http://www.nrcan.gc.ca/sites/www.nrcan.gc.ca/files/mineralsmetals/files/pdf/rmd-rrm/GoodPractices2ed_En.pdf. [13] JOGORKU KENESH OF THE KYRGYZ REPUBLIC, Article 9, Law of the Kyrgyz Republic “On Subsoil.” (in russian ) Статья 9 Закона Кыргызской Республики “О недрах”, August 9, 2012 № 160, (2012). Retrieved March 2, 2017, , from database of Ministry of Justice of the Kyrgyz Republic: http://cbd.minjust.gov.kg/act/view/ru-ru/203760?cl=ru-ru. [14] BBC NEWS KYRGYZSTAN, Interview of the Chairman of the Committee of Industry, Energy and Subsoil Use of the Kyrgyz Republic, (2017). Retrieved on June 5, 2017, from http://www.bbc.com/kyrgyz/kyrgyzstan-40049672. [15] CARBONELL, H., “Zinc, lead and silver mega-deposits in San Cristobal (Bolivia).” EJOLT Factsheet, (2014). Retrieved on April 5, 2017, from file http://www.ejolt.org/wordpress/wp- content/uploads/2015/02/FS_017_San-Cristobal.pdf

Speaker: Ms Aisha Karpaeva (Subsoil Use Licensing Department of the State Committee of Industry, Energy and Subsoil Use of the Kyrgyz Republic)

135 Thorium and Rare Earth Element Comprehensive Extraction Projects in Argentina: Assessment Using The United Nations Framework Classification For Resources (UNFC)

INTRODUCTION This case study looks explicitly into how integrated thorium and associated rare earth elements (REE) projects could contribute to thedevelopment of the minerals sector in Argentina[1-2]. Thorium could be used as fuel for low-carbon nuclear power generation, while REE is widely accepted as a critical material required for renewable energy technologies, among other uses[3]. For the accurate assessment and planning the progression of resources, United Nations Framework Classification for Resources (UNFC)is used in this case study. In particular, the specific guidelines for uranium and thorium resources in acomprehensive recoveryprojectswere used in this case study[4]. In general, UNFC uses a three-dimensional classification system with (i) Socio-economic viability (E); (ii) Technical feasibility (F) and; (iii) Geological knowledge (G) as the three major criteria for assessment. Thorium resources in Argentina, as in most other countries, have not been subjected to systematic studies. Most of the existing anomalies, showings and deposits were discovered as a result of uranium exploration, where airborne radiometric surveys played a relevant role as a prospecting technique [5-6].Incidentally, REE potential was also estimated as part of the examination of high-Th radiometric records and field geological characterization. More recently and due to the renewed worldwide interest in REEs and other critical materials, exploration companies have initiated different projects in Argentina, which have shown encouraging geological prospectivety for thorium and REE; additionally, thorium resources have been evaluated and reported. In 2013, the CNEA carried out a plan for the expeditious reexamination of the radiometric anomalies related to Th and U in the Ambargasta and Sumampa Ranges in Santiago del Estero Province. This study allowed defining the sites with the most mining potential, where high radioactivity areas were mostly related to carbonatites [7]. The only reported production of REE-Th minerals in Argentina, was the recovery of 1,010 kg of monazite, without recovery of REE and Th from the Teodesia mine (Valle Fertil Range) during 1954 to 1956. DESCRIPTION The REE interest covers vast areas of the country in the Puna, Cordillera Oriental and Pampean Ranges regions, focused mainlyon Upper Jurassic-Cretaceous carbonatite rocks intruded in extensional geotectonic settings.The geological types of REE-Th deposits that have been found in Argentina are carbonatites, pegmatites and placers. Main projects of interest and their status in UNFC scheme can be described as follows: Rodeo de los Molles REE (Th, U) Deposit/ Project: This deposit was discovered by the CNEA in the early 1980s while mapping and prospectingthe area identified by regional airborne radiometric anomalies.The deposit is hosted in ‘fenitized’ alkaline igneous rocks (Jurassic) of the Las Chacras igneous complex, and it is LREE dominant. Rodeo de los Molles is the most significant undeveloped REE project in Argentina with a historicalgeologic resource of 5.6 Mt of mineral ore, containing an estimated 117,600 tREO and 950 tU. About 10,000 tTh were estimated with a lesser degree of confidence.The first resource estimate was prepared in 1992, including metallurgical test work that demonstrated the amenability of bastnasite to REErecovery; this estimate was based on approximately 6,000 m of rotary air blast drilling. [8].Significant quantities of uranium could be produced as by- or co-product from this project. About 15 tU in G2 and 950 tU in G3 categories are estimated in this project. The Th resources of Rodeo de losMolles project arealso considered as a potential by- or co-product of the project, but the quantities are estimated with a lower level of confidence. Hence they are assigned to a G4 category. In San Luis Province, where this project is located, the Law 634/2008 prohibits the use of chemicals in all forms and stages of metalliferous mining and processing. Under the UNFC, Rodeo de los Molles REE-U project is considered as a “Potentially Commercial Project” within the subclass “Development On Hold” with categories E2, F2.2, G2-G3.The Th quantities are at present classified separately as an “Exploration Project”. With additional data availability, these quantities can be progressed to higher G categories and merged with the REE-U project. Puna and Cordillera Oriental Thorium (REE) Deposits:These deposits are located in the Northwestern Region of Argentina in Salta and Jujuy Provinces. The depositsshow a complex mineralogical composition and are linked to Jurassic-Cretaceous alkaline magmatism that took place in anextensional geotectonic setting.Identified resources of 23,900 tTh at a grade of 0.37% Th and 35,300 tREO+Y (Rare Earth Oxides and Yttrium) at a grade of 0.58% REO+Y derive from nine mineral deposits [9-10].The quantities associated withthese deposits have been estimated with a low level of confidence.In the case of REO+Y resources, itis considered that economic viability of recovery cannot yet be determined due to insufficient information and the justification as commercial developments may be subject to significant delay. Th resources, even though currently considered as having no reasonable prospects for economic recovery, can be produced as a by- or co-product along with the primary REE production. Hence, Puna and the Cordillera Oriental projectsare classified as “Non Commercial Projects” with sub-class“Development Unclarified” (E3.2, F2.2, G3). III River and V River Surveys:In the 1950s and 1980s, the CNEA addressed some specific thorium recognition studies on the detrital deposits along the III River (Cordoba Province) and V River (San Luis Province) [11-12]. Th resources in both sites and Th and REO resources in III River site were evaluated, based on raw material and monazite tonnages and monazite chemical compositions.The areas involved are densely cultivated and mining the resources may implicate access to large tracts of agricultural land. Because of these constraints, the projects had become unattractive, and no project was identified to potentially recover the resources. The quantities of 850 tTh and 15,500 tREO in III River and 260 tTh estimated in V River project are assumed tobe presently unrecoverable, as no development project has been identified. The quantities fall in the UNFC class of “Additional Quantities in Place”, with UNFC criteria of E3.3, F4 and G4. Exploration Projects:Several new REE (Th) projects are active today in Argentina such as Jasimampa, Susques, Cachi and Cueva delChacho [13-14].In these projects, economic viability and feasibility of recovery cannot yet be assessed due to insufficient information and limited technical data; eventualreported quantities associated with these mineralizations would be considered as undiscovered resources. Therefore, in the UNFC these projects are qualified as “Exploration Projects” (E3.2, F3, G4). DISCUSSION AND CONCLUSIONS Although the potential for mineral resources are very high in Argentina, the mining sector plays only a minor role in the socio-economic development of the country. Most of the mineral potential of the country is underdeveloped, which therefore offers a possible opportunity for future investments. Rare earth element potential of the country is significant,and its potential development in the future is one that may be worth serious consideration. This case studyspecifically looks into how integrated REE and associated thorium and other valuable materials projects could contribute to the solid mineral sector development in Argentina. Argentina has no current plans to use Th as a nuclear fuel. However, it can be pointed out that all three existing HWR nuclear power plants offer potential capabilities for large-scale irradiation of naturalTh-232 to produce U-233.More recently, due to the renewed interest in REE worldwide, the private sector has set up different exploration projects, which exhibit encouraging geological prospectivety. As a result, thorium resources are started to be evaluated and reported. In the case of possible future production of REEs, Th and some other materials such as U, it can be assumed to be produced as a by- or co-product. While REE has crucial applications, especially in the renewable energy sector, the Th produced can be stored for future use. Thorium resource assessment in the country is far from complete, and most thorium resource estimations correspond to undiscovered resources because specific exploration and comprehensive resource estimation of REE and thorium deposits have been conducted at a very preliminary level. When mapping REE and thorium resources in the UNFC scheme,the Argentine projects currently have neither economic and social conditions nor technical feasibility that are sufficiently matured to indicate a reasonable potential for commercialrecovery and sale in the foreseeable future. Except for the Rodeo de losMolles project, which has been classified as a “Potentially Commercial Project” no other project has matured well for commercial recovery in the near-future. However, when considered as comprehensive recovery projects, there are projects with significant potential for future development. Thorium and other valuable materials, in that case also become significant, andcould be produced without major additional investment as by- or co-products. This case study on the application of demonstrates the potential for assessing REE and Th as an integrated project, thereby increasing the project maturity of the combined project. The application of UNFC contributes to a better understanding of the availability of reliable nuclear and associated critical material resources, especially for green energies in Argentina, and helps in understanding where the focus should be in future. The role of REE to contribute to Argentina’s GDP could be reassessed with this in view. This contribution is a summary of several studies that were conducted by the National Atomic Energy Commission (Argentina), the Argentine Geological Mining Survey and different exploration companies. The authors are grateful to many companies and institutions for allowing the information to be assessed and presented here. REFERENCES [1] UNITED STATES GEOLOGICAL SURVEY, Mineral Yearbook-Argentina (advanced release)(2013), http://minerals.usgs.gov/minerals/pubs/country/2013/myb3-2013-ar.pdf [2] DELOITE& CO. S.A., Industry outlook.Mining in Argentina.Financial Advisory Services Argentina(2016), https://www2.deloitte.com/content/dam/Deloitte/ar/Documents/finance/ Industry%20Outlook%20-%20Mining%20in%20Argentina.pdf [3] VAN GOSEN, B.S., et al.,The rare-earth elements—Vital to modern technologies and lifestyles: U.S. Geological Survey Fact Sheet 2014–3078, 4 p.(2014), http://dx.doi.org/ 10.3133/fs20143078 [4] UNITED NATIONS ECONOMIC COMMISSION FOR EUROPE, Guidelines for Application of the United Nations Framework Classification for Fossil Energy and Mineral Reserves and Resources 2009 for Uranium and Thorium Resources, ECE ENERGY SERIES No. 55 (2017)http://www.unece.org/fileadmin/DAM/energy/se/pdfs/comm24/ECE.ENERGY.2015.7_e.pdf [5] LÓPEZ, L., Radiometric Baselines in Uranium Exploration – Production Areas of Chubut Province (Argentina). International Atomic Energy Agency Technical Meeting on "Best Practices in Environmental Managementof Uranium Production Facilities",Saskatoon, Saskatchewan, Canada, 20-25 June 2004(2004); Contributed Papers (CD-ROM). [6] SERVICIO GEOLÓGICO MINERO ARGENTINO, Catálogo de Productos (2017)http://www.segemar.gov.ar/statics/files/catalogo_2016.pdf [7] ÁLVAREZ, J., PARRA, F., SALVATORE, M., RevisiónTécnica de AnomalíasAéreas de Torio en las Sierras de Sumampa y Ambargasta. National Atomic Energy Commission (CNEA) internal reports, unpublished (2013). [8] WEALTH MINERALS LIMITED,Rodeo de Los Molles Rare Earth Element Project,WM Ltd. Internal report, unpublished (2011). [9] SANTOMERO, A.,Estudios de Depósitos de Torio y TierrasRarasdelNoroeste Argentina. National Atomic Energy Commission (CNEA) internal reports, unpublished (1956-1958). [10] ZAPPETTINI, E.,Depósitos de Torio y TierrasRaras de la Puna y Cordillera Oriental, Salta y Jujuy. E.O. Zappettini (Ed.), Recursos Minerales de laRepública Argentina, Anales No. 35 SEGEMAR, pp. 979-985 (1999). [11] LUCERO, H., Evaluación de los Recursos de Torio de las ArenasMonacíticasdel Río Tercero,NationalAtomicEnergyCommission (CNEA) internalreport, unpublished (1950). [12] SANTOMERO, A.,Evaluación de los Recursos de Torio de las ArenasMonacíticasdel Río Quinto,NationalAtomicEnergyCommission (CNEA) internalreport, unpublished (1978). [13] ARTHA RESOURCES CORPORATION, Form 51-102F1: Management Discussion and Analysis for the Year Ended, AR Corp. internal report, unpublished (2011). [14] PACIFIC BAY MINERALS LIMITED, Press release (2010)http://www.pacificbayminerals. com /pacific-bay-minerals-ltd-strong-rare-earth-values-at-chacho-show-high-ratio-of-heavy-ree

Speaker: Mr LUIS LOPEZ (CNEA (Argentina))

136 URANIUM AND ITS ENVIRONMENTAL BEHAVIOUR: A NEW IAEA TECHNICAL REPORTS SERIES PUBLICATION

Uranium is a naturally-occurring element that is present at low concentrations in all environmental media, but elevated concentrations of uranium can be found in some minerals e.g. uranium-rich ores. Assessments of the impact of uranium on humans and other biota are a specific challenge because of the combination of different types of hazards and potential exposures. The IAEA is preparing an overview document intended to provide IAEA Member States with information on the environmental behaviour of uranium for use in environmental impact assessments of routine discharges and accidental releases, for uranium impact assessments in different contamination scenarios and for remediation planning of sites contaminated with uranium. This report covers the behaviour of uranium in the atmosphere, terrestrial, freshwater and marine environments. The primary focus of the report is the environmental behaviour of uranium, as the environmental behaviour of uranium progenies (such as radioisotopes of radium, radon, polonium and thorium) are considered in other IAEA documents. The information presented is relevant to the environmental transfer of uranium to both humans and non-human biota.

Speaker: Mrs Andra-Rada Iurian (IAEA)

137 URANIUM LEGACY SITES OF THE FORMER SOVIET UNION IN TAJIKISTAN: PROBLEMS AND THE WAY FORWARD

During the second half of 20th century, Tajikistan was one of the uranium raw material suppliers in the former Union of Soviet Socialist Republics (former USSR). More than 20% of produced uranium in the former USSR was delivered from Tajikistan. Altogether, 10 uranium mining tailing dumps covering 170 hectares and containing more than 55 million t of waste were accumulated, with an activity of more than 6.5 kCi, from the beginning of the uranium industry in Tajikistan on the territory of six districts in the Soghd region. An essential limitation on carrying out the required remediation measures is a lack of relevant infrastructure. In this regard, the regulatory authority of Tajikistan faces many challenges, such as: (a) Development of legislative basis; (b) Assessment of radiological consequences on uranium industry sites; (c) Assessment of the condition of remediation measures; (d) Analysis of compliance with international standards and recommendations; (e) Development of an action plan on minimizing the impact of uranium industry sites on public and environment; (f) Having sufficient and suitable analytical equipment for monitoring. It is necessary to mention that implementation of international projects with the active participation of the IAEA has facilitated expanding cooperation and mutual understanding among Central Asian countries in issues concerning environmental protection. Re-establishment of radiation control systems on former uranium industry sites in Tajikistan is the first step to their full remediation.

Speaker: Prof. Ulmas Mirsaidov (Nuclear and Radiation Safety Agency)

138 Uranium Mine Operations in Indonesia

INTRODUCTION Mineral and coal mining in Indonesia regulated by Act No. 4 Year 2009 [1]. In the Act, minerals divided into four category which are: rock, metal, non metal, and radioactive minerals. Implementation of the Act regulated in the derivative Government Regulations from Act No. 4 Year 2009 that cope the arrangement of region, business license, and inspection activities. However, arrangement for the radioactive minerals excluded from Act No. 4 Year 2009 on Mineral and Coal Mining, and delegate the arrangement to the Act No. 10 Year 1997 on Nuclear Energy [2]. The term nuclear material mining in Nuclear Energy Act is compatible with term radioactive minerals in Mineral and Coal Mining Act. Currently, Indonesia in the development phase for Government Regulations as implementation of the Act No. 10 Year 1997 on Nuclear Energy for nuclear material mining. It will regulated the detailed arrangement for business, license, and inspection activities. This paper describe the main idea of arrangement for nuclear material mining, for example uranium mining as the main focused activity in this paper, in the draft of Government Regulations which is in the development phase. DESCRIPTION Indonesian government opening up opportunities for parties to running uranium mining business. The interested party, called applicant, can be a National Nuclear Power Agency (BATAN), a state-owned enterprise, a cooperative, or a business entity. The applicant to conduct activities related to uranium business can apply for a Nuclear Mining Permission Mining license to the Nuclear Energy Regulator Agency (BAPETEN). BATAN is a government institution having duties and functions as the nuclear promoting body, and BAPETEN is a government institution that has duties and functions nuclear regulatory body. There are two major phase for the activities to running uranium mining business, which are: • General Investigation, Exploration, and Exploitation Phase; and The initial phase of uranium mining processes is through feasibility study activities based on the results of general investigation and exploration activities. A state-owned enterprise, a cooperative, or a business entities that interested in conducting activities in this phase must cooperate with BATAN. • Mining Phase Mining in this context define as a phase of activities that includes excavation, temporary storage, processing, transportation, and sale of nuclear material mining. The party interested in performing this phase activity must meet administrative, technical and financial requirements. The requirement proves to the State, in this case to BAPETEN, that the applicant has the ability to ensure the safety of the workers, the community and the environment of its uranium mining activities. General Investigation, Exploration, And Exploitation Phase Furthermore for the initial phase, before conducting activities the party shall submit notification to the head of BAPETEN. The information submitted in the notification are: • map of activity area; A state-owned enterprise, a cooperative, or a business entities shall obtain a territorial designation and appointment to conduct uranium mining activities from BATAN. • document of planning program for general investigation, exploration and exploitation activities; and • cooperation contracts In the case of general investigation, exploration and exploitation activities carried out by state-owned enterprise, a cooperative, or a business entities cooperating with BATAN. The Head of BAPETEN conduct verification after receiving the notification, includes: • verification of documents; and • field verification. Based on the verification, the head of BAPETEN provides technical recommendations regarding radiation safety during general investigation activities, and exploration and exploitation take place. Mining Phase In the case of uranium mining carried out by state-owned enterprise, a cooperative, or a business entities, the parties should ask for letter of mining appointment (SPP) from the head of BATAN. SPP granted in the territorial designation of uranium mining (WPP) based on the results of general investigation, exploration and exploitation. Head of BATAN when grant the SPP, give priority and taken into account state-owned enterprise, a cooperative, or a business entities cooperating with BATAN in conducting general investigations, exploration and exploitation. In the case of no state-owned enterprise, a cooperative, or a business entities are not interested continuing to the mining phase, the head of BATAN offer selection to other business entities. The SPP is granted for a maximum period of 20 (twenty) years and can be extended 2 (two) times at the maximum of 10 (ten) years. The holder of SPP can conduct the activities of uranium mining which includes: • excavation; • temporary storage; and • processing. Nuclear Mining License Requirement The applicant for obtaining Nuclear Mining License must submit to the head of BAPETEN and fulfill the requirements: • Administrative requirements; • Technical requirements; and • Financial requirements. For administrative requirements, applicant should provide evidence of obtaining SPP from head of BATAN, evidence of incorporation of legal entities; and proof of payment of application fee for nuclear mining license. For technical requirements, applicant should provide the evidence the ability to ensure the safety of the workers, the community and the environment of its uranium mining activities, such as: • Capable person to conduct activities and maintain safety as the top priority especially radiation protection; • Tools or equipment for maintain radiation safety; • Documents that proves applicant well known about the activities conducted, such as: procedures related to the uranium mining activities, document of safety analysis report for uranium mining, document of management system, document program of protection and radiation safety, document of physical protection plan, document of safeguard system, and document of emergency preparedness and response systems; • Document that proves applicant taken into account the environment conservation, such as: document for handling of radioactive waste, document of closure plan after the end of the activities, a statement of ability to comply with laws and regulations in the field of environmental protection and management; and approval of environmental documents in accordance with the provisions of legislation from ministry of environment and forestry; and • Local society participation taken into account for SPP. For financial requirements, applicant should provide the evidence the ability to finance all activities during: • Maintain operation in the safely condition; • Conduct remediation in the end of activities. DISCUSSION AND CONCLUSION Indonesia received benefit from IAEA activities related to the uranium mining, which are Technical Meeting of the Uranium Mining and Remediation Exchange Group (UMREG) and Workshop on Planning for Remediation of Legacy Sites under the International Working Forum on Regulatory Supervision of Legacy Sites (RSLS). The activities give positive feed back and knowledge that support the development of the regulation. Lesson learnt from other countries and knowledge shared from IAEA expert give constructive feedback to be adopt and implement in Indonesian regulation, such as: • Environment factor after the end of activities should be considered seriously in the license requirement; • Even thought the project implement by government, the responsibility to maintain safety, including environment factor, during operation and after the end of activities should be demonstrated; IAEA approach to regulate mining activities descried in the guideline at Nuclear Law Handbook [3] also become consideration for developing requirement. Requirement developed to maintain and ensure safety always implemented in the entire phase of the uranium mining activities, including after the end of activities. REFERENCES [1] Indonesian Act No.4 Year 2009 on Mineral and Coal Mining. [2] Indonesian Act No.10 Year 1997 on Nuclear Energy. [3] INTERNATIONAL ATOMIC ENERGY AGENCY, Handbook on Nuclear Law: Implementing Legislation, Vienna (2010).

Speaker: Mr Widi Laksmono (Bapeten)

139 URANIUM MINERALIZATION IN THE KHETRI SUB-BASIN, NORTH DELHI FOLD BELT, INDIA

INTRODUCTION Palaeo-Mesoproterozoic North Delhi Fold Belt (NDFB) [1&2] of the Aravalli craton trending NE-SW extends from Delhi in the north to Ajmer in the south in parts of Rajasthan and Haryana states. The NDFB is characterised by presence of synkinematically emplaced granites yielding 1.73 - 1.70 Ga age (combined zircon U-Pb ages and Lu-Hf isotope data) [3-5]. This belt comprises three sub-parallel volcano-sedimentary sub-basins namely Khetri, Alwar and Lalsot-Bayana from west to east. Among these Khetri Sub-basin is identified as an important host for copper [6], uranium [7-12] molybdenum, iron and fluorite mineralisation. This paper deals with uranium mineralisation of Khetri Sub-basin in light of its geological attributes and potentiality. GEOLOGICAL SET-UP The folded sequences of Palaeo-Mesoproterozoic Delhi Supergroup (DS) of rocks form a narrow belt extending from Haryana in the north to Gujarat in the south. This belt is further sub divided into older North Delhi Fold Belt (NDFB) and younger South Delhi Fold Belt (SDFB) [2]. This subdivision is based largely on the Rb-Sr whole-rock isochron data from synkinematically emplaced granites that yielded 1.65 - 1.45 Ga and ~ 0.85 Ga ages, respectively in NDFB and SDFB [4-5]. These belts are separated by a migmatitic gneiss tract around Ajmer [13]. The NDFB is constituted of three sub-basins designated as Khetri, Alwar and Lalsot-Bayana sub- basin from west to east respectively. The Mangalwar Complex of Banded Gneissic Complex (BGC) forms the basement and comprises high grade metamorphic and migmatised rocks in the southern parts of Alwar sub-basin. The grade of regional metamorphism recorded in the rocks of the Delhi Supergroup is upto amphibolites facies. The Khetri Sub-basin (KSB) exposes rocks of DS over basement comprising gneisses, paragneiss and mica schists of Mangalwar Complex. DS in this sub-basin is further subdivided into Alwar Group, followed by Ajabgarh Group with gradational contact. Alwar Group comprises mainly arenaceous units and Ajabgarh Group is predominantly argillaceous and calcareous. Occurrence of felsic tuff was recorded in the quartzite of upper part of Ajabgarh Group which has been dated 1830 Ma [3]. The lithounits of KSB have experienced three phases of deformations related to Delhi Orogenic cycle [14 & 15]. The first and second phases of folds are coaxial and trending NE-SW direction. F1 folds are isoclinal and F2 folds are normal upright to inclined with moderate plunge due northerly. F3 folds have their axial plane trending along WNW-ESE direction. The lithounits of DS of KSB have experienced two major events of regional metamorphism. The first phase of metamorphism is prograde upto amphibolite facies while second phase of metamorphism is retrograde to greenschist facies. Several phases of acidic and basic igneous activities including emplacement of granites and pegmatites have been recorded in this sub basin. This sub-basin is characterised by presence of broad zones of albitisation [16-18] including 20km linear zone in the Khandela-Kerpura-Guhala sector of southern Khetri copper belt [12] and two other zones in Maonda-Sior sector of northern Khetri copper belt and Sakun Ladera sector of NDFB, which define a narrow zone of approximately 170 km length along NNE – SSW direction. S. K. Ray [16] defined this zone as ‘Albitite Line’ indicated by linearly arranged albitite, albitised and alkali metasomatised rocks along deep seated fracture zones. Majority of the litho-units in the vicinity of albitite zones have been subjected to albitisation. These albitite zones follow NNE-SSW trend which is also trend of Kaliguman and Khetri lineaments. A few other albitite occurrences have been subsequently reported by other researchers which form a linear zone about 130 km in length and 5–12 km in width from Neorana in the north to Nayagaon in the south. This zone has regional NE-SW trend and forms another albitite line about 20-40 km east of the known albitite line (18). Polymetallic occurrence of Narda is reported along this albitite zone. Thus different episodes of albitisation have been observed in this sub-basin. URANIUM MINERALISATION Uranium exploration including heliborne geophysical survey, ground radiometric survey, hydro-, litho- and pedo-geochemical surveys carried out in this sub-basin by Atomic Minerals Directorate for Exploration and Research (AMD) helped in delineating several potential zones for uranium mineralisation [19-23]. Multi-parametric, high resolution heliborne geophysical surveys including aeromagnetic, frequency domain electromagnetic (FDEM) and time domain electromagnetic (TDEM) surveys and gamma ray spectrometry identified potential zones for U mineralisation within Ajabgarh Group in soil covered areas. Ground geophysical surveys in selected blocks helped in delineating low magnetic, high chargeability trends and low resistivity zones for further exploration. Radiometric survey during last six decades brought to light more than 400 radioactive anomalies. These anomalies are predominantly confined to litho-units of Ajabgarh Group and associated with structurally weaker and altered zones. The KSB can be sub-divided into three blocks namely Southern, Central and Northern. The Central Block extending from Rohil to south of Kantli lineament, is characterised by intensive albitisation and other alterations with more number of uranium occurrences and polymetallic mineralisation. Rohil and Jahaz uranium deposits are located in this block. Southern block extending from Rohil to Khatundra along NE-SW direction is characterised by comparatively less albitisation and less number of uranium occurrences as compared to Central Block. Northern Block, extending from north-east of Kantli lineament to Narnaul, is characterised by presence of extensive copper mineralisation and lesser number of uranium occurrences and lesser albitisation. Uranium occurrences in KSB are broadly associated with two NE-SW trending (eastern and western) albitite zones. Rohil, Guman Singh Ki Dhani, Narsinghpuri, Maota, Jahaz, Bagholi uranium occurrences are associated with western albitite zone, while Buchara, Ladi Ka Bas, Geratiyon Ki Dhani, Kalatopri, Rela-Ghasipura are associated with eastern albitite zone. DISCUSSION AND CONCLUSION Uranium exploration in Khetri sub-basin brought to light the presence of a low grade and medium tonnage ‘metasomatite type’ uranium deposit at Rohil and significant uranium occurrences in the contiguous area viz. Jahaz-Maota-Bagholi, Narsinghpuri, Guman Singh Ki Dhani, Hurra Ki Dhani, Ladi Ka Bas - Geratiyon Ki Dhani, Rajasthan and Rambas-Gorir, Haryana, which are under prospecting and evaluation. Uranium mineralisation in KSB is mainly associated with deep seated fractures/shears and axial region of F2 folds with intense hydrothermal activities and is preferably hosted by sheared / fractured, albitised and altered metasediments viz. quartz-biotite-chlorite schist, quartzite, carbonaceous/graphitic phyllite, quartz amphibole schist and calc-silicate of Ajabgarh Group. Alterations recorded in this area are mainly albitisation, chloritisation, silicification, sericitisation, calcitisation and sulphidisation [23]. Uraninite is the dominant uranium mineral in addition to minor brannerite and coffinite. It occurs in clusters, as disseminations of subhedral grains and in vein/veinlets. The geochemistry of the mineralised rock indicates polymetallic (U-Cu-Mo) nature of mineralisation associated with sulphides like chalcopyrite, molybdenite, pyrite and pyrrhotite. The uranium mineralisation of KSB exhibits its similarity to ‘metasomatite type’ [24] especially with Na-metasomatite subtype of uranium deposits of Australia, Ukraine, Brazil, Canada and Guyana as indicated by its close association with albitite zone, high Na2O content and high Na2O/K2O ratio. Presence of coarse sized dispersed uraninite in albitite veins also supports close relation of albitisation and uranium mineralisation. The age of uranium mineralisation in Rohil and Jahaz are 830±5Ma and 841±26Ma respectively [25]. Presently, heliborne geophysical data is being utilised in conjunction with detailed surface and sub-surface geological, geochemical and geophysical investigations for prioritising potential target areas for uranium mineralisation in other parts of Khetri sub-basin for follow-up exploration. High chargeability zones with low magnetic anomalies have emerged as a geophysical guide for exploration for concealed uranium mineralisation in Khetri sub-basin, North Delhi Fold Belt in parts of Rajasthan. The authors express their sincere gratitude to Director, AMD for giving the opportunity to publish the extended abstract. The authors also express their gratitude to numerous field geologists of AMD and various laboratories for their support. REFERENCES [1] Heron, A. M. (1953). The geology of Central Rajputana. Mem. Geol. Surv. India, v. 79, p. 1-389. [2] Sinha-Roy, S., Malhotra, G. and Mohanti, M. (1998). Geology of Rajasthan. Geol. Soc. Ind., First Edition, 278pp. [3] Parampreet Kaur, Armin Zeh, Naveen Chaudhria and Nusrat Eliyas (2017). Two distinct sources of 1.73-1.70 Ga A-type granite from northern Aravalli orogen, NW India: Constrainsts from in situ U-Pb ages and Lu-Hf isotope. Gondwana Research, v. 49, p. 164-181. [4] Crawford, A.R. (1970). The Precambrian geochronology of Rajasthan and Bundelkhand, Northern India, Canadian Jour. Earth. Sci., v. 7, p. 91-110. [5] Choudhary, A. K.; Gopalan, K.; Sastry, C. Anjaneya (1984). Present status of the geochronology of the Precambrian rocks of Rajasthan, Tectonophysics, v. 105(1-4), p. 131-140. [6] Shukla, M.K. (2015). Mineral and Exploration Potential of Khetri Copper Belt; A Review. Journal of Economic Geology & Geo Resource Management, Prof. C Mahadevan Commorative Special Volume No.10, p. 111-132. [7] Narayandas, G.R., Sharma, D.K., Govind Singh and Rajendra Singh (1980). Uranium mineralisation in Sikar District, Rajasthan. Jour. of Geol. Soc. of India, v. 21, p. 432-439. [8] Singh, G., Singh, R., Sharma, D.K., Yadav, O.P. and Jain, R.B. (1998). Uranium and REE potential of Albitite-Pyroxenite-Microclinite zone of Rajasthan, India. Expl. Res. At. Min., v.11, p.1-12. [9] Jain, R. B., Yadav, O. P., Rahman, M.,Thippeswamy,S., Fahmi.,S., Sharma, D.K. and Singh, G.(1999). Petrography and geochemistry of radioactive albitites and their genesis: Maonda area, North Rajasthan. Jour. Geol. Soc. India, v. 53 (4), p. 407-415. [10] Khandelwal, M.K., Bisht, B.S., Tiwary, A., Dash, S.K., Mundra, K.L., Padhi ,Ajoy.K., Nanda, L.K. and Maithani, P.B. (2008). Uranium-copper–molybdenum association in the Rohil Deposit, North Delhi Fold Belt, Rajasthan. Mem.Geol.Soc.Ind., v.73, p. 117-130. [11] Khandelwal, M.K., Jain, R.C., Dash, S. K., Padhi, A.K. and Nanda, L.K. (2010). Geological characteristics and ore body modeling of Rohil Uranium Deposit, District Sikar, Rajasthan. Mem. Geol. Soc. India, v. 76, p. 75-85. [12] Khandelwal, M.K., Nanda, L. K. and Maithani, P.B. (2011). Five decades of Uranium Exploration in Khetri Sub Basin, Rajasthan: Potentialities and Future Challenges. The Indian Mineralogist, v. 45 (1), p. 165-178. [13] Sinha-Roy, S., Malhotra, G. and Mohanti, M. (1998). Geology of Rajasthan. Geol. Soc. Ind., First Edition, 278p. [14] Das Gupta, S. P. (1968). The structural history of the Khetri Copper Belt, Jhunjhunu and Sikar districts, Rajasthan. Memoir, Geological Survey of India, v.98, p.170. [15] Naha, K., Mukhopadhyay, D.K. and Mohanti, R. (1988). Structural Evaluation of Rocks of the Delhi Group around Khetri, northeasterm Rajasthan. In Precambrian of the Aravalli Mountain, Rajasthan, India (A. B. Roy ed.), Geol. Soc. of India, Mom. 7, p. 207-245. [16] Ray, S.K. (1987). Albitite occurrences and associated ore minerals in the Khetri copper belt, North Eastern Rajasthan. Records, Geol. Surv. of India, v. 113(7), p. 41-49. [17] Ray, S.K. (1990). The albitite line of Northern Rajasthan- a fossil intra-continental rift zone. Jour. Geol. Soc. of India, v. 36, p. 413-423. [18] Yadav, G. S., Muthamilselvan, A., Shaji, T.S., Nanda, L. K. and Rai A. K. (2015). Recognition of a new albitite zone in northern Rajasthan:its implications on uranium mineralization. Current Science, v. 108 (11), p. 1994-1998. [19] Yadav, O.P., Hamilton, S., Rajiv Vimal, Saxena, S.K., Pande., A.K. and Gupta, K.R.(2002). Metesomatite-Albitite-Hosted Uranium Mineralisation in Rajasthan. Expl. Res. At. Min., v.14, p.109-130. [20] Yadav, O.P., Nanda, L.K., Jagadeesan P. and B.Panigrahi (2010). Concealed uranium mineralization in Hurra ki Dhani-Maota-Jahaz sector, North Delhi Fold Belt, Rajasthan, India – An exploration strategy. Expl. Res. At. Min., v.20, p.43-50. [21] Bhatt, A.K., Yadav, O. P., Sinha, D. K., Nanda, L. K. and Rai, A. K. (2013). Soda metasomatism in the North Delhi Fold Belt and its implication on uranium mineralisation, North Rajasthan, India. Paper presented in technical meeting on the Metasomatite uranium occurrences and deposits, held at IAEA, Vienna, 17-19 Jan. 2013. [22] Ajoy K. Padhi, S.L. Aravind, Kamlesh Kumar, D.K. Choudhury, R.K. Purohit, L.K. Nanda & A.K. Rai (2016). Uranium potential of North Delhi Fold Belt, Rajasthan, India: An overview. Expl. and Res. for Atom. Minerals, Hyd,v. 26,p.53-70. [23] A.K.Jain, Ajoy K. Padhi, Kamlesh Kumar, Anubhooti Saxena, P.K.Kothari, G.V.Giridhar, R.K.Purohit, L.K.Nanda, and A.K.Rai (2016).Geology,Petrology and Trace Element Geochemistry of Uranium Mineralisation of Jahaj area, Khetri Sub Basin, Delhi Supergroup, Jhunjhun District, Rajasthan, India. Expl. Res. At. Min., v.26, p.91-103. [24] Bruneton, P., Cuney, M., Dahlkamp, F. and Zaluski, G. (2014). IAEA geological classification of uranium deposits. In: International Symposium on “Uranium Raw Material for the Nuclear Fuel Cycle: Exploration, Mining, Production, Supply and Demand, Economics and Environmental issues”, URAM 2014, IAEA–CN–216, p. 12–13. [25] Pandey, U. K. and Sastry, D. V. L. N. (2016). Unpublished Geochronology Report No 2215500_gel_UKP_DVLNS_2016/3_300616, Atomic Minerals Directorate for Exploration and Research, Hyderabad.

Speaker: Mr BRUNDABAN MISHRA (GOVERNMENT OF INDIA DEPARTEMNT OF ATOMIC ENERGY ATOMIC MINERALS DIRECTORATE FOR EXPLORATION AND RESEARCH)

140 URANIUM MINING IN THE UNITED REPUBLIC OF TANZANIA: CURRENT STATUS, CHALLENGES AND OPPORTUNITIES

1. INTRODUCTION Tanzania is heading for a new dimension in large scale uranium mining [1]. Significant uranium deposits have been identified in various parts of the country [2, 3]. More than 25 companies are conducting exploration of the uranium in different deposits in the country. These explorations are based on the already radiometric surveys conducted in the 1970’s, which pointed to uranium enrichments in various places in the country [1]. One of the major uranium development projects is the Mkuju River Project, located in southern Tanzania, about 470 km southwest of Dar es Salaam. The project’s operator is Russia’s Uranium One Inc. Currently (2016), the project maintains an active status since research and preparatory operations are under way. The mineral resource base of the project is currently representing approximately 58,500 tons of uranium. The company has already acquired a prospective mining license from the Ministry of Energy and Minerals but they are not yet started mining due to depression on the uranium price. 2. CHALLENGES There are a number of challenges encountered during the exploration as well as expected to be encountered during mining and processing of the ore, some of these challenges are explained below; a. PUBLIC ACCEPTANCE There is a public concern in the deposits which are found in the farming fields of some villages. This concern has been experienced in the areas around Bahi and Manyoni deposits located in the central zone of the country [4]. In this region, there are wetlands areas which are mostly utilized for agricultural activities as well as livestock keeping. Most of the villagers, with help of Non-Governmental Organizations have been rioting against the government’s decision to permit the exploration projects in their areas [1]. People everywhere in Bahi and Manyoni districts are rejecting uranium projects, they are afraid of losing their land to uranium mining companies without proper compensations. Apart from the fear of losing their land, there is a big issue of environmental impact in the areas of Bahi and Manyoni. Most of the exploration sites are within the agricultural fields, therefore the issue of contamination should be considered [5]. Most of the population in these areas are depending on underground water through boreholes drilled either locally using b. REGULATORY FRAMEWORK Experiences from historical uranium production sites all over the world have consistently shown that unregulated uranium mining practices have led to significant damage of water, soil, put persons at risk and resulted high cost of clean up the environment [6]. In Tanzania, the primary legislation, which control practices of ionizing radiation is the Atomic Energy Act 2003 [7] and associated regulations: Mining (Radioactive Minerals) Regulations of 2010 [8] and the Atomic Energy (Radiation Safety in the Mining and Processing of Radioactive Ores) Regulations of 2011 [9]. According to the Act an ore is classed as radioactive mineral if its total activity concentration exceeds 74 Bq/g [6]. In this context, the activity concentrations of economical uranium ores which are likely to exceed this activity are classed as radioactive ores and thus subject to stringent regulatory control. The dose limits applicable in these regulations are those recommended by the ICRP (1977) for both occupation-al and public exposure to ionizing radiation [10]. The dose limits are as follows: maxi-mum occupational dose of 50 mSv in any year with a mean of 20 mSv over any five years, and a public dose limit of 1 mSv in any single year. In addition, the regulatory authority has a clear role to enforce regulatory compliance with the national and international standards. Although a legal framework and relevant infrastructure for the management and control of occupational and public exposure, waste and the environment are in place, there are challenges for effective monitoring of the uranium mining industry in Tanzania [11]. Finance and technical resources sounds as major limitations that may hinder the regulatory authorities to complete its primary responsibilities. Establishing baseline environmental data by the regulatory authority and the mining company prior to project development is of crucial importance and cannot be underestimated. Lack of comparable data could prevent the effective monitoring of changes in compliance with the environmental standards during and after the mining activities [11]. Since data that established after the mining activities commences cannot be used to relate the impacts of uranium mining have on the environment and public exposure. Because the anticipated area in need of pre-mining data is vast and time available to establish them before actual uranium mining commences is very short, the regulatory authority need substantial amount of resources. Big cost required establishing the baseline data and building technical capability wholly resting on the government funds are big challenges. Implicit, inadequate budget and technical capability could lead to impairment on assessing and effective controlling the uranium mining. c. URANIUM PRICE Uranium price has been declined for the past 11 years [12]. According to the source, U3O8 was down more than 25% in 2016 with the UxC broker average price sliding to 25.69 USD per lb. The price, according to the source was the cheapest uranium price has been since May 2, 2005. This decline in uranium price has led the Uranium One, an international mining company of Russian State Nuclear Energy Corporation to apply to suspend the Mkuju River Project [13]. This is a big challenge for the country due to the fact that, the project becomes the first uranium mine to receive license from Tanzania’s Ministry of Minerals (formerly Ministry of Energy and Minerals). As of March 2013, the project had measured and indicated resources of 48,000 tU plus inferred resources of 10,600 tU at average grade of 0.026% U [13]. d. WILDLIFE CONSERVATION ISSUES Despite the suspension application by Uranium One, the project area was initially part of the UNESCO World Heritage since 1982. UNESCO agreed to change the boundary, therefore enable uranium mining in this unique conservation area [14]. Selous, being the largest Game Reserve in Africa is inhabited by most important populations of the critically endangered wild hunting dogs as well as elephants. The UNESCO describes the Game Reserves as an immense sanctuary of 50,000 km2 which is relatively undisturbed by human impact and which is inhabited by large number of elephants, black rhinoceroses, giraffes, hippopotamuses and crocodiles. The reserve has variety of vegetation zones, ranking from dense thickets to open wooded grassland. The UNESCO accepted a boundary change of the reserve and thus enabled the mining of uranium in the conservation area. The planned mine is situated in an elephant corridor between Tanzania and Mozambique, and will approximately utilize the area of about 200 km2. The mining methods preferred in this project after the exploration results and nature of the area was either Open-Pit or In-Situ Leaching (ISL) due to the nature of the deposits in the area. Both methods have environmental impacts in the mining area as well as areas beyond the mining site. For the case of open-pit, the environment suffers with enormous heaps of tones of radioactive waste which may lead to the contamination of large area of the project and beyond the mining area [12]. Control of water from surface runoff and underground aquifers plays an essential role in an effective pit operation. If not well controlled, contaminated runoff will pose threats to the game reserve inhabitants. In case of ISL, the risk of spreading of leaching liquid outside of the uranium deposits, involving subsequent ground water conditions after completion of the leaching operations. Moreover, ISL releases considerable amounts of radon, and produces certain amounts of water slurries and waste water during recovery of the uranium from the liquid. 3. OPPORTUNITIES Despite the fact that uranium exploration and mining pose some great challenges, there are opportunities during the exploration activities as well as expected opportunities when the mining starts. The following are the opportunities: - a. EMPLOYMENT Uranium projects in Tanzania have created a number of employment opportunities during explorations and are also expected to create a number of jobs during the mining and milling of the ore. Some 1,600 people are expected to be employed during construction and will be 750 permanent jobs when the mine starts operation [12]. At present, there are 120 employees who are involved in exploration activities. Also in order to ensure maximum implementations of the regulations which ensure maximum safety in the industry, regulatory authorities involved in the uranium control will need to increase number of skilled staffs. This will in turn, increase the number of job vacancies to be filled. b. EXPORT EARNINGS The Mkuju River Project is expected to attract Foreign Direct Investment (FDI) amounting to about USD 1bn [12]. This will boost the country’s economy to support the government’s desires to improve the economy of the country to a middle-income economy. Other opportunities include government royalties, taxes and fees as well as infrastructure development in the regions where the mining activities are carried on. 4. CONCLUSION Uranium mining has seen to have the capacity to improve the economy of the country. Currently the price of the commodity is depressing. However, the demand is expected to rise in the near future due to a number of expected nuclear power constructions in various countries. The expected rise in demand and price is going to benefit the mining companies as well as the countries with uranium deposits. However, despite benefits which may be expected, the challenge seems to outweigh the opportunities. REFERENCES [1] Lyamunda, A.B., Boniface, M.P., Kurz, M., Imminent uranium mining in Tanzania, FEMAPO report, 2010 [2] Mantra EIS, (2010), “Mantra Tanzania Limited Environmental Impact Assessment for the proposed Uranium Mining Project at Mkuju River Project Namtumbo”. Vol. 1, Final Report, March 2010 [3] URANEX (2010) Australian based Uranium Exploration and Development Company with a diverse pipeline of projects in Australia and Africa. New uranium mineralization discovered at Manyoni and Bahi. [4] Community Scoping Study in the Exploration Areas and the legal framework, Uranium mining in Tanzania: are we ready (1st edition, 2012) [5] INTERNATIONAL ATOMIC ENERGY AGENCY, Environmental contamination from uranium production facilities and their remediation. http://www-pub.iaea.org/MTCD/publication/PDF/Pub1228_ web.pdf [6] CESOPE Fact Sheet: Radiating Africa – The menace of uranium mining in Tanzania (2014) [7] Tanzania Atomic Energy Commission, Atomic Energy Act No. 7 of 2003 [8] MEM (2010) Ministry of Energy and Minerals. The Mining (Radioactive Minerals) Regulations. [9] Tanzania Atomic Energy Commission, The atomic energy (radiation safety in the mining and processing of radioactive ores) regulations, 2011 [10] ICRP (1977) Recommendations of the International Commission on Radiological Protection. ICRP Publication 26, Ann. ICRP 1 (3). [11] Banzi, F.P., Msaki, P., Mohammed, N., Challenging issues in regulating uranium mining in Tanzania, International 7th conference uranium mining and hydrogeology & UMREG meeting, 2014, 21 – 25, September, 2014 [12] Fact sheet on uranium mining 3, how uranium is mined, Preconference of the IPPNW-World congress, University of Basel, 26th August, 2010 [13] Source: http://en.africatime.com/tanzanie/articles/tanzania-uranium-project-buoy-economy accessed on 18th January, 2018. [14] WNN, http://www.world-nuclear-news.org/UF-Tanzania-uranium-project-suspended-1007178.html, 2017 [15] http://old.uranium1.com/index.php/en/development/mkuju-river-tanzania, accessed on 25th February, 2018 [16] source: www.mining.com/uranium.market-getting crushed accessed on 15th January 2018

Speaker: Mr Ebenezer Kimaro (Ministry of Education, Science and Technology)

141 URANIUM POTENTIAL IN GREENLAND: AN UPDATE

The uranium potential in Greenland is considered relatively high with several known uranium occurrences. In 2016, a workshop on the ‘Assessment of the uranium potential in Greenland’ was held. Three uranium deposit types were chosen for the assessment: intrusive, sandstone hosted and unconformity-related. The main conclusion of the workshop was that the intrusive and unconformity-related deposits have the highest probability of having formed uranium deposits in Greenland. Existing evidence from aeroradiometric and drainage surveys combined with field investigations points to South Greenland as the most prospective region for additional hidden or unrecognised intrusive-type uranium occurrences. Highest ranked tracts were the Mesoproterozoic Ilímaussaq and Motzfeldt alkaline igneous intrusions. In addition, both the Central Domain and the Southern Domain of South Greenland were ranked as having a high potential for containing undiscovered intrusive deposits. Favourable geological settings for unconformity-related uranium mineralisation were identified. The highest ranked tracts comprise the two Mesoproterozoic basin formations that rest unconformably on Palaeoproterozoic or Archaean basement, namely the Eriksfjord Formation in South Greenland and the Thule Supergroup in North Greenland.

Speaker: Dr Kristine Thrane (Geological Survey of Denmark and Greenland)

142 Uranium recovery from acid mine drainage treatment residue – Caldas, Brazil case

The generation of acid mine drainage on mining areas, an effluent generated due to the presence of a sulphide minerals (usually pyrite, FeS2) in contact with oxygen and water, is a huge environmental problem. The Osamu Utsumi Mine, the first uranium mine in Brazil, located in Caldas, Minas Gerais, which had its operations ceased in 1995, presents this environmental issue. The acid solution is produced from the waste rock piles and leaches residual metals, including uranium. This effluent is treated continuously with lime and the residue, an alkaline mud, is deposited into the mine pit. This alkaline mud contains uranium and rare earths and several projects are being carried out in order to recover these products. This paper presents the comparison between efforts on developing acid and alkaline leaching processes to extract and to concentrate uranium liquor from this residual material. As the uranium concentration in the residue ranges from 1.800-3.000 mg/kg U3O8, this recovery is interesting not only from the economical point of view but also from the environmental one, as the material can be deposited in a safer way during the mine closure process.

Speaker: Mr Raul Villegas (Brazilian Nuclear Energy Comission)

143 USING NUCLEAR TECHNOLOGY FOR DETECTION AND DETERMINATION OF MINERALS AND FOR PREPARING STANDARD REFERENCE MATERIAL

The role of mining sector in Sudan economic support is approximately 4% . At present, the only resources mined in Sudan are: gold, chromium ore, salt and building materials are mainly cement raw materials. we want to ensure future availability and add more minerals to the exploration mineral list that plays important roles in the economy, the actions need to be taken. More efficient and economical methods of exploration and extraction of raw materials need to be developed. Effective production methods must be used that provide energy and raw materials . It also influences the relevant nuclear and analytical techniques such as X-ray fluorescence (XRF) and Neutron Activation (NA) analysis. The analytical techniques MIN will be used for this study besides the extrapolation of the coupled plasma mass spectrometer (ICP-MS) as they have great potential to improve the efficiency of the results from Raw materials. Since the main task of the Sudanese Atomic Energy Commission (SAEC) is to promote the safe use of nuclear energy through the use of nuclear analytical techniques in the exploration, extraction and treatment of metallic or non metallic elements uranium minerals are most important to be investigated.

Speaker: Ms HOIAM SAYED (SUDAN ATOMIC ENERGY COMMISSION)

144 WNU SUP – Efficient Capacity Building Tool In U-Production Cycle

INTRODUCTION The World Nuclear University - School of Uranium Production (WNU SUP) international training centre was founded in 2006 and is operated by the DIAMO State Enterprise under the auspices of the World Nuclear University in London and in collaboration with OECD/NEA and IAEA. Making use of knowledge and equipment of the DIAMO State Enterprise and the connections it has with universities, research institutions, supervisory authorities and other experts from the Czech Republic and abroad, the International Training Centre develops and presents schemes focused on professional training throughout the range of aspects of uranium production, be it deposit surveys and extraction using various means, treatment of uranium ores, environmental protection and protection of the health of workers, and even removal of the consequences of mining operations. DIAMO State Enterprise was chosen to be the seat. The decision-making process took into account the extensive experience of the staff of this state-owned company in the underground acid uranium leaching method, one that can be used with success even at new sites abroad. Furthermore, the DIAMO State Enterprise offers extensive experience in remediating sites after conventional exploitation and treatment of uranium ores, remediating the bedrock environment after chemical extraction of uranium, treatment of mine water, radiation protection of staff and populations, environmental protection, etc. In addition to these technical aspects the DIAMO State Enterprise also has the option to arrange relaxation and learning events for course participants. MOTIVATION AND MISSION The increase in the global demand for uranium, particularly in countries where uranium mining is on the rise such as China and India, Pakistan, Brazil, Argentina and others, has led to an increase in global market prices and a re-evaluation of the stock of the material. Contrasting to the above is the significant shortage of skilled professionals in uranium mining and processing observed in the last twenty years. In recent years, termination of uranium mining has been under way around the world. Many countries need to deal with the disposal and remediation of the consequences of uranium mining, which includes removal of old uranium burdens such as deep mines, ISL mines, treatment plants and tailings ponds. This sector is also experiencing a shortage of qualified experts globally. In accordance with the fact that the proper management of uranium production requires skilled personnel and a broad dissemination of scientific, engineering and social knowledge, WNU School of Uranium Production aims to: • Educate students in all stages of the uranium production cycle, including surveys, planning, development, operations, as well as remediation, rehabilitation, treatment of mine water and other environmental aspects of closure of uranium mining and production plants; • Contribute to the improvement in the areas of surveys, mining and remediation after extraction of uranium through research and development; • Provide a forum for exchanging information and lessons learned - best practices in the field of uranium mining and processing. COURSES Each of the courses consists of a theoretical, lecture-based part and accompanying programmes that take the form of technical field trips to the DIAMO State Enterprise sites and premises, whose structure conveniently covers all aspects of the mining process. The high professional level and practical experience of specialized staff members of the enterprise is also leveraged with success. In addition to the DIAMO State Enterprise staff, teaching activities also involve lecturers from abroad, originating from mining institutions or freelance consultants active in diverse fields such as geology, hydrogeology, geomechanics, chemical technology, radiation protection, environmental protection, etc., with regard to the focus of the individual courses. The courses are designed for groups of 5 to 18 participants. Examples of the courses: • “Extraction using underground in situ leaching (ISL), both alkalic and acidic leaching” is a 2 or 4 weeks course for operators or 2-5 days course for managers; • “Remediation of the consequences of in situ leaching” offers 1- or 2-week course focused on the remediation of the underground rock environment after acidic ISL, pump and treat method, processing of the acid solutions in the surface technologies and liquidation and reclamation of the surface. • “Survey” - 2 or 4 weeks of a combined course focused on surveying uranium deposits and extraction in sandstone type deposits (ISL preferred); • “Remediation of consequences of uranium mining and processing.” 1-week course focused on remediating heaps and tailings ponds, environmental monitoring, and radiation protection; • “Alkaline-based uranium processing” is 1- or 2-week course focusing on the uranium ore mineralogy, technological requirements and processing, handling waste water and sludge, radiation protection and environmental monitoring, and field hands-on sessions in GEAM (uranium treatment plant); • “Legal aspects of uranium mining” - 1-week course for senior management and supervisory staff focused on discussions with representatives of national authorities in charge of extraction and radiation protection; hands-on sessions in the field, in the DIAMO State Enterprise premises; • “Radiation protection in mining practice” - 1-week course for senior management and supervisory staff; • “Treatment of underground and mine water” offers 1- or 2-week course focusing on treatment of waste water, hydrochemistry, sampling, analysis, and technology; • “Application of mathematical modelling in the U-production cycle and remedial process” – one week course targets on the use of different mathematical models during the geological survey, mining process and remedial activities, modelling of groundwater flow and transport of contaminants, environmental models for the risk analysis. • “On-demand custom courses” can be designed to meet your individual needs. The course date, scope and contents can be specified upon agreement based on what is required by the applicant. PARTNERS The School of Uranium Production cooperates with a number of world-renowned institutions and uses their expert capacities and experience. From the cooperating institutes we can name International Atomic Energy Agency with the Headquarters in Vienna, Nuclear Energy Agency in Paris, World Nuclear Association in London, World Nuclear University in London, University of Nottingham, Czech Technical University in Prague - Faculty of Nuclear Sciences and Physical Engineering, Technical University of Ostrava, Charles University in Prague and State Office for Nuclear Safety in Prague. CONCLUSION From its very day of establishment the International Training Centre became a globally renowned facility of professional training. The number of participants - from a total of more than 20 countries - passing almost 50 distinct programmes has already reached 500. This number includes both projects of technical cooperation with IAEA and commercial contracts.

Speaker: Mr Vojtech Vokál (DIAMO, s. e., Department of International Cooperation)

145 YELLOWCAKE PRODUCTION AND ENVIRONMENTAL REMEDIATION AT THE SIERRA PINTADA MINE, ARGENTINA: LACK OF SOCIAL LICENCE

The Sierra Pintada uranium mine was in production between 1975 and 1995 when the operations were stopped for economic reasons. In 2004, a project was presented to the provincial authorities proposing the recommencement of production and the concomitant fulfilment of environmental liabilities. The response of the authorities was that before the recommencement of productive activities, the operator (Comisión Nacional de Energía Atómica) had to manage the existing environmental liabilities and establish a scale of priority for their management based on their characteristics. In 2006, a project was presented for the management of environmental liabilities as a first priority, which was technically approved although the required public hearing did not materialize. As a result, authorization was not granted to commence environmental management tasks. In 2014, a new project for remediation was presented and is being evaluated by the provincial authorities. During the entire period of operation and until the cessation of activities, Sierra Pintada had had general approvals for its normal operation. During the time of trying to resume production in synchrony with the remediation, the Government and the social licence were revoked. The mine site became a deposit with apparent resources, with all the facilities needed to resume production, but without authorization to operate. In this context, the future of the project is uncertain.

Speaker: Mr Sergio Dieguez (National Commission of Atomic Energy)

Thursday, 28 June

Applied Geology and Geometallurgy of Uranium and Associated Metals

Conveners: Mr Luis LOPEZ (CNEA (Argentina)), Martin Fairclough (International Atomic Energy Agency)

146 Regional forecasting of sandstone type uranium deposits

1. Introduction The Neogene-Quaternary collision of the African, Arabian and Indian plates from the south and the Mesozoic-Cenozoic subduction of the Pacific plate from the east led to the formation of large orogenic belts in the regional parts of the Eurasian plate. Each of them is characterized by its metallogenic peculiarities. The analysis of spatial distribution of endogenous and exogenous uranium deposits within the limits of separate orogenic areas creates preconditions for exposure peculiarities of metallogenic zonation in every large geological block. It allows to plan in them the place sandstone deposits of uranium in different under the terms of the formation sedimentary basins. Leading ore localizing factor – the groundwater and interlayer oxidation zones controlling uranium mineralization were established for all objects of sandstone type. United source of uranium – domestic the recharge areas of adjacent mountain structures were proposed for overwhelming number of deposits. The metallogeny of uranium was most fully studied within the limits of the Alpine-Himalayan tectonic belt. 2. The metallogeny of uranium of the Alpine-Himalayan belt A number of major segments allocated spanning orogenic regions and adjacent to suborogenic sections of activated platform. 2.1. The Mediterranean segment. The subduction of the African plate on the western end of the Eurasian continent began at the end of Miocene in the Pliocene. The Mediterranean segment is subdivided into orogenic and suborogenic regions. The orogenic area from 300 to 700 km is located in the extreme south of folded belt. Typically, a foreland zone is situated within the orogeny boundary. It is characterized by thrusts, over-thrust sheets, and is frequently capped with red-colored molasses at the frontier. In this given segment the notion of suborogen is seen as the slightly activated part of the Western-European platform. The French Massif Central and the Bohemian Massif are included in it. The Metallogenic sequence was quite clearly outlined within the limits of the segment. Here the Permian uranium ore epoch was widely displayed – that is the time of origin of stratiform deposits of uranium of Bikhor type on the large area. Its genesis is still widely debated today. Small, seldom middle deposits (Pb, Zn, As, CaF2 and others) were formed in the Mesozoic-Cenozoic period (elementary stage of subduction). They are not infrequently conjugated with small granitoid intrusions. Small sandstone deposits (Grezio and others) were later revealed in the depressions of the French Massif Central within the limits of suborogen. The deposits Gamr and Königstein tightly connected with effusions of the Bohemian Massif in the regional part of suborogen completed metallogenic evolution of the European section of the West-European platform conditioned by subduction of the African plate. In general, the Mediterranean segment presents a full metallogenic picture. It was created as a result of subduction of the African plate under the southwestern part of the Eurasian continent. 2.2. The Arabian segment. The subduction of the Arabian plate at the southern part of the Eurasian plate determined the formation of the 500 km wide orogenic belt spanning the territories of Iran, Turkey and Caucasus. We divide it into three sectors – Anatolian, Caucasian and Kopet Dagh. The Oligocene dates the beginning of intensive orogenesis. The first point of analysis within this segment is area development at product regions of volcanic activity. The second is the influence of a long, narrow trough of land on the region’s metallogeny; once situation during the early Miocene period at the current location of the Caucasian ridge. The last appeared in place of the trough in late Miocene, at the time of the young volcanoes (Elbrus, Kazbek). The third and final peculiarity of the Caucasian region is high oil content. As a result, the following incomplete metallogenic series was loomed. 1) Large accumulations of hydrocarbons within the limits of the Persian Gulf, Iran, Iraq and the North-Caspian depression. 2) Orogen, endogenous deposits of Cu, Mo, Co, Au, Mn and others, and hydrothermal uranium deposits (Byk, Beshtau) located on the external front are localized. 3) The area of suborogen in the Ciscaucasia with titanium-zirconium placers and accumulations of hydrocarbons (the North-Caucasian basin), and at the eastern slope of the Stavropol arch weakly developed groundwater oxidation zones (Balkovskoe) were discovered in the young sediment of Paleo-Don. 2.3. The Indian segment is the most uranium productive in the extended belt Tethys. In orogenesis intensity the Indian segment has surpassed all such processes in the World. The collision of the Indian plate converted at a distance of over 1500 km into the depths the Eurasian plate and differentiated the orogenic area along the vertical by horsts till +9000 m and grabens till -5000 m. It is divided into the Pamir and the Himalayan sectors. They differ in structural peculiarities and scale of ore content. Three types of metallogenic zones controlling roll-type deposits of uranium were marked in the Pamirs sector. With all the uniqueness of each zone’s type, they have in common the confinedness of the largest and unique deposits – giants to suborogen, where they gravitate to areas most remote from orogen. Obviously, that collision model of development of this region is only answering to existing geodynamic situation of the region. The Pamir "wedge" is the result of the drawn out collision between the Indian plate coming on the Eurasian plate. All deposits-giants of roll-type are located within the limits of the suborogenic (activated) part adjacent to the Turan platform and the southern edge of Kazakh "shield". We have shown that the main conveyer of roll-type uranium deposits-giants in the area of transit were initially only surface and ground, and only later interlayer waters originating in the North and the Median Tien-Shan at the zone of the maximum collisional stress. The tight spatial and paragenetic connection of the influent flow of uranium waters, forming uranium deposit-giant roll-types with the most actively advanced site on the Indian plate – the Pamir "wedge". The most productive metallogenic zones originate at supposed sites of mantle uranium accumulation at whose closure deposits-giants are situated. The Himalayan sector is characterized by a more complicated geological structure in comparison with Pamir. One of the unsolved problems of the Himalayan sector is the reason for such a small uranium content. The absence of large deposits of uranium within the limits of the Himalayan sector is explained by intensive promotion to the northeast of the orogenic area border during the N-Q period. This exacerbated frequent recharge area fluctuations, active migration of hydrocarbons, and an absence of regional stable centers of unloading. This hampered the broad development of ore-forming interlayer oxidation zones. It should be noted, that industrial deposits of uranium in the area of hinterland were revealed only in the northern edge of the Indian subcontinent. Here the preconditions were created for the formation in the Neogene-Quaternary sedimentary basins of the groundwater and interlayer oxidation zones and the uranium ore. 3. The metallogeny of uranium of the Pacific belt The high metallogenic potential of the Pacific ore belt meridional is determined by the Mesozoic-Neozoic subduction of the Pacific plate. This process affected the tectonic blocks of the Eurasia continent to depths from 500 to 1500 km. It should be noted, that insignificant deposits of uranium (Ningyo-Toge, Tono and others) in the small graben tectonic structures accomplished with coarse-grain bed and lake sediments of the Cretaceous and the Miocene-Pliocene age were discovered within the limits of the Japanese islands and the south of Korean peninsula. The ores were formed by ground waters. We emphasize, that the eastern part of the Eurasia plate has undergone significant changes in the course of subduction. Within the limits of the activated part, the areas with the mode of intracontinental rifting and passive margin are escaped. Endogenous deposits of calderas connected with volcano-tectonic structures of the Mesozoic age. On the external part of the belt sandstone type uranium deposits of the Cenozoic age are located. in tight spatial connection with young covers of basalt predominate on the external (the western) front of uranium ore belt in the same districts. These covers fix the western border manifestation of subduction in the east of the Eurasia continent and confirm the western meridional border of the Baikal-South-China uranium ore belt. The above model allows supposing tight spatial connection abyssal geodynamical processes in the Mesozoic-Cenozoic era with the accommodation of uranium deposits. Distinct separation of metals in the diametrical section of belt is outlined. In it’s internal part uranium is conjugated with Au (caldera Aldan), Mo, Pb-Zn and CaF2 (caldera Streltsovskaya), with Pb, Zn, W, Mo, Au, CaF2 (caldera Dornod) and with Mo, Ti, CaF2 (caldera Xiangshan). The uranium is often separate from other metals on the external front of uranium ore belt. This is evidently explained by its high mobility. To the west, basalt magmatism was intensively displayed in the area of damping in the passive margin of the continental block. The uranium is often separated from other metals on the external front. This is apparently explained via its high mobility. Toward the west, basalt magmatism was intensively manifested in the field of attenuation of the passive margin of continental block. Sandstone type uranium deposits in the Transbaikalia (Vitim district), in Mongolia (ore manifestation Sul and others) and on the western end of the South-China platform (Yunnan) are spatially closely connected with it. All these objects are covered with the Quaternary basalts. The infiltration deposits of uranium out of touch with young volcanism were revealed within the limits of cover of the Sino-Korean craton in the Ordos basin and Erlian depression of China. Perhaps, even the greater part of them were discovered within the limits of these structures were formed from domestic sources of alimentation. The subduction process of the Pacific plate is owed to a full set of natural metallogenic zones spanning from the deep rear of the subduction zone along its external damped front. 4. Conclusion The marginal part of the Eurasian continent was divided into a number of segments, each of which is characterized with its own metallogenic specialization caused by the processes collision and subduction. The sandstone type uranium deposits were on the external fading collision front and were located within the limits of area of suborogen in three structures – the Mediterranean and the Indian segments, and the Pacific belt. Different metallogenic specialization and the scale of manifestation of hydrogenic ore process within the limits of the Pacific belt and the Indian segment of the Alpine-Himalayan belt, the formation of which is caused by the similar the Mesozoic-Cenozoic global geodynamical processes, are determined by a number of reasons. The uranium on the external front of fading geodynamic processes (within the limits of suborogen) turned out in different structural, lithological and hydrogeological environments. Within the limits of the Baikal-South-China belt it was localized in the restricted by area paleo-valley basins and depressions. The deposits are often spatially and in age are mated with covers of young basalts. Large endogenic deposits of uranium in the local structural blocks (calderas) are localized in the rear parts of the belt. The scales of objects of sandstone type within the limits of the Baikal-South-China of uranium ore belt do not exceed average. The deposits of uranium within the limits of the Indian segment (The Pamir sector) are localized in the vast basins of suborogen type and major extensive paleo-valley in the artesian basins with running mode. It is characterized by a weak expression of young volcanic activity in the district and insignificant on scales endogenic uranium deposits in the rear parts of province (mountain Tien Shan). Considering the south framing of the Eurasian continent (area of collision of the Indian plate), we distinctly see the basic similarity in the position of infiltration uranium deposits of the Tien Shan megaprovince and the Baikal-South-China uranium ore belt – component part of the Pacific metallogenic belt. They gravitate towards area of attenuation of geodynamical processes in both cases. The endogenous uranium objects take places near the area of contact of collision plates. Their sizes both endogenous and exogenous are noticeably different in the south and the east of the Eurasian plate. The scale of infiltration deposits of the Tien Shan megaprovince is on the order more deposits of the Baikal-South-China belt. This is due to the wide areas of transit and many-tier geochemical barriers, favorable for localization of uranium from the oxygen-containing uranium-bearing waters, moving through the Cretaceous and the Paleogene deposits of Turan plate and major basins of the South Kazakhstan. However, endogenous uranium deposits of the Tien Shan are significantly inferior in scale to major uranium objects of the Mesozoic age of the Pacific ore belt. The reasons of such phenomena require further study. Given the material is evidence about tight spatial relation of part of infiltration uranium deposits with endogenous deposits of uranium confined to volcanogenic-tectonic structures. Moreover, those and others types of uranium objects are confined into a single ore metallogenic zoning. The last is entirely due to global geodynamical processes occurring in the crust and mantle in the marginal parts of the Eurasian plate.

Speaker: Dr Igor Pechenkin (All-Russian Scientific-Research Institute of Mineral Resources, Moscow, Russia)

147 GENESIS OF SANDSTONE TYPE URANIUM DEPOSIT IN DHOK PATHAN FORMATION, SIWALIK GROUP OF TRANS-INDUS SALT RANGE (SURGHAR RANGE), PAKISTAN

Abstract The Surghar Range (Trans Indus Salt Range) is a part of Himalayan Fold & Thrust Belt of Pakistan. The 5300 meters thick Siwalik rocks represent molasse type clastic sediments of fresh water nature. The Siwalik Group in Pakistan is divided into three subgroups: upper, middle and lower according to the lithological characters. The Middle Siwaliks Dhok Pathan Formation varies in thickness from 807 – 1540m typically represents cyclic alternation of fluvial fining upward rhythm. Detailed petrographic and geochemical study of surface and sub-surface core samples led to the characterization of the formation of uranium ore body and allowed to propose a metallogenic model. Scanning electron microscope (SEM) observations evidenced that a significant amount of uranium is precipitated in interstitial spaces, on and along grain boundaries in the reduced zone mainly as micro to nano crystals of UO2 & USiO4 as well as adsorbed on clay minerals in amorphous form. The uranium mineralization corresponds to synsedimentary / diagenetic concentrations which has been redistributed and remobilized due to successive phases of Himalayan Tectonics. The ore body has attained the present horizontal position, 15 – 25m below present day water table. The sandstone depositional model and geochemical data suggest that the source of uranium mineralization was contained within the sediments. Introduction The NW Himalayan foreland Fold and Thrust belt formed by progressive south directed folding and over- thrusting of slices of Indian Plate crust during the ongoing collision between India and Eurasia [1]. Following the onset of collision along the Main Mantle Thrust and its lateral equivalents during Latest Cretaceous to Early Tertiary [2], thrusting generally progressed southward with time. Most of the youngest thrusting has occurred along the frontal thrust system in the Salt Range in the east and the Trans Indus Ranges in the west. The Surghar – Shinghar Range (SSR) of the outer Himalayas represents the eastern end of the Trans-Indus Salt ranges of North Pakistan [3]. The range exhibits east-west structural trend along the southern margin of the Kohat Plateau and changes to north-south trend along the eastern flank of the Bannu Basin. The SSR forms asymmetrical, over-folded anticlinal structure plunging to the south near the Kurram River, with Permian strata exposed in the core, overlain by Mezozoic and Plaeogene rocks [4]. The western limb of the range is well exposed (present study area), while its eastern limb is deeply eroded exposing older formations. The end of marine sedimentation in SSR is marked by the deposition of fluvial rock units of Siwalik Group. The Neogene-Quaternary Siwalik Group preserved in the Himalayan foreland basin have been extensively documented along the Himalayan arc from Pakistan to Nepal, providing valuable information on mountain building in space and time, past organization of drainage networks, and paleoclimate [5]. Geologically, the Siwaliks represent molasse type clastic sediments of fresh water nature. These sediments had been accumulated in a foreland basin of the Himalaya during the third and most intense phase of deformation during the middle Miocene to Pleistocene. The Siwalik Group sediments are one of the most comprehensively studied fluvial sequences in the world. They comprise mudstones, sandstones, and coarsely bedded conglomerates deposited at times when the region was a colossal basin during Middle Miocene to Upper Pleistocene. Rivers flowing southwards from the Greater Himalayas, resulting in extensive multi-ordered drainage systems, deposited these sediments. Following this deposition, the sediments were uplifted through intense tectonic regimes (commencing in Upper Miocene times), subsequently resulting in a unique topographical entity - the Siwalik Hills or the Siwaliks [6]. The Siwalik Group in Pakistan can be clearly divided, according to the lithological characters, into the usual three subgroups: Lower, Middle and Upper, and further into their formation scale lithostratigraphic units. The Lower Siwaliks (Kamlial and Chinji Formations) consist of a sequence of sandstone-mudstone couplets with a marked dominance of the mudstones over the sandstones. The Middle Siwaliks (Nagri and Dhok Pathan Formations) are dominantly arenaceous, consisting of multistoried coarse to fine grained (generally medium grained), light grey, bluish grey massive sandstones with subordinate representation of siltstones, mudstones and clays. The Upper Siwalik (Soan Formation) is mainly conglomeratic in nature. These sedimentary deposits are 5300 meters thick in this area. Thickness of the Dhok Pathan Formation varies from 807 to 1540meters and represents alternate fining upward sedimentary rhythms of shale, siltstone and sandstone units [7]. The Dhok Pathan Formation of this area has assigned an age ranging from 7.5 - 2.5 Ma based on the magnetostratigraphy studies [8]. The Dhok Pathan Formation is hosting a small scale tabular sandstone type uranium deposit named as Qubul Khel Uranium Deposit after a small nearby village located in the southern part of SSR. The present contribution is aimed to understand the genesis of this uranium deposit and to propose a metallogenic model. Methods and Results i. A comprehensive geological map has been prepared with the help of high resolution satellite data, selective traversing of the area and ArcGIS 10.2 software. ii. Detailed sedimentological and lithofacies analyses of different sandstone and mudstone units of Dhok Pathan Formation resulted in the identification of seven distinct lithofacies (Gt, St, Sh, Ss, Sl, Fm, and Fl) which had been deposited under traction current, low and upper flow regime conditions by sand dominated large river. Paleocurrent studies indicated 210ᵒ direction of paleoflow with a braided stream pattern. iii. The XRD and SEM analyses of different sandstone and mudstone units (38 samples) reveal that kaolinite, smectite (montmorillonite & saponite), illite, vermiculite, and chlorite (clinochlore & chamosite) are the main clay mineral suits present in the Dhok Pathan Formation. The morphology of clay mineral suits is indicative as weathering products or the contribution from source areas. The sandstones units are classified as lithic arkose to feldspathic lith arenite based on petrographic studies. iv. Organic rich samples were analyzed for carbon isotopes that characterized type III kerogen mainly derived from terrestrial plants. v. The analyses at serial number iii & iv were carried out at State key laboratory, Breeding Base of Nuclear Resources and Environment, East China University of Technology (ECUT), Nanchang, China. vi. To understand the geochemical variations 28 surface and sub-surface drill core samples were analyzed for 42 elemental analyses on XRF and LA-ICP-MS at Beijing Research Institute of Uranium Geology (BRIUG). Analyses show a range SiO2 55.2 – 68.35%, Al2O3 12.54 – 14.59%, Fe2O3(total) 3.07 – 6.03%, MgO 1.8 – 4.03%, CaO 5.08 – 7.86, Na2O 2.35 – 2.61%, K2O 1.51 – 2.91%, MnO 0.06 – 0.96%, TiO2 0.36 – 0.67%, P2O5 0.078 – 0.159%, U 0.0001 – 0.16%, Th 0.0007 – 0.0012%, Pb 0.001 – 0.002%, V 0.006 – 0.015%. Discussion and Conclusions The Qubul khel uranium deposit developed in the basal part of host sandstone belonging to the upper part of Dhok Pathan Formation of Middle Siwalik Group. The host sandstone is about 100 – 400m thick with occasional grit and calcified, concordant sandstone lenses of varied size. The host sandstone dips 21 – 38ᵒ SW with the strike varying from N26ᵒW to EW. The sandstone is friable to weakly cemented, generally medium grained and light grey to bluish grey on fresh surface. The mineral assemblage includes quartz 26 - 30%, feldspar 14 – 16%, igno-metamorphic rock fragments 12 – 21%, micas 6 – 7%, amphibole 2%, clay minerals 2 – 18%, calcite 8 – 12% and magnetite, hematite/limonite, tourmaline and garnet as accessories. The ore body is of irregular tape like configuration; it has a NW-SE length of some 200 m, a thickness commonly from 2 to 15 m averaging 6.5 m, persists over a depth interval from 68 to 118 m below the surface, and averages 0.053% U [9]. The study of the Qubul Khel uranium deposit evidenced that a significant amount of uranium is precipitated in interstitial spaces, on and along grain boundaries in the reduced zone below the present day water table mainly as pitchblende (UO2) micro to nano crystals which also occur as cluster of micro fine globules. Minor amount of coffinite (USiO4) occur as pore fillings and coating along grain boundaries and a considerable amount is still present as adsorbed on clay minerals and earthy iron oxide in amorphous form. Uranium mineralization does not show any preferred affinity for any sedimentary, textural or structural feature of the host sandstone however adsorption on clay minerals, organic matter and iron oxide are common. Detrital uraninite and its alteration products such as schoepite, metaschoepite, carnotite and uranophane are typical uranium mineralization for oxidized environments. Studies of nature and evolution of organic matter indicate type III kerogen which is inherited from land plants as coaly phytoclasts, thermally immature and devoid of any free hydrocarbon. Two different morphological types of pyrite are characterized (i) framboidal pyrite in replacement of organic matter and (ii) idiomorphic pyrite which may have been crystallized during diagenesis. The Qabul Khel uranium deposit is thought to have evolved through multiple reworking by infiltration. Continual leaching and migration of uranium to its present position occurred during successive tectonic activity and related fluctuation of the water table in response to Himalayan tectonism. U precipitation was caused by permeability barriers combined with upward migrating hydrocarbons, which are considered to have provided the required reductants [9]. The careful investigations led to understand the plausible uranium concentration processes. Uranium was first concentrated in the basin at synsedimentary stage which may have been reduced directly or shortly after the first step of adsorption on clay mineral surfaces and organic matter, as UO2 micro to nano crystals disseminated in the host sandstone. Uranium reduction probably happened during early diagenetic processes within the reduced depositional environment. The uranium concentration processes were gradually upgraded within the depositional environment or in the host sediment which were interacting with the surface water involved in on-going sedimentation. At diagenetic stage uranium may be liberated from organic matter during its replacement by pyrite or by desorption from clay minerals. The presence of framboidal pyrite in replacement of organic matter and the occurrence of phosphorous-rich uranium minerals most likely reflect the metabolic activity of sulfate reducing bacteria [10]. Microorganism activity may have occurred during diagenetic evolution of the host-sediments and is most likely responsible for iron sulfidization and possibly uranium reduction, H2S produced by bacteria being a strong reductant [11]. After burial of the host sediments, Himalayan tectonic events may have caused groundwater movements and thus in situ and local redistribution and remobilization of uranium characterized by recrystallization of pitchblende and coffinite. The Qubul Khel uranium deposit experienced three main stages of uranium concentration processes : (i) a synsedimentary / early diagenetic stage concentrating uranium in reduced environment, possibly most if not all the uranium stock present in the deposit has been brought; (ii) a late diagenetic stage with formation of different morphologies of pyrite followed by a nearly in situ uranium mineralization; and (iii) finally, the uranium mineralization of Qubul Khel uranium deposit was redistributed and remobilized during the successive upheaval of Himalayan tectonics and the ore body attains the present position 15 – 25m below present day water table. The organic matter, framboidal & idiomorphic pyrite are the main reductants involved in the uranium concentration processes. The system is devoid of any free hydrocarbon as was previously thought that permeability barriers combined with upward migrating hydrocarbons have provided required reductants [9]. The presence of detrital uraninite grains and its alteration products are evident that the source of uranium mineralization was within the sediments. The contribution of other uranium bearing detrital minerals like zircon, monazite, uranothorite is limited as these behave as refractory minerals and have not released their uranium. Acknowledgment The authors would like to thank M/s Abdul Majid Azhar, Khalid Pervaiz, and Muhammad Ahsan Amin for critically reviewing and improving the manuscript. We also would like to thank the PAEC & CNNC, for providing facilities to carry out this research at East China University of Technology (ECUT), Nanchang, China as part of Ph.D studies. Special thanks to IAEA for providing funding and facilities for presentation & publication of this article. The authors acknowledge the support of Qazi Mujeeb ur Rehman, Dr. Imtiaz Ahmed, Muhammad Abbas Qureshi, Saira Imtiaz, Imran Asghar, Muhammad Naeem Iqbal, Ghulam Shabbir Khan Faridi, Ghulam Rasool, and Asif Imran. References [1] Blisniuk, P. M., Sonder, L. J., Lillie, R. J., Foreland normal fault control on thrust front development northwest Himalayan. Tectonics, vol. 17, no. 5, (1998), 766-779. [2] Yeats, R. S., Hussain, A., Timing of structural events in the Himalayan foothills of northwestern Pakistan, Geol. Soc. Am. Bull., 99, (1987),161-176. [3] Powell, C. McA., A speculative tectonic history of Pakistan and surroundings: some constraints from the Indian ocean. In Farah, A. & DeJong, K.A., (Eds), Geodynamics of Pakistan, Geological Survey of Pakistan, Quetta, 5-24 (1979). [4] Akhtar, M., Stratigraphy of the Surghar Range. Geol. Bull. Univ. Punj. 18, (1983), 32-45. [5] Najman, Yani, The detrital record of orogenesis: A review of approaches and techniques used in the Himalayan sedimentary basins. Earth-Science Reviews, vol. 74, 1–2, (2006), 1-72. [6] Chauhan, P.R., The importance of India in human origins studies with special reference to the Siwalik Hills & the Narmada Basin. In National Workshop on Pleistocene environments and hominin adaptations in South Asia: Problems & Prospects, March 29-31, (2003), Delhi, India. [7] Abbas, A., Pan, J., Yan, J., Imran, A., Muhammad Ahsan, A., Litho-facies analysis, clay mineralogy and depositional model of Dhok Pathan Formation (Siwalik Group), Surghar-Shingar Range, Pakistan, (2018), (in preparation). [8] Khan, M. J. & Opdyke, N. D., Magnetic-Polarity stratigraphy of the Siwalik Group of the Shingar and Surghar ranges, Pakistan. Geol. Bull. Univ. Peshawar 20, (1987), 111- 127. [9] Dahlkamp, F. J.(Ed), Uranium deposits of the world Asia, Springer, (2009), pp 508. [10] Bonnetti, C., Cuney M., Malartre, F., Michels, R., Liu, X., Peng, Y., The Nuheting deposit, Erlian Basin, NE China: Synsedimentary to diagenetic uranium mineralization, Ore Geology Reviews 69, (2015), 118 – 139. [11] Machel, H.G., Bacterial and thermo-chemical sulphate reduction in diagenetic settings - old and new insights. Sediment. Geol. 140, (2001), 143–175.

Speaker: Mr Abbas Ali (East china University of Technology)

148 The Karoo Sandstone-hosted Uranium Deposit at Dibwe East, Mutanga, Zambia

INTRODUCTION The late Carboniferous – early Jurassic Karoo rift basins of southern Africa are an important emerging uranium province. A number of sandstone-hosted deposits have been identified, although only Paladin Energy’s Kayelekera deposit in Malawi is currently being mined. The deposits are typically tabular, with variable proportions of primary and secondary uranium minerals. They generally occur at “energy drops” in fluvial sandstone successions, where organic material accumulated and subsequently acted as a reductant for uranium dissolved in basin waters (G.Yeo, 2011). The Dibwe-East is part of GoviEx Uranium Zambia Limited, Mutanga Project licenses (13880-HQ-LML and 13881-HQ-LML) encompassing 457.3 square kilometers. The mining licenses a have a term of 25 years to April 2035. The mining licenses are located in Siavonga district in southern Zambia, approximately 180km south of the nation’s capital Lusaka and 36km from Siavonga town. Dibwe-East geologically, lies in the Mid-Zambezi Rift Basin of southern Zambia; the fluvial Escarpment Grit sandstones unconformably overlie the late Permian lacustrine Madumabisa Mudstone and are conformably overlain by the early Triassic fluvial Interbedded Sandstone and Mudstone Formation. GEOLOGY In the Mid-Zambezi Rift Basin of southern Zambia, the fluvial Escarpment Grit sandstones unconformably overlie the late Permian lacustrine Madumabisa Mudstone and are conformably overlain by the early Triassic fluvial Interbedded Sandstone and Mudstone Formation (Nyambe and Utting,1997). The Dibwe-Mutanga Corridor uranium deposits are located within the Zambezi Rift Valley which is hilly with large fault bounded valleys filled with Permian, Triassic and possibly Cretaceous sediments of the Karoo Supergroup. The Mid-Zambezi Valley is characterized by a series of NE-trending, fault-bounded cuestas or fault blocks, uplifted to the NW and dipping to the SE. Rocks of the Karoo Supergroup (late carboniferous to Jurassic) occupy the rift trough of the Zambezi Valley (Money and Prasad, 1977). Dibwe-East is predominantly composed of Escarpment Grit Formation (EGF). The surface geology is characterised by a few scattered sandstone outcrops. Two major units can be distinguished, the “Braided facies” member (EGFb-f) of the lower EGF and the “Meandering facies” member (EGBm-f) of the upper EGF In core, the two units appear to be transitional from one another. The “Braided Facies” which covers mostly half of the northern prospect is distinguished in outcrop as gritstones, very-coarse-grained to coarse grained sandstones and pebbly sandstones. Ripple lamination is common and mudstone beds are laterally continuous. The absence of any marker beds is typical of braided river successions. Broad lithologic features, however, including zones of largest average and maximum grain size, relatively abundant pebbles, mudstone beds and mudclasts can be matched from hole to hole. On the basis of these features, three subdivisions have been distinguished within the EGF (Lusambo, V., 2011): The “Braided Facies”, which is at least 120 m thick at Mutanga, was subdivided into three subunits: • Unit A, bounded by the underlying Madumabisa mudstone and the lowest EGF conglomerate bed, is characterized by cross-bedded, low-angle cross-bedded and ripple-laminated, coarse- to medium-grained sandstones with local mudchips, interbedded with mudstones and very fine-grained sandstones. Thickness variations in Unit A probably reflect deposition on an irregular paleotopographic surface. Whereas there is no apparent unconformity between Units A and B, that contact is the best datum to use in any stratigraphic reconstruction. • Unit B is characterized by the presence of conglomerates, gritstones, very-coarse-grained to coarse grained sandstones and pebbly sandstones, locally with mudclasts derived from interbedded mudstones. The upper boundary of unit B can be defined by the last appearance of mudstone or mudclasts associated with pebbly sandstone. Whereas, the historic AGIP graphic logs did not distinguish mudclasts, on this profile the B/C boundary was taken as the highest mudstone bed. Unit B appears to thicken toward the southeast, presumably reflecting increased syndepositional subsidence in that direction, as noted above. • Unit C is dominated by gritstones and coarse-grained, rarely pebbly sandstones. Mudstones are rare; hence mudclasts are uncommon in this unit. The scarcity of mudstones and mudclasts suggests that Unit C should be more permeable than Unit B. This may be a factor in localization of mineralization near the contact between these units. The southern part for the prospect is mostly “Meandering Facies” reaching in excess of 8m and is distinguished in outcrop as massive, or trough and tabular planar cross-bedded, fine- to medium-grained sandstone, locally with scattered small pebbles. In core, the “Meandering Facies” sandstones show ripple lamination as well as cross-bedding. Sandstone beds typically grade up from coarse-grained bases to medium grained or fine grained tops (Lusambo, V., 2011). Mudclasts and pebble lag layers are common It is distinguished from the braided facies by scarcity of pebbly sandstones and conglomerates and by the presence of extensive mudstone beds. MINERALISATION The uranium mineralization identified to date appears to be restricted to the Escarpment Grit Formation of the Karoo Supergroup. Within the tenement area, the Karoo sediments are in a northeast trending rift valley. They have a shallow dip and are displaced by a series of normal faults, which, in general, trend parallel to the axis of the valley. The Madumabisa Mudstones form an impermeable unit and are thought to have prevented uranium mineralization from moving further down through stratigraphy. Mineralization is associated with iron-rich areas (goethite) as well as secondary uranium being distributed within mud flakes and mud balls as well in pore spaces, joints, and other fractures. Mineralization at Dibwe East is similar to that at the Mutanga deposit in that it is composed of coarse Autunite in fracture zones within an upper oxidized horizon overlying more fine grained disseminated mineralization within a pyritic reduced zone. Coffinite is dominant at Depth (70 – 100m zone) whilst Phurcalite (similar chemical formula as Autunite) is dominant (0 – 40m zone and 40 – 70m zone). Thus it appears primary mineralization is at depth giving the high grade zones with secondary mineralization at surface 0 – 70m zone. Mutanga lies 40 km via all-weather road from a major paved highway and only 35 km from the Kariba hydro dam. There is strong local community and government support for the project. EXPLORATION STATUS Exploration for uranium in the Middle Zambezi valley during the early 1970’s revealed the existence of several uranium deposits. The most interesting occur in the vicinity of Siavonga and are currently held by GoviEx Uranium Zambia Limited. In 2006 a detailed aeromagnetic and radiometric survey (Symons & Sigfrid, Report on the Interpretation of Aeromagnetic and Radiometric data, 2006) was completed over the areas of interest which were revealed during an earlier pre-digital airborne survey. The 2006 survey has confirmed the position and tenor of the existing targets and identified additional, targets. 1. The EGF appears to have two clear radiometric signatures; a. A reddish brown ternary radiometric signature indicates the presence of K in the Formation, consistent with description of the EGF as feldspathic sandstone. This part of the EGF was mapped and designated as D1 b. The areas marked as D2 appear to have a similar K response but with additional uranium producing a white ternary radiometric signature. 2. The structures identified indicate an extensional half-graben regime with normal faults trending in a generally NE direction. The movement on these faults appears to down throw blocks to the NW. Later faulting in a NW, WNW and NNE direction crosscutting the Karoo stratigraphy is also noted. CONCLUSIONS • Exploration data suggest that the likely environments of uranium mineralization are meandering stream depositional systems within paleochannels, with fine- to coarse-grained sands and silts containing some organic and pyrite material, which could serve as reductant for the precipitation of uranium. • At least three mineralized zones (“sand packages”) have been identified. • A stacked series of three mineralized horizons extend from near surface down to nearly 150m along nearly a 4km NE-SW strike, with their thickness ranging from 2m to 14m. • Coffinite is dominant at depth (70 – 100m zone) whilst Phurcalite (similar chemical formula as Autunite) is dominant (0 – 40m zone and 40 – 70m zone). Thus it appears primary mineralization is at depth giving the high grade zones with secondary mineralization at surface 0 – 70m zone. REFERENCES [1] Yeo, G. (2011). AGIP STRUCTURAL GEOLOGY – DIBWE-MUTANGA CORRIDOR (18 MAY 2011). Internal report for Denison Mines. [2] Nyambe, I., & Utting, J. (1997). STRATIGRAPHY AND PALYNOSTRATIGRAPHY, KAROO SUPERGROUP (PERMIAN AND TRIASSIC, MID-ZAMBEZI VALLEY, SOUTHERN ZAMBIA. Jornal of African Earth Sciences v. 24, 563-583. [3] Money, J., & Prasad, R. (1977). URANIUM MINERALIZATION IN THE KAROO SYSTEM OF ZAMBIA. Geologic Survey of Zambia Occasion Paper, 14. [4] Lusambo, V. (2011). LOCAL GEOLOGY OF DIBWE EAST PROSPECT (DIBWE MUTANGA CORRIDOR). Internal report for Denison Mines Zambia Limited. [5] Staley, R.; Chapewa, D.; Lusambo, V.; Mbomena, G. (2009). THE MUTANGA URANIUM PROJECT, SOUTHERN PROVINCE, REPUBLIC OF ZAMBIA - SUMMARY EXPLORATIN AND GEOLOGY REPORT FOR THE PERIOD OCTOBER 1, 2007 TO DECEMBER 19, 2008. Denison Mines Zambia Ltd. [6] (2011). Mineralogical Analysis of Uranium Ore. ALS Minerals submitted to Denison Mines Zambia Limted. [7] (2012). TECHNICAL REPORT FOR DIBWE EAST PROJECT , SOUTHERN PROVINCE, REPUBLIC OF ZAMBIA. NI-43101.

Speaker: Mr Victor Lusambo (GoviEx Uranium Zambia Ltd)

149 3D Modeling of roll-front type uranium deposits in Kazakhstan

Nowadays Inkai is one of the unique deposit of uranium resources in the world. Resources of uranium are estimated more than 700 000 tonnes. The owners of site 1, site 2 and site 3 at Inkai are National Company “Kazatomprom” and Cameco Corporation. Inkai is roll front sandstone deposit where mineralization of U is related to redox zone. The main uranium minerals are sooty pitchblende (85%) and coffinite (15%). Average grades of U - 0,06-0.07%. Resource estimation was performed by using the GT estimation method on two-dimensional blocks in plan view. Nowadays due to implementation of various types of software into mining process an approach to mineral resource estimation and geology interpretation was essentially revised. JV Inkai with Cameco corporation assistance made decision regarding 3D modeling adoption into the workflow. At the current time project of 3D implementation has achieved its median but we already value all potential and advantages of using 3D tools. Taking into account that Kazakhstan is in CRIRSCO family since 2016 the practice of applying block modeling for resource estimation and public reporting will be encouraged.

Speaker: Ms Olga Gorbatenko (Inkai Joint Venture)

150 The Fluid Flows and Uranium Mineralization in the Northern Ordos Basin, North China

1 INTRODUCTION A huge quantity of uranium reserves discovered in the northern part of the Ordos basin in north China is interesting more and more uranium geologists in the world. The uranium mineral belt, including a series of deposits, such as Dongsheng Deposit, Nalinggou Deposit, Daying Deposit and West Daying Deposit, extends from east to west >100km long. Moreover, the new deposits are still under discovery. Current exploration situation shows a great potential in the west and south of the belt. 1.1 Change of Exploration Strategy The exploration work in the Ordos Basin have been undergone an unusual history. During the 1990’s, the uranium geologists thought the Ordos Basin is unfavorable to form a large quantity of uranium reserves because the modern ground water goes out of the basin into the Yellow River surrounding the basin. It is then speculated that uranium could not accumulate in the case of going-out water hydrogeological condition. But this hypothesis was soon overturned by the discovery of the Dongsheng Deposit in 2000. Reconsideration of tectonic evolution for the Ordos Basin demonstrates that the water- going-out condition has come into being only because the Yellow River faulted sub-basin separates the northern part of the basin with the uplifted mountainous area since the Cenozoic. Prior to the Cenozoic, the uranium-oxygen-bearing fluids (UOF) sourced from the northern uplifted mountains can flow into the basin and form the uranium ore deposits. The breakthrough of the Dongsheng Deposit encouraged uranium explorers to look for more deposits in the basin. 1.2 Characteristics of Ore Bodies The burial depth of ore bodies varies from 200~300m in east to 700~800 m in west of the north basin. The uranium mineralization is hosted only in the upper part of the Zhiluo FmⅠ in east and in both the upper and lower of the Zhiluo FmⅡ in west. In general, the whole uranium mineral belt is at large controlled by the paleo- oxidized front which is EW-trending snakelike on the plane geologic map. A single ore body is always tabular, lenticular and cystic in all deposits. None of the typical rollfront bodies have been found up to now. Some lenticular ore bodies are controlled by deep-seated fault, such as the Bojianghaizi Fault in the Nalinggou Deposit. Averagely, the mineralization zone is 9000m long, 500~2000m wide and 3~4m thick in Nalinggou and 2000~8000m long, 5.26m thick in Daying. 1.3 Atypical Interlayered Oxidized Zone It is worthy noticing that the oxidized sandstone in all deposits is not yellow or red and has been turned into green in color. Usually, the ore bodies are lie in the boundary between green and grey sandstones both horizontally and vertically. I.e., the sandstone is green to the north and grey to the south of the mineralized zone belt. Above is green the sandstone and below is grey. Hence, the interlayered oxidized zone seems to be atypical comparing to typical oxidized zone in a sandstone-type uranium deposit. 2 GEOLOGICAL SETTINGS 2.1 Tectonic Evolution The tectonic evolution of the northern part of the Ordos Basin is accordant to that of the Yin Shan tectonism. The coupling of the mountain and basin determines the relationship between uplift and subsidence. At the end of Permian, the North China Plate collided with the Siberian Plate caused closure of the paleo-Asian ocea【1】【2】【3】【4】【5】【6】. During the period of Triassic, strong compression resulted in the uplifting of Yin Shan, and formation of large-scaled folds and thrust faults with strong magmatism【7】【8】【9】. From the Early to Middle Jurassic, a wide spread coal-bearing rock series deposited within the depression area of both uplift and sub-basin. The target layer hosting uranium deposited from the large-scaled fluvial to delta system【10】. During the Late Jurassic, Yin Shan re-uplifted and re-thrusted again due to the regional shortening 【11】【12】【13】. Accordingly, the Anding Fm and Fenfanghe Fm deposited from the fluvial to lacustrine environments. During Cretaceous, the basin underwent early extension with deposition of the Dongsheng Fm, then late uplifting and being eroded due the compression again【14】【15】with eruption of basalt magma at the end of the Mesozoic【16】. Since the Cenozoic, especially Oligocene, the rapid subsidence surrounding the basin due to the normal faults caused formation of the Hetao, Yinchuan and Fenwei faulted basins, with regional eruption of basalt magma and earthquake【17】【18】. The northern part of Ordos has been gradually separated from Yin Shan. 2.2 Target Layers and Depositional Facies Up to present, three rock series have been verified as the target layer for sandstone-type uranium deposits in the Ordos Basin. They are the Yan’an Fm (J2y), the lower Zhiluo FmⅠ(J2z1-1) and the upper Zhiluo FmⅠ(J2z1-2). The Yan’an Fm is composed of thick coal beds intercalated with thin sandstone and mudstone beds, which deposited in swamp and lacustrine at the damp climate. The Zhiluo Fm unconformably overlain the Yan’an Fm with an apparent weathered crust abundant in kaolinite. Different from the Yan’an Fm, the Zhiluo Fm consists of thick layered sandstone and thin to thick layered mudstone, which deposited in braided (J2z1-1) and meandering (J2z1-2) fluvial systems【10】. The Zhiluo Fm Ⅰabundant in organic matter is partially interbedded with thin coal beds which indicates the damp climate environmental setting. 3 METHOD AND RESULT In order to study uranium-oxygen-bearing flow and its mineralizing processes, we have sampled both the uplifted area (Yin Shan) and drilling cores in the basin deposits. 3.1 Heavy Minerals We have taken 32 samples from 18 boreholes in Nalinggou Deposit, Xinsheng Deposit and west Daying Deposit. Firstly, the samples are crashed, then acidified and washed with water and baked. All heavy minerals are separated with heavy solutions. After the 0.063 ~ 0.5mm mineral grains are separated from heavy solution, all minerals are identified by binocular microscope. Statistics shows that heavy minerals are garnet (41.78%), zircon(6.41%), sphene(1.93%), hornblende(1.54%), tourmaline(1.34%), rutile(1.31%) and so on. It is inferred that the uplift source rock for the target layer (J2z) is mainly metamorphic rocks and neutral to acidic igneous rocks combining with the thin sections. 3.2 SEM & XRD 37 samples for XRD and 18 samples for SEM are selected from the Nalinggou Deposit. Samples for XRD were analyzed with D/max-2500 and TTR at the laboratory of Research Institute of Petroleum Exploration and Development. Samples for SEM were analyzed under NovaSEM450 and X-Max at the Key Laboratory of Nuclear Resources and Environment of Ministry of Education, East China University of Technology. Clay minerals in target sandstone include smectite, kaolinite, chlorite and illite. The average of clay minerals in sandstone is about 15.6%. Among clay minerals, smectite in gray sandstone ranges from 44% to 76% with av.59.4%, in grey green sandstone from 28% to 60% with av.50.1% and in green sandstone from 12% to 62% with av.42.5%. Kaolinite ranges from 15% to 34%, av. 24.9% in gray sandstone, 18% to 44%, av.25.8% in grey green sandstone and 17% to 42% with av.26.5% in green sandstone. Chlorite ranges from 6% to 17% with av.10.8% in grey sandstone, 12% to 41% with av.19.5% in grey green sandstone and 13% to 48% with av.27% in green sandstone. Morphologically, smectite is semi-euhedral to anhedral. It is cotton-like coating the grains of feldspar and quartz, sometimes honeybee-nest like in pores. Kaolinite is usually booklet-like and vermiform in pores of sandstone. Chlorite is light green and foliated, sometimes flower-like and spheroidal, coexisting with pyrite. Overall, illite is less in content and hard to be identified under SEM. 3.3 EMPA (U Minerals and Chl) In this study the electron probe microanalysis (EPMA) was accomplished in the Key Laboratory of Nuclear Resources and Environment of Ministry of Education, East China University of Technology using: (1) a JXA-8100 electronic microprobe, (2) a IncaEnery energy disperse spectroscopy, (3) an acceleration voltage: 15.0KV and (4) a probe diameter with 1μm beam probes: 2.00×10-8 A. First a rough qualitative analysis was done by the IncaEnery energy disperse spectroscopy and then quantitative analysis on several uranium minerals selected from uranium-bearing ores by means of the observation and analysis of the mineral grains shown in the electron back-scattering Images. Coffinite is the most important uranium mineral in all deposits. It is several μm to several ten μm in size with UO250~70%wt and SiO2 10~20%wt and coating grains or filling the pores among grains or in the cleavage plane of biotite. Coffinite sometimes replaces the blocky matrix in sandstone. Coffinite usually co-exists with pyrite and ilmenite. The second important uranium mineral is pitchblende. It is 3 to 15μm in size with UO2>80%wt, CaO≈4%wt and SiO2<2%wt. Generally, pitchblende is well crystallized and filling the pores among grains in sandstone. Brannerite and Titanium-bearing uranium minerals are special in sandstone-type uranium deposit because they are formed under higher temperature. They are several μm to about 100μm in size with UO2 46~53%wt, SiO2 6~16%wt and TiO2 8~15%wt and coexisting with calcium cement among sandstone grains. It is worthy to mention that there are some low temperature hydrothermal sulphide minerals such as galena, clausthalite and brookite in mineralized sandstone. Chlorite is particularly analyzed by EMPA in this study. The composition of chlorite is as following (in wt): SiO2 24.02 ~ 31.87% (av.28.45%), Al2O3 17.16 ~ 21.31%(av.18.63%), FeOT 21.80~36.39%(av.27.31%), and MgO 5.80~16.35%(av.12.42%). The inverse relationship of iron with magnesium means they are replaced each other in chlorite crystal. The gradual decease of silicon from green to grey green to grey sandstones implies that the solution precipitating chlorite turns to less acidic. 4 DISCUSSION AND CONCLUSION 4.1 About Structural Inversion Structural inversion occurred in early period of Cenozoic is eventful in the evolution of tectonism for the Ordos Basin. During the late Mesozoic, the west and north area to the basin were under compression. The slope between the uplift (Yin Shan) and Yimeng Uplift (in basin) is favorable for UOF to flow into basin. A large quantity of uranium via solution was brought into target layers (Zhiluo Fm). But this metallogenic process was ceased because the Yinchuan faulted subbasin and Hetao faulted subbasin began to form at about 40Ma (the middle Eocene). The strong faulting occurred at about 20Ma (Miocene) with rapid subsidence and thick-layered sediments in subbasins. This extensional tectonism is favorable to upward migration of deep seated hydrothermal solution. 4.2 Target Sandstone Petrology The clastic grains in target sandstone in the Ordos Basin amount to 76~92%, which mainly consist of quartz, feldspars and lithic fragments. Quartz, sub-angular to sub-rounded and clean on surface, ranges from 33% (in vol.) to 76%, av.50%. Feldspars, including plagioclase, microcline and perthite, ranges from 10% to 50%, av. 30%. Clayization, epidotization and zoisitization are common within feldspars. Feldspars are sometimes replaced and cut through by carbonate minerals. Lithic fragments range from 5% to 50%, av.30%. The metamorphic rock dominates lithic fragments. The others are quartzite, siliceous rock and granite. Based on the ternary diagram of Folk(1968) 【19】, the target sandstones, petrologically, are mainly lithic arkose and partially arkose and feldsparthic lithic sandstones. 4.3 About Uranium Source Jiao et al. (2012) `s【20】 study shows there are three kinds of uranium source suppliers, metamorphic rocks, igneous rocks and sandstone itself. As stated above, the sediment source of target sandstone is the rocks of Yin Shan uplift. The metamorphic gneiss contains 2.54×10-6 uranium with –ΔU 43.7% (lost uranium). The igneous rock (acidic intrusions) contains 9.29×10-6 uranium with –ΔU 36.9%. Sandstone itself can contribute uranium to ore deposits. Uranium content in grey sandstone ranges 0.01 to 47.63×10-6, av.5.75×10-6. Grey green sandstone contains uranium at 0.01～9.56×10-6, av.2.16×10-6. Red sandstone contains uranium at 0.01～9.39×10-6, av. 2.63×10-6. Both green and red sandstone (residual) lost more uranium than other colors of sandstone. Hence, uranium in deposits can source from multiply rocks. 4.4 Genetic Model and Hydrothermal Reworking The enrichment of huge amount of uranium in the Ordos Basin has undergone three stages as following. (1) Pre-enrichment stage. Sediments sourced from the uranium-bearing metamorphic and igneous rocks were transported by surface water via fluvial systems into the basin during the middle Jurassic time. Uranium in sandstone grains and matrix can be dissolved later. So, the depositional process plays pre-enrichment role in mineralization. (2) Interlayered Oxidation Stage. The large quantity of uranium-oxygen-bearing fluids leaching both the uplift provenance rocks and pathway sandstones flow into underground target in the basin during late Jurassic to Cretaceous time. UOF can be reduced at the redox zone created by organic matter to form tabular, and/or rollfront uranium ore bodies. (3) Hydrothermal and Petroleum Reworking Stage. The Yimeng Uplift area in the northern part of the basin was cut off from the Yin Shan (uplift) by the Yinchuan and Hetao faulted sunbbasins under regional extensional stress since the Miocene time. The hydrothermal fluids migrate through normal faults into the uranium ore bodies and redistribute the original mineralization. During this process, a large amount of pitchblende has turned into coffinite because of combination of silicon released from feldspar alteration with uranium in pitchblende, with hydrothermal sulphide minerals forming and coexisting with uranium. At the same time, tabular/rollfront ore bodies changed into tabular, and/or lenticular and cystic. This is the reason why none of rollfront ore body has been found in all deposits. Moreover, a large-scaled petroleum migrated from the hydrocarbon source rock turns the red and/or yellow oxidized sandstones into green in color. The explorers may make good use of this model to predict the uranium ore bodies and drill the exploration boreholes in the future. 5 REFERENCES [1] REN J S, NIU B G, LIU Z G. 1999. Soft collision, superposition orogeny and polycyclic suturing. Earth Science Frontiers, 6(3): 85-93. [2]XIAO W J，WINDLEY B F，HAO J，ZHAI M G. 2003. Accretion leading to collision and the Permian Solonker suture，Inner Mongolia, China: Termination of the Central Asian orogenic belt. Tectonics, 22: 1069-1089. [3] LI J Y, GAO L M, SUN G H, LI Y P, WANG Y B. 2007. Shuangjingzi middle Triassic syn-collisional crust-derived granite in the east Inner Mongolia and its constraint on the timing of collision between Siberian and Sino-Korean paleo-plates. Acta Petrologica Sinica, 23(3): 565-582. [4] LI, Y L, ZHOU, H W, ZHONG Z Q, ZHANG X H, LIAO Q A, GE M C. 2009. Collision processes of north China and Siberian plates: Evidence from LA-ICP-MS zircon U-Pb age on deformed granite in Xar Moron suture zone. Earth Science-Journal of China University of Geosciences, 34(6): 931-938. [5] CHEN A Q, CHEN H D, XU S L, LIN L B, SHANG J H. 2011. Sedimentary filling of north Ordos and their implications for the soft collision process of hing gan mts.-Mongolia orogenic belt in late Paleozoic. Journal of Jilin University (Earth Science Edition), 41(4): 953-965. [6] LI D P, CHEN Y L, WANG Z, LIN Y, ZHOU J. 2012. Paleozoic sedimentary record of the Xing-Meng Orogenic Belt, Inner Mongolia: Implications for the provenances and tectonic evolution of the Central Asian Orogenic Belt. Chinese Science Bulletin, 57(7): 550–559. [7] XU, Z Y, LIU Z H, YANG, Z S. 2001. Mesozoic orogenic movement and tectonic evolution in Daqingshan region, Inner Mongolia. Journal of Changchun University of Science & Technology. 31(4): 317-322. [8] CHEN Z Y, LI Y X, WANG X L, YANG S S, HUANG Z Q. 2002. Thrust nappe structure in the Baotou-northern Hohhot area, Inner Mongolia. Regional Geology of China, 21(4): 251-258. [9] ZHANG Q, WANG Y, JIN W J , WANG Y L, LI C D, XIONG X L. 2008. Mountain range in northern North China during the Early Mesozoic: evidence from granite. Geological Bulletin of China, 27(9): 1391- 1403. [10] JIAO, Y Q, CHEN A P, YANG Q, PENG Y B, WU L Q, MIAO, A S, WANG M F, XU Z C. 2005. Sand body heterogeneity:one of the key factors of uranium metallogenesis in Ordos basin. Uranium Geology, 21(1): 8-15. [11] ZHENG Y D, DAVIS G A, WANG C, DARBY B J, HUA Y G, 1998, Major thrust sheet in the Daqing Shan Mountains, Inner Mongolia, China. Science in China (Ser.D), 41(5): 553-560. [12] DAVIS G A, WANG C, ZHENG Y D. 1998. The enigmatic Yinshan fold-and-thrust belt of northern China：New views on its intraplate contractional style. Geology, 26(1): 43-46. [13] DONG S W, ZHANG Y Q, LONG C X, YANG Z Y, JI Q, WANG T, HU J M, CHEN X H. 2007. Jurassic Tectonic revolution in China and new interpretation of the Yanshan movement. Acta Geologica Sinica, 81(11): 1449-1461. [14] ZHU S Y. 1997. Nappe Tectonics in Sertengshan-Daqingshan, Inner Mongolia. Geology of Inner Mangolia, (1): 47-48. [15] GAO D Z, LONG L, ZHANG W J. 2001. Tectonic characteristics and evolution of the central segment of the Linhe-Jining fault belt, Inner Mongolia. Regional Geology of China, 20(4): 337-342. [16] XU H, LIU Y Q, LIU Y X, KUANG H W. 2011. Stratigraphy, sedimentology and tectonic background of basin evolution of the late Jurassic-early Cretaceous Tuchengzi formation in Yinshan-yanshan, north China. Earth Science Frontiers, 18(4): 88-106. [17] YANG X P, RAN Y K, HU B, GUO W S. 2002. Active fault and paleoearthquakes of the piedmont fault (Wujumengkou-dongfeng village) for Seertang mountains, Inner Mongolia. Earthquake Research in China, 18(2): 127-140. [18] CHENG S P, LI C Y, YANG G Z, REN D F, 2006. The denudational-surface sequence and controls on the landscapte development in the Langshan mountains-Seertengshan mountains, Inner Mongolia. Quaternary Sciences, 26(1): 99-107. [19] JIAO Y Q, WU L Q, RONG H, PENG Y B, WAN J W, MIAO A S. 2012. Uranium reservoir architecture and ore-forming flow field study: a key of revealing Dongsheng sandstone-type uranium deposit mineralization mechanism. Geological Science & Technology Information, 31(5), 94-104. [20] FOLK R L, 1968. Petrology of sedimentary rocks, Hemphill, Austin, TX, p.124.

Speaker: Prof. Fengjun Nie (East China University of Technology)

Tailings and waste management

Conveners: Prof. Jim Hendry (University of Saskatchewan), Dr Peter H. Woods (IAEA)

151 A REVIEW OF THE GEOCHEMICAL CONTROLS ON ELEMENTS OF CONCERN IN URANIUM MILL TAILINGS, ATHABASCA BASIN, CANADA

INTRODUCTION The Athabasca Basin of northern Saskatchewan (and a small part of Alberta), Canada is a major source of global uranium (U) supplies. Uranium mined from the Basin comprised 22% of the world’s supply in 2015, and, as of 2014, there are 235,000 tons of known economically mineable U in reserve in the Basin [1, 2]. There are three U mills currently operating in the Basin (Rabbit Lake, Key Lake, and McClean Lake). Uranium production began at Rabbit Lake in 1975. Key Lake was commissioned in 1983. The McClean Lake mill began operation in 1999. A fourth mill, Cluff Lake, was commissioned in 1980 and decommissioned in 2003 [3]. Conventional U milling processing in the Basin follows the pathways: comminution (crushing and grinding), leaching (using sulfuric acid under oxic conditions and resulting in a solution rich in Fe, Al, Mg, Si, As, Ni, Se, Mo, SO4, and U (among other elements), solid-liquid separation, purification, precipitation of the dissolved metal(loid)s (as secondary minerals as the solution pH is neutralized to neutral to alkaline pH with slaked lime), and packaging. Tailings slurries from the mill process can contain elevated concentrations of elements of concern (EOC) including As, Ni, Se, Mo, and 226Ra. Above ground tailings management facilities (TMF) were first used to store tailings [4]. Subsequently, above ground TMFs were replaced with in-pit TMFs located in mined-out open pits [5]. These in-pit TMFs were engineered to optimize tailings consolidation, and, after decommissioning, minimize groundwater flow through the tailings and ensure EOC transport is dominated by diffusion. The first in-pit TMF was constructed at Rabbit Lake in 1984 (termed the RLITMF) [5]. The second in-pit TMF was constructed at Key Lake in 1996 (termed the DTMF) [6]. The third TMF was constructed at McClean Lake in 1999 (termed the JEB TMF) [7]. All three mills discharge tailings sub-aqueously to the TMFs to prevent transportation of contaminated dust and to spread the tailings more evenly across the TMF [8]. This study summarizes the extensive existing literature on the mineralogical controls on the EOCs in tailings in in-pit TMFs in the Athabasca Basin compiled over that past two decades. METHODS Many methods have been used to study the geochemical controls on EOCs in Athabasca Basin tailings. These include solids and aqueous sampling during the neutralization steps at individual mills, analysis of decades-old porewater and solids samples from TMFs, and batch and continuous mode laboratory experiments to generate precipitates of synthetic raffinate solutions. The aqueous and solid phase chemical compositions were measured and used in geochemical models and to study spatial and temporal trends in the tailings. Generally, solid samples were subjected to complementary characterization techniques including sequential extractions, X-ray diffraction (XRD), electron microscopy (EM), and X-ray absorption spectroscopy (XAS). RESULTS, DISCUSSION AND CONCLUSIONS Uranium Ores The U ores in the basin are dominated by uraninite and pitchblende [9]. A strong association of U minerals with sulfide- and arsenide-rich mineralizations including gersdorffite, niccolite, rammelsbergite, pyrite, chalcopyrite, and arsenopyrite exists. Mineralogy of Tailings The precipitates in the neutralization processes from the three mills studied are highly dependent on the process pathway, which differs between mills. Different pH setpoints at each stage in each mill affects the saturation state of minerals and influences the final mineralogy of the precipitates. The initial concentrations of the major raffinate elements (which determines the mass of the minerals that precipitates) and the pH setpoints of the neutralization steps determine the solubility controls of EOCs driven by surface complexation or co-precipitation. Secondary minerals constitute 10-20% of the total tailings mass, with the remaining being leach residues. With the exception of gypsum, these precipitates are generally amorphous or nanocrystalline because of the rapid neutralization at high saturation conditions and ambient temperature and pressure inhibiting crystallization [10]. Differences exist in raffinate compositions between mills and between samples collected from the same mill at different times. These differences are attributed to variability of ore deposits and heterogeneity of ores from the same deposit. These variations render it difficult to generalize what secondary minerals will precipitate from the neutralization processes, although general trends exist. The dominant Fe mineralogy of the final mill precipitates in all three neutralization processes is ferrihydrite. The lower terminal pH at McClean Lake is, however, more favorable for increased concentrations of ferric arsenate. Raffinates processed at Key Lake contain much greater concentrations of Al compared to raffinates processed at McClean Lake and Rabbit Lake due to the ores used. Aluminum and Mg comprise 1-5% of the secondary precipitates by mass in Key Lake tailings [11, 12]. Calcium comprises 10-20% of the final neutralized precipitates and is mostly as gypsum [12, 13]. Mineralogical Controls on Elements of Concern in Mill Tailings Research shows that Fe and Al secondary minerals provide the dominant mineralogical controls of EOCs in the precipitates from raffinates [7, 14-20]. Most studies of Ca mineralogical controls on As and Mo show that Ca minerals provide a minor control compared to Fe and Al minerals [5, 16 21-24]. Co-precipitation with barite (barium chloride is added to the neutralization processes to precipitate 226Ra) is an important mineralogical control on 226Ra [25, 26]. However, adsorption of 226Ra to ferrihydrite appears to be the dominant sequestration mechanism [26]. Co-precipitation of ferric arsenate and the adsorption of arsenate to ferrihydrite are major mechanisms of As sequestration [14, 17, 19]. Molybdenum is primarily removed from raffinate by outer-sphere complexation with ferrihydrite at low pH neutralization stages [21, 23, 27, 28]. Studies of mineralogical controls of dissolved Ni are less prominent than As and much of the data is only qualitative or semi-quantitative [5, 6, 15, 17, 18, 24, 28, 29]. There is a lack of literature on the removal of Se during the neutralization processes. Arsenic remaining in solution after the low pH stage forms bidentate adsorption complexes with amorphous Al(OH)3 and hydrotalcite at pH 9.5. Between 41% and 71% of adsorbed As in pH 9.5 precipitates is associated with these Al phases [13, 29]. In a final tailings slurry samples collected at pH 10.9, 59% of solid phase As was associated to Al phases (amorphous Al(OH)3 and hydrotalcite) and the remainder associated with Fe phases [29]. This distribution may be attributed the higher point of zero charge of Al-hydroxides relative to Fe-hydroxides, resulting in As desorbing from the ferrihydrite surface and re-adsorbing to the Al phases during the pH adjustment [30]. The dissolution of ferric arsenate could also be a source of As adsorption to Al phases. Most studies of EOC controls by Al and Mg minerals were determined on Key Lake samples [13, 28, 29]. As an example, Al was measured to control 5-25% of As at low pH stages (pH 4) through adsorption with amorphous AlOHSO4 (bidentate-binuclear bonds) [13, 28]. In a final tailings slurry sample collected at pH 10.9, 59% of solid phase As was associated to Al phases (amorphous Al(OH)3 and hydrotalcite) and the remainder with Fe phases [29]. Robertson et al. (2017) determined that Ni is controlled by amorphous Al(OH)3 and Ni-Al layered double hydroxide surface precipitates on the surface of hydrotalcite. This observation is in contrast to results from other studies of laboratory and in situ tailings that suggest Ni is predominantly controlled by adsorption to ferrihydrite or precipitation of theophrastite, annabergite, or cabrerite [15, 17, 18]. Long-term financial support for much of this work was provided by Cameco Corporation and the Natural Sciences and Engineering Research Council of Canada (NSERC) through a Senior Industrial Research Chair to MJH (grant 184573). Numerous individuals from our research group contributed to this body of work over many years. These include (but are not limited to): B. Moldovan, J. Bissonnette, K. Shacklock, R. Frey, S. Das, T. Bonli, J. Fan, J. Chen, R. Donahue, and Fina Nelson. Input from Areva Resources Canada is acknowledged. REFERENCES [1] SASKATCHEWAN MINING ASSOCIATION. URANIUM IN SASKATCHEWAN, http://www.saskmining.ca/uploads/general_files/24/uranium-fact-sheets-2014-final-iii-april-29.pdf (2016). [2] WORLD NUCLEAR ASSOCIATION, Nuclear Power in the World Today, http://www.world-nuclear.org/information-library/current-and-future-generation/nuclear-power-in-the-world-today.aspx (2016). [3] WORLD NUCLEAR ASSOCIATION, Uranium in Canada, http://www.world-nuclear.org/information-library/country-profiles/countries-a-f/canada-uranium.aspx (2016). [4] DONAHUE, R., Geochemistry of Arsenic in Uranium Mill Tailings, Saskatchewan, Canada, University of Saskatchewan (2000). [5] DONAHUE, R., HENDRY, M. J., LANDINE, P., Distribution of Arsenic and Nickel in Uranium Mill Tailings, Rabbit Lake, Saskatchewan, Canada. Appl, Geochemistry 15 (2000) 1097. [6] SHAW, S. A., HENDRY, M. J., WALLSCHLÄGER, D., KOTZER, T., ESSILFIE-DUGHAN, J., Distribution, Characterization, and Geochemical Controls of Elements of Concern in Uranium Mine Tailings, Key Lake, Saskatchewan, Canada, Appl. Geochemistry 26 (2011) 2044. [7] MAHONEY, J., LANGMUIR, D., GOSSELIN, N., ROWSON, J., Arsenic Readily Released to Pore Waters from Buried Mill Tailings, Appl. Geochemistry 20 (2005) 947. [8] IAEA, The Long Term Stabilization of Uranium Mill Tailings (2004). [9] JEFFERSON, C. W., THOMAS, D. J., GANDHI, S. S., RAMAEKERS, P., DELANEY, G., BRISBIN, D., CUTTS, C., PORTELLA, P., OLSON, R. A., Unconformity-Associated Uranium Deposits of the Athabasca Basin, Saskatchewan and Alberta, In EXTECH IV: Geology and Uranium Exploration Technology of the Proterozoic Athabasca Basin, Saskatchewan and Alberta; Jefferson, C. W., Delaney, G., Eds., Geological Survey of Canada, Bulletin 588 (2007) 23. [10] DEMOPOULOS, G. P., Aqueous Precipitation and Crystallization for the Production of Particulate Solids with Desired Properties, Hydrometallurgy 96 (2009) 199. [11] ROBERTSON, J., HENDRY, M. J., ESSILFIE-DUGHAN, J., CHEN, J., Precipitation of Aluminum and Magnesium Secondary Minerals from Uranium Mill Raffinate (pH 1.0–10.5) and Their Controls on Aqueous Contaminants, Appl. Geochemistry 64 (2016) 30. [12] ROBERTSON, J., SHACKLOCK, K., FREY, R., GOMEZ, M. A., ESSILFIE-DUGHAN, J., HENDRY, M. J., Modeling the Key Lake Uranium Mill’s Bulk Neutralization Process Using a Pilot-Scale Model, Hydrometallurgy 149 (2014) 210. [13] BISSONNETTE, J., ESSILFIE-DUGHAN, J., MOLDOVAN, B. J., HENDRY, M. J., Sequestration of As and Mo in Uranium Mill Precipitates (pH 1.5–9.2): An XAS Study, Appl. Geochemistry 72 (2016) 20. [14] ESSILFIE-DUGHAN, J., HENDRY, M. J., WARNER, J., KOTZER, T., Arsenic and Iron Speciation in Uranium Mine Tailings Using X-Ray Absorption Spectroscopy, Appl. Geochemistry 28 (2013) 11. [15] ESSILFIE-DUGHAN, J., HENDRY, M. J., WARNER, J., KOTZER, T., Microscale Mineralogical Characterization of As, Fe, and Ni in Uranium Mine Tailings, Geochim. Cosmochim. Acta 96 (2012) 336. [16] ESSILFIE-DUGHAN, J., PICKERING, I. J., HENDRY, M. J., GEORGE, G. N., KOTZER, T., Molybdenum Speciation in Uranium Mine Tailings Using X-Ray Absorption Spectroscopy, Environ. Sci. Technol. 45 (2011) 455. [17] LANGMUIR, D., MAHONEY, J., ROWSON, J., MACDONALD, A., Predicting Arsenic Concentrations in the Porewaters of Buried Uranium Mill Tailings, Geochim. Cosmochim. Acta 63 (1999) 3379. [18] MAHONEY, J., SLAUGHTER, M., LANGMUIR, D., ROWSON, J., Control of As and Ni Releases from a Uranium Mill Tailings Neutralization Circuit: Solution Chemistry, Mineralogy and Geochemical Modeling of Laboratory Study Results, Appl. Geochemistry 22 (2007) 2758. [19] MOLDOVAN, B. J., JIANG, D. T., HENDRY, M. J., Mineralogical Characterization of Arsenic in Uranium Mine Tailings Precipitated from Iron-Rich Hydrometallurgical Solutions, Environ. Sci. Technol. 37 (2003) 873. [20] MOLDOVAN, B. J., HENDRY, M. J., Characterizing and Quantifying Controls on Arsenic Solubility over a pH Range of 1 - 11 in a Uranium Mill-Scale Experiment, Environ. Sci. Technol. 39 (2005) 4913. [21] BLANCHARD, P. E. R., HAYES, J. R., GROSVENOR, A. P., ROWSON, J., HUGHES, K., BROWN, C., Investigating the Geochemical Model for Molybdenum Mineralization in the JEB Tailings Management Facility at McClean Lake, Saskatchewan: An X-Ray Absorption Spectroscopy Study, Environ. Sci. Technol. 49 (2015) 6504. [22] DONAHUE, R., HENDRY, M. J., Geochemistry of Arsenic in Uranium Mine Mill Tailings, Saskatchewan, Canada, Appl. Geochemistry 18 (2003) 1733. [23] HAYES, J. R., GROSVENOR, A. P., ROWSON, J., HUGHES, K., FREY, R. A., REID, J., Analysis of the Mo Speciation in the JEB Tailings Management Facility at McClean Lake, Saskatchewan, Environ. Sci. Technol. 48 (2014) 4460. [24] PICHLER, T., HENDRY, M. J., HALL, G. E., The Mineralogy of Arsenic in Uranium Mine Tailings at the Rabbit Lake In-Pit Facility, Northern Saskatchewan, Canada, Environ. Geol. 40 (2001) 495. [25] GOULDEN, W. D., The Geochemical Distribution of Radium-226 in Cluff Lake Uranium Mill Tailings, University of Saskatchewan (1997). [26] LIU, D. J., HENDRY, M. J., Controls on 226Ra during Raffinate Neutralization at the Key Lake Uranium Mill, Saskatchewan, Canada, Appl. Geochemistry 26 (2011) 2113. [27] BISSONNETTE, J. S., Sequestration of Arsenic and Molybdenum during the Neutralization of Uranium Mill Wastes: Key Lake Mill, Saskatchewan, Canada, University of Saskatchewan (2015). [28] GOMEZ, M. A., HENDRY, M. J., KOSHINSKY, J., ESSILFIE-DUGHAN, J., PAIKARAY, S., CHEN, J., Mineralogical Controls on Aluminum and Magnesium in Uranium Mill Tailings: Key Lake, Saskatchewan, Canada, Environ. Sci. Technol. 47 (2013) 7883. [29] ROBERTSON, J., ESSILFIE-DUGHAN, J., LIN, J., HENDRY, M. J., Coordination of Arsenic and Nickel to Aluminum and Magnesium Phases in Uranium Mill Raffinate Precipitates, Appl. Geochemistry 81 (2017) 12. [30] ADRA, A., MORIN, G., ONA-NGUEMA, G., BREST, J., Arsenate and Arsenite Adsorption onto Al-Containing Ferrihydrites. Implications for Arsenic Immobilization after Neutralization of Acid Mine Drainage, Appl. Geochemistry 64 (2016) 2.

Speaker: Prof. Jim Hendry (University of Saskatchewan)

152 REMEDIATION OF FORMER URANIUM MILL TAILINGS FACILITIES: CONCEPTS AND LESSONS LEARNED

INTRODUCTION Between 1946 and 1990 in total 216,300 t U were produced by mining and milling facilities in the Eastern part of Germany[1]. A Soviet and later Soviet-German-joint-Stock company was responsible for the uranium production in the German Democratic Republic prior to the German unification when uranium production was stopped due to economic and political reasons. As successor of the uranium mining company Wismut GmbH is responsible for the remediation of the legacies of these former activities in the densely populated areas of the German federal states Thuringia and Saxony. The remediation activities are funded by the Federal Budget due to a decision of the German Parliament Bundestag made in 1991 allocating a total budget of 6.2 billion € [1]. The remediation of the 4 biggest mill tailings facilities Helmsdorf, Dänkritz 1, Trünzig and Culmitzsch with a total ca. 160 Mio m³ of tailings stored at an area of 570 ha is part of this remediation project. Generally, the design of these tailings facilities was carried out not considering base sealing. The millings residues were dumped in former open pits where up to 57 m high dams were partly erected to create additional storage volume. The processing sludge was transported through pipelines to the tailings facilities and discharged predominantly from the outer rim of the ponds resulting in a separation of the material by grain size with fine particles mostly found in the centre of the ponds leading to variable geotechnical and geochemical conditions within the tailings facilities. At the Seelingstädt site as one of the two main milling sites processing was done using either an acidic or alkaline processing scheme which depended on the ore composition. The residues of these schemes were dumped separately resulting in 2 ponds within the two separate tailings facility Trünzig and Culmitzsch located at the Seelingstädt site. Tailings from acidic processing were neutralized before being discharged. While the works at the tailings facilities in Helmsdorf, Dänkritz 1 and Trünzig are nearly completed contouring and covering works at Culmitzsch are still ongoing. GENERAL REMEDIAL SOLUTION The remediation of the former tailings facilities follows the same general strategy while the particular technical solutions are adapted to the site specific conditions. Apart from the long-term geotechnical stabilisation of the tailings facilities remediation activities have to ensure that the additional equivalent dose rate to the general public from all pathways has to be below 1 mS/year according to the radioprotection ordinance [2]. First securing measures against acute risks were implemented starting in 1991 when the beach areas were covered with an interim cover to stop deflation of fine radioactive particles. In parallel additional effort was put in collection and treatment of contaminated waters. The mining and milling objects are situated in a densely populated area imposing a high risk to the general public. Based on a cost benefit analysis made in the mid 1990s the dry in-situ remediation was chosen as the general technical approach for stabilisation and final closure. The analysis was made based on the conditions of the Helmsdorf site where it was found that dry in-situ remediation is the most appropriate in terms of total costs among the potential remediation scenarios [3]. The dry in-situ remediation of tailings facilities requires a set of technological steps. Expelling supernatant water, interim covering and geotechnical stabilisation of the dams and the tailings are preconditions for a safe access to the site but require also an extended time frame. With sufficient bearing capacity contouring earthworks can proceed to gain a long-term stable morphology ensuring the safe discharge of surface waters and protecting the facility from erosion. A final cover on top of the contoured facility is required to control the infiltration of precipitation water and to ensure sufficient conditions for stable vegetation. This approach was generally adopted at all tailings management site under the responsibility of Wismut. The necessary activities as well as the status achieved e.g. at the Seelingstädt site are documented in more detail in [4]. An important aspect at all sites is the collection and treatment of seepage as well as contaminated surface and groundwaters. An extensive technical system including treatment plants utilising lime treatment is available at all sites. This water collection and treatment system is expected to be necessary also in the long-term to ensure capturing contaminated waters irrespective of the individual remediation solution. SITE SPECIFIC APPROACH While the general remediation approach is implemented at all sites a number of differences can be found locally due to site specific conditions. The differences mainly consider the requirements for reduction of the infiltration of precipitation into the deposited tailings material which are defined specifically for each site. Especially at the Thuringian site in Seelingstädt the covering concepts were intensively discussed between Wismut and the permitting authorities which were supported by a consultant providing an extensive peer assessment. As a result of this time consuming process basic requirements for planning of the final contour and cover of the tailings facilities were established. This has led to differences in the cover concepts followed at the different sites but also at the single facilities themselves. The main focus in determining the site-specific cover concept was the expected long-term contaminant release from the sites. It was found that this release very much depends on the properties of the tailings material itself and therefore varies widely over the facility. Another important factor was the availability of appropriate contouring and cover materials at the individual sites. Preference was given to locally available materials. Mine waste rocks and processing residues available from former mining activities were used for contouring and partly as cover material depending on the radiological composition and technical requirements. This allowed reducing the mining induced footprint at the sites and the import of material from other sources. On the other hand it required an adopted logistics to supply the materials with the required geotechnical and radiological characteristics depending on the respective remediation progress. At the Seelingstädt site tailings were disposed in former uranium open pits. A part of the waste rock material from the overburden here is to be classified as radioactive material. Material with elevated radiological content was used for contouring while the cover was constructed using waste rock material with specific activity less than 0.2 Bq/g or material from external sources. At the Seelingstädt site the reduction of the infiltration rate was at a special focus. In contrast to the implementation of the evaporative cover concept at other Wismut tailings management sites with a storage layer as the main functional layer the cover system at the Culmitzsch tailings facility is far more complex. By adapting the final contour offering steeper and shorter slopes as well as constructing an additional sealing and drainage layer the predicted infiltration rate is reduced by more than 75 % compared to the original mainly evaporative cover concept. In addition to more specific material requirements for the various functional layers the effort for implementation of such a cover system increased considerably. Therefore, this cover system is implemented only on top of the more sandy tailings beaches with a higher hydraulic conductivity over the tailings profile. The areas with finer tailings will have significantly lower hydraulic conductivities in long term when compaction and pore water release will be finished. This process is enforced by additional drainage measures in line with contouring to generate a long term stable tailings surface and to achieve the sealing properties of these layers. As consequence of this self sealing the seepage rates are reduced more significantly as it could be achieved in the long term by a highly engineered cover system. This allows to take credit while constructing the final cover on these parts with less stringent requirements for the infiltration rates to be achieved in the long term. PRESENT AND FUTURE CHALLENGES With construction works coming to an end the harmless surface water run-off has to be ensured in the long-term. This has to consider the quality and quantity of the waters released from the former tailings facilities. While the retention of the impact of heavy rainfall events is an important design criteria for the contouring as well as additional measures of temporary storage of runoff waters the compliance with the requirements for the water quality have to be proven for the surface as well as seepage waters. Management of newly developed landscape at the sites is required even after the end of the construction works. A landscape development concept is one of the requirements for the necessary permits covering nature conservation aspects, too. This concept defines the after-use while allocating areas as open grass land or for forestry. The implementation of the landscape development concept is a lengthy process and requires effort for the necessary management and maintenance. This is essential even with the main concept of a close to nature development of the sites but with the pre-defined nature conservational prospects to be achieved based on the permitting documents. Water collection, treatment and residual storage is a task extending over the end of the construction period. Irrespective a successful implementation of the remediation activities at the site a necessity of water treatment is clearly expected due to the long-term release of pore water from static sources in the tailings facility as well as the remaining inflow of water to the deposited tailings material. In addition groundwater with elevated concentrations in the aquifers is found downstream of the tailings influenced by seepage waters during the uranium production period. The concentrations will decrease slowly due to limited inflow from the covered tailings facility and its immediate surroundings. Over a long period uranium was in the main focus concerning the contaminant release. Meanwhile salt load becomes more of a concern. While treatment of waters for uranium in seepage waters is state of the art and could be implemented effectively reduction of salt content faces technological and economic challenges especially in terms of a long-term stable storage of the residues. There is no feasible technological option available under the present site conditions. Because of continuous tightening of the environmental standards and requirements additional long-term effort will be needed over the time frame of the remediation works at the site itself. After finishing the construction works environmental monitoring and maintenance is required due to the provisions made in the permitting process. On one hand the remediation success has to be demonstrated. Otherwise the achieved status after remediation has to be ensured by regular maintenance of the constructed elements. While simple cover systems solely based on a sealing and evaporative cover concept should show a natural behaviour adjusted to the specific site conditions for other engineered elements with specific functions as drainage or water discharge a potential deterioration has to be avoided and maintenance is required for the eternity. DISCUSSION AND CONCLUSIONS Operation of uranium mill tailings storage facilities impacts not only the radiological conditions at the site but also other environmental media. Remediation faces complex requirements aimed at reduction of potential risks and present impacts in combination with the need to stimulate the long-term use of the site under strict economic constraints. As the examples of the legacies of former mining and milling sites show a sound closure concept defining the status to be achieved after operation is not just necessary for the mining permits but also essential baseline for the operator. However the time frame of remediation activities clearly extend over the period of construction works and has to be considered in terms of effort and costs at an early stage of the planning procedure. These long-term activities in most cases comprise monitoring and maintenance especially at sites with radiological hazards but can also require a costly water management and treatment. A sound funding for these activities has to be ensured. REFERENCES [1] LEUPOLD, D., PAUL, M., „Das Referenzprojekt Wismut: Sanierung und Revitalisierung von Uranerzbergbau-Standorten in Sachsen und Thüringen“ (The reference project Wismut: Remediation and re-vitalisation of uranium mining sites in Saxony and Thuringia), In Proceedings: Internationales Bergbausymposium Wismut (2007) 21-30. [2] BARNEKOW, U., ROSCHER, M., BAUROTH, M., MERKEL, G., VOSSBERG, M., “Conception for Diversion of Runoff – Implementing the Trünzig Uranium tailings pond into the regional catchment area”, In MERKEL, B., Schipek, M., “The New Uranium Mining Boom – Challenges and lessons learned” (Proc. Conf. Freiberg, Germany) (2011) 299-306. [3] PELZ, F., JAKUBICK, A.T., KAHNT, R., “Optimising the remediation of sites contaminated by Wismut uranium mining operations using performance and risk assessment”, Post-Mining 2003, (Proc. Conf. Nancy, France) (2003). [4] BARNEKOW, U., METSCHIES, T., MERKEL G., PAUL, M., “Remediation of Wismut's uranium mill tailings pond Culmitzsch - progress achieved and challenges ahead”, Mine Closure 2015 (Proc. Conf. Vancouver, Canada) (2015) 251-262

Speaker: Mr Thomas Metschies (Wismut GmbH)

153 ENVIRONMENT ASPECTS OF Th-230 ACCUMULATED IN RESIDUES COMPONENTS AT THE URANIUM PRODUCTION LEGACY SITE PRIDNEPROVSKY CHEMICAL PLANT

INTRODUCTION This paper presents the results of recent studies carried out at the former Uranium production facility Pridneprovsky Chemical Plant (PChP) in Ukraine and describes specific activity concentrations of radionuclides of U-Th decay series with specific focus on identified high activity concentrations of 230Th associated with different environment compartments, such as soils, aerosols, bottom sediments and U-production residues accumulated in the tailings and uranium extraction facilities remained at the PChP site. The Production Association “Pridneprovskiy Chemical Plant” (PChP) was one of the largest facilities of the military complex of the former Soviet Union, where production of uranium for the Soviet atomic programme was carried out starting in 1949 till 1992. The plant is situated in a densely populated area in the industrial zone of Kamyanske town (formerly Dniprodzerzhynsk) and close located to the Dnieper River. The processing procedures for uranium ores at the “PChP” were typical for technologies used in the former USSR, including grinding, hydrometallurgical extraction, sorption, radiochemical separation and purification of U-concentrate from radium and thorium impurities. Sulphuric and nitric acid were used for leaching of the uranium containing ores of different origin from deposits located in Ukraine and also Germany and Check republic. Since 1984 the phosphorus ore from Kazakhstan (Melovoe deposit), containing uranium were processed as well. The phosphorus ore processed at the site are considered as a main source of thorium-230, which currently dispersed at the PChP site. Since 1992, when PChP uranium industrial production complex was ceased, no measures have been taken to decommission and remediate uranium production facilities. The ambitions remediation planning activities were initiated during recent years with financial assistance of EC and funded by also several national remediation projects. In order to provide safety assessment and collect data for remediation planning the extended site characterization and monitoring programs were carried out at the PChP legacy site during recent decade, including detailed spatial gamma-dose survey and assessment of contamination status of the environment by radionuclides of U-Th decay series and safety conditions at the uranium tailings facilities [1]. Specific interest to the specific activities and chemical speciation of 230Th at this site was determined by presents of huge amount of thorium containing materials at the site (up to 6 ton of thorium concentrate produced annually due to uranium ore purifying process) and its relatively high activity concentrations observed at the many locations of PChP site, which is exceeding level of exclusion from regulatory control such as 1Bq per gram, as well as its high radio-toxicities in the environment. METHODS AND RESULTS The methods used in this study consist of several components such as: historical analyses of the technologies, which determined existing state of thorium-230 in a complex of other radionuclides of U-Th series and its physical and chemical speciation in the affected environment; application of analytical methods used for determination of thorium isotopes and other radionuclides of U-Th decay series in soil, aerosols and tailings material samples using modern gamma and alpha-spectrometry methods with radiochemical supporting procedures [2] and also dose assessment methodology, providing site specific safety assessment and estimating contribution of thorium presence in the present safety conditions forming at the legacy site and remediation strategy planning. Methods for remediation of the high contaminated environment as well as strategy for management of remediation wastes containing thorium and other radionuclides of 238U decay series are discussed as well. Determination of the radioactivity of thorium isotopes in different environmental entities such as soil spill and sludge materials, dust, bottom sediment and water samples, which were collected at the PChP legacy site, have been carried out in the frame of state remediation and site specific monitoring projects. In general, activity concentrations of thorium isotopes (230Th, 234Th, 232Th, 228Th) were quantified by gamma spectrometry analysis, using a high purity Germanium detector coaxial n-type HP Ge detector GMX (Ortex) with 40% relative efficiency and resolution of 1.8 keV for 1,332.5 keV 60Co energy. The detector efficiency was determined using a mixed standard solution of known activity containing 152Eu, 241Am, 226Ra in fixed sample geometry. The emission gamma spectrum was analysed using GammaVision32 application software in according to UNI 10797:1999 with sealing the beaker. The concentrations of 230Th were measured directly from their gamma peak at 67.67 keV with emission probabilities 0.38%. Activity 234Th daughter radionuclide of the 238U was determined by its gamma peaks at 63.29 keV with emission probabilities of 3.7 %. For the determination of 232Th, assuming secular equilibrium in the sample, the gamma lines of 911.2 keV, 338.4 keV with emission probabilities of 26 %, 11 %, respectively. The calibration quality control was carried out by means of a soil standard sample SRM (IAEA-434), IAEARGU-1 and IAEA-RGTh-1 whose concentrations of the main natural radionuclides have been certified by the IAEA in the same geometry the measurement. Quality checking of determination of Th isotopes in the UHMI laboratory has been regularly tested by IAEA Proficiency Tests (for instance as it was published in IAEA-CU-2008-03: “Determination of naturally occurring radionuclides in phosphogypsum and water”). To verify the accuracy of the determination of 230Th and other thorium isotopes by gamma spectrometry the alpha-spectrometry method with radiochemical pretreatment was used. Radio-analytical procedures consists of chemical dissolution of samples, chemical separation of thorium by ion-exchange method, preparation of counting source by electro-deposition method and measurement of thorium by alpha spectrometry method. Thorium in water sample was separated by co-precipitation method. For determining the chemical yield the 229Th tracers were used. The relative errors were lower than 20 % between both analytical techniques used. The basic set of monitoring data collection and site characterization analyses carried out in UHMI during recent decade, contains long-term time series specific activity concentrations of radionuclides of U-Th decay series (such as: 238U, 234U, 230Th, 226Ra, 210Pb, 210Po), containing in the U-ore raw materials, production residues and contaminated environment at the site, which may vary in wide range between less of 1.0 Bq/g to 3-4 thousands Bq/g. Special attention in this study is given to the analyses of spill and sludge materials, containing high activity concentration of thorium, which are in large amount still accumulated in some buildings used for thorium removal and at the sludge pond accumulating complex compound of the thorium fractions before its transportation to the storage facility. Since different technologies used for purifying uranium concentrates from thorium impurities have been applied, different concentrations of thorium are contained in various objects of the uranium production legacy site, which vary from several Bq/g to hundreds of Bq/g in the environment. The background activity concentrations of 230Th outside of PChP site vary in range 0.04-0.07 Bq/g. High activity concentrations of 230Th were found in many locations of the PChP legacy site and in particular in soils and also spill materials accumulated in the former U-extraction facilities and buildings used for removal and purifying of uranium concentrates from thorium contained impurities. In many locations high 230Th activities were observed in the residue production in range between several tens to several hundred Bq per gram. In some locations the horizons of soils with highest 230Th activities concentrations are located at the soils top surface, while at other places the layers with maximal activities are covered with clean soils with relatively low contamination and radionuclides of U-Th series identified on a depth up to 1.5 m. Results of vertical profile studies of radionuclide U-Th series of different origin are discussed in this report. The ratios between 238U, 230Th and 226Ra in soils at the different locations, which may characterized the impacts of the uranium production residue by different origin and technologies applied for purifying uranium containing ores are presented in paper as well. Sufficient amount of residue materials from U-production, containing high activity concentrations of 230Th, were identified at several cells of sedimentation sludge ponds. In the lower layers of sludge materials accumulated in sedimentation pond, specific activities of thorium-230 were found in range from 10 to 170 Bq/g. Other naturally occurring radionuclides in the most of samples taken from the sludge columns were characterized by specific activity in range value 1Bq/g and less. Some by-products of uranium productions, containing thorium need for defining the regime of regulatory control, because thorium in sufficiently high activities identified in some NORM product, produced at the site is a significant limiting factor in further use of these materials. The surface layer of sludge in sedimentation pond also has high levels of radium-226 and other radionuclide and chemical pollutants. Specific activity concentration in the spill materials remained on the floor and in some filled tanks with dry residue of the complex radiochemical solutions 226Ra activity concentration may reach several hundred Bq per gram of dry samples. In the spill materials of “yellow cake” production found in several locations of the Building 103 high concentrations of Uranium were dominated reaching several thousand Bq per gram of dry samples and relatively low 230Th activity concentrations. Specifically high activity concentrations of 230Th in spill materials were found in several locations of Building 104m which was used for thorium removal from phosphorus ores. Specific activities of 226Ra and 210Pb in such spill materials varied in relatively low value range from 2-3 Bq/g up to 20-30 Bq/g. The same samples were characterized Th-232 in range of activity concentrations between 2,3-4.4 Bq/g. In spite of relatively low activity concentration of uranium and radium isotopes were found, 230Th activity concentrations in such spill materials are reached in some locations 200-600 Bq/g. Such dispersed materials presented in the dust fractions and having very high thorium activity concentrations comparing with exemption level such as 1Bq/g, may pose a significant risk of inhalation exposure for remediation workers. Therefore detailed radiation protection plan and possible decontamination of these buildings before dismantling of most contaminated equipment and demolishing are strictly required. The levels of Th-230 activity concentration in aerosols were measured just in limited number of samples collected in the contaminated buildings and at the surrounding areas. The results of the measurements showed that in the buildings where the uranium concentrate from phosphorus ore was purified, the content of thorium in dust and aerosols exceeded the activity of uranium and radium by 10-100 times. In other buildings of uranium extractions after leaching and purifying, the thorium-230 in the production residues and tailings materials were found in much more lower activity concentration with domination of radium-226. The variety of conditions and forms of radionuclides of uranium-thorium series at various sites of uranium production heritage determines also the variety of radiological risks of irradiation for personnel in the territory of the former uranium production. At most sites and sites of the uranium object, the main contribution to the radiation dose is determined by direct gamma irradiation, which is mainly formed by radium 226. The averaged doses for 1 hour presence in the most contaminated facilities were estimated in wide range between 3-10 μSv/h (at the locations with low concentration of the radioactive residues) and up to 1 mSv/h in some buildings near tanks where high activity concentrates of 226Ra in the residues is still stored. The main dose factor in such buildings is high gamma dose rate. In the facilities characterized by high thorium-230 contamination, the highest doses were created by gamma dose exposure as well and also relatively high Rn-222 ambient activity air concentration. In general contribution of inhalation exposure due to aerosol particles containing radionuclides of U-Th series is estimated as no more than 10% of the total exposure dose. However in some specific cases maintenance with spill materials contained thorium with high activity concentrations in spill and dust materials may created sufficient inhalation dose exposure for remediation workers. In previous assessments at the stage of the safety assessment, it was assumed that the uranium, radium and thorium contents in dust and aerosols are approximately equilibrium. In fact, as has been shown by our investigations, the content of thorium-230 in dust and materials that can form aerosol contamination in some buildings and in storage facilities for the residues of thorium concentrates can be tens and hundreds of times higher than for equilibrium conditions. Therefore, the dose estimates of inhalation exposure, which were obtained at the stage of rehabilitation measures planning, taking into account the high radio-toxicity and dominance of thorium in some former uranium production facilities, can be significantly underestimated. The results of assessment and actions proposed to reduce risks are discussed as well. REFERENCES 1. Lavrova T., O. Voitsekhovych. (2013). Radioecological assessment and remediation planning at the former uranium milling facilities at the Pridnieprovsky Chemical Plant in Ukraine. Journal of Environmental Radioactivity, 115, 118-123. 2. Godoy, J. M., Lauria, D. C., Godoy, M. L. D., & Cunha, R. P. (1994). Development of a sequential method for the determination of 238U, 234U, 232Th, 230Th, 228Th, 228Ra, 226Ra, and 210Pb. in environmental samples. Journal of Radioanalytical and Nuclear Chemistry, 182(1), 165-169.

Speaker: Mr Oleg VOITSEKHOVYCH (PhD)

154 The Removal of Radiation and other Impurity from Copper Sulphide Concentrates

INTRODUCTION High-grade, copper sulfide concentrates, (typically greater than about 25% w/w Cu), are commonly treated via pyrometallurgical routes, while hydrometallurgical routes are typically favoured for lower grade or impurity bearing concentrates. The processing routes for the treatment of copper concentrates can also be influenced by the presence of minor valuable metals such as silver, gold, uranium, palladium and platinum, as well as deleterious metals such as nickel, cobalt, lead and zinc. Many copper iron sulfide concentrates contain radioactive uranium and its daughters. Other elements such as zinc, nickel, cobalt and aluminium also add to the impurity load. This paper addresses a process that has been successfully demonstrated to remove very significant levels of the radioactivity whilst at the same time upgrading the concentrate so that it attracts reduced transport and treatment costs at smelters. The upgraded concentrates have demonstrated that they satisfy the IAEA Regulations for the Safe Transport of Radioactive Material (2012) (SSR-6) for the transport, trade and processing thereof. IMPURITY REMOVAL APPROACH The objective of radionuclide and impurity removal is to produce a smelter quality copper-iron-sulfide concentrate which can be sold, transported across borders and smelted with zero harm. To minimize the prospect of attention at border crossing or port, the concentrate should contain no more than 0.3 to 0.4 Bq/g for 238U, 230Th and 226Ra and no more than 0.8 to 0.9 for 210Pb and 210Po. The radionuclides removed can be disposed with the concentrator tailings in appropriately lined tailings storage facility. Impurities are invariably locked within the valuable mineral particles. If not locked, they would typically be separated in the flotation process. It is postulated that where the mother (238U) resides, the daughter products, resulting from decay over long time periods, are in close proximity and so if a pathway can be developed to remove the mother (238U), then the same pathway could be exploited to access the daughters. In addition, the superficially transformed nuclides of 210Pb, 210Bi and 210Po possibly exist in different chemical form to those same nuclides locked in the sulfides minerals. The concentrate leach in a combined sulfate and chloride lixiviant provides not only the opportunity for radionuclides removal but also the removal of other penalty elements such as nickel, cobalt, lead and zinc. Additionally, the copper concentrate is upgraded resulting in a lower mass “super concentrate’’ being made and hence this will reduce the concentrate transport costs. In some cases, with this mass loss, silver can be rendered “payable” in the upgrade process. If the removal of radionuclides is not required, then a more targeted concentrate leach in a sulfate lixiviant can be applied. IMPURITY REMOVAL MECHANISM Early work was conducted in South Africa [1]. It was recognised at the time that the only way for an upgrade to be effective and majority of the copper and sulfur to remain unleached was to adopt the classical metathesis and hydrothermal approach [2][3][4] employed in some Southern African autoclave systems. The hydrothermal mechanism is kinetically slower than the preferred metathesis metallurgy. As in the case of the metathesis mechanism, the hydrothermal step also requires a mild oxidant for it to be effective. Metathesis is an electrochemical process in which the soluble cupric cation exchanges for a more electronegative element in the concentrate. For example in the case of iron, the more electronegative element, is solubilised while the copper cation is received into the concentrate matrix in a reduced form. These two mechanisms create pathways into the mineral structure for the other locked elements to escape. Mineralogically, the mineral metathetic alteration commences as a “rimming” effect in which covellite (CuS) is formed and thereafter further sulfur depletion ensues to form chalcocite/digenite minerals. Depending on the copper activity in the aqueous phase, sulfur depletion (oxidation) and hence final copper in concentrate grade can be influenced. The use of a combined sulfate and chloride lixiviant is suited for the mobilisation and extraction of other elements that have preferred sulfate or chloride lixiviation metallurgy. The hydrothermal alteration of chalcopyrite is thought to proceed in a different manner. The chalcocite layer once nucleated in the hydrothermal process moves both outwardly and inwardly to convert chalcopyrite to covellite. However, the total conversion to chalcocite may not be economic and consequently, the process is normally terminated with covellite being the dominant mineral in the alteration process [6]. To permit treatment and to maximise the value of a copper concentrate, the levels of impurities in the concentrate needs to be reduced below the limits set by the smelters and in some cases the authorities in the producing and receiving countries. This paper presents a method of impurity (specifically radionuclides) removal for copper concentrates. CHEMISTRY Copper concentrates are upgraded via the metathesis process in an autoclaving step called Nonox (a mildly oxidative high temperature environment). Typical chemistry of the upgrade are as shown in equation 1 and 2 below. Eq 1 : 3CuFeS2(s) +6CuSO4(aq) +4H2O(l) → 5Cu1.8S(s) + 3FeSO4(aq) + 4H2SO4(aq) Eq 2 : Co3S4(s) +4CuSO4(aq) + H2O(l) → 3CoSO4(aq) + Cu4S3(s) + S°(s) + H2SO4(aq) The possible chemical reactions for the alteration of other non-sulfide impurities in the concentrate leach are described in equation 3 to 8 below. In sulfate only lixiviant, 238U and 230Th are able to be removed to a level below 1 Bq/g in the copper concentrate. In addition, impurities such as cobalt and nickel are removed. In chloride only lixiviant, there will be no transformation. In sulfate and chloride lixiviant, 238U, 230Th, 226Ra, 210Pb, 210Bi can be removed to a level below 1 Bq/g and to a level below 2Bq/g for 210Po. Eq 3 : Uranium : UO2(s) + 2CuSO4(aq) + 2H2SO4(aq) ↔ H4(UO2)(SO4)3(aq) + Cu2SO4(aq) Eq 4 : Thorium : ThSiO4(s) + 2H2SO4(aq) ↔ Th(SO4)2(aq) + 2H2O(l) + SiO2(aq) Eq 5 : Radium : RaSO4(s) + 2NaCl(aq) ↔ RaCl2(aq) + Na2SO4(aq) Eq 6 : Bismuth : Bi2(OH)2(SO4)2(s) + 6NaCl(aq) +H2SO4(aq) ↔ 2BiCl3(aq)+ 3Na2SO4(aq) + 2H2O(l) Eq 7 : Lead : PbSO4(s) + 4NaCl(aq) ↔ Na2PbCl4(aq) + Na2SO4(aq) Eq 8 : Polonium : Po(s) + 2Na2CuCl4(aq) ↔ Na2PoCl4(aq) + 2CuCl(aq) + 2 NaCl(aq) FLOWSHEET The principal reagents required in the concentrate treatment flowsheet are a copper ion source, water, sodium chloride (salt) and elevated temperature. In a typical [5] two stage autoclave flowsheet, the copper concentrate to be upgraded is repulped in recycled brine before it is fed into the Nonox leach autoclave. The copper ions required in Nonox are supplied from a separate close-coupled oxidative Copper Pressure Leach (CPL) autoclave. A portion of the Nonox product is employed in a CPL autoclave which under oxidative conditions is autogenous in temperature. Steam is injected into the Nonox autoclave to control the autoclave at approximately 210°C. Typical conditions in the Nonox autoclave are as follows: • 2 to 3 hours leach time • 15-30% w/w concentrate in the autoclave feed slurry • Greater than 35g/L chloride in Nonox with a Chloride/Sulfate ratio >0.3 • 2500kPa(g) • 250 to 280 mV and pH of 0.7 to 1.2 The Nonox autoclave discharges into a flash tank. The Nonox discharge slurry is filtered and the filtrate is transferred to the barren liquor treatment circuit for treatment while the filter cake is repulped in clean water. In the event where it is economical to recover uranium and thorium as by product, the filtrate from the Nonox discharge filter can be treated through a Continuous Ion Exchange unit where uranium and thorium can be recovered. The barren liquor from the ion exchange is then processed to recover the brine. A portion of the repulped Nonox product is fed to the CPL autoclave while the remainder is treated in scavenging atmospheric leach (SAL) to further remove 226Ra, 210Pb and 210Po. In the SAL, the concentrate is treated with a two-stage alkali - acid sodium chloride lixiviant. The product from the scavenging atmospheric leach is filtered to produce the final copper concentrate product and the SAL filtrate is incorporated in the barren liquor treatment circuit. In the barren liquor treatment circuit, the Nonox filtrate is treated using limestone to precipitate the dissolved iron and radionuclides. The barren liquor treatment discharge slurry is then filtered and the filtrate is recycled to the concentrate repulp. The barren liquor treatment residue contains iron and gypsum and essentially all the impurities including radionuclides that were leached in the Nonox autoclave. The filter cake could be disposed in the concentrator tailings facility. In a preferred variant of the flowsheet a single stage autoclave can be employed to replace the two stage Nonox plus CPL. In the Single Stage Autoclave, a strong oxidative leach is undertaken on the concentrate in the early compartments of the autoclave to produce the cupric lixiviant and this then passes to a mildly oxidative final section of the vessel. These Single Stage autoclaves have been employed in similar duties in Europe and Africa and are not without precedent. RESULTS The copper concentrate treatment process has been able to reduce the radionuclides and other impurities to lower levels. A summary of impurity removal and upgrade results for secondary copper sulfide concentrates was as follows: • 238U level reduced from 1.4 Bq/g to 0.12 Bq/g. • 230Th level reduced from 1.5 Bq/g to 0.56 Bq/g. • 226Ra level reduced from 0.99 Bq/g to 0.73 Bq/g. • 210Pb level reduced from 6.4 Bq/g to 0.35 Bq/g. • 210Po level reduced from 7.0 Bq/g to 0.62 Bq/g. • Copper in the concentrate feed was simultaneously upgraded from 48.6% to 56%. • The feed concentrate contained the following copper minerals: bornite (39%), chalcocite (32%), chalcopyrite (13%) and pyrite (8%). • The upgraded concentrate contained predominantly of chalcocite/digenite (64%), covellite (17%), Pyrite (7%). Primary concentrates displayed a similar trend in radionuclide and other impurity element removal in a Two Stage Leach. However, there was a more significant upgrade in copper in the primary concentrate compared to secondary concentrates: • Copper was upgraded from 28% to 60% consisting primarily of chalcocite (82%), pyrite (10%) and idaite (7%) • Chalcopyrite (57%), pyrite (24%) and bornite (14%) were the dominant minerals in the feed concentrate. In a Single Stage Autoclave Leach a primary concentrate was upgraded as follows: • Copper from 28% to 59%. • Silver from 20ppm to 43ppm. • Gold from 13.5ppm to 25ppm. • The product concentrate contained predominantly chalcocite (46%), covellite (29%) and pyrite (19%) with a mass loss of approximately 50% and no loss of gold and silver. DISCUSSION AND CONCLUSION The concentrate treatment process has the potential to reduce radionuclides 238U, 230Th, 226Ra, 210Pb, 210Bi to a level below 1 Bq/g and to a level below 2Bq/g for 210Po. In addition to radionuclides, other impurities that may attract penalties at the smelters such as nickel, cobalt and lead are also removed in the concentrate treatment process. Economically recoverable uranium can be recovered as by-product employing ion exchange. Simultaneously, the copper in the final concentrate is raised to 55-60%. This upgrade and hence mass reduction results in reduced transportation and treatment costs. Most importantly, there are minimal copper and silver losses. Gold losses are negligible. REFERENCES [1] Private communications from GM Dunn, Hydromet Pty Ltd. [2] Jang, J.H. and Wadsworth, M.E., Hydrothermal Conversion of Chalcopyrite Under Controlled EH and pH, The Paul E.Queneau International Symposium Extractive Metallurgy of Copper, Nickel, and Cobalt, Volume 1: Fundamental Aspect, The Minerals, Metals and Materials Society, 1993. [3] Vinals, J et. al., Transformation of Sphalerite Particles into Copper Sulfide Particles by Hydrothermal Treatment with Cu(II) Ions, Hydrometallurgy Volume 75, 2004 [4] Peterson, R.D. and Wadsworth, M.E., Enrichment of Chalcopyrite at Elevated Temperatures, EPD Congress, 1994. [5] Dunn, G.M. et.al., Truncated Hydrometallurgical Method for the Removal of Radionuclides from Radioactive Copper Concentrates, Australian Provisional Patent Application 2015904596, 2015. [6] Weidenbach, M, Dunn, G., and Teo, Y Y., Removal of Impurities from Copper Sulfide Mineral Concentrates, Alta Conference, Australia, 2016.

Speaker: Mr Grenvil Dunn (Orway Mineral Consultants (WA) Pty Ltd)

155 HYDROMETALLURGICAL CONTROLS ON ARSENIC, MOLYBDENUM AND SELENIUM IN URANIUM MILL EFFLUENT AND TAILINGS

INTRODUCTION Contamination of groundwater and surface water by arsenic, molybdenum and selenium derived from both natural and anthropogenic sources is an issue of global concern. Uranium-bearing ore material often contains all three of these elements of concern. Sulphuric acid leaching of these ores results in liberation of arsenic, molybdenum and selenium. In the hydrometallurgical process for uranium purification and concentration these elements must be separated from uranium either via solvent extraction or ion-exchange processes to achieve the required product quality for uranium ore concentrate. Often, these elements are of little or no economic value to the operator. As a result, arsenic, molybdenum and selenium are treated with the waste streams and must be removed prior to re-using the water in the process (to avoid a circulating load) or release of treated effluent to the receiving environment. As, Mo and Se (among other elements and radionuclides) removed from the uranium mill process waste water are often combined with the mill tailings and the final mill tailings are ultimately emplaced in engineered tailings management facilities. It is imperative that the precipitated As, Mo and Se are geochemically stable and do not dissolve in the tailings management facility as transport of As, Mo or Se from the tailings facility to the local groundwater or surface water system has the potential to negatively impact the regional biota. It is therefore important for uranium processors to have well-defined and effective effluent treatment processes. In addition, the operational process must ensure geochemical stability of elements emplaced in the engineered tailings management facility. DESCRIPTION The Key Lake uranium mill is located approximately 650 km north of Saskatoon, Saskatchewan, Canada. The climate is sub-arctic with a mean annual temperature of 4 °C (ranging from -45 to 25 °C) [1]. The mill is located within the Athabasca Basin which contains the world’s richest uranium deposits. The Key Lake mill began production in 1983 and two open pit mines were mined from 1983 to 1997. Stockpiled ore continued to feed the mill from 1997 to 1999 and in 1999 the Key Lake mill began to receive ore from the McArthur River mine located approximately 80 km to the north of the Key Lake mill [2]. The Key Lake mill blends the high-grade ore from the McArthur River mine (~18% U308 wt/wt) with low grade (~0.2% U3O8 wt/wt) material stockpiled at the Key Lake uranium mill. The resulting leach feed slurry head grade is about 5% U3O8. Leaching of the leach feed slurry takes place in agitated leach tanks where sulfuric acid and oxygen are added along with steam. Retention time is approximately 24 hours and the resulting uranium recovery averages 99.2%. Following the leaching process the undissolved sandstone material is separated from the leach aqueous solution in a series of eight thickeners. Acidic wash water is introduced in a counter current fashion to wash adsorbed uranium from the leach residue solids. This occurs at each stage of thickening. The resulting leach aqueous solution is then fed to the solvent extraction (SX) circuit where the uranium is purified and concentrated. The resulting purified and concentrated uranium-bearing loaded strip solution is then forwarded to the yellowcake precipitation circuit where the uranium is precipitated as ammonium diuranate. The ammonium diuranate precipitate is thickened, washed, dewatered and then calcined at 850 °C to produce a jet-black free flowing uranium oxide powder. The uranium-free waste aqueous solution from the SX process (raffinate) contains the dissolved metals (including As, Mo, Se) and radionuclides liberated in the leaching process. This solution is forwarded to the effluent treatment process and mixed with other process waste waters. The mixture of waters is progressively neutralized with lime in a series of four pachucas with target pH of 1.2, 3.5, 6.5 and 9.5 [3]. Barium chloride is also added at the second stage of neutralization to co-precipitate Ra-226 as Ba/Ra-SO4. The chemical precipitates formed in this neutralization series are settled in a thickener. The overflow solution is pH adjusted with dilute acid to a target pH of 6.2. The solution is forwarded to a final clarifier before being transferred to monitoring ponds for analysis and certification before being released to the environment. Off-spec treated effluent is redirected to a contaminated water reservoir and reintroduced to the effluent treatment circuit for reprocessing. This effluent treatment scenario resulted in removal efficiency for As, Mo and Se of 99.8%, 21% and 19%, respectively. Correspondingly, the average daily concentration of As, Mo and Se in the Key Lake mill final effluent was 0.006 mg/l (n=81; Range = 0.003 to 0.017 mg/l; Standard Deviation = 0.002), 0.74 mg/l (n=81; Range = 0.27 to 1.8 mg/l; Standard Deviation = 0.27) and 0.073 mg/l (n=81; Range = 0.052 to 0.094 mg/l; Standard Deviation =0.010), respectively. This resulted in average annual loadings of As, Mo and Se of 9 kg/y, 1,110 kg/y and 110 kg/y, respectively to the downstream receiving environment. Environmental studies in the downstream receiving environment of the Key Lake mill effluent concluded that Mo and Se could have an impact if loading of these elements to the lake sediments was not reduced. Arsenic, at the annual current loading, was determined to not be having an impact on the downstream receptors. The environmental studies further concluded that if annual loadings of Mo and Se remained below 600 kg and 40 kg respectively, the long-term impact would be reduced to a level that was in keeping with the original environmental impact statement for the Key Lake mill. Therefore, technical and operations personnel were required to enhance the current effluent treatment process to increase the removal efficiency of Mo and Se while at the same time not increasing the loading of As (or other elements of concern) to the environment. In an effort to increase the removal efficiency of Mo and Se and subsequently reduce the concentrations of the elements in the mill final effluent several treatment options were evaluated and tested. These options included: • Reverse osmosis • Ion exchange • Co-precipitation of oxy-anions with ettringite • Reduction and adsorption with zero valent iron • Microbial reduction • Photocatalytic reduction using UV Light and TiO2 • Adsorption of oxyanions to ferrihydrite followed by gypsum encapsulation The criteria for testing and ultimately selecting a treatment option included the following: • The selected option must integrate well with the current processing infrastructure • Must be capable of achieving the desired targets on a consistent basis • It must not increase the concentration of any other regulated/non-regulated element in the mill final effluent • It must be robust and circuit availability (uptime) must not be affected (currently was at 95% uptime) • Capital and operating costs must be considered when selecting a final option. DISCUSSION The above noted seven treatment options were evaluated and tested based on the criteria identified. A brief summary of the results of each treatment option is summarized below. 1. Reverse osmosis Reverse osmosis was considered as a processing option to remove As, Mo and Se from the mill effluent. Results showed that the high concentration of Ca and SO4 in the effluent (near saturation) feeding the RO system resulted in significant scaling and rapid fouling of the RO membranes. As a result this technology was not considered any further. 2. Ion exchange Ion exchange resins were tested for their affinity for As, Mo and Se. In all cases the high ionic strength of the mill effluent (saturation with respect to Ca and SO4) resulted in scaling of the column and resin beads and also resulted in excessive back pressure on the column. This caused flow restrictions in the IX columns in all resins tested. As a result this technology was not considered further. 3. Co-precipitation of oxy-anions with ettringite Ettringite (Ca6Al2(OH)12(SO4)3) precipitates from solutions containing Al, Ca and SO4 at high pH levels (pH >11) [4]. Selenium (as selenite or selenate), arsenic (as arsenite or arsenate) and molybdenum (as molybdate) can substitute SO4 in the ettringite lattice thereby removing these elements of concern from solution. Results from testwork showed that Se was removed solution but not to the level required. Removal efficiencies for As and Mo were not improved with this chemical treatment process. Finally, to effectively precipitate ettringite the addition of aluminum was required at stoichiometric levels and this resulted in an increased in the concentration of aluminum in the mill final effluent. This was not acceptable as Al in the effluent can have a negative impact on downstream receptors. As a result this technology was not considered any further. 4. Reduction and adsorption with ferrous iron or zero valent iron (ZVI) Test work results showed that selenium removal improved when ferrous sulphate (“green rust”) was added to the water stream at pH ~4. However this option was not pursued further due to excessive sludge levels to tailings, high reagent costs when compared to marginal process performance improvement. ZVI iron in the form of iron filings was also tested on a bench scale, again yielding marginal improvement and was observed to be prone to surface passivation. 5. Microbial reduction The use of microbes to electrochemically reduce As, Mo and Se to elemental form thereby significantly reducing the concentration of these elements of concern in the final effluent combined with a geochemically stable species in the mill tailings was evaluated. Results showed that it was difficult to sustain the biomass as it was sensitive to changes in temperature and redox conditions. Further, traces of SX organic carry over in the raffinate also had a detrimental effect on the biomass. Results further showed that these aspects would cause a rapid deterioration in the biomass and it took several days for the biomass to recover. Should this happen at the plant scale, if the process were to be implemented, the resulting mill final effluent has the potential to be off-spec with respect to Mo and Se for several days while the biomass stabilized. This was unacceptable from a process perspective. As a result this technology was not considered any further. 6. Photocatalytic reduction using UV Light and TiO2 Photo-assisted electrochemical reduction of oxyanions (e.g. As, Mo and Se) using semiconductor particles as catalysts was investigated. Of all semiconductors, titanium dioxide is suited for photocatalytic processes [5-7]. Titanium dioxide is highly stable, non-toxic and has the potential to be reused following its recovery from the treated effluent stream. The ability of titanium dioxide to function as a photocatalyst arises from its semiconducting properties. Illumination of semiconductor particles with electromagnetic radiation (e.g. UV light) of energy greater than their band-gap results in the promotion of an electron from the valence band (VB) to the conduction band (CB). This process generates pairs of electrons (e-) and holes (h+) in the CB and VB, respectively. The CB becomes electron-rich, and hence possesses a reducing ability while the VB hole is deficient of electrons thereby possessing an oxidizing ability [12]. Titanium dioxide has an adsorption affinity for oxidized oxyanions. In the context of Se(IV) or Se(IV) reduction, the electromagnetic radiation produced CB electrons are transferred to either the adsorbed Se(IV) or Se(VI) species, reducing them to elemental Se. The same mechanism was hypothesized for As and Mo oxyanions in solution. Results on clean distilled water spiked with As, Mo and Se (as AsO4-3, SeO2-4 and MoO4-2) showed excellent results for Se removal with >99% of the Se converted to elemental Se. Removal efficiencies for As and Mo were lower (10% and 15%). This was attributed to a lower adsorption affinity of TiO2 for As and Mo oxyanions. The application of photocatalytic reduction using UV light and TiO2 was also tested on Key Lake mill effluent. Results showed significantly reduced removal efficiencies for As, Mo and Se as compared to results achieved with spiked clean distilled water. Removal efficiencies of 48%, 5% and 7% were observed for Se, As and Mo, respectively. The difference was the reduced photon flux from the UV light in the mill effluent sample due to the higher total dissolved solids concentration. Based on these results and limited commercial plant-scale applications this technology was not considered any further. 7. Adsorption of oxyanions to ferrihydrite followed by gypsum encapsulation Dissolved iron in solution forms two-line ferrihydrite at pH 3.2 and has a strong adsorption affinity for As, Mo and Se oxyanions in solution due to the net positive surface charge of ferrihydrite at this pH [8-9]. Test work completed on mill effluent showed very good removal efficiency of As, Mo and Se over the pH range 3.5-4.5. The target pH of the mill final tailings is pH 11 and the surface charge of ferrihydrite changes from net positive to net negative above pH 8.1, thereby desorbing As, Mo and Se. Pre-neutralizing the adsorbed Fe – As/Mo/Se complex from pH 4.5 to 7.5 using lime increased the geochemical stability of this complex when it was mixed with the final tailings at pH 11. Aging studies confirmed that this adsorption complex combined with gypsum encapsulation at pH 7.5 resulted in a stable complex within the tailings management facility. Based on these positive results the Key Lake mill effluent treatment circuit was modified to include enhanced Eh control, a low pH (pH 4.5) thickener and a gypsum encapsulation tank. RESULTS ACHIEVED The selected ferrihydrite precipitation hydrometallurgical treatment method achieved excellent results at full plant scale. Prior to the installation of the required process equipment and subsequent process changes the daily concentrations of As, Mo and Se in the mill final effluent were as follows: As average concentration = 0.006 mg/L (n = 81; Range = 0.003 mg/L to 0.017 mg/L; Standard Deviation = 0.002). Mo average concentration = 0.74 mg/L (n = 81; Range = 0.27 mg/L to 1.8 mg/L; Standard Deviation = 0.27). Se average concentration = 0.073 mg/l (n = 81; Range = 0.052 mg/l to 0.094 mg/l; Standard Deviation = 0.010). After the installation of the thickener the average daily concentration of As, Mo and Se were as follows: As average concentration = 0.005 mg/L (n = 145; Range = 0.001 mg/L to 0.019 mg/L; Standard Deviation = 0.003). Mo average concentration = 0.10 mg/L (n = 145; range = 0.005 mg/L to 0.70 mg/L; Standard Deviation = 0.086). Se average concentration = 0.018 mg/L (n = 145; Range = 0.004 mg/L to 0.031 mg/; Standard Deviation = 0.004). As a result of these changes to the effluent treatment circuit the removal efficiency for As remained high and was 99.8% before process changes and 99.9% following the changes. Significant improvement was observed for Mo and Se where the removal efficiencies increased from 21% to 90% for Mo and from 19% to 80% for Se. Finally the annual loading of Mo and Se to the environment decreased from 1,110 kg/y to 100 kg/y for Mo (on average) and from 110 kg/y to 18 kg/y (on average) for Se. Finally, following implementation of the effluent treatment process improvements, the Key Lake mill met environmental performance expectations (as per the environmental impact statement) with respect to effluent quality. The annual loadings for Mo and Se after process improvements were below the limit of 600 kg/y for Mo and 40 kg/y for Se. REFERENCES [1] CAMECO CORPORATION, Environmental Impact Statement: Key Lake Operation, (1979). [2] CAMECO CORPORATION, Key Lake Annual Report, (2001). [3] BISSONNETTE, J., ESSILFIE-DUGHAN, J., MOLDOVAN, B. J., HENDRY, M. J., Sequestration of As and Mo in Uranium Mill Precipitates (pH 1.5–9.2): An XAS Study, Appl. Geochemistry 72 (2016) 20. [4] ZHANG, M., REARDON, E.J., Removal of B, Cr, Mo and Se from Wastewater by Incorporation in Hydrocalumite and Ettringite, Environ. Sci. Technol. 37 (2003) 2947-2952. [5] FUJISHIMA, A., HAHIMOTO, K, and WATANBE, T., Photocatalysis: Fundamentals and Applications, ed. D.A. Tryk. 1999, Japan: BKC Inc. 124. [6] CARP, O., HUISMAN, C.L., RELLER, A., Photoinduced Reactivity of Titanium Dioxide, Progress in Solid State Chemistry 32 (2004) 33-177. [7] NGUYEN, V.N.H., BEYDOUN, D., AMAL, R., Photocatalytic Reduction of Selenite and Selenate using TiO2 Photocatalyst, Journal of Photochemistry and Photobiology A: Chemistry 171 (2005) 113-120. [8] MOLDOVAN, B. J., JIANG, D. T., HENDRY, M. J., Mineralogical Characterization of Arsenic in Uranium Mine Tailings Precipitated from Iron-Rich Hydrometallurgical Solutions, Environ. Sci. Technol. 37 (2003) 873. [9] MOLDOVAN, B. J., HENDRY, M. J., Characterizing and Quantifying Controls on Arsenic Solubility over a pH Range of 1 - 11 in a Uranium Mill-Scale Experiment, Environ. Sci. Technol. 39 (2005) 4913.

Speaker: Dr Brett Moldovan (IAEA)

10:40 Break

Applied Geology and Geometallurgy of Uranium and Associated Metals

Conveners: Mr Christian Polak (AREVA MINES), Dr Susan Hall (U.S. Geological Survey)

156 Unconformity-type Uranium Deposits: A new IAEA technical document

The IAEA has produced several volumes focussed on uranium deposit types that were the result of several expert-led working groups. In the last 25+ years, since these volumes have been published, there has been considerable research and advances in the understanding of uranium deposits, particularly for unconformity type deposits. Up until 2009, the world’s largest share of production came from unconformity-type deposits and identified resources account for 10% of the world total. They are one of the most economically viable deposit types mainly due to their relatively high-grades in comparison to other deposit types, and warrant a technical document that can be used as a reference to properly assess the potential to discover and exploit these deposits. Currently, unconformity-type deposits are only being worked in Canada and Australia but there are known occurrences and potential worldwide, which should be evaluated. This new technical document will provide a summary on unconformity-type uranium deposits including geology, mineralogy, metallurgy, mining methods, resources, genesis, exploration techniques and other topics that would be useful for evaluation. Users should be able to utilize this document to assess the potential to evaluate the potential to discover and exploit unconformity-type deposits.

Speaker: Dr Adrienne HANLY (IAEA)

157 Fluid inclusion evidence for uranium extracted from the Athabasca Basin as a source for unconformity-related uranium mineralization

It is generally accepted that the ore-forming fluids in unconformity-related uranium deposits of the Athabasca Basin in northern Saskatchewan were derived from evaporitic seawater in the basin. However, it remains controversial whether uranium was extracted from the basin sediments or from basement rocks. It has been argued that oxidizing conditions and availability of fluid in the basin were favorable for uranium leaching from the sediments, and the present-day low concentrations of uranium in the sedimentary rocks reflects such leaching. However, no direct evidence for this mechanism has been documented. Microthermometric and LA-ICP-MS analyses of fluid inclusions in quartz overgrowths from sandstones distal to ore deposits in the Athabasca Basin, as documented in this study, reveal the presence of Ca-rich and U-rich brines within the basin. Such fluids have been previously found within the unconformity-related uranium deposits and interpreted to indicate a local basement derivation of the metals. The development of such fluids throughout the basin during diagenesis suggests that at least part of the uranium in the unconformity-related uranium deposits was derived from the basin. This finding is important for the refining of exploration model of unconformity-related uranium deposits.

Speaker: Mr Guoxiang Chi (Department of Geology, University of Regina)

158 NEW U–Pb AGES AND GEOCHEMISTRY FROM THE WHEELER RIVER URANIUM DEPOSITS, ATHABASCA BASIN, CANADA

The Wheeler River Project hosts the high-grade Phoenix (sandstone-hosted) and Gryphon (basement-hosted) U deposits within the eastern part of the Athabasca Basin. The conditions and timing of mineralization event(s) at each deposit were established from the isotopic ages and geochemistry of uranium oxides from 13 samples. The oldest zones of analyzed UO2 (i.e. 1433 +/-15 Ma, 1340 +/- 17 Ma, 1275 +/-17 Ma) for most of the samples are considered tentatively to be primary mineralization ages. These ages and their chemical contents are different for each sample, indicating different P-T-X conditions and timing for the formation of the UO2 at Wheeler River. This difference is visible between deposits, but also at the scale of one deposit (Phoenix). Younger age determinations within all of the samples are interpreted to reflect secondary fluid events. These new results provide excellent evidence for multiple U events related to changes through time on the Wheeler River property. Such results demonstrates that the evolution of the Wheeler River property, and at a larger scale of the Athabasca Basin, has been complex since the deposition of the basin and could thus explain the exceptional characteristics of the unconformity-related U deposits

Speaker: Dr julien mercadier (georessources)

159 Comparison between the uranium deposits in the Alligator River Uranium Field and the Westmoreland area (Northern Territory and Queensland, Australia)

INTRODUCTION The Northern Territory (Australia) hosts about 30% of Australia’s low-cost uranium sources with 361 uranium occurrences [1]. The production of U3O8 concentrates in Northern Territory to 2012 was 128 017 t. The uranium deposits of the Northern Territory can be subdivided into five main types [2]. The two on which this study is focused are the “unconformity-related” and the “Westmoreland-Murphy” types. The Alligator River Uranium Field (ARUF) hosts numerous unconformity-related deposits such as Ranger, Nabarlek, Jabiluka and Koongarra. They are located exclusively in basement rocks, near the unconformity between an Archean to Paleoproterozoic basement complex (~2670-1818 Ma) and the Paleo- to Mesoproterozoic McArthur Basin (1815-1492 Ma) and mostly grade above 0.1% U3O8 [1, 3, 4]. In the Westmoreland area, on the southern margin of the McArthur Basin, former uranium mines and current prospects belong to the Westmoreland-Murphy type (e.g. Eva in Northern Territory and Redtree and Junnagunna in Queensland). They are located within the Westmoreland Conglomerate and Seigal Volcanics that are part of the McArthur Basin, near the unconformity with the Paleoproterozoic Murphy Inlier (1855-1830 Ma) and grade 0.07-0.1% U3O8 [1]. As the two types of deposits share similar settings and are associated with the same basin (McArthur Basin), it is critical to establish detailed comparison of their timing, mineralogy and geochemistry in order to determine if they could be linked to the same ore-forming event or ore-forming processes. While unconformity-related deposits have been extensively studied [5–9], much less is known about the Westmoreland-Murphy-type deposits [10, 11]. In this work, we complement the existing data on ore mineralogy, geochemistry, geothermometry, age dating and fluid inclusions on Westmoreland-Murphy-type deposits and compare them with published data from unconformity-related deposits. METHODS AND RESULTS The new data obtained on U deposits from the Westmoreland area is based on mineralized samples collected in the Westmoreland conglomerate from Junnagunna and Redtree deposits. Petrographic investigation was carried out using optical microscope and SEM at GeoRessources laboratory (Vandœuvre-lès Nancy, France). Early diagenesis is represented by hematite and quartz overgrowth over detrital quartz grains. This was followed by an episode of quartz dissolution that corresponds to the beginning of peak diagenesis [10]. Quartz precipitates after this episode, and hematite, chlorite and then apatite, clays minerals and uraninite (10-50µm) (hereafter referred to as “intergranular uraninite”) take turns, filling intergranular voids between quartz grains in the sandstone. Intergranular uraninite is texturally associated with clays minerals and hematite and also occurs as micron-sized grains within hematite grains [10] Apatite is older than the intergranular uraninite because small fractures within apatite grains are filled with uraninite, which also surrounds the apatite grains. After these diagenetic events, veins containing quartz, uraninite (hereafter referred to as “vein uraninite”), pyrite and chalcopyrite develop. In this study, we focused on both intergranular and vein uraninite. By comparison, the main stage of uranium mineralization in the ARUF consists of very fine grained (10–50 μm diameter) euhedral uraninite (U1) disseminated within chlorite and intergrown with tourmaline. A second generation of uraninite (U2) is represented by fine-grained uraninite inclusions within veinlets of disordered graphitic carbon. The final stage of uranium mineralization is represented by veinlets of massive uraninite (U3) [6]. Intergranular and vein uraninite were dated by U-Pb using SIMS at CRPG laboratory (Vandœuvre-lès Nancy, France). The average age for both generations yielded by the analysis is 559 ±33 Ma, which is consistent with the youngest age already obtained for these deposits [10]. The oldest published ages (1606 ± 80 and 1655 ± 83 Ma) in Westmoreland area are 207Pb/206Pb ages from two analyses obtained by LA-HR-ICPMS on very fine-grained intergranular uraninites inclusions in hematite (6-8µm) [10]. This very fine uraninite has not been dated yet in this study. U-Pb dating of a thin layer (1mm) of euhedral apatite grains has also been carried out by SIMS. Apatite shows abnormally high U content probably due to the vicinity of uraninites or to tiny UO2 inclusions. As a consequence, on 31 spot analyses, only 9 could be used to constrain an age of 1685 ±65 Ma, consistent with the diagenesis processes dated on illite [10]. According to the analytical uncertainties, the oldest published age for small intergranular uraninite is compatible with that of the apatite dated here [10]. By comparison, the ages obtained on uraninites in the ARUF show a first mineralizing stage around 1720-1680 Ma [6, 7, 9]. Lots of uraninite ages are younger than 1400 Ma and this wide range of ages doesn’t allow any relevant comparison between the two areas [6, 8–10]. Significant amounts of illite have K-Ar ages that indicate crystallization between ∼1680 and 1520 Ma in the ARUF [12]. This corresponds to the initiation of the diagenetic/hydrothermal fluid circulations. Illite from Westmoreland Conglomerate has a plateau 40Ar/39Ar age at 1680 ± 18 Ma that confirms basinal-brine migration in the Westmoreland Conglomerate at this period [10]. REE-patterns on dated intergranular and vein uraninites from Westmoreland have been established by LA-ICP-MS at GeoRessources laboratory (Vandœuvre-lès Nancy, France). The uraninite REE-patterns in Westmoreland do not exhibit the “bell-shape” (i.e. high concentrations of Tb and Dy) typical of unconformity-related U deposits [13]. The REE-patterns on intergranular UO2 is enriched in LREE in comparison with patterns from unconformity-related, basement-hosted deposits from ARUF (Nabarlek and Koongarra) [13]. For vein uraninite, the patterns show some similarities with vein-type deposits worldwide although the latter are generally considered to be formed at higher temperature in the presence of magmatic and/or metamorphic fluids. Even if some post crystallization modification of the REE patterns may have contributed to the LREE enrichment, such phenomenon is not sufficient to explain the differences of the REE patterns between the two zones. Therefore, the REE-patterns of UO2 differ between the North and the South of the McArthur Basin, which indicates different modes of U transport and deposition. The major element composition of chlorite associated with intergranular UO2 was determined using EPMA at GeoRessources laboratory (Vandœuvre-lès Nancy, France). Major element (Si, Al, Fe and Mg) composition was used to determine the chlorite species which turn out to be chamosite and to calculate crystallization temperatures [14]. A lot of compositions give temperatures in excess of 300°C according to the model used [14]. Previously-published data on chlorite from the Seigal Volcanics and the Westmoreland Conglomerate indicate that chlorite formed at 230° ± 30°C [10]. However, the composition of some chlorites from the conglomerate indicate high temperatures of crystallization (364°C) that was explained by the vicinity of the Seigal Volcanics which could have provided excess of Fe leading to high calculated temperature. The reason explaining these high calculated temperatures in both previously-published and new data are under investigation but could also be linked to the emplacement of the Seigal Volcanics just above the Westmoreland Conglomerate that might have brought additional heat to the system. In the ARUF, chlorite gives temperatures between 200°C and 310°C [8]. Temperature estimates on syn-ore illite were calculated based on illite crystallinity. They compare well between the Westmoreland area (200 ±30°C) [10] and the ARUF 180-230°C [8, 9]. Previously published data on the salinity, temperature and pressure of the fluid inclusions hosted in diagenetic quartz overgrowth and quartz veins have also been investigated. The compilation of all the available primary or pseudo-secondary fluid inclusion data have been plotted in a homogenization temperature (Th) vs salinity diagram. In both areas, the data lie into a triangle-shape pattern defined by a low-temperature (100-150 °C) and high-salinity (35 wt% eq. NaCl) end-member and two low-salinity end-members, one at high temperature (until 350°C) and one at low temperature (100°C). In the ARUF, mineralizing events occur in a small range of temperature (100 to 175°C) [8, 9, 15–18]. In Westmoreland area, at least two stages of fluid mixing associated with the mineralization (U-Cu) occurred. Firstly, there was mixing between a CaCl2 ± LiCl-rich brine and a NaCl-rich brine to produce a fluid of intermediate composition. This fluid then mixed with a low salinity fluid [11, 19]. In the ARUF, Cl/Br and cation ratios indicate that the high-salinity brine is probably a primary brine, resulting from the evaporation of seawater [16]. Reconstructed isotopic (O, H) compositions based on the composition of quartz veins and associated alteration minerals have been also compiled. In Westmoreland, compositions are the followings: δ18O = 4 ± 1‰ and δD = –31 ± 6‰ [10], whereas in the ARUF δ18O = 3.5 ± 2‰ and δD = –25 ± 15‰ [5, 8, 9]. According to isotopic compositions, the brines are evolved basinal brines with comparable δ18O and δD values in the two regions. DISCUSSION AND CONCLUSION From the previously-published and newly-acquired data presented here it appears that Australian unconformity related U deposits from the ARUF and Westmoreland-Murphy-type U deposits share some striking similarities in terms of alteration and ore mineralogy, temperature, fluid composition but also noticeable differences. Age dating suggests that uranium mineralization might have started about 65 Ma earlier in the ARUF compared to Westmoreland area. However, the measured errors are sometimes substantial and some crystallization stages could be synchronous. A common ore-forming event is recorded around 1680-1600 Ma, which corresponds to the primary mineralization in Westmoreland and Pine Creek region. Both deposit types have undergone successive episodes of U remobilization/recrystallization since then which significantly disturbed the isotopic and chemical compositions of the uranium oxides. REE patterns of UO2, which are diagnostic features of deposit types, differ significantly between the two zones. It seems that the oldest UO2 generation in both areas have distinct REE patterns. Therefore, probable contemporaneous ore-forming events at both localities were related to distinct ore-forming processes. Further work is planned to compare the composition of the Na-Ca-Cl brines which appear to be involved in both areas. A comparison of fluid inclusions characteristics (pressure, temperature, composition) show that the mixing between low-salinity fluids and brines is a key process for ore deposition in both areas. Raman spectrometry of fluid inclusions will allow identifying trace gases in the mineralizing brines (CO2, CH4, N2, H2, O2), which may provide information on the redox state of the brines, the mechanisms for UO2 deposition and fluid-rock interaction. LA-ICPMS analysis of fluid inclusions will allow determining the major and trace element (including U) content of the brines, which will provide crucial information on their origin, the fluid-rock interaction they underwent and their metal-transporting capacities. Finally, noble gas and halogen analysis of fluid inclusions will provide invaluable information on the origin of the salinity and the interaction of the fluids with various surficial and crustal reservoirs (atmosphere, sediments, basement rocks etc…). From an exploration point of view, it seems that defining the pathways for the Na-Ca-Cl brines along and both sides of the unconformity could be critical for discovering new U deposits in the Westmoreland area. This could be carried out, for example, by careful lithogeochemistry and mapping of alteration minerals in basal conglomerates and sandstones as well as along the unconformity and major structures cutting across [20]. However, conceptual models for the brine origin and potential pathways based on detailed fluid inclusion analysis, as planned in this project, will be an important prerequisite for more efficient exploration targeting. REFERENCES [1] AHMAD, M., MUNSON, T.J., NORTHERN TERRITORY GEOLOGICAL SURVEY, Geology and Mineral Resources of the Northern Territory, (2013). [2] LALLY, J.H., BAJWAH, Z., Uranium deposits of the Northern Territory. Northern Territory Geological Survey, Report 20, (2006). [3] JACKSON, M.J., SCOTT, D.L., RAWLINGS, D.J., Stratigraphic framework for the Leichhardt and Calvert Superbasins: review and correlations of the pre-1700 Ma successions between Mt Isa and McArthur River, Aust. J. Earth Sci. 47 3 (2000) 381. [4] RAWLINGS, D.J., Stratigraphic resolution of a multiphase intracratonic basin system: the McArthur Basin, northern Australia, Aust. J. Earth Sci. 46 5 (1999) 703. [5] KYSER, K. et al., Diagenetic fluids in Paleo-and Meso-Proterozoic sedimentary basins and their implications for long protracted fluid histories, Mineral. Assoc. Can. Short Course 28 (2000) 225. [6] SKIRROW, R.G., MERCADIER, J., ARMSTRONG, R., KUSKE, T., DELOULE, E., The Ranger uranium deposit, northern Australia: Timing constraints, regional and ore-related alteration, and genetic implications for unconformity-related mineralisation, Ore Geol. Rev. 76 (2016) 463. [7] HILLS, J.H., RICHARDS, J.R., Pitchblende and galena ages in the Alligator Rivers region, Northern Territory, Australia, Miner. Deposita 11 2 (1976) 133. [8] POLITO, P.A. et al., Significance of alteration assemblages for the origin and evolution of the Proterozoic Nabarlek unconformity-related uranium deposit, Northern Territory, Australia, Econ. Geol. Bull. Soc. Econ. Geol. 99 1 (2004) 113. [9] POLITO, P.A., KYSER, T.K., THOMAS, D., MARLATT, J., DREVER, G., Re-evaluation of the petrogenesis of the Proterozoic Jabiluka unconformity-related uranium deposit, Northern Territory, Australia, Miner. Deposita 40 3 (2005) 257. [10] POLITO, P.A., KYSER, T.K., RHEINBERGER, G., SOUTHGATE, P.N., A Paragenetic and Isotopic Study of the Proterozoic Westmoreland Uranium Deposits, Southern McArthur Basin, Northern Territory, Australia, Econ. Geol. 100 6 (2005) 1243. [11] MERNAGH, T.P., WYGRALAK, A.S., A fluid inclusion study of uranium and copper mineral systems in the Murphy Inlier, Northern Australia, Russ. Geol. Geophys. 52 11 (2011) 1421. [12] CLAUER, N., MERCADIER, J., PATRIER, P., LAVERRET, E., BRUNETON, P., Relating unconformity-type uranium mineralization of the Alligator Rivers Uranium Field (Northern Territory, Australia) to the regional Proterozoic tectono-thermal activity: An illite K–Ar dating approach, Precambrian Res. 269 (2015) 107. [13] MERCADIER, J. et al., Origin of uranium deposits revealed by their rare earth element signature: Origin of U deposits revealed by the rare earth elements, Terra Nova 23 4 (2011) 264. [14] BOURDELLE, F., CATHELINEAU, M., Low-temperature chlorite geothermometry: a graphical representation based on a T–R²⁺ –Si diagram, Eur. J. Mineral. 27 5 (2015) 617. [15] DEROME, D. et al., A detailed fluid inclusion study in silicified breccias from the Kombolgie sandstones (Northern Territory, Australia): inferences for the genesis of middle-Proterozoic unconformity-type uranium deposits, J. Geochem. Explor. 80 2–3 (2003) 259. [16] DEROME, D. et al., Paleo-fluid composition determined from individual fluid inclusions by Raman and LIBS: Application to mid-proterozoic evaporitic Na-Ca brines (Alligator Rivers Uranium Field, northern territories Australia), Chem. Geol. 237 3–4 (2007) 240. [17] YPMA, P.J.M., FUZIKAWA, K., Fluid Inclusion Isotope Studies of the Nabarlek and Jabiluka Uranium Deposits, Northern Territory, Australia, Proceedings of International Uranium Symposium on the Pine Creek Geosyncline, IAEA, Vienna (1980) 375–395. [18] DURAK, B., PAGEL, M., POTY, B., Températures et Salinités Des Fluides Au Cours Des Silicifications Diagénétiques d’une Formation Gréseuse Surmontant Un Gisement d’uranium Du Socle: L’exemple Des Grès Kombolgie (Australie), Comptes Rendus de l’Academie des Sciences, 296 (II), Paris (1983) pp. 571– 574. [19] POLITO, P.A., KYSER, T.K., JACKSON, M.J., The role of sandstone diagenesis and aquifer evolution in the formation of uranium and zinc-lead deposits, southern McArthur basin, Northern Territory, Australia, Econ. Geol. 101 6 (2006) 1189. [20] POLITO, P.A., KYSER, T.K., ALEXANDRE, P., HIATT, E.E., STANLEY, C.R., Advances in understanding the Kombolgie Subgroup and unconformity-related uranium deposits in the Alligator Rivers Uranium Field and how to explore for them using lithogeochemical principles, Aust. J. Earth Sci. 58 5 (2011) 453.

Speaker: Mrs Joséphine Gigon (Laboratoire GeoRessources)

160 Geochemical signatures of U-bearing metasomatic deposits of the Central Mineral Belt, Labrador, Canada.

INTRODUCTION The Central Mineral Belt (CMB) of Labrador hosts multiple U±Cu±Mo±V prospects and deposits, including some with affinities with albitite-hosted uranium deposits and others with iron-oxide-copper-gold (IOCG) deposits [1, 2, 3]. Extensive exploration campaigns during the mid-2000s generated a large amount of industry geophysical and geochemical data. Worldwide, IOCG deposits hosts significant polymetallic resources with the Olympic Dam deposit being the largest uranium producer in the world. Over the past decade, the demonstration of a diagnostic evolution of alteration facies within IOCG systems has led to the development of geochemical tools useful to detect prospective areas [4]. In the CMB, geological and mineralogical characteristics analogous to those of IOCG systems include pervasive regional sodic alteration prior to brecciation and iron oxide ± K-feldspar alteration and subsequent mineralization. Thus, it is worthwhile to explore potential links between IOCG and the CMB uranium mineralization as means to advance exploration models. The Central Mineral Belt uranium geochemistry database (CMBUG; [5]) consists of over 40 000 data entries compiled from Geological Survey of Newfoundland and Labrador data files and drill core geochemistry submitted in mineral assessment reports for the period 2002 to 2011. In this work, we provide a general characterization of the CMBUG data in terms of their alteration types, along with a preliminary principal component analysis done on a smaller data suite of the CMBUG. GENERAL GEOLOGY The regional geology of the CMB described herein is summarized from [1, 6, 7, 8, 9, 10, 11, 12, 13],]. The Archean Nain Province gneisses are the basement to the variably deformed tonalite, granodiorite and granite intrusions of the Kanairiktok Intrusive Suite (KIS), both of which are transected by 2.23 Ga Kikkertavak dykes. The Paleoproterozoic (younger than 2.2 Ga) metavolcanic and metasedimentary packages of the Moran Lake and Post Hill groups unconformably overly the Archean gneisses and KIS intrusions. The Post Hill Group (northeastern CMB) is overlaid by mixed sedimentary and bimodal volcanic rocks of the Aillik Group. The Moran Lake Group (southwestern CMB) is unconformably overlain by the Bruce River Group, which consists of conglomeratic arkose and sandstone covered by a thick sequence of 1.7 Ga felsic volcanic rocks. The youngest supracrustal sequences in the CMB are the Letitia and Seal Lake groups. The ca. 1.3 Ga Letitia Lake Group is dominated by alkaline volcanic rocks that are overlain by sedimentary and mafic volcanic rocks of the Seal Lake Group. The Archean intrusions and Paleoproterozoic sequences were metamorphosed (up to amphibolite facies) and variably deformed by at least three orogenic episodes (Makkovikian: ca. 1.8–1.7Ga; Labradorian: 1.7–1.6 Ga; Grenvillian: ca. 1.0 Ga). The CMB U±Th±Cu±Pb±Zn mineralization occurs within all the Archean to Paleo- to Mesoproterozoic intrusive (e.g. Two Time prospect), volcanic (e.g. Moran Lake Upper C and Michelin deposits) and sedimentary (e.g. Anna Lake prospect) rocks. Mineralization styles include breccia- (e.g. Two Time and Moran lake Upper C zone) and fracture-hosted (e.g. Anomaly No. 17 prospect) plus disseminated (e.g. Anna Lake prospect) mineralization. However, in most cases ore-bearing events are preceded by moderate to pervasive sodic metasomatism (e.g. Michelin deposit) and iron oxide replacements or breccia infill (mainly hematite). ANALYTICAL METHODS The major and trace element analyses compiled in the CMBUG were obtained from various laboratories mainly using ‘total digestion’ (TD) techniques. The TD techniques rely on a mixture of three to four different acids to attempt to fully dissolve samples followed by inductively couple mass spectrometry analysis to provide relatively complete geochemical results. Although TD techniques are typically effective, incomplete digestion of the sample is still possible due to the presence of highly resistive minerals. Thus, the TD is best considered a ‘near-total’ digestion. In addition, elements that may volatilize during TD (e.g. As, Se, Te and U) may be under-represented in the analyses. Less commonly, samples in the CMBUG were analyzed by a mixture of lithium metaborate/tetraborate fusion, instrumental neutron activation analysis (INAA) and X-ray fluorescence (XRF) techniques. The combination of these techniques allow a better quantification of major and trace elements contained in resistive minerals (e.g. magnetite; rare-earth bearing minerals). DATA DISTRIBUTION The CMBUG encompasses over 40 000 data points from multiple locations within the CMB. However, over 95% of the data are from six main areas: Moran, Jacques Lake, Snegamook, Michelin, Anna Lake, Kitts-Post Hill and Kanairiktok (see figures 1 and 2 in [5]). These areas may represent one or many prospects and/or deposits. For example, the Moran dataset includes the Moran Lake Upper C Zone deposit and Moran Lake B and Armstrong prospects. On the other hand, the Jacques Lake dataset only comprises samples from the Jacques Lake deposit. In this report, data characterization is restricted to the aforementioned main locations and no further geographical distinction was considered. ALTERATION CHARACTERIZATION The alteration facies hosting uranium mineralization in the CMB were evaluated through the [4] alteration discrimination plot. For this purpose, only samples having non-zero Al, Na, K, Ca, Mg and Fe concentrations are selected. To better illustrate the data description below we refer the reader to figures 1, 5 and 6 in [14]. In general, the CMBUG samples present significant scatter with most samples plotting in the least altered and Na and Fe-(Mg) alteration fields. In the Snegamook and Jacques Lake areas, most samples are Na-altered and a lower portion of those data plot mainly within the unaltered and K alteration fields. In the Anna Lake, Kanairiktok, and Michelin areas, most samples plot within the least altered and Na alteration fields, with less significant clusters consistent with K, Ca-K-Fe and K-Fe altered rocks. The Moran Lake data accounts for the greatest portion of the CMBUG database and shows the largest scatter. Similar to other CMB locations, most samples are contained in the least altered, Na and Fe-(Mg) alteration fields, with a relatively minor portion plotting within the K, Ca-K-Fe, K-Fe, Fe-rich Ca-K-Fe and Ca-Fe alteration fields. Notably, it is observed that distribution of high uranium contents is not associated to a particular type of alteration type, instead uranium mineralization is found in almost all fields on the alteration plot, including that representing least altered rocks. In IOCG deposits, sodic alteration is commonly associated with deeper and higher temperature parts of the hydrothermal system that evolve in time and over distance to Ca-Fe and K-Fe alteration assemblages [2, 3, 4, 15, 16]. Generally, rocks contained in the K-Fe field are considered as geochemically ‘mature’ and economically fertile in terms of base, precious and speciliazed metals. In the CMB, the data suite as a whole does follow the prograde path of IOCG evolution, rather it either evolves from the Na to Fe-(Mg) alteration or from the Na to K alteration which is typical of telescoping of alteration facies. Such telescoping leads to significant overprints that result in a shift of major elements contents into the least altered field. However, it is possible that mineralization hosted in veinlets, fracture-coatings and/or disseminated in relatively unaltered rocks could also account for the high uranium content of rocks in the least altered field. In summary, the preliminary interpretations of the data distribution in the alteration plot are that: i) Na alteration is the most common alkali alteration in the CMB; ii) emplacement of iron oxide minerals is generally decoupled from potassium (few samples located in the K-Fe alteration field); and iii) the mineralization is not necessarily strictly associated with alkali or iron oxide altered rocks. However, the latter may result from alteration overlaps that shift the major element composition of mineralized rocks to the least altered field. Furthermore, as the CBUG relies on industry data submitted for analysis (i.e., targeting a specific style of mineralization such as the uranium-bearing Na+/-Fe style observed at the Michelin deposit), there is potential for sampling bias in the data. As such, it is possible that certain alteration facies are underrepresented in the database. PRINCIPAL COMPONENT ANALYSIS The statistical characterization of whole-rock geochemistry requires data treatment prior to analysis. The centred log-ratio transformation overcomes the closure constraint inherent to geochemical data [17]), which allows the use of multivariate statistical tools (e.g. principal component analysis) to identify geochemical processes. A suite of ca. 5000 whole rock analyses obtained from TD were transformed using the centred log-ratio technique prior to principal component analysis (PCA). As a whole, base metals tend to co-variate roughly together with cobalt, vanadium and iron forming a sub-group distinct from cadmium, chromium, zinc, copper and nickel. The association of the iron, cobalt and vanadium is likely related to the incorporation of the latter two elements in iron oxides such as magnetite and hematite. From the PCA it is also remarkable that alkali alteration related elements (e.g. potassium and sodium) do not correlate directly with uranium, as is also suggested by the alteration plot. However, this lack of association, especially with sodium, might be masked by the fact that proportionally, the sodium alteration in the CMB is more common and regionally widespread in comparison to the local occurrences of uranium mineralization. In addition, uranium might have been remobilized and concentrated along structural traps (e.g,. unconformity, shear zones) even though it was first precipitated within the iron oxide alkali-calcic alteration systems CONCLUSIONS Evaluation of the data in the alteration plot indicates that: i) sodic alteration is the most common alkali alteration in the CMB; ii) the emplacement of iron oxide minerals is generally decoupled from potassium; and iii) uranium mineralization is not necessarily associated to alkali or iron oxide altered rocks. Nevertheless, alteration type overlaps may shift the major element composition of mineralized rocks to the least altered field. The absence of an association of uranium and other base metals with alkali elements is also recorded by PCA. However, further statistical analysis based on the individual alteration types and by geographical location of the CMBUG is necessary to fully characterize the mobility of uranium and base metal elements and their association with alteration facies. This report is a contribution to NRCan’s Targeted Geoscience Initiative (TGI) program, under the metal pathways and traps in polymetallic (U +/- Fe, Cu, Au, REE) metasomatic ore systems activity. REFERENCES [1] SPARKES, G.W., 2017, Uranium mineralization within the Central Mineral Belt of Labrador: A summary of the diverse styles, settings and timing of mineralization: Government of Newfoundland and Labrador, Department of Natural Resources, Geological Survey, St. John’s, Open File LAB/1684, 198 p. [2] CORRIVEAU, L., MUMIN, A.H., AND SETTERFIELD, T., 2010, IOCG environments in Canada: Characteristics, geological vectors to ore and challenges, in Porter, T.M., ed., Hydrothermal iron oxide copper-gold and related deposits: A global perspective, volume 4–advances in the understanding of IOCG deposits: Porter Geoscience Consultancy Publishing, Adelaide, p. 311–344. [3] CORRIVEAU, L., MONTREUIL, J.-F., POTTER, E.G., 2016, Alteration facies linkages among IOCG, IOA and affiliated deposits in the Great Bear magmatic zone, Canada; Economic Geology, v. 111, p. 2045–2072. [4] MONTREUIL, J.-F, CORRIVEAU, L., AND GRUNSKY, E.C., 2013. Compositional data analysis of hydrothermal alteration in IOCG systems, Great Bear magmatic zone, Canada: To each alteration type its own geochemical signature; Geochemistry: Exploration, Environment, Analysis, v. 13, p. 229–247. [5] ACOSTA-GÓNGORA, P., DUFFETT, C., SPARKES, G., AND POTTER, E.G., 2018. The Central Mineral Belt uranium geochemistry database; Geological Survey of Canada, Open File 8352, 9 p. [6] GOWER, C.F., FLANAGAN, M.J., KERR, A., AND BAILEY, D.G., 1982. Geology of the Kaipokok Bay–Big River area, Central Mineral Belt, Labrador; Government of Newfoundland and Labrador, Department of Mines and Energy, Mineral Development Division, Report 82-7, 77 p. [7] ERMANOVICS, I., 1993. Geology of Hopedale Block, southern Nain Province, and the adjacent Proterozoic terranes, Labrador, Newfoundland; Geological Survey of Canada, Memoir No. 431, 161 p., [8] KERR, A., 1994. Early Proterozoic magmatic suites of the eastern Central Mineral Belt (Makkovik Province), Labrador: Geology, geochemistry and mineral potential: Government of Newfoundland and Labrador, Department of Mines and Energy, Geological Survey Branch, Report 94-03, 167 p. [9] KERR, A., RYAN, B., GOWER, C.F., AND WARDLE, R.J., 1996. The Makkovik Province: Extension of the Ketilidian Mobile Belt in mainland North America; in Brewer, T.S., Precambrian Crustal Evolution in the North Atlantic Region; Geological Society of London, Special Publication 1112, p. 155–177. [10] WILTON, D.H.C., 1996. Metallogeny of the Central Mineral Belt and adjacent Archean basement, Labrador; Government of Newfoundland and Labrador, Department of Mines and Energy, Geological Survey, Mineral Resources Report 8, 178 p. [11] HINCHEY, A.M., 2007. The Paleoproterozoic metavolcanic, metasedimentary and igneous rocks of the Aillik Domain, Makkovik Province, Labrador (NTS map area 13O/03); Current Research, Report 07-1, p. 25–44. [12] HINCHEY, A.M. AND LAFLAMME, C., 2009. The Paleoproterozoic volcano-sedimentary rocks of the Aillik Group and associated plutonic suites of the Aillik domain, Makkovik Province, Labrador [NTS map area 13J/14]; Current Research, Report 09-1, p. 159–182. [13] SPARKES, G.W., DUNNING, G.R., FONKEW, M. AND LANGILLE, A. 2016. Age constraints on the formation of iron oxide-rich hydrothermal breccias of the Moran Lake area: evidence for potential IOCG-style mineralization within the Central Mineral Belt of Labrador: Current Research, Report 16-1, p. 71-90. [14] ACOSTA-GÓNGORA, POTTER, E.G., in press. Preliminary geochemical characterization of the Central Mineral Belt uranium geochemistry database; Geological Survey of Canada, Open File 8373, p. 57-64. [15] CORRIVEAU, L., POTTER, E.G., ACOSTA-GONGORA, P., BLEIN, O., MONTREUIL, J.-F., DE TONI, A.F., DAY, W., SLACK, J.F., AYUSO, R.A., HANES , R., 2017, Petrological mapping and chemical discrimination of alteration facies as vectors to IOA, IOCG, and affiliated deposits within Laurentia and beyond; Proceedings of the 14th SGA Biennial Meeting, 20-23 August 2017, Québec City, p. 851–855. [16] CORRIVEAU, L., 2017. Iron-oxide and alkali-calcic alteration ore systems and their polymetallic IOA, IOCG, skarn, albitite-hosted U±Au±Co, and affiliated deposits: A short course series. Part 1: Introduction; Geological Survey of Canada, Scientific Presentation 56, 80 p. [17] AITCHISON, J. 1986. The Statistical Analysis of Compositional Data. Monographs on Statistics and Applied Probability. Chapman & Hall Ltd, London. The Blackburn Press, Caldwell, NJ.

Speaker: Dr Pedro Acosta Gongora (Geological Survey of Canada)

Health, Safety, Environment and Social Responsibility

Conveners: Dr Gabi Schneider, Mr Harikrishnan Tulsidas (UNECE)

161 IAEA SAFEGUARDS ASPECTS OF, AND ISSUES IN, URANIUM MINING AND ORE PROCESSING

As part of the efforts to strengthen international safeguards, including enhancing its ability to provide credible assurance of the absence of undeclared nuclear material and activities, the International Atomic Energy Agency (IAEA) is making use of increased amounts and types of information on States' nuclear and nuclear-related activities. This information includes declarations provided by States (e.g., in accordance with Safeguards Agreements and/or the Additional Protocol), information collected by the Agency (e.g., inspectors' findings, environmental sampling data), and other information available to the Agency (e.g., open sources, satellite photographs and data). In seeking technical tools to aid enhanced information analysis, the IAEA Department of Safeguards developed the Physical Model under Task 5 of Programme 93+2. It includes all the main activities that may be involved in the nuclear fuel cycle. Volume 1 of the Physical Model addresses the key aspects and indicators associated with uranium mining and processing. The revised Volume 1 “Mining and Ore Processing” is the product of a group effort of experts from within the Department of Safeguards, other Departments of the IAEA, and Member States. This presentation will provide an overview of the role of Volume 1 of the Physical Model.

Speaker: Mr Brian Boyer (IAEA)

162 IAEA-TDL-003: A CORNERSTONE FOR NUCLEAR SECURITY FOR URANIUM ORE CONCENTRATES FOR NEWCOMERS

United Republic of Tanzania is a potential future uranium producer with an estimated annual production of 2300 tU from Mkuju River uranium project. Nuclear Security for Uranium ore concentrates was not existing in the country. There was literally no guidance directly related to uranium ore concentrates (UOC) which explicitly explained how to implement prudent management practice as recommended by conventional on physical protection of nuclear materials (CPPNM) and NFCIRC/225. To ensure the applicable nuclear security recommendations on prudent management practices are incorporated into national legislations and regulations, TAEC requested for technical assistance from International Atomic Energy Agency (IAEA) to provide national training course on nuclear security for uranium ore concentrates in 2014. IAEA TDL- 003 “nuclear security in the uranium extraction industry” was the main reference document during the national training course. The training methodology was classroom lecturing, interactive table top practical exercises and real life simulation of event and how to deal with worse case scenarios in protecting UOC. This paper presents the experience acquired from IAEA TDL-003 technical assistance and experience in drafting nuclear security for UOC regulations in Tanzania.

Speaker: Mr Dennis Amos Mwalongo (Tanzania Atomic Energy Commission)

163 GUIDANCE AND TRAINING FOR NUCLEAR SECURITY IN THE URANIUM EXTRACTION INDUSTRY

Regardless of its chemical form, uranium ore concentrate (UOC) is a valuable commodity in the commercial nuclear market and a potential target for unauthorized removal. With the global expansion of uranium production capacity, the protection and control of UOC is emerging as a potential link of concern in the nuclear supply chain. In response to requests for assistance from States producing UOC, those planning such activities or involved in the protection of UOC during transport, the IAEA Division of Nuclear Security (IAEA DNS) developed a guidance document TDL-003 “Nuclear Security in the Uranium Extraction Industry” and a subsequent training course led by members of the consultancy team that drafted TDL-003. The publication was prepared in a series of seven consultancy meetings with input from more than thirty experts from ten Member States, including experts from three operating organizations of uranium extraction industry facilities.The publication describes a suggested interpretation of “prudent management practice” in the context of the uranium industry and the information provided is not international consensus guidance, but rather an attempt to show States and organizations that wish to follow the suggested approach how it can be done.

Speaker: Mrs Assel Khamzayeva (IAEA)

164 PRACTICAL APPROACH TO IMPROVING CONVENTIONAL SAFETY PERFORMANCE AND CULTURE IN URANIUM MINES AND MILLS

Conventional safety management in uranium mines and mills is equally as important as radiation protection, and unfortunately conventional mining accidents are known even at modern, well managed uranium operations. Management of conventional safety performance in daily operations must be a core value of all employees and contractor personnel, from the most senior managers and executives, through middle management and the professional and technical ranks, to all workers. This presentation will provide a global overview on leadership, management oversight, operational attitudes and behaviour, impact that the business climate has on safety performance, competence and training, hazard identification, risk tolerance, communication and safety-based reporting. Finally, this presentation will highlight some effective and proven practical steps to improve safety performance and ultimately improve safety culture in the workplace. The IAEA will be including the promotion of the importance of conventional industrial safety, as well as radiation protection, in several uranium-related technical and training meetings in the coming years.

Speaker: Dr Brett Moldovan (IAEA)

165 UMEX Project, an IAEA Survey of Global Uranium Mining and Processing Occupational Doses

INTRODUCTION With the current level of interest in nuclear power, there has been an increase in uranium exploration and in the development of new uranium production facilities in many countries [1]. Such facilities include in situ leaching operations and facilities for the mining and processing of uranium ore. Workers engaged in uranium production receive external exposure to gamma radiation emitted from uranium ore, process materials, uranium products, tailings and other process residues. In addition, they receive internal exposure from the inhalation of airborne dust particles containing long-lived alpha activity and from the inhalation of radon and its short-lived decay progeny [2, 3]. The number of uranium production workers may increase substantially over the next few years. Against this background, the IAEA has established the Uranium Mining Exposure (UMEX) project. The general aim of the project is to strengthen and enhance the radiation protection of uranium production workers, while more specific aims are to increase the opportunities for optimization of protection and to support quality assurance programmes across the industry. Within the framework of the project, the following key activities have been initiated with respect to uranium production workers worldwide: (a) Development of an information system for occupational exposure; (b) Evaluation of the current occupational radiation protection situation; (c) Identification of instances of good practice, opportunities for improvement and, where appropriate, actions to be implemented for assisting employers, workers, regulatory bodies and other stakeholders in implementing the principle of optimization of protection and safety. In 2012, the IAEA developed a questionnaire which was distributed to uranium producing countries. In 2013, responses to the questionnaire were received from 36 operating facilities which, between them, accounted for about 85% of worldwide uranium production. This paper presents: (a) The results of the information survey and a preliminary analysis thereof; (b) A summary of current practices for monitoring and reporting of occupational exposure; (c) A summary of occupational exposures reported for 2012. ANALYSIS OF RESULTS Total annual effective dose (a) For mining and processing facilities at sites using underground extraction, the overall dose was heavily influenced by one operator owing to the large number of occupationally exposed workers recorded for this particular facility. (b) Among the mining and processing facilities at sites using opencast extraction, two operators had by far the highest numbers of occupationally exposed workers and therefore had a major influence on the overall dose. (c) For facilities using in situ recovery, one operator had the highest number of occupationally exposed workers but, because this was an amalgamation of 15 facilities which were treated separately in the weighted averaging process, the overall dose was not unduly influenced and was therefore considered representative of in situ recovery facilities in general. Contributions from the three exposure pathways (a) In underground mines, the contributions from external gamma exposure and internal exposure to inhaled short-lived radon decay progeny were similar (47% and 43%, respectively), while the contribution from the inhalation of long-lived radionuclides in airborne dust was much smaller (10%). This reflects the approach taken in modern underground mines, namely, a combination of dust suppression, good ventilation and shielding against gamma radiation. (b) In the processing of ore derived from underground mining, the contributions from external gamma exposure and internal exposure to inhaled long-lived radionuclides in airborne dust were similar (44% and 34%, respectively), while the contribution from internal exposure to inhaled short-lived radon decay progeny was smaller but still significant (22%). However, since background subtraction was not generally used for exposure to radon decay progeny, a significant proportion of this contribution may not have been related to the ore processing operation. (c) In opencast mining operations, the main contribution was from external gamma exposure, as would be expected for modern mining methods. Gamma shielding is not generally possible beyond that provided by the heavy earthmoving equipment that many workers operate. The next most significant contribution was that from the inhalation of long-lived radionuclides in airborne dust — this was dominated by some operators which were both in semi-arid regions where airborne dust was likely to be more prevalent because of less water being available for dust suppression and more rapid drying of material. The inhalation of short-lived radon decay progeny was the least significant exposure pathway, as would be expected given the natural dispersal of radon within large open pits. (d) In the processing of ore derived from opencast mining, the relative contributions to the total dose were, as expected, similar to those in facilities processing ore from underground mining. (e) In operations involving in situ recovery, the main contributor to the total dose was external exposure to gamma radiation. It should be noted, however, that this result is almost totally related to one operator which is an amalgamation of 15 separate facilities, none of which applied a correction for background gamma radiation, leading to the likelihood of a significant overestimation of occupational exposure from this pathway. (f) Facilities categorized as ‘other’ included facilities for uranium recovery from rehabilitation, waste water treatment and a form of contract processing known as ‘toll milling’. The relative contributions from the three exposure pathways varied widely. One of the operator provided only gamma exposure data and this pathway was therefore recorded as the only contributor to the total dose. In the case of one operator , a contract processing operation which had the largest number of occupationally exposed workers, external gamma exposure was the largest contributor to the total dose — this was expected given the nature of a purely contract processing operation. MAIN OBSERVATIONS AND CONCLUSIONS A worldwide survey of occupational radiation exposure in the production of uranium was performed in 2013. Responses were received from 36 operating facilities covering nearly 85% of global uranium production. A review of information from the responses to the UMEX questionnaire has identified several observations of a general nature as well as more specific observations on assessments related to individual exposure pathways. These are summarized as follows: (a) General observations: (i) Although several methods have been adopted for the production of uranium, the most widely used method is in situ leaching, followed by underground and opencast mining of uranium ore; (ii) The most widely used technique for the processing of uranium ore is acid leaching, followed by alkaline leaching; (b) Assessment of external exposure to gamma radiation: (i) Most facilities use TLD methods for the assessment of individual doses; (ii) The most widely used assessment strategy is the monitoring of all occupationally exposed workers, followed by the monitoring of average exposures of selected groups and the monitoring of selected individuals; (iii) Approximately 50% of facilities do not use background subtraction, leading to an overestimation of the doses received by workers; (c) Assessment of internal exposure from the inhalation of long-lived radionuclides in airborne dust: (i) Approximately 50% of facilities use workplace dust sampling and 50% use personal dust sampling; (ii) Most facilities use gross alpha counting methods for assessing the alpha activity in dust samples; (iii) Most facilities use periodic monitoring for the assessment of exposure; (iv) Most facilities do not routinely use bioassay monitoring techniques, although some facilities are using urine analysis; (d) Assessment of internal exposure from the inhalation of short-lived radon decay progeny: (i) The most widely used monitoring technique is active workplace monitoring of radon progeny in conjunction with the use of timesheets, followed by active monitoring of radon progeny using personal dosimeters; (ii) The most widely used monitoring strategy is work group averaging, followed by individual monitoring; (iii) Most facilities do not use background subtraction, which may lead to some overestimation of the dose; (e) Dose assessment: (i) The most widely used method for the determination of occupancy time is the timesheet method, followed by the use electronic devices; (ii) While various dose conversion factors are being used, most facilities use factors specified by the regulatory body or by international recommendations or standards; (iii) There is a need for global harmonization with respect to the selection of dose conversion factors in order to provide a common basis for comparison; (iv) In order to obtain a more reliable estimate of the dose from inhalation of radionuclides in airborne dust, parameters such as particle size, solubility and radionuclide composition should be included in the dose calculation. Overall findings showed an industry in compliance with international standards on radiation protection and a strong commitment to optimisation of protection. A new survey has been proposed and will be introduced. REFERENCES [1] INTERNATIONAL ENERGY AGENCY, World Energy Outlook (2016) [2] INTERNATIONAL ATOMIC ENERGY AGENCY, INTERNATIONAL LABOUR OFFICE, Occupational Radiation Protection in the Mining and Processing of Raw Materials, IAEA Safety Standards Series No. RS-G-1.6, IAEA, Vienna (2004) [3] INTERNATIONAL ATOMIC ENERGY AGENCY, Assessing the Need for Radiation Protection Measures in Work Involving Minerals and Raw Materials, Safety Reports Series No. 49, IAEA, Vienna (2007)

Speaker: Mr H. Burcin Okyar (International Atomic Energy Agency)

166 NATURAL RADIATION EXPOSURE TO THE PUBLIC IN THE URANIUM AND THORIUM BEARING REGIONS OF CAMEROON: FROM MEASUREMENTS, DOSE ASSESSMENT TO A NATIONAL RADON PLAN

ABSTRACT The present paper summarizes the findings of studies carried out since 2014 in the uranium and thorium bearing regions of Poli and Lolodorf respectively located in northern and southern Cameroon. It also underlines future prospects to strengthen the radiological protection of members of the public exposed to environmental natural radiation in Cameroon. In-situ gamma spectrometry and car-borne survey were performed in the above regions to respectively determine activity concentrations of natural radionuclides in soil and air kerma rates to assess effective external dose received by members of the public. High natural radiation areas were located and selected for indoor radon, thoron and thoron progeny measurements. Raduet detectors and thoron progeny monitors were deployed in 300 dwellings to measure radon, thoron and thoron progeny indoors to assess inhalation dose received by members of the public. External effective dose ranges between 0.15-0.63 mSv.yr-1 with the average value of 0.4 mSv.yr-1 in the uranium bearing region of Poli and between 0.1-2.2 mSv.yr-1 with the average value of 0.33 mSv.yr-1 in the uranium and thorium bearing region of Lolodorf. The inhalation dose due to radon and thoron ranges respectively between 0.87-2.7 mSv y-1 and 0.08-1 mSv y-1 with the average values of 1.55 mSv y-1 and 0.4 mSv y-1 for Poli, between 0.6-3.7 mSv y-1 and 0.03-3 mSv y-1 with the average values of 1.84 mSv y-1and 0.67 mSv y-1 for Lolodorf. Contribution of thoron to the total inhalation dose ranges between 3-34% with the average value of 20.3% in the uranium region of Poli and between 1-79% with the average value of 27% in the uranium and thorium bearing region of Lolodorf. Thus thoron can not be neglected in dose assessment to avoid biased results in radio-epidemiological studies. INTRODUCTION Since one decade many environmental radiation surveys were carried out in Cameroon [1-10]. Most of these studies deal with natural radioactivity measurements and corresponding dose assessment in mining and ore bearing regions of Cameroon. They started by collecting soil, foodstuff and water samples and by deploying Electret Ionization Chambers (EIC) (commercially E-PERM) and passive integrated radon-thoron discriminative detectors (commercially RADUET) in dwellings before determining activity concentrations of natural occurring radionuclides. This determination is followed by assessing inhalation, ingestion and external radiation dose helpful to perform radiation risk assessment. The present work uses car-borne survey method to measure air absorbed dose rates and in-situ gamma spectrometry to determine activity concentrations of natural radionuclides in soil in all the uranium and thorium bearing regions of Poli and Lolodorf. The radiological mapping of these regions was established to locate the high natural radiation areas. This information was used to deploy RADUET and thoron progeny monitors in 400 houses for radon (222Rn), thoron (220Rn) and thoron progeny measurements indoors. Measurements of absorbed dose rates in air, 238U, 232Th, and 40K activity concentrations in soil, radon, thoron and its progeny indoors were followed by external and inhalation dose assessment helpful to assess radiation risk of members of the public in the above regions. The above results highlight the importance to put in place a national radon plan in Cameroon in agreement with the International Atomic Energy Agency (IAEA) Safety Standards Series No. GSR Part 3: Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards [11]. A Technical Cooperation (TC) project (CMR9009) on Establishing national radon plan for controlling public exposure due to radon indoors was initiated and is ongoing for IAEA TC cycle 2018-2019. MATERIAL AND METHODS Car-borne survey The detailed method of the car-borne survey was described in many publications [12-14], only an outline is described here. A car-borne survey which used a 3-in × 3-in NaI(Tl) scintillation spectrometer (EMF-211, EMF Japan Co., Japan) was carried out in the uranium and thorium bearing regions of Poli and Lolodorf from November 2015 to August 2016. This spectrometer was positioned inside the car and the car speed was kept around 30-40 km h-1. Measurements of the counts inside the car were carried out every thirty seconds along the route. In order to generate a dose rate distribution map, the latitude and longitude coordinates were recorded using a global positioning system (GPS) in each measurement point at the same time as the gamma-ray count rates. Since count rate is measured inside the car, it is necessary to estimate a shielding factor of the car body towards terrestrial gamma-rays in order to represent the unshielded external dose rate. The shielding factor was estimated by making measurements inside and outside the car at 150 points. Those measurements were recorded consecutively at 30-s intervals during a total recording period of 2 min. Measurements of gamma-ray pulse height distributions were also carried out 1 m above the ground surface outside the car for 15 min at 24 points along the survey route. The gamma-ray pulse height distributions were unfolded using a 22 × 22 response matrix for the estimation of absorbed dose rate in air. These dose rates were used to evaluate the dose rate conversion factor (nGy h–1 cpm–1). Radon-thoron discriminative measurements indoors To determine the concentrations of radon and thoron, RADUET detectors developed at the National Institute of Radiological Sciences (NIRS) in Japan were used in this study [15]. CR-39 was used to detect alpha particles emitted from radon and thoron as well as their progenies. To determine conversion factors of radon and thoron concentrations, these detectors were placed into the radon and thoron chambers at NIRS, respectively [16, 17]. After exposure tests, CR-39 plates were taken out of the chamber and chemically etched with a 6.25 M NaOH solution at 90°C over 6 h, and alpha tracks were counted with a track reading system. The evaluation of track in Image J and Microscope methods is well described by Bator et al [18]. Using two alpha track densities of low and high air-exchange rate chambers (NL and NH), radon and thoron concentrations were determined by solving the following equations [15]: (formula 1, 2) where XRn and XTn are the mean concentrations of radon and thoron during the exposure period in Bq m-3, CFRn1 and CFTn1 are respectively the radon and thoron conversion factors for the low air-exchange rate chamber in tracks of 2.3 cm-2 kBq-1 m3 h-1 and 0.04 cm-2 kBq-1 m3 h-1, CFRn2 and CFTn2 are respectively the radon and thoron conversion factors for the high air-exchange rate chamber in tracks of 2.1 cm-2 kBq-1 m3 h-1 and 1.9 cm-2 kBq-1 m3 h-1, T is the exposure time in hours, and B is the background alpha track density on the CR-39 detector in cm-2. The lower detection limit of the detector was practically estimated on the basis of the fact that one concentration depends on the other. The lower detection limits were 3 Bq m-3 for radon and 4 Bq m-3 for thoron. RADUET detectors were placed at a height of 1–2 m and 20 cm from the wall in 100 and 150 dwellings of the uranium and thorium bearing regions of Poli and Lolodorf respectively for 2-3 months. Spot outdoor and indoor gamma dose rate measurements were performed using a RadEye dose rate survey meter calibrated by comparison to a Gamma-RAD5 NaI(Tl) scintillation spectrometer. Measurements were conducted at 1 m height above the ground surface. Inhalation dose due to radon and thoron The inhalation dose is given by the following equation [19]: formula (3) XRn and XTn are the median radon and thoron concentration, einh,Rn is the inhalation dose conversion factor of 9 nSv/(Bq h m-3) for radon and einh,Tn is the dose conversion factor of 40 nSv/(Bq h m-3) for thoron, Focc is the occupancy factor of 0.6 for the studied areas, FRn, Tn is the equilibrium factor considered of 0.4 for radon and 0.02 for thoron, t corresponds to a year expressed in hours. The occupancy factor was derived from an in situ inquiry performed in the studied areas during field work. The equilibrium factor used is the default value given by United Nations Scientific Committee on Effects of Atomic Radiation (UNSCEAR) [19]. RESULTS AND DISCUSSION In the uranium bearing region of Poli, activity concentrations of 238U, 232Th, and 40K range respectively between 13-52 Bq kg-1, 10-67 Bq kg-1, and 242-777 Bq kg-1 with respective average values of 32 Bq kg-1, 31 Bq kg-1, and 510 Bq kg-1. In the uranium and thorium bearing region of Lolodorf, those activity concentrations range between 6-158 Bq kg-1, 6-450 Bq kg-1, and 98-841 Bq kg-1 with 34 Bq kg-1, 58 Bq kg-1, and 200 Bq kg-1 as respective mean values. The world average values for these radionuclides given by UNSCEAR [19] are respectively 33 Bq kg-1, 45 Bq kg-1, and 420 Bq kg-1. Air kerma rates range respectively between 25- 102 nGy h-1 and 11-357 nGy h-1 for the uranium and thorium bearing regions of Poli and Lolodorf with the mean values of 57 and 54 nGy h-1. At the worldwide level, they range between 24-160 nGy h-1 with the average value of 57 nGy h-1. The annual effective dose ranges respectively between 0.20- 0.83 mSv y-1 and 0.1-2.2 mSv y-1 with the mean value of 0.35 mSv y-1 and 0.33 mSv y-1 less than the world average value of 0.5 mSv y-1 given by UNSCEAR [19]. In the uranium region of Poli, radon and thoron concentrations indoors range respectively between 46-143 Bq m-3 and 18-238 Bq m-3 with the average values of 82 Bq m-3and 94 Bq m-3. The inhalation dose due to radon and thoron ranges respectively between 0.87-2.7 mSv y-1 and 0.08-1 mSv y-1 with the average values of 1.55 mSv y-1 and 0.4 mSv y-1. The total inhalation dose due to radon and thoron range respectively between 0.95-3.7 mSv y-1 with the average value of 1.95 mSv y-1. In the uranium and thorium bearing region of Lolodorf, radon and thoron concentrations indoors range respectively between 31-197 Bq m-3 and 6-700 Bq m-3 with the average values of 97 Bq m-3 and 159 Bq m-3. The inhalation dose due to radon and thoron ranges respectively between 0.6-3.7 mSv y-1 and 0.03-3 mSv y-1 with the average values of 1.84 mSv y-1and 0.67 mSv y-1. The total inhalation dose ranges between 0.6-6.7 mSv y-1. At the worldwide level inhalation dose due to radon ranges between 0.2-10 mSv y-1 with the mean value of 1.26 mSv y-1. The contribution of thoron to the total inhalation dose in the uranium and thorium bearing regions of Poli and Lolodorf ranges respectively between 3-34% and 1-79% with the average values of 20.3% and 27%. Thus thoron can not be neglected in dose assessment to avoid biased results in radio-epidemiological studies. CONCLUSION Natural radioactivity in most of the surveyed areas is normal. However there are high natural radiation areas found in most of the study areas. Radon and thoron exposure is reality in Cameroon. Thoron contribution to inhalation dose is higher than 20%. Thus thoron can not be neglected in dose assessment. Thoron is abundant in the uranium and thorium regions of Poli and Lolodorf. However extensive measurements of radon and thoron at nationwide scale are needed. In case high inhalation doses are confirmed, epidemiological study could be planned. A project (CMR9009) dealing with Establishing a national radon plan for controlling public exposure due to radon indoors is ongoing since the beginning of 2018. This two years project is funded within the framework of the technical cooperation between the International Atomic Energy Agency (IAEA) and Cameroon. REFERENCES 1. Saïdou, Bochud F, Baechler S, Kwato Njock M, Ngachin M, Froidevaux P. Natural Radioactivity measurements and dose calculations to the public: case of the uranium-bearing region of Poli in Cameroon. Radiation Measurements 46 (2011), 254-260. 2. Saïdou*, Bochud F, Baechler S, Kwato Njock M, Froidevaux P (2014). Baseline Radiological Survey of the Uranium bearing Region of Poli (Northern Cameroon). Proceedings of the International Conference on Remediation of Land Contaminated by Radioactive Material Residues, 18-22 May 2009, Astana, Kazakhstan. ISBN 978–92–0–142310–8 3. Saïdou*, Abdourahimi, Tchuente Siaka YF, Bouba O. Indoor radon measurements in the uranium regions of Poli and Lolodorf, Cameroon. Journal of Environmental Radioactivity 136 (2014), 36-40. 4. Saïdou*, Abdourahimi, Tchuente Siaka YF, Kwato Njock MG. Natural Radiation Exposure of the Public in the oil-bearing Bakassi Peninsula, Cameroon. Radioprotection, Vol 50 (2015), 35-41. 5. Saïdou*, Elé Abiama P, Shinji Tokonami. Comparative study of natural radiation exposure in three uranium and oil regions of Cameroon. Radioprotection 50(4) (2015), 265-271 6. Saïdou*, Tokonami S, Janik M, Bineng G, Abdourahimi, Ndjana Nkoulou II J. Radon-Thoron discriminative measurements in the high natural radiation areas of Southwestern Cameroon. Journal of Environmental Radioactivity 150 (2015), 242-246. 7. Saïdou*, Tokonami S, Elé Abiama P. Natural Radiation Survey in the uranium and thorium bearing regions of Cameroon. Radiation Environment and Medicine 5(1) (2016), 53-58. 8. Dallou Guy Blanchard, Ngoa Engola Louis, Ndjana Nkoulou II Joseph Emmanuel, Saïdou*, Tchuente Siaka Yvette Flore, Bongue Daniel, Kwato Njock Moïse Godfroy. NORM measurements and radiological hazard assessment in the gold mining areas of East-Cameroon. Radiation Environment and Medicine Vol. 6 (2017), No. 1. 9. Ngoa Engola Louis, Ndjana Nkoulou II Joseph Emmanuel, Masahiro Hosoda, Bongue Daniel, Saïdou*, Naofumi Akata, Koukong Heya, Kwato Njock Moïse Godfroy, Shinji Tokonami. Air Absorbed Dose Rate Measurements and External Dose Assessment by Car-Borne Survey in the Gold Mining Areas of Betare-Oya, Eastern-Cameroon. Accepted for publication in Japanese Journal of Health Physics. 10. Elé Abiama, P., Owono Ateba, P., Ben-Bolie, G.H., Ekobena Fouda, H.P. and El Khoukhi, T. High background radiation investigated by gamma spectrometry of the soil in the southwestern region of Cameroon, J Environ Radioact, 101 (2010), 739–43. 11. International Atomic Energy Agency (IAEA). Safety Standards Series No. GSR Part 3: Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards. 12. Hosoda, M., Tokonami, S., Omori, Y., Sahoo, S.K., Akiba, S., Sorimachi, A., Ishikawa, T., Nair, R.R., Jayalekshmi, P.A., Sebastian, P., Iwaoka, K., Akata, N. and Kudo, H. Estimation of external dose by car-borne survey in Kerala, India, PLoS ONE, 10 (4) (2015). 13. Hosoda, M., Inoue, K., Oka, M., Omori, Y., Iwaoka, K., and Tokonami, S. Evaluation of Environmental Radiation Level by Car-borne Survey – The Outline of the investigation of Aomori Prefecture - , Jpn. J. Health Phys., 51(1) (2016), 27-40. 14. Inoue, K., Arai, M., Fujisawa, M., Saito, K. and Fukushi, M. Detailed Distribution Map of Absorbed Dose Rate in Air in Tokatsu Area of Chiba Prefecture, Japan, Constructed by Car-Borne Survey 4 Years after the Fukushima Daiichi Nuclear Power Plant Accident. PLoS ONE 12(1) (2017). 15. Tokonami, S., Takahashi, H., Kobayashi, Y., Zhuo, W. Up-to-date radon-thoron discriminative detector for a large scale survey. Rev. Sci. Instr. 76 (2005), 113505. 16. Janik, M., Tokonami, S., Kranrod, C., Sorimachi, A., Ishikawa, T., Hassan, N.M., 2010. International intercomparisons of integrating radon/thoron detectors with the NIRS radon/thoron chambers. Radiation Protection Dosimetry 141 (4), 436–439. 17. Tokonami, S., Ishikawa, T., Sorimachi, A., Takahashi, H., Miyahara, N. The Japanese Radon and Thoron Reference Chambers. AIP Conf. Proc. 1034 (2008), 202–205. 18. Bator, G., Csordas, A., Horvath, D., Somlai, J., Kovacs, T. A comparison of a track shape analysis-based automated slide scanner system with traditional methods. J Radioanal Nucl Chem. (2015) DOI 10.1007/s10967-015-4013-9. 19. United Nations Scientific Committee on the Effects of Atomic Radiation. UNSCEAR 2000 Report. Sources and Effects of Ionizing Radiation Vol. 1. (2000), United Nations, New York, USA.

Speaker: Prof. SAÏDOU (Institute of Geological and Mining Research)

13:00 Lunch Break

Advances in Exploration

Conveners: Dr Mark Mihalasky (U.S. Geological Survey), Dr Ziying Li (Beijing Research Institute of Uranium geology)

167 CONTRIBUTION TO THE CHARACTERIZATION OF THE HOST FORMATION OF THE FRANCEVILLIAN URANIUM MINERALIZATION (HAUT OGOOUÉ PROVINCE, GABON): PETROGRAPHY, SEDIMENTOLOGY, STRATIGRAPHY, AGE AND NEW ISOTOPIC DATA

INTRODUCTION Five uranium deposits, within the Francevillian mineral lease, trapped in the paleoproterozoique sandstone of the non-metamorphosed Francevillian basin in Gabon has been explored starting in the 60’s and exploited by the company COMUF. A total of 26,600t of uranium metal have been exploited during 38 years in open-pit and underground mines (Mounana, Boyindzi, Oklo, Okélobondo and Mikouloungou). Recent exploration drill cores, done by AREVA, in Bagombé, Mikouloungou and Suly district (close to Oklo deposit), have highlighted undescribed geological features as pluri-centimetric fine grained yellow sedimentary layers interbedded in the tidal FA sandstone formation, host of the main mineralization. These original layers have been found in several drill cores on each explored area and then have been studies to identify their origin. New mineralization types of occurrences have also been discovered as uranium mineralization veins in the basement. This discovery arouses interest on the genetic model of theses occurrences and a general review of the uranium metallogeny of the district has been launched, using modern technics for isotopic dating and trace elements measurement. YELLOW LAYER CHARACTERISATION One of the remarkable lithologic and petrographic features of the Mikouloungou and Bagombé Francevillian sandstone FA formation is the presence of yellow strips (“YS”), interbedded in the sandstone series. At the macroscopic scale, the “YS” are marked by their contrasting yellow color and fine to medium grained texture with strong lamination, as well as sliced contacts. It can be founded within medium to coarse sandstone, conglomerate or at the unconformity between the granito-metamorphic basement and the sedimentary cover. These “YS” have a thickness of a few centimeters and disintegrate easily because of the lamination which seems to be rich in phyllitic material (micas and clays). Assumptions made by onsite geologists for the “YS” origin were: (i) kind of small scale “mylonitic” zones resulting from horizontal glide accommodation; (ii) bottom set of dune or (iii) volcanic layers (cineritic type). Around ten occurrences of this these formations have been sampled in three areas distant from each other of about thirty kilometers. Thin sections have been made in each sample and have been studied using optical microscopy and SEM. All the sections present the same main characteristics: - the matrix constituted by fine micas and clays is dominant. The clay result from the alteration and give the yellow color of the formation at the macroscopic scale. - all the elements are floating in the matrix and orientated, highlighting the stratification. - the major elements are mainly quartz and few feldspar. The quartz are limpid and often flat, angular sometime as splinters and often cup-shaped on the edges. Some quartz are slightly stocky and present evidence of crystalline hiatus (rhyolitic). - there is a strong concentration of accessory heavy minerals as zircons and monazites, as observed in volcanic tuffs. All these specific observations argue for characteristic volcanic quartz and for local cineritic deposits (hypothesis iii). They possibly represent good stratigraphic marker at the regional scale and additional studies could be necessary to attempt a correlation. This could help to better constrain the discussed age of the Francevillian basal FA formation. This identified volcanic contribution within the FA sandstone could be a supply for the uranium stock in the basin. URANIUM MINERALIZATION • SAMPLING & ANALYTICAL METHODS Following the discovery of fractures filled with uranium mineralization in the basement, at the contact with the sedimentary FA formation in Mikouloungou deposit, several mineralization of different type of uranium occurrences have been sampled. To compare them with known mineralization, samples from Oklo deposit have also been collected to be reanalyzed with the same modern technics. Samples have been studied using traditional optical and electronic microscopy for petrographic observation, ion microprobe (CAMECA IMS1280) for punctual U-Pb isotopic dating. For Oklo samples, laser ablation (LA-ICP-MS) for punctual REE analyze on uranium oxides has also been applied. • MIKOULOUNGOU RESULTS The UO2 mineralization occupies three types of habitus: (i) in the porosity of sandstones, (ii) included within organic matter (O.M.) or in relation with it, and (iii) filling of micro-fractures affecting unconformity basement samples with associated sulfides (chalcopyrite, galena and pyrite). 346 punctual isotopic U-Pb analyses have been measured on several thin sections. This set of measures gives the following group of age: - Around 800 Ma, between 860 and 750 Ma, mainly in basement fractures; - Around 520 Ma, between 630 and 410 Ma, for pitchblende in the porosity or uraninite crystals in organic matter, with some isolated values around 246 Ma or around 1730 Ma, the latter being linked to micro-inclusions of galena in the uraninite crystals. - The Concordia diagrams show sometimes low intercept around 120 Ma indicating a reset of the system at that time. All the dated mineralization in this work on Mikouloungou give only the younger ages described so far [1] for Oklo deposit. However the oldest ages described in Oklo deposit [2] has not been found. • OKLO RESULTS In order to confirm the oldest ages obtained on Oklo mineralization with punctual analyzes some samples of massive pitchblende and uraninite from Oklo natural reactors were recently studied with the ion probe for isotopic U-Pb data. Three samples from the quarry outcrop (supposed to be out of the reactors) presenting uranium mineralization in cracks or associated with O.M., have also been analyzed. Isotopic disequilibrium Oklo mineralization has been, in some places, affected by a natural fission reaction which has consumed a part of the 235U, called natural reactor, leading to a disequilibrium compared to all the natural uranium on the Earth [3-4]. The set of isotopic analyze measured with the IMS 1280 ion probe, has been adapted for these special samples, to measure more precisely the 235U and calculate the isotopic disequilibrium. Standard used for calibration is an uraninite from Zambia. The 235U/238U of the standard is constant and gives a value of 0.007104. The ratio (235U/238U) sample/(235U/238U)standard, should be 1 if the uranium isotopes are at the equilibrium. Results from 4 samples from the drill hole D73-S2 intersecting the reactor n°10 give statistic results between 0.88 and 0.73, which confirm the disequilibrium. Age For the reactor samples, Concordia diagrams show dispersed high intercept of the Discordia around 1700 ± 100 Ma without 235U correction. Considering the 235U loss, it is possible to apply a correction factor which changes the slope of the Discordia giving focused range of high intercepts distributed between 1979 ± 18 Ma and 2028 ± 30 Ma. The three samples coming from the quarry present younger ages ranging from 533 ± 27 Ma to 557 ± 6 Ma, similar to main group of age from the sandstone uranium mineralization of Mikouloungou. REE signature On the Oklo reactors samples, rare earths elements have measured by laser ablation ICP-MS. The rare earths spectra, normalized to the Chondrite C1, show reproducible spectra with identical forms, characterized by high LREE and low HREE and a gadolinium negative anomaly. Theses spectra show a double “tetrad effect” in the LREE and low REE as already described in previous works [5]. • DISCUSSION All the dated mineralizations for this work on Mikouloungou give younger ages than those historically established for the mineralization of the Francevillian basin [2]. The older ages close to 2 Ga are always linked, in his study, to natural nuclear reactors. No evidences of these older ages have been seen in the other type of mineralization. These ages are younger than the emplacement of dolerite veins (955-970 Ma [6]), and part of them are synchronous with the phase of pan-African deformation between 500 and 600 Ma. The last group of age, linked to the lower intercept in the Concordia diagram could results from a resetting of the isotopic system link to opening event of the Atlantic Ocean.   CONCLUSION These works issued from exploration staff of Orano Mining Group (Areva) combined with specific sedimentological, petrographic and metallographic works in the R&D programs, conduct to original results, (i) on specific volcanic origin for yellow strips constituting possible regional stratigraphic marker and possible synsedimentary source for at least a part of the uranium in the basin; (ii) ages of different mineralization types in Mikouloungou younger than the first mineralization event in Oklo; (iii) 235U loss in the uraninite crystals of Oklo reactors due to the natural fission and conducting to an old age around 2 Ga as given by former data, with other analytical technic [7] and (iv) the original spectra with double “tetrad effect” for the same Oklo reactors uraninite crystals. REFERENCES [1] NAGY B. et al., Organic matter and containment of uranium and fissiogenic isotopes at the Oklo natural reactors, Nature, Vol. 354, p. 472–475, 1991 [2] GAUTHIER-LAFAYE F., Time constraint for the occurrence of uranium deposits and natural nuclear fission reactors in the Paleoproterozoic Franceville Basin (Gabon), GSA Mem. 198, p.157-167., 2006. [3] BODU R., BOUZIGUES H., MORIN N., PFIFFELMANN J-P., Sur l’existence d’anomalies isotopiques rencontrées dans l’uranium du Gabon, CEA, Compte Rendu de l’Académie des Sciences, Vol. 275, p. 1731-1734, 1972. [4] NEUILLY M., BUSSAC J., FREJACQUES C., NIFF G., VENDRYES G., YVON J., Sur l’existence, dans un passé reculé, d’une réaction en chaine naturelle de fissions dans le gisement d’uranium d’Oklo (Gabon), CEA, Compte Rendu de l’Académie des Sciences, Vol. 275, p. 1847-1849, 1972. [5] HIDAKA, H. et al., Lanthanide tetrad effect observed in the Oklo and ordinary uraninites and its implication for their forming processes, Geochemical Journal, Vol. 26, pp. 337 to 346, 1992. [6] BONHOMME M.G. et al., An example of lower proterozoic sediments: The Francevillian in Gabon, Precambrian Research, Vol. 18, p. 87-102, 1982 [7] GANCARZ, A.J., U-Pb age (2.05 x 109 years) of the Oklo uranium deposit, COLLECTION COMPTES RENDUS DE GROUPES D’ETUDE PANEL PROCEEDINGS SERIES. Les réacteurs de fission naturels, Natural fission reactors, IAEA-TC-119/40, 1978.

Speaker: Dr Marc BROUAND (Orano Group)

168 Radon Monitoring in the Soil Air with Nuclear Track Detectors – Uranium Exploration Method

INTRODUCTION The nuclear track detector uranium exploration method was presented and its limitations due to the effect of the moisture content in material that covers uranium mineralization as well as the thickness and uranium concentration of that overburden were considered. The radon survey was carried out over uranium anomalies that were confirmed by drilling. The radon results were used to optimize targets for future exploration drilling programs. METHODOLOGY DESCRIPTION Radon in U-orebodies and their overburden Radium 226 of the uranium decay series generates the inert radioactive gas radon (222Rn) that has a half-life of 3.8 days. Radon can “migrate” relatively long distances towards the ground surface from uranium mineralization and/or a uranium anomaly. The principal mode of radon transport in soil/sediment that covers any uranium mineralization is diffusion. A less common but very important mode of radon transport is flow through geological cracks and voids. The radon gas diffusion process in any porous media can be almost inhibited by water saturation. The radon activity concentration in air, RnAC(Bq/m3), that is contained in the uranium ore intergranular space can be calculated as follows [1]: RnAC(Bq/m3) = a(226Ra)ρE where a(226Ra) is the specific radium activity of the ore, ρ(kg/m3) is the bulk density of uranium ore and E is the radon emanation coefficient. After the following values were substituted for a(226Ra) = 12,400 Bq/kg (the equilibrium specific activity of 226Ra of the 0.1% U-ore is 12,400 Bq/kg), ρ=1,500 kg/m3 and E = 0.2 the equilibrium radon activity concentration in air of approximately 3,700,000 Bq/m3 was calculated for the uranium orebody. The radon air activity concentration profile, RnAC(X), for a thick layer of porous non-radium bearing material can be approximately described by the following formula: RnAC(X) = RnAC(0) exp(-λ222Rn/D . X) where X is the distance from the surface of the uranium mineralization, RnAC(0) is the radon activity concentration at the orebody/cover layer boundary, D (m2 s-1) is the radon diffusion coefficient and λ222Rn (2.1 10-6 s-1) is the radon decay constant [2]. The effect of the moisture content on the radon activity concentration in uranium ore intergranular pores and in its covering material is well known and is mainly governed by the diffusion constant changes with the relative water content [3]. For example if a 5 m wide uranium mineralization with 0.1% uranium ore grade is overlayed by a 5 m thick earth material layer with relative moisture content of 4%, 11%, 15%, 16% and 18% respectively, the long-term average radon activity concentration at 0.1 m below the surface of that layer could be calculate as 35,000 Bq/m3, 24,000 Bq/m3, 21,000 Bq/m3, 1.9 Bq/m3, and 0.01 Bq/m3 respectively [2]. Since the overburden of a uranium source also contains some uranium and radium, the measured radon activity concentration below the surface of the overlaying material includes its radon activity concentration in addition to an incremental radon activity concentration caused by the radon diffusion from the mineralization. The radon air activity concentration in the 5 m thick porous overburden layer with 1 ppm U can be calculated by the following formula [2]: RnAC(X) = 12.4 ρ E [1 – [cosh(λ222Rn/D X)/(cosh(λ222Rn/D XL)] where 12.4 Bq kg-1 is the equilibrium specific activity of 226Ra of overlay material layer and XL(m) = 5 m is the thickness of the layer. The radon air activity concentrations of 220 Bq m-3, 330 Bq m-3, 370 Bq m-3, 950 Bq m-3, and 2,700 Bq m-3 respectively were calculated considering the relative moisture content of 4%, 11%, 15%, 16% and 18% respectively. RADON MONITORING BY NUCLEAR TRACK DETECTORS The short-term radon air activity concentration near the surface of the material cover of uranium orebodies is affected by wind, ground temperature, rain water, etc. In order to minimize these short-term effects on the measured radon air activity concentration it is necessary to use a radon monitoring technique that measures the long-term average radon activity concentration and be able to measure the radon activity concentration within a range of about 50 – 1,000,000 Bq m-3. The most appropriate and “robust” radon monitor suitable for large scale field application is a nuclear track detector. In the seventies and eighties this method was used for uranium exploration [4]. However, it is not known if the method with its nuclear track detector arrangement was instrumental in any new uranium deposit discovery. In 1980 the first author developed the nuclear track detection method for radon monitoring in the soil air and in water [5], [6], [7]. Based on the previously published work the Nuclear Track Uranium Ore Exploration Tool (NTUOET) was developed. The NTUOET includes the nuclear track detector Kodak LR-115(type 2) that is situated inside a plastic “cavity badge” (the Passive Radon Monitor, PRM). A moisture protector is used also prevents the entry of Thoron to the PRM. The PRM is inserted into a 17 cm long plastic conduit with its top opening sealed with a plastic cap (The PRM is held inside the plastic cap with a piece of foam. The NTUOET is inserted into a 20 cm deep hole with the top of the plastic cap at the surface. It is required to slightly compact dirt around the conduit. This robust design enables a large number of NTUOET units to be deployed during one day. The units are then collected after an exposure time of 2 – 3 weeks. As this method is relatively inexpensive an exploration manager can use a number of units to obtain a more detailed radon activity concentration contour plan of the site that can be used to optimize the drilling program and thus to carry out uranium exploration more cost-effectively. DevEx RESOURCES LIMITED URANIUM EXPLORATION AT NABARLEK The history of the Nabarlek uranium mine The deposit was delineated by diamond drilling in 1970 and 1971. Open cut mining took place between June and October 1979 with the ore stockpiled for milling. 546,437 t of ore were mined at an average grade of 1.84% U3O8. The mill commenced operation in June 1980 and ran until 1988, during which time 11,084 t U3O8 were produced. The site was rehabilitated by 1995 (Lally, J. & Bajwah, Z. (2006). As the geology around the old Nabarlek uranium deposit includes a number of outcrops with elevated uranium DevEx Resources Limited (the Company) acquired exploration leases that include the old Nabarlek mining leases. The Nabarlek uranium exploration program The Company carried out several exploration/drilling campaigns since acquiring the Nabarlek Project. This presentation summarises the most recent results of a radon survey that was carried out by the Company in 2016. In order to improve the accuracy of radon monitoring a scintillometer was also used to take a gamma count reading at radon sampling locations showing elevated radon. The radon survey was carried out over three areas with NTUOET units positioned over a 100m (west-east) by 200m (north-south) grid. The first area served to test a largely unexplored region within a valley defined by sandstone escarpments located 12 km southeast of the Nabarlek mine site. The second area was to test a line of drilling from 2015 comprising four reverse circulation (RC) drillholes at the GC11 prospect. The third area was situated about 2 km west of the GC11 prospect to test for radon leakage over a ground gravity anomaly. NTUOET units placed within the sandstone valley showed a distinct elevated radon anomaly trending southeast along a potential fault delineated by radon readings ranging 3,018 - 53,444 Bq m-3 within a background range of 95 – 2000 Bq m-3. Radon stations to the north and south of this trend are at background levels and sharply constrain the anomaly. This anomaly represents a strong exploration target and is recommended for drill testing. Two RC drill holes at the GC11 prospect intersected elevated uranium concentrations within dolerite, with the best results including 2m @ 2,354ppm U3O8 from 135m downhole in drillhole NAR7537; and 5m @ 1,065ppm U3O8 from 169m downhole in drillhole NAR7535. Following this drilling program it was decided to place a number of NTUOET units within and near the area where the drill holes were situated. The radon air activity concentrations that were measured within the 50 m radius of each drill hole were within a range of 2,041 – 4,043 Bq m-3 with a background range of 282 – 1,339 Bq m-3. We compared the radon measurements with results of the exploration drilling program and confirmed a relationship between elevated radon and anomalous subsurface uranium concentrations. The NTUOET readings west of the GC11 prospect showed elevated radon towards the east of the survey line within the range of 2,955 – 7,121 Bq m-3 with a background range of 282 – 1,960 Bq m-3. These elevated readings are situated around a region of interpreted structural complexity based on ground gravity data and may represent a migration pathway for radon gas. DISCUSSION AND CONCLUSSIONS Northern Australia where the DevEx Resources Limited Nabarlek exploration leases are situated has a sub-tropical climate with the majority of rainfall occurring during the ‘wet season’ i.e. between November and April. Therefore, the radon survey was carried out during September – October 2016 i.e. at the end of the ‘dry season’ when the ground is more likely “dry”. Although some moisture content was detected inside of some NTUOET units, the trends of measured radon air activity concentrations did not indicate that soil moisture content affected the survey outcomes. Scintillometer readings taken over radon stations of interest showed counts per second (CPS) measurements that were less than the defined upper background limit of 200 CPS. These results indicate the source of radon is not near-surface and could represent a uranium source at depth. The authors are grateful to the management of DevEx Resources Limited for providing data of the exploration program and for giving permission to publish this abstract. REFERENCES [1] INTERNATIONAL ATOMIC ENERGY AGENCY, Measurement and Calculation of Radon Releases from Uranium Mill Tailings, Technical Reports Series No. 333, IAEA, Vienna (1992). [2] Alekseev, V.V. et all., Radiometric method for the prospecting and exploration of uranium ores. Translaction of State Scientific-technical Publishers of Literature on Geology and Mineralogy Resources Conservation. US Atomic Energy Commission Report No. AEC-tr-3738 (Book 2), (1957). [3] Hart, K., Radon Exhalation from Uranium Tailings. Volume 1 of a thesis submitted to the University of NSV for the degree of Doctor Philosophy, page 259, (1986). [4] US Patent, Reducing Noise in Uranium Exploration, US Patent US4063087 (Expired), Author: Robert L. Fleischer (1976). [5] Kvasnicka, J., Radon Concentration in the Soil Air Measured by Track Detectors, Nuclear Instruments and Methods, 174, pp. 599-604 (1980). [6] Kvasnicka, J., Radon Concentration in Water Measured by Track Detectors, Nuclear Instruments and Methods, 206, pp. 563-567 (1983). [7] Kvasnicka, J., Theory of Alpha Activity Measurement by Nuclear Track Detectors, Nuclear Tracks and Radiation Measurements, Vol. 11, Nos. 1-2 pp. 81-84 (1986). [8] Lally, J. & Bajwah, Z., Uranium Deposits of the NT, Report 20, Northern Territory Geological Survey, ISBN 0-7245-7107-8 (2006).

Speaker: Dr Jiri Kvasnicka (Radiation Detection Systems)

169 Uranium-Lithium Deposits at Macusani, Peru: Geology, Processing & Economics along the path to production

INTRODUCTION The swarm of near-surface uranium orebodies of the Macusani district, southern Peru, controlled by Plateau Uranium Inc., contain mineral resources of 51.9 Mlbs at 248 ppm U3O8 (20.0 ktU at 210 ppm U - Measured & Indicated) and 72.1 Mlbs at 251 ppm U3O8 (27.8 ktU at 212 ppm U - Inferred) using 75 ppm U economic cut-off [1]. This Preliminary Economic Assessment study has shown the easily leachable, near surface mineralization constitutes a major, potential low-cost uranium source capable of producing uranium at cash costs of US$17.28/lb U3O8 (US$44.5/kgU). The deposits are genetically anomalous: although the predominant host-rocks are rhyolitic volcanics and hypabyssal intrusions with geochemical affinities with the U-rich Hercynian S-type granites, the hexavalent uranium mineralogy, comprising meta-autunite and weeksite, is akin to that of other surficial systems [2], and differs fundamentally from all recognized high- and low-temperature uranium deposit clans [3]. The uniqueness of the district is also highlighted by the exceptional, inherent, lithium endowment of the host volcanics. Both the Miocene bedrock geology and the Plio-Pleistocene geomorphology and climatic history of the district are critical to an understanding of the origin of these unique uranium deposits. This unique origin is key to the excellent potential economics of these near surface, low-grade uranium deposits. GEOLOGICAL SETTING The Macusani uranium district is located at Lat. 13° 57’ S; Long. 70° 37’ W in northern Puno Department, southern Peru, and is essentially cospatial with the Quenamari Meseta at an elevation ranging from ca. 4400 to 5000 m a.s.l. The Quenemari meseta separates the WNW-trending Carabaya-Apolobamba and Vilcanota segments of the Cordillera Oriental (Eastern Cordillera). The high plateau is underlain by an Upper Miocene (10.1-6.7 Ma) succession of subaerial glass-rich and unwelded rhyolitic flows assigned [4] to the Macusani Formation, which attains thicknesses in excess of 500 m and covers an area approaching 1500 km2. The Macusani Formation is the youngest unit of the Quenamari Group, locally the youngest major magmatic unit of the Central Andean Inner Arc Domain [5], and represents the sole important host for uranium mineralization. The rhyolites are dominated by lapilli-crystal-ash tuffs and pumice flows, extremely rich in broken phenocrysts, and lacking fabrics ascribable to ignimbritic, ash-flow processes. No early Plinian explosive stage occurred, and eruption of extremely viscous magma into an actively-subsiding tectonic basin is envisaged as occurring as frothy debris-flows ]6] from vents around the southern margin of the field. Subsidence and volcanism were nucleated by a series of NNW-striking, sinistral, transcurrent, crustal-scale faults which accommodated the initial rotation of the Bolivian Orocline in the latest-Oligocene, representing the beginning of the ongoing Quechua Orogeny [7]. The rhyolites are strongly-peraluminous (A/CNK, including Li = 1.19-1.35; normative corundum exceeding 2), exemplified by phenocrystic muscovite, andalusite, tourmaline, sillimanite and cordierite/osumulite, but are also enriched in alkalis (K, Na, Li, Rb, Cs), as well as lithophile metals (Sn, Nb, Be), HFSE (Ta, W, U), and “volatile” elements (B, F, P). Magmas were generated at moderate temperatures (max. 800°C) and high pressures through vapour-undersaturated, low-fraction, partial melting of batches of mature, pelitic metasediments, probably induced by mantle melt incursion into thickening continental crust [7, 8, 9]. Magmatism occurred in a transpressional tectonic regime accompanying antithetic subduction and delamination of Brazilian Shield lithosphere. The uranium content of unaltered rhyolites, hosted by accessory monazite and apatite, but predominantly by pumiceous and matrix glasses, averages 10-30 ppm, and the rhyolites display geochemical affinities to the uraniferous, post-collisional SP, S-type, two-mica Hercynian granites [7,8]. The lithium potential of the district is entirely represented by the inherent magmatic endowment of the main succession of rhyolites. These average 400-600 ppm Li (8,9), hosted in part by phenocrystic biotite, muscovite and sodic plagioclase, but predominantly in volcanic glass, making 70% of the Li easily leached in dilute sulphuric acid at moderate temperatures of 85°C. GEOMORPHOLOGICAL SETTING The Macusani Formation flows dip at ca. 3° NE, but the surface of the meseta is defined by a more gently, NE-dipping, sub-planar, erosional pediment, generated through uplift under semi-arid climatic conditions at ca. 5 Ma.. To the west, the meseta surface exhibits an abrupt backscarp rising to the 5645 m a.s.l. Quelccaya temperate mountain ice-cap. Although Quelccaya is fast receding, it remains the world’s largest tropical ice mass [10], with a firn-line at 5250 m and surrounded by steeply-plunging outlet glaciers. Quelccaya formed part of a continuous ice-cap extending from northern Bolivia to southern Peru in the Early Pleistocene, but had become isolated by the Late Pleistocene. It has expanded and contracted radically and abruptly over the past ca. 700 ka [11,12]. The meseta, now stripped of glacial/fluvioglacial sediments, is traversed by a series of ENE-trending fluvial canyons, converging on the valleys of the Macusani and San Gaban rivers which, in the austral summers channel warm, humid Atlantic air from the contiguous Amazonian lowlands. Annual precipitation, largely as rain, averages 3000 mm. URANIUM MINERALIZATION The major uranium mineral in the Macusani district is finely acicular-to- platy, yellow-orange meta-autunite (Ca[(UO2)(PO4)]2(H2O)6-8) [13,14] with subordinate weeksite (K2(UO2)2(Si5O13)(H2O)4) [3]. Despite previous descriptions [15], no uraninite or pitchblende has been observed. Meta-autunite and weeksite occur as disseminations in rhyolite, replacing apatite phenocrysts and infilling original volcanic cavities, and as stockworks of 1-3 cm-wide veins, controlled by subvertical cooling joints and steeply-dipping, NE-striking faults, as well by flat-lying structures sub-parallel to volcanic stratigraphy. Deposition of the uranyl minerals is sometimes associated with powdery to crudely botryoidal, black oxide mineraloids, largely Mn-rich, but locally dominated by Fe and Si. White, clay-like moraesite (Be2(PO4)(OH)·4H2O) occurs erratically with the uranium minerals, or forms separate veinlets. Over 95 percent of the strictly primary uranium mineralization is hosted in rhyolite flows and hypabyssal stocks, but high-grade mineralization occurs locally in coarse terrigenous clastic and epiclastic interbeds along the eastern margin of the volcanic field. With the exception of radiation-induced smokiness in quartz phenocrysts, no hydrothermal alteration is associated with the deposits, and there is no evidence of uranium depletion surrounding mineralization, implying that the uranium was not largely locally derived. Although the rhyolites are enriched in lithophile metals, only beryllium appears to have been mobilised with uranium. Earlier hydrothermal activity, ranging from post-magmatic F-rich (topaz-muscovite-quartz) greisening, in the vicinity of intrusive bodies, to more widespread intermediate-argillization (F-rich illite and Ca-montmorillonite/ nontronite) was similarly ineffective in concentrating Sn, Nb, Ta, W and U. Barren, advanced-argillic (kaolinite-quartz) alteration is intense both in the vicinity of the faulted Rio Macusani trough and along contiguous interflow contacts, but predated uranium mineralization. The uranium orebodies are focused in at least two 15-60 m-thick mantos, sub-parallel to the surface of the meseta, but discordant to volcanic stratigraphy. Mineralization is concentrated within ca. 200 m of surface, in the upper, 7 ±1 Ma flow sequence [4]. Here, the majority of the deposits occur adjacent to the upper slopes of the canyons dissecting the plateau, with a striking areal concentration in the vicinity of their confluence with the main Macusani River valley. However, high-grade mineralization with higher weeksite content occurs locally within and at the base of the 10 ±1 Ma flows, beneath the floor of the valley. URANIUM DEPOSITION CONDITIONS Fluid inclusions have not been observed in either meta-autunite or weeksite, but a low temperature and/or unusually brief duration of ore formation may be inferred from the preservation of the magmatic high-sanidine, disordered crystal structure of translucent K-feldspar phenocrysts in immediate contact with uranium mineralization. Investigation of the nature of the ore-forming aqueous fluids through light-stable isotopic chemistry is inhibited by the absence of mineral-water oxygen and hydrogen fractionation data for uranyl minerals, but the structural affinities of meta-autunite and smectite suggests that the latter may serve as a proxy. The δ18O and δ2H compositions of the meta-autunite, respectively are 5.2-14.7 and -141 to -83 per mil, and fall well outside the “magmatic box”, implying that meteoric waters were responsible for uranium mineralization. Application of the fractionation factors determined for smectite [16,17], and assuming that ore deposition took place at ca. 15°C, ambient near-surface temperatures on the meseta, yields oxygen and hydrogen isotopic water compositions of -21.7 to -12.2 per mil and -181 to -123 per mil, respectively [3], defining a field overlapping extensively with that of the Quelccaya ice-cap [18]. Similar water oxygen isotopic compositions are estimated [3] by applying the incremental fractionation calculation proposed for hydroxyl-bearing silicates by Zheng [19] to meta-autunite. AGE OF MINERALIZATION Application of U-Pb geochronology to the Macusani deposits [20] is precluded by the high content of common lead and minimal radiogenic lead in meta-autunite, evidence for youthful crystallization but defining only very imprecise ages in the approximate range 350 ka to 1.06 Ma. In contrast, U-series (U-Th-Pa) geochronology [21,22] applied using LA-ICP-MC (Multicollector)-MS analysis of natural and cut surfaces of meta-autunite and weeksite vein-fill from six prospects at the eastern/northeastern margin of the meseta, yields acceptable dates for crystallization or re-crystallization, all extremely young. The technique utilizes the gradual increase in 230Th and 231Pa through, respectively, 234U and 235U decay, until secular equilibrium is attained at, respectively, ca. 500 and 300 ka. Isotopic ratios for multiple sites in small volumes of mineral are plotted on Concordia diagrams with calculated 231Pa/235U activity ratios as the ordinate and 230Th/234U ratios as the abscissa. Four samples yielded concordant or near-concordant data, with ages of +500, 335, 130 and 75-65 ka, while five defined discordia extending from the origin to Concordia, with upper intercepts of +500, 397, 218-207 and 113-103 ka. Other samples gave discordant compositions with no meaningful intercepts with Concordia. The data are evidence for open-system behaviour, most probably involving variable, and in cases mutually differing, gains and losses of 230Th and 231Pa, a process extending over at least the past 500 ka, i.e., through much of the Late Pleistocene. Several samples, including one comprising both meta-autunite and weeksite, reveal multiple episodic mineralization events. ORE-GENETIC MODELLING The Macusani uranium mineralization has been widely assigned [e.g., 23] to the IAEA clan of “volcanic-related” deposits, exemplified by, Strel’tsovskoe, Sierra Pena Blanca and BaiYangHe. However, although uranium was certainly derived from strongly-peraluminous silicic magmas, the Macusani deposits lack U+4 minerals – the U+6 minerals, meta-autunite and weeksite are primary, not supergene. In addition, although post-magmatic and lower-temperature activity was widespread, this caused no mobilization or concentration of either uranium or lithophile metals. Instead, the uranyl minerals were directly precipitated at low temperatures from entirely meteoric waters at least 4 Ma after the local cessation of magmatic activity. Mineralization does locally occur in terrigenous sediments at the eastern margin of the basin, but, uranium precipitation is not associated with reductants as in traditional sandstone-hosted systems: in contrast, the close association with Mn-Fe oxide mineraloids is inferred to reflect their highly-absorbing nature, promoting meta-autunite precipitation even in undersaturated conditions [24]. Although the environment of mineralization is largely near-surface, it extends locally to depths of several hundreds of metres, precluding analogies with other “surficial” uranium deposit clans [e.g., 2, 23]. A critical constraint on ore-genetic modelling is the age of mineralization. The Macusani uranium deposits are undoubtedly extremely young, but the U-Th-Pa geochronology does not unambiguously discriminate between original deposition and subsequent modification of the dominant uranium mineral, meta-autunite. Nonetheless, the radiogenic isotope relationships show clearly that the ore assemblages were subject to multiple reconstitution since ca. 500 ka, demonstrating that surficial conditions in the Late Pleistocene were favourable for uranium transport and precipitation. A major consideration here is the enormous volume of meteoric water which was repeatedly required, both for leaching, largely from volcanic glass, and the rapid transport of several hundreds of millions of lbs. of uranium. The inherently porous rhyolites clearly acted as permeable aquifers, the through-going channels represented by flat-lying flow-contacts and faults, and steeply-dipping joints (hydrologically, “pipes”) and faults (collectively, “macropores”), being interconnected by the cavity-rich ashy matrix of the tuffs. This hydrological environment, continuously opened up by ongoing orogenic surface uplift, would have permitted extensive mixing of overland and infiltrating shallow waters with “old” resident water stored in the volcanics, the latter providing an effective leaching agent for glass-bound uranium. Deep penetration of shallow waters would be optimized during flood run-off, channelled along pre-existing and actively deepening fluvial canyons, feeding the baseline drainage along the Macusani-San Gaban river valley. In this model, mineralization would be precipitated in riparian environments during episodes of sub-surface storm- flow. The abrupt and radical shrinkage of the Quelccaya ice cap during the Tarantian (late-Late Pleistocene) and early Holocene revealed by terminal moraine dating [10,11], as well as the vastly more extensive glacial cover documented for the preceding Plio-Pleistocene [25], provides a rigorous geomorphological and climatic context for the inferred flooding events: the mineralization episodes documented by U-series dating correspond strikingly with climatic events of low The δ18O values and low ice volume (high sea-level) in the low-latitude oceanic, foramanifera-derived, time -scale [e.g., 26]. Concordant dates for mineralization coincide with events at 315 ka, 120 ka and 69-79 ka, while the upper-intercept dates match events at 397 ka, 210-217 ka and 103-113 ka, which accounts for all of the major warming interglacial events of the Late Pleistocene. The Macusani mineralization represents the final episode in the evolution of the major Carabaya polymetallic (Sn, Au, Pb, Zn, Ag, W) metallogenetic sub-province of northern Puno Department [5], with uranium deposits generated in an unparalleled periglacial environment resulting from catastrophic episodic flooding during Late Pleistocene global interglacial periods. The Macusani Uranium district truly hosts a unique class of uranium deposit, but with aspects of both surficial and sandstone systems. ACKNOWLEDGEMENTS This communication is based on Valeria Li’s doctoral research at Queen’s University, Kingston, Canada, funded by Cameco Corporation, Vena Resources Inc., Macusani Yellowcake Inc., Queen’s University, The Society of Economic Geologists and The Natural Sciences and Engineering Research Council of Canada. Don Chipley was essential in designing and operating the U-series dating programme. REFERENCES [1] SHORT, M et al., NI 43-101 Report – Macusani Project Preliminary Economic Assessment prepared for Plateau Uranium Inc., (2016) 326. Filed on: www.sedar.com [2] CUNEY, M. & KYSER, T.K., 2015, The Geology and Geochemistry of Uranium and Thorium Deposits, Min. Assoc. Canada Short Course Series 46, Montreal. [3] LI, V., V., 2016, The Uranium Mineralization of the Macusani District, Southern Peru: Geochemistry, Geochronology and Ore-Genetic Model, Ph.D. thesis, Queen’s University, Kingston, Ontario, 192p [4] SANDEMAN, H.A. et al., Lithostratigraphy, petrology and 40Ar/39Ar geochronology of the Crucero Supergroup, Puno Department, SE Peru, 10 J. South Amer. Earth Sci. (1997), 223. [5] CLARK, A.H. et al., Geologic and geochronologic constraints on the metallogenic evolution of the Andes of southeastern Peru, 85 Economic Geology, 1520. [6] SANDEMAN, H.A. et al. Petrographic characteristics and eruption styles of peraluminous, rhyolitic pyroclastic rocks of the Quenamari Group, Puno, southeastern Peru (abstract), Geol. Assoc. Canada/Mineral. Assoc. Canada, 19, Program with Abstracts, A98. [7] SANDEMAN, H.A. et al. An integrated tectono-magmatic model for the evolution of the southern Peruvian Andes (13°20’S) since 55 Ma, 37, International Geology Rev., 1039. [8] PICHAVANT, M, et al. The Miocene-Pliocene Macusani Volcanics, SE Peru: I Mineralogy and magmatic evolution of a two-mica aluminosilicate-bearing ignimbrite suite, 100, Contrib. Mineral., Petrol. (1988), 300. [9] PICHAVANT, M. et al. The Miocene-Pliocene Macusani Volcanics, SE Peru: (II) Geochemistry and origin of a felsic peraluminous magma, 100, Contrib. Mineral. Petrol (1988), 325. [10] MERCER, J.H. et al. Peru’s Quelccaya ice cap: glaciological and glacial geological studies, 10, Antarctic Journal of the U.S. (1975),19. [11] MARK, B.G. et al. Rates of deglaciation during the Last Glaciation and Holocene in the Cordillera Vilcanota-Quelccaya Ice Cap region, southeastern Peru, 57, Quaternary Research, 287. [12] GOODMAN, A.Y. et al. Subdivision of glacial deposits in southeastern Peru based on pedogenic development and radiometric ages, 56, Quaternary Research , 31. [13] HERRERA, W. & ROSADO, F., Las manifestaciones uraniferas en rocas volcanicas de Macusani (Peru): Geologia y Metalogenesis de los Depositos Uraniferos de Sudamerica; INTERNATIONAL ATOMIC ENERGY AGENCY , Vienna, 219. [14] RIVERA, R.C. et al. Metalogenia del Uranio en las Regiones de Cusco y Puno, Inst. Geol., Minero Metalurgico, Boletin, Ser. B., Geol. Econ., Lima, 121 p. [15] ARRIBAS, A. & FIGUEROA, E. , Las mineralizaciones de uranio en las rocas volcanicas de Macusani (Peru), 41, Estudios Geologicos ,323. [16] SAVIN, S.M. & LEE, M. , Isotopic studies of phyllosilicates, Baley, S.W., ed., Hydrous Phyllosilicates (Exclusive of Micas), 19, Reviews in Mineralogy, 189. [17] CAPUANO, R.M. The temperature-dependence of hydrogen isotope fractionation between clay minerals and water: evidence from a geopressured system, 56, Geochimica et Cosmochimica Acta, 2547. [18] THOMPSON, L.G. & DANSGAARDS, W. Oxygen isotope and microparticle studies of snow samples from Quelccaya Ice Cap, Peru, 10, Antarctic Journal of the U.S., (1975) 24. [19] ZHENG, Y-F. Calculation of oxygen isotope fractionation in hydroxyl-bearing silicates, 120, Earth & Planetary Sci. Letts (1993), 247. [20] LI, V.V. et al. The uranium deposits of the Macusani district, Puno, southeastern Peru: a new genetic model (abstract), Soc. Econ. Geologists, 2012 Conference, Lima, Peru. [21] CHENG, H. et al. Uranium-thorium-protactinium dating systematics, 62-21/22, Geochimica et Cosmochimica Acta (1998), 3437. [22] BOURDON, B. et al. Uranium-Series Geochemistry, Reviews in Mineralogy and Geochemistry, ed. Bourdon, B., et al., 2003, 1-21. [23] DAHLKAMP, F.J. Uranium Deposits of The World, Springer, Berlin, 520 p. [24] SATO. T. et al. Iron nodules scavenging uranium from groundwater, 31, Environmental Science and Technology (1997), 2854. [25] CLAPPERTON, C.M. The glaciation of the Andes, 2, Quaternary Sci. Revs. (1983), 83. [26] BASSINOT, F.C. et al .The astronomical theory of climate and the age of the Brunhes-Matuyama magnetic reversal, 126, Earth & Planetary Sci. Letts.(1994), 91.

Speaker: Mr Terrence O'Connor (Plateau Uranium Inc)

170 Advanced technologies for sustainable exploitation of uranium-bearing mineral resources in Finland

Efficient metal recovery from complex polymetallic and low-grade large-tonnage mineral resources is a major challenge, both metallurgically and in ensuring compliance with environmental and social legislation and expectations. In recent years, several exploration and mining projects in Finland have focused on the exploitation of uranium-bearing polymetallic deposits, in which the primary targeted commodity includes gold, nickel, cobalt and other base metals, as well as rare earth elements. Mineral parageneses and the relationship between these metals and the deportment of uranium of ores must be carefully documented in order to develop an optimum flowsheet for processing. Our current research is aimed at combining this mineral characterization with the development and demonstration of new techniquess for the effective recovery of uranium from process and mine waters, even at low concentrations. These approaches cover the utilization of different bisphosphonate adsorbents, hybrid materials of nanoporous silicon carbide frameworks and BPs, and biological/bioelectrochemical uranium reduction. We have selected several metallogenically diverse uranium-bearing deposits in Finland, representing sedimenatry hosted and metamorphosed, Au-Co-U deposits and intrusive-related REE mineralization. In addition to microscopic (MLA, EPMA, SEM, microCT) and isotopic (LA-ICPMS) mineralogical characterization we perform a range of laboratory-scale bulk leaching experiments at the GTK Mintec processing plant. Both process waters and minewaters collected from dormant open pits are being tested for selective recovery and isolation of not only uranium, but also other metals, with the aim of integrating these bisphosphonate and biosorption techniques into processing flowpaths, for metal recovery and environmental management. Bench-scale experiments have demonstrated the effectiveness of both the biosorption of activated sludge and bisphosphonates and hybrid derivative materials in adsorption of uranium from solution, even at very low concentrations, with the additional advantage of allowing rapid and efficient recycling and reuse of sorbent materials.

Speaker: Mr Peter Sorjonen-Ward (Geological Survey of Finland)

171 Features of geological modelling, Mineral Resources and Reserves estimation of uranium roll-front deposits

INTRODUCTION Roll-front deposits in Kazakhstan are the source of 40% of the world uranium production [1]. These deposits are characterized by having low production costs due to the use of in-situ recovery (“ISR”) methods for uranium extraction. Consulting companies prepared reports based on international standards (NI 43-101, JORC) and local standards (GKZ system) before 2012. This approach often led to an underestimation of Mineral Resources [2]. CSA Global developed a robust methodology for geological modelling, Mineral Resource and Ore (Mineral) Reserve estimation for roll-front deposits in Kazakhstan from 2012 through 2017. This methodology was applied to Budenovskoye and South Inkai deposits in Chu-Sarysu province, and Zarechnoye and Kharasan-1 deposits in Syrdarya province [3], [4], [5], [6], [7]. CHARACTERISTICS OF ROLL-FRONT DEPOSITS The first characteristic of roll-front deposits is the very complicated morphology of mineralisation. Uranium mineralisation occurs in unconsolidated lacustrine-alluvial sediments of Late Cretaceous – Paleogene horizons in two regional basins in South Kazakhstan: Chu-Sarysu ans Syradarya. Mineralised bodies of these deposits are represented as weaving ribbons of various width and length per unit area and are controlled by the oxidation zone boundary. The mineralised bodies consist of several morphological elements, including noses, knees, upper and lower wings (limbs), and residual bodies (satellites) located at the rear of the roll front. An important feature is the variation in the proportion of uranium and radium throughout these bodies. Uranium dominates in the nose and decreases in the wings, whereas radium dominates in the residual bodies. The uranium to radium ratio is described by the radioactive equilibrium factor ("REF"), which is part of a more general definition of radiological factors. The width of the deposits may vary from tens to hundreds of meters and is often dependent on the thickness and frequency of impermeable lenses / interbeds, which complicate the boundary of the zone of formation oxidation (“ZFO”). The extended upper limb of a roll, complicated by step-wise “sliding” of the geochemical boundary, is, as a rule, observed when the thickness of the horizons is considerable, and several confining lenses are available in the area of ZFO boundary thinning. Multistage bodies consisting of a number of mineralised lenses are typical of the deposit stratigraphy and confirm the extreme complexity of the enclosing rock sequence. The second characteristic of roll-front deposits is the use of ISR methods. ISR transfers a significant proportion of hydrometallurgical processing to the subsurface to directly obtain solutions of uranium. For ISR to be successful, deposits need to be permeable, and the uranium readily amenable to dissolution by leaching solutions in a reasonable period of time, with an acceptable consumption of leaching reagents [8]. MODELLING AND MINERAL RESOURCE ESTIMATION Modelling and Mineral Resource estimation of roll-front uranium deposits consist of the following stages which takes account of the characteristics of these deposits: • Selection of mineralised intervals by correct application of radiological factors. The first radiological factor is radon removal/concentration which is evaluated based on a comparison between gamma-logging results and the results of core sampling and analysis for radium [9]. The second step is determination of a radium cut-off grade, being 0.01% U equivalent in different geochemical zones (oxidized, reduced), which allows radium halos to be excluded around uranium mineralised bodies. Radium halos at the boundaries have a significant influence on mineralised intersections. These halos are diffuse and manifest as mineralised intersection margins in which equilibrium is shifted towards an abundance of radium. Finally, a correction for REF = С (radium) / С (uranium) is introduced to calculate the uranium grade after establishing mineralised interval boundaries and calculation of the average radium grade. REF studies are carried out for various geological and geochemical environments such as the nose, wing and residual parts of rolls, as well as permeable and impermeable sediments, and different mineralised horizons. The ratio between uranium and radium is calculated using assay data for uranium and radium and extrapolation of defined patterns to intervals defined by gamma-logging. • Estimation of permeable / impermeable intervals. Electrical logging (resistivity logging and spontaneous polarization) is the most common method for lithological interpretation. Comparison of core lithological logging, granulometry and electrical logging allows identification of impermeable zones. • Modelling of sedimentary cycles (horizons) which are controlled by continuous clay/silt horizons and controls the distribution and location of ZFOs. Analysis of the distribution of mineralised intervals and oxidised sediments shows that mineralisation in different horizons (cycles) occurs in separate roll-fronts. However, sometimes mineralisation “overflows” between horizons due to breaks in the clay horizons between cycles. Digital terrain models (“DTMs”) are used for modelling borders between sedimentary cycles. Continuous impermeable layers should be modelled at this stage together with sedimentary cycles. • Mineralised intervals are divided into morphological elements – nose, knee, upper wing, lower wing and residual parts separately for each ZFO. This is completed by using geochemical data as follows: o The intervals where mostly reduced rocks are developed both in the mineralised interval and above and below are attributed to the nose or knee. o The intervals where reduced rocks are developed in the mineralised interval and mainly and above are attributed to the upper wing. o The intervals where reduced rocks are developed in the mineralised interval and mainly on lower side are attributed to the lower wing. o The intervals where there are mainly oxidised rocks developed above or below the mineralised interval are attributed to the residual part. The mineralised interval itself can be represented both by reduced and oxidised rocks. The distribution of nose / knee parts is controlled by the ZFO. 3D modelling of roll-front deposits allows morphology to be clarified and positioning of ZFOs and oxidized sediments, which control the distribution of mineralisation. For example, at the Zarechnoye deposit, the location of the ZFOs were changed and as result understanding the direction of flow of uranium-bearing solutions. The orientation was changed from north-west to south-west. New uranium mineralisation was discovered due to the new interpretation. • Modelling of interbeds of impermeable sediments inside mineralised horizons. This allows construction of a lithological wireframe model with mineralised bodies and permeable/impermeable sediments and can be used for design of operation blocks and define intervals for screens (filters). • Interpolation of grades into mineralized bodies by Ordinary Kriging or Multiple Indicator Kriging. • A gridded model is generated for each wireframe in order to estimate uranium Grade-thickness (“GT”) based on block models. GT or productivity cut-off is more appropriate for ISR deposits than cut off grades [8]. The vertical extent of the cells of the gridded model depends on the thickness of the mineralisation. Uranium GT is calculated by multiplying the vertical size of the cells by the uranium grade. Gridded models are two-dimensional. In order to estimate the GT in three-dimensional space, it is necessary to compare each cell of the gridded model with a column of cells in the original block model. This is completed by indexing the block model cells by comparison with the cells of the gridded model. Using the indices, the GT values of the mineralised bodies from the gridded model is coded into the block model. • Depletion of Mineral Resources. For ISR deposits, the depletion of Mineral Resources is measured not by how much rock is removed, as is the case with most traditionally mined resources, but rather by lowering of uranium grade (and GT). ORE (MINERAL) RESERVE ESTIMATION ‘Modifying Factors’ are considerations used to convert Mineral Resources to Ore (Mineral in NI 43-101) Reserves. These include, but are not restricted to, mining, processing, metallurgical, infrastructure, economic, marketing, legal, environmental, social and governmental factors [10]. The main technical Modifying Factors for Ore Reserve estimation are mining and metallurgy. The ratio of Liquid to Solid (L:S) required to achieve the desired extraction of uranium. This ratio is calculated based on the volume of solutions that pass through the operational block over the entire period of operation, and on the tonnage of the operational block [8]. Graphic extraction vs L:S is the most relevant consideration for exploration target evaluation. Usually target extraction is calculated by decreasing uranium concentrations in pregnant solutions to breakeven cut-off grade, that reflect on the graph by a flattening curve. Dilution is included in the operational block calculation as the volume is based upon the effective thickness of the production zone. The Mineral Resource estimate includes Measured and Indicated Resources within the operation blocks. Dilution estimates are prepared based upon the difference in tonnage between the Mineral Resource estimate and the operation block tonnage estimate. DISCUSSION AND CONCLUSION Application of 3D modelling techniques for roll-front deposits allows the creation of lithologicl and resource models and reliable Mineral Resource / Ore (Mineral) Reserve estimation. Based on the experience of the author, the difference between Mineral Resources and Ore (Mineral) Reserves, based on operational wells and the geological / resource model, does not exceed 5–7%. These models are used for more accurate screen set ups in operational wells, hydrodynamic and physic-chemical modelling of uranium leaching in operational blocks and, and finally, more accurate estimation of Mineral Resource depletion after constraining of operational blocks. The author is grateful to the Uranium One Inc. for giving permission to publish this abstract. REFERENCES [1] WORLD NUCLEAR ACCOCIATION: http://www.world-nuclear.org/information-library/facts-and-figures/uranium-production-figures.aspx [2] Boytsov A., Thys H., Seredkin M. Geological 3-D modelling and resources estimation of the Budenovskoye uranium deposit (Kazakhstan). Uranium Raw Material for the Nuclear Fuel Cycle: Exploration, Mining, Production, Supply and Demand, Economics and Environmental Issues. IAEA-CN-216 Abstact 038. Vieanna, 2014 [3] Seredkin M., Bergen R.D. Technical NI 43-101 Report on the Akbastau Uranium mine, Kazakhstan, prepared for Uranium One Inc. by CSA Global Pty ltd., 2013 [4] Seredkin M., Bergen R.D. Technical NI 43-101 Report on the Karatau Uranium mine, Kazakhstan, prepared for Uranium One Inc. by CSA Global Pty ltd., 2013 [5] Seredkin M., Bergen R.D. Technical NI 43-101 Report on the South Inkai Uranium mine, Kazakhstan, prepared for Uranium One Inc. by CSA Global Pty ltd., 2014 [6] Seredkin M., Bergen R.D. Technical NI 43-101 Report on the Zarechnoye Uranium mine, Kazakhstan, prepared for Uranium One Inc. by CSA Global Pty ltd., 2015 [7] Seredkin M. Technical NI 43-101 Report on the Khorasan-U Uranium mine, Kazakhstan, prepared for Uranium One Inc. by CSA Global Pty ltd., 2017 [8] Seredkin M., Zabolotsky A., Jeffress G. In situ recovery, an alternative to conventional methods of mining: Exploration, resource estimation, environmental issues, project evaluation and economics. Ore Geology Reviews 79 (2016) 500–514 [9] Vershkov A., Drobov S., Arustamov A. et al., 2015. Report on the results of exploration of the central area of the area Kharasan-1 of the uranium deposit North Kharasan with estimated reserves and resources of uranium. Almaty, 2015 [10] Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves. Prepared by: The Joint Ore Reserves Committee of The Australasian Institute of Mining and Metallurgy, Australian Institute of Geoscientists and Minerals Council of Australia (JORC), 2012

Speaker: Dr Maxim Seredkin (CSA Global Pty. Ltd.)

Economic Evaluation of Uranium Projects

Conveners: Mr Nicolas Carter (The Ux Consulting Company, LLC), Mr Richard Schodde

172 Falea: an unconformity-type polymetallic deposit, Mali, West Africa

INTRODUCTION The Falea Project consists of a polymetallic body hosted within the Neoproterozoic portion of the lowerTaoudeni basin, where it overlies a heavily deformed Birimian basement of schists and metasediments. The project consists of three exploration permits covering 225 km2 and is located in Western Mali approximately 350 km west of the capital, Bamako. The Falea permit covers 75 km2 and hosts ore bodies with an Indicated Mineral Resource of 6.88 million tonnes at 0.115% U3O8 (0.098%U) 0.161% Cu, and 73 g/t Ag and an Inferred Mineral Resource of 8.78 million tonnes at 0.07% U3O8 (0.059%U), 0.20% Cu, and 17 g/t Ag using a cut-off grade of 0.03% U3O8. [1] HISTORY Uranium mineralization was discovered by COGEMA in 1977, having identified the area of southern Mali and adjoining Senegal and Burkina Faso as having potential as early as 1957. COGEMA drilled 86 holes on a nominal 800m grid over the Falea Permit, and a more concentrated 200m grid on the Central deposit. COGEMA abandoned the project in 1982, at the time of low uranium prices. [1] Delta Exploration obtained the permit in 2006 from the Mali government, with Rockgate Capital, a Canadian company, funding the exploration as of 2007 during the uranium resurgence for equity in the company resulting in acquisition of Delta in 2008. The exploration carried out by Delta/Rockgate, started at the known Central deposit and progressed northward to define the north zone and ultimately defined the current resource. They also carried out hydrological, environmental and social studies [1]. Denison Mines Corp., acquired the project in 2014, and carried out an airborne geophysical survey as well as soil and termite mound sampling. The Falea project was acquired by Goviex Uranium Inc.(GoviEx) from Denison Mines Corp. on June13, 2016. GEOLOGY The project is situated in the Falea-North Guinea-Senegal (FSG) sedimentary basin on the southern edge of the western province of the Taoudeni Basin. The Taoudeni Basin is a Neoproterozoic (750 million years) to Carboniferous, intracratonic basin. The FSG consists mostly of the sedimentary rocks of “Supergroup 1” which is the lowermost sequence. This group consists of a basal, predominantly fluvial package grading upwards into a series of shallow shelf sandstones and mid shelf mudstones (total thickness 500 - 550m). The FSG is situated within the West African craton between the Archean rocks to the South East and Birimian rocks to the North, East and West. In the Falea region this lowermost sequence sits unconformably on the Birimian Basement. The basal package (approximately 10-30 metres thick) consists of conglomerates (VC), the Kania Mudstone with stromatolite (KI), Kania Sandstone (KS) and the ASK mudstones. The ASK is marine but the VC and KS represent a fluvial sequence of channel and inter-channel sedimentation with a minor marine incursion (KI mudstone plus thin stromatolite). The sedimentary rocks are largely unfolded and sub-horizontal with a very shallow dip to the West (<10 degrees). The sequence is intruded by Carboniferous dolerite sill up to 80m thick in places, and make up the spectacular cliffs of the area. The North and Central zones are bisected by a North-South trending reverse fault, the Road Fault (RF). The RF verge to the west and repeats the stratigraphy and the mineralization in the zone proximal to it. The vertical throw is 70 metres. The main deposits are spatially associated with this fault. The eastern portions of the central and North zones have depths of 180 -280 metres below the plateau whereas the western blocks are at depths of 250 to 350 metres. The Bodi zone is NW of the North zone but only hosts sporadic U mineralisation. The East Zone is located 4 kilometres west of the main deposits and is a small area of Cu-U-Ag mineralisation also spatially associated with NS faulting [1,2]. MINERALOGY The Falea deposits consist of four separate zones known as Bodi, Central, North, and East. The North and Central deposits have been intercepted at depths of 180 to 300 metres below surface and are the principal deposits. The Bodi, Central, and North zones occur along a three-kilometre-long, north-south trending mineralized corridor. The East Zone is located approximately four kilometres to the east of the Central and North zones. The Falea deposit is interpreted as an unconformity-associated polymetallic deposit with associations of uranium, silver and copper. The deposit shows similarities with historic districts in Cobalt, Ontario and Erzgebirge-Bohemia district, Germany-Czech Republic [3,4,5,6] The mineralisation is mainly within the KS unit and averages 3.6 metres in width. It is also present in the VC, KI and at the base of the ASK. Mineralisation can be distributed throughout the KS when it is thin (<4 m) but is most commonly seen at the contacts of the KS with VC or KI or at the lower contact with the ASK. The main gangue minerals detected by XRD in the Falea ore are quartz and muscovite / illite. Chamosite, clinochlore, dolomite, calcite and albite are less abundant. Sulfide mineralization consist of argentite (Ag2S), silver copper arsenic sulfide (tennantite (Cu,Ag,Zn,Fe)12As4S13), galena (PbS), sphalerite (ZnS), cobaltite (CoAsS), arsenopyrite (FeAsS) and covellite (CuS) were confirmed by SEM/EDS analysis. The main uranium mineral is uraninite (pitchblende) but includes coffinite and brannerite. [7] Uranium is spatially associated with silver in the North deposit, where native Silver can be seen in core. The copper is low grade but ubiquitous and seen in just about every hole drilled. Uraninite often forms rims around chalcopyrite. Copper mineralisation is also present at the base of the ASK formation for widths of one to four metres. DEPOSIT TYPE The Falea deposit has been previously postulated to represent a combination of two mineralization events. The first event was similar to sedimentary exhalative (SEDEX) event and the second event was interpreted to be a roll-front deposit, that is, an epigenetic uranium deposit at a redox interface occurring on top of a SEDEX deposit. [2] In 2011, Rockgate reinterpreted the Falea deposit as an unconformity-associated uranium deposit, using a polymetallic egress model for the geological model. The unconformity at Falea is between the Birimian and overlying sedimentary sequences. The egress model was applied due to the presence of the Road Fault, which could have introduced fluids into the sandstones. Unconformity-associated deposits are high-grade concentrations of uranium that are located at or near the unconformity between relatively undeformed quartz rich sandstone basins and underlying metamorphic basement rocks. The compositional spectrum of unconformity-associated uranium deposits can be described in terms of monometallic (simple) and polymetallic (complex) end-members on the basis of associated metals. Polymetallic deposits are typically hosted by sandstone and conglomerate, situated within 25 m to 50 m of the basement unconformity. Polymetallic ores are characterized by anomalous concentrations of sulfide and arsenide minerals containing significant amounts of nickel, cobalt, lead, zinc, and molybdenum. Some deposits also contain elevated concentrations of gold, silver, selenium, and platinum-group elements. Deposits with egress halos (Figure 8-2) include both basement-hosted and sandstone hosted types, and the alteration ranges between two distinctive end-member types: 1) quartz dissolution + illite; and 2) silicified (Q1 + Q2) + later illite-kaolinite-chlorite+dravite [8; 9, 1]. WORK COMPLETED AND DISCUSSIONS There are 231887m of drilling over 944 drill holes were completed over the Falea deposit, most holes were diamond core from surface, with a small amount with RC pre collars. Drilling was completed to define the resource, which leaves us with abundant exploration potential outside of the main deposit area. Other work completed over the area include soil surveys for gold over subcropping Birrimian, as wellas soil and termite mound survey over the Falea deposit; radon cup surveys and geological mapping along the range fronts, which included scintillometer surveys. Helicopter-borne geophysical data was collected by Rockgate in 2012 and Denison in 2015. They included Airborne magnetics, TEM and Radiometrics. This data was recently remodeled. The structural complexity of the area becomes evident as a series of NS, and conjugate NE-SW and NW-SE fault pattern divide the area into what appears horsts and graben, bringing target horizon of the lower Taoudeni and particularly the Kanya Sandstone closer to the surface. The thick dolerite unite unformtunately does tend to blind the EM and deeper magnetic signatures. In some areas however we can correlation of the Analytical signal trenght of the magnetic data, the EM conductivity and the higher U values from the radiometrics. [10]. Isopach analysis was undertaken in house on the main deposit and concentrated on the sequence between the base of ASK unit to the top of Birrimian (the unconformity surface) and the thicknesses of KS, VC and KI. The Birrimian surface forms a NS palaeochannel just east of the Road Fault . The VC unit is thicker in this channel whereas the KI unit (thin shale) is only well-developed east of the channel. Similarly, the KS unit attains greater thicknesses (+6m) east of the channel. This evidence suggests that the Road Fault was probably a hinge line or small scarp during sedimentation and created a channel for conglomerate deposition whereas channel edge and interchannel areas were dominated by sand and shale during the brief marine incursion of KI. The channel and interchannel areas formed a sedimentary trap for the focus and the precipitation of metals from saline, metal bearing brines at a later stage. Similarly, the Eastern zone is also spatially associate with a NS structure and has variable VC thickness. The following points are evident from the isopach work: • There is a clear relationship between the Road Fault and the distribution of the VC conglomerate supporting the fault scarp hypothesis. Using the base of ASK to the top of Birrimian this is the thicker accumulation just east of the fault (paleo-low area) In the field conglomerates next to the fault displayed some boulder sized pebbles. • The KS sandstone is better developed (thicker) to the east of the fault zone in the paleo-high area. The VC and KS may represent facies changes i.e. channel versus interchannel areas. • The channel relationship is not so clear if sea level is used as a datum . Base of ASK is considered better because it’s the first major marine incursion • Grade accumulation spans both high and low areas with U and Ag mirroring each other and Cu showing higher concentrations to the east. • A closer look at the northern zone highlights the strong relationship between a thin KI unit (mudstone and stromatolite) and better grades for Ag and U. Again, Cu shows a preference for a thicker KI as a preferred trap. The KI unit represents a marine incursion which was clearly only thinly developed once it encountered the paleo-high. • The relationships in the Central zone are not as clear although if the KS is too thin then mineralisation seems to reduce in tenor and quantum . • The Isopach work is highlighting the importance of the sedimentology in creating a suitable trap for precipitation of metals from metalliferous brines which were mobilised AFTER basin formation and relating to fluid movement triggered by a later deformation event. Whereas there has not been any proper analysis of alteration patterns of the hanging wall and footwall rocks at Falea, visual inspection of the core reveals that the sandstones contain primary quartz, muscovite and some feldspar (minor); alteration includes chlorite, sericite/illite and carbonates (calcite and Dolomite. Albite and Riebeckite have been observed. Apatite, rutile, zircon and anhydrite are noted. Hematite staining is common. In the east fault zone, there is abundant hematite staining and silicification which has pervaded both basement and HW units. Bleached zones and hematite staining was observed in the HW package. Chlorite and sometimes hematite were noted in the basement rocks. The delineation of the deposit and comparison to large, rich, historic districts may point to considerably larger resources occurring in the area. ACKNOWLEDGMENTS The authors would like to thank previous workers as well as David Reading for their contributions. REFERENCES [1] Roscoe Postle and Associates (2015) Technical report on the Falea Uranium, Silver and Copper deposit, Mali, West Africa prepared for Denison Mines Corp [2] Minxcon (Pty) Ltd (December 2012). An Independent Technical Report on the Mineral Resources of Falea Uranium, Copper and Silver Deposit, Mali, West Afrcia, prepared for Rockgate Capital Corp. 7[R] Ring, P. Freeman Development of the Falea polymetallic uranium project- URAM2014 8 Jefferson, C.W., Thomas, D.J., Gandhi, S.S., Ramaekers, P., Delaney, G., Brisbin, D., Cutts,C., Quirt, D., Portella, P., and Olson, R.A. (2007). Unconformity associated uranium deposits of the Athabasca Basin, Saskatchewan and Alberta, in Goodfellow, W.D., ed., Mineral Deposits of Canada: A Synthesis of Major Deposit-Types, District Metallogeny, the Evolution of Geological Provinces, and Exploration Methods: Geological Association of Canada, Mineral Deposits Division, Special Publication No. 5, pp. 273-305. Also in Jefferson, C.W. and Delaney, G. eds., EXTECH IV: Geology and Uranium Exploration Technology of the Proterozoic Athabasca Basin, Saskatchwean and Alberta, Geological Survey of Canada Bulletin 588, pp. 23-67. 9 Golder Associates Ltd. (February 2011). January 2011 Technical Report and Resource Estimate Update, Falea Property, Prefecture of the Kenieba, District of Kayes, Republic of Mali, prepared for Rockgate Capital Corp 10 Zengerer, M and Pugh, D. 2017 Magnetics, radiometrics and electromagnetics interpretation and modelling report, Falea, mali- Goviex Internal report. [3] Andrews, A.J., Owsiacki, L., Kerrich, R., and Strong, D.F., 1986a, The silver deposits of Cobalt and Gowganda, Ontario. I: Geology, petrology and whole-rock chemistry: Canadian Journal of Earth Sciences, v. 23, p. 1480–1506 [4 [Baumann, L., 1967, Zur Frage der varistischen und postvaristischen Mineralisation im sächsischen Erzgebirge: Freiberger Forschungshefte C, v. 209,p. 15–38. —1994, Ore parageneses of the Erzgebirge—history, results and problems: Monograph Series, Mineral Deposits, v. 31, p. 25–46. [5 [Baumann, L., and Weber, W., 1996, Crust activation in central Europe and their metallogenetic importance for the Erzgebirge: Freiberger Forschungshefte C, v. 467, p. 27–58. [6[Marshall, D. D. and Watkinson, D.H., 2000, The Cobalt mining district: Silver sources, transport and deposition: Exploration and Mining Geology, v. 9, p. 81–90.

Speaker: Mr Jerome Randabel (Goviex)

173 Central Jordan Uranium Project: Monitoring the Project Maturity via the application of the UNFC-2009

The uranium deposits in the CJUP are primarily hosted by the Muaqar Chalky Marl (MCM) Formation of upper Maastrichtian age, part of the Upper Cretaceous to lower Tertiary Belqa Group. Uranium exploration and resource estimation were performed over two phases in this project, Phase I (2009-2014) and Phase II (201). Metallurgical testwork indicated the amenability of the ore to static leaching using alkaline lixiviants. Higher level process development and engineering endeavors are currently culminating into the construction of a processing pilot plant. This case study demonstrates the advantages of using UNFC-2009 to monitor the project maturity of CJUP over different phases of exploration and technical viability. The project progressed from a “Potentially Commercial Projects/Development on Hold” project in Phase I to a more mature “Potentially Commercial Projects/Development Pending” in Phase II. The application of UNFC-2009 to the CJUP study in Jordan clearly demonstrates the advantage of tracking the project from a lower maturity level of assessment to a higher level. Therefore, classification and reporting of uranium project results using UNFC-2009 have clear advantages for policy makers in Jordan, as well as for internal company requirements for monitoring the progress of a project over time.

Speaker: Dr Hussein ALLABOUN (Jordanian Uranium Mining Company and Jordan University of Science and Technology)

174 Economic Evaluation of Uranium Projects (Niger case study)

I- PRESENTATION OF NIGER REPUBLIC i- Geographical framework of Niger Landlock country located in West Africa, the Republic of NIGER covers 1,267,000 Km2 with a population of 17.1millions. It is a democratic country with stable institutions and elected representatives at all levels. It is a decentralized country with eight (8) Regions: Agadez, Diffa, Dosso, Maradi, Niamey, Tahoua, Tillabéri and Zinder; Niamey is the capital. ii- Geological framework of Niger The geological framework of Niger is characterized by four (4) basements which include: 1- Liptako Gourma (North-East of west African craton): gold, lithium , phosphates, iron, copper, molybdenum, zinc, titanium, dolomite, vanadium chromites, manganese etc.; 2- Air mountains to the northern part of the country: uranium, coal, gold, molybdenum, etc; 3- Damagaram Mounio et South Maradi in central South: Gold; 4- Djado to the North-East: gold, gypsum, phosphates, uranium etc. II- OVERVIEW OF URANIUM POTENTIALS IN NIGER Uranium minerals have been found in the Iullemmeden basin which is a sedimentary basin. The Iullemmeden basin is composed of two sub-basins: 1- The Tim Mersoi basin which is located in the north part; 2- The Ader Doutchi located to the south west. This basin contains the following mineralization indices: coal, phosphates, gypsum, limestone, benthonite, manganese, oil etc; Uranium occurs mainly in the first basin. There are two types of uranium minerals characteristics:  tretravalent uranium minerals (pechblende et coffinite) caracterized by reduced areas ;  hexavalent uranium minerals (vanadates, phosphates, silicates, arsenites and molybdenum) which are characterized by oxided deposits area. These two types of uranium minerals have been used to identify two types of uranium deposits which are:  Carboniferous uranium deposits (Akouta, afasto-Ouest, Arlit, Madaouela, Tassa N’Taghalgué) ;  Jurassic and Cretaceous uranium deposits (Imouraren, Azelik, Assaouas); i- Uranium resources of exploration projects Two major exploration projects have been carried out: a- Sekiret project from 1985-1986, conducted by the association of ONAREM-PNC. The drillings have cross Tchirezrine 2 to Guezouma. All the activities have been centred on the Illummeden basin. In the Guezouman, uranium mineralization is 2.25 m thick with a grade of 0.04 % eU3O8). b- Techili project from 1989 to 1990, the aim of this project is to evaluate uranium resources in the sectors of Madaouela and north Arlit. The thickness of the mineralization is 3,4 m with average grade of 0,2%. ii- Uranium resources of exploitation projects There are four companies extracting uranium in Niger. Unfortunately, due to the fall of uranium price, two companies (IMOURAREN and SOMINA) have closed. The two remaining companies (SOMAIR and COMINAK) are under a programme of social plan to reduce the number of employees. III- ECONOMIC EVALUATION PROCESS OF URANIUM PROJECTS IN NIGER Economic evaluations of mining projects include the examination and the assessment of technical, financial, social and political aspects of the environment in which the mineral deposit is located. These include the estimation of mineable ore deposits, the production rates, capital expenses and cost of operations. The financial assessment will be set according to the fiscal regime of the host country to generate standard project evaluation criteria such as NPV and IRR. i- steps of uranium projects evaluation In Niger, any mining project evaluation is based on a specific guide line called “canevas” and a working committee. The guide line is based on the following points: a- a general presentation of the project; b- a presentation of the investors; c- Juridical analysis; d- Market analysis; e- Environmental and social impact assessment; f- Technical analysis; g- Financial and rentability analysis and; h- Risks analysis. The activities conducted by the working committee will be based on this schedule. For this, some ministries and other related structures will be identified to make up this committee. ii- Parties involved in the evaluation process The parties involved in the evaluation process come from the following entities: • The General Secretary or his representative, • The General Director of Mines; • The Director of Mines; • One representative of the Ministry of Finances; • One representative of the Ministry of Environment; • One representative of the General Direction of Customs; • One representative of the Ministry of Water Resources; • One representative of the Ministry of Agriculture and Wild life; • One representative of the General Direction of Taxes; • One representative of the Bureau of Environmental Impact Assessment; • One representative of the Presidential Cabinet; • One representative of the Prime Minister Cabinet; • One representative of SOPAMIN; • One representative of each technical Direction within the Ministry of Mines. After the selection, the committee will be set up by decree signed by the Ministry of Mines, the General Secretary or the General Director of Mines will be the president of this committe. The report of the feasibility study will be done through the following chapters:  Chapter I: Introduction, Summary and Conclusions;  Chapter II: Geology and hydrogeology;  Chapter II: Resources;  Chapter IV: Mine;  Chapter V: Mineral processing;  Chapter VI: Alternative mines and processing designs  Chapter VII: Infrastructures;  Chapter VIII: Transports and logistics;  Chapter IX: Employment and training;  Chapter X: Structure and organisation of the project;  Chapter XI: Environment;  Chapter Xii: Health, security and radioprotection;  Chapter XIV: Communication;  Chapter XV: Economic evaluations and;  Chapter Social and impacts for the Country. It is important to notify that the demand for exploitation licence is accompanied by the licence of Environmental Impact Assessment, and the report of environmental assessment. The report of the feasibility study will be sent to each member of the committee at least one month before the meeting of the committee. Before the convocation of this meeting, the Direction of Mines has to do a preliminary economic evaluation. Once the committee meets, some working groups are set up according to the areas of expertise of each participant. A place and time will be allocated to each working group. It should also be noted that representatives of the company which submit the Feasibility studies will attend to the workshop to answer to the questions of the committee and to defend their work. Once each group has made a decision to accept or reject the part on which they have worked on, all the groups meet to take a final decision. A succinct summary deliberated from the decision may usually be: - The feasibility study submitted by such company is accepted subject to integrate the observations made by the committee or; - The feasibility study submitted by such company is rejected for lack of conformity, insufficiency etc. The economic evaluation of mining project is mainly based on the Net Present Value (NPV) and the Internal Rate of Return (IRR) which are two parameters used to evaluate the degree rentability of a project through its lifespan. To determine these two parameters, there is need to build a financial model to confirm the results of the economic evaluation presented in the feasibility study. After building the financial model, we pass to the sensitivity analysis to know which of the technical or economic parameters which impacts more the NPV. Sensitivity analysis - sensitivity to the ore grade The impact of a variation in the ore content may be small or significant in terms of cash flows, but the increase in this content may cause a decrease or increase of metal covered depending on the type of treatment applied (static or dynamic). - Sensitivity to the type of ore processing. This analysis always shows that the ore processing efficiency varies with the ore grade. - Sensitivity of technical and economic parameters The analysis consists in evaluating the impact of these parameters on cash flows. These parameters include: cost of mining of the ore, cost of ore processing (static or dynamic), cost of metal treatment (static or dynamic), recovery rate of the plant by the type of treatment (static or dynamic), fixed costs, sales price. IV- The socio-economic benefits for the country: - Job creation ; - Capacity buildings ; - Creation of revenues (dividends, royalties, taxes) ; - Sustainability of mining activities; - Building of infrastructures such as: schools, health center, roads; water infrastructures, etc. V- Risk analysis The risk analysis is based on the study of some parameters such as: the political context of the country, the security, the stability of the fiscal regime, the market long term price etc. VI- CONCLUSION Mineral project assessment requires the evaluation of technical inputs such as: the mineable reserves, the production rates, recoveries, costs and revenues. These parameters form the basis of mine project evaluation together with the tax regime of the host country. REFERENCES 1. Association ONAREM-PNC, Projet sekiret, Rapport de fin de la 5e champagne, 1985-1986 ; 2. Association ONAREM-PNC, Projet Techili, rapport de fin de la campagne 1989-1990 ; 3. H.E. K. ALLEN, Aspects of evaluating mining projects, Imperial College of Science and technology, London, UK.

Speaker: Mr Hassane Garba Barke (Ministry of Mines)

175 REGIONAL FRAMEWORK FOR THE CLASSIFICATION OF URANIUM DEPOSITS: AFRICA’S APPROACH TO ADOPTING UNFC-2009 THROUGH IMPLEMENTATION OF AFRICAN MINING VISION

INTRODUCTION: Minerals are found where they occur! The existence of minerals does not necessary look at nearness to the supporting infrastructure such as energy, roads, railways, water, human capital and many other requirements. Existence of particular minerals in an area is wholly dependent on the geology of the area. It requires Host Countries of any mineral(s) to know where exactly these minerals are found, their quantities and qualities which can determine the mineral’s possibility to be exploited and even the expected environmental considerations to be taken on board. To know the existence and quantities of a particular mineral, it takes intensive work of geological experts and associated technology. It is widely known that, knowing the occurrence of a mineral alone is not adequate for any potential investor to come up with an investment decision. There is always a great need for comprehensive studies on the mineral deposit to determine quantities and qualities. It is until the investor is fully convinced on these two key parameters that he can classify them as reserves or resources. Due to inadequate geological information in Africa, companies across the globe make decisions to invest in the African region on a high risk base. They invest with an expectation that they will conduct exploration activities up to the point where there will be huge certainty of occurrence of the ore deposit. Despite this, as a legal requirement in most governing Laws in Africa, companies are required to classify their mineral deposits and report them so that Host States can make sound decisions on the investment arrangements. In some cases, companies prepare the National Preparedness Matrix to check the stage at which they are and their readiness to exploit such a resource. Uranium deposits have often times been treated the same. For many years, investors in Africa have been using different reporting and classification frameworks and this further showed the challenges of Host State Government to understand such technical reports and report the same to all other stakeholders. In most sectors in Africa, there has been chaos in the way the sectoral reports on Uranium has been reported to institutions requiring such information. This has resulted into the receiving party to have inconsistent information from a single deposit or from different deposit which were classified and reported using different reporting frameworks. In Africa, the investors have been using frameworks such as the Australian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (the JORC CODE), the South African Code For the Reporting of Exploration Results, Mineral Resources and Mineral Reserves (SAMREC), Committee For Mineral Reserves, International Reporting Standards (CRIRSCO), Canadian Instrument 43- 101 and many others. Unfortunately, these have been considered as frameworks used for purely commercial purposes. In this regard, African member states considered this challenge and through the African Mining Vision which was adopted by African Heads of States in 2009 that a regional reporting and classification instruments should be developed. Considering the urgent need for such a regional reporting framework and the associated long period which can be taken to develop a ‘home-grown’ framework, a decision was made through African Minerals Development Centre (AMCD) which is an organ of the African Union to consider adopting the United Nation Framework for Classification of Mineral Resources (UNFC 2009). The AMDC noted that member states are fully aware of the existence of the UNFC 2009 and that some African experts took part in developing it. The continent’s participation was supported by the International Atomic Energy Agency (IAEA) with an intention of using the framework for reporting the Uranium deposits in Africa. Through AMDC, African geologists decided to extrapolate its usage from purely Uranium deposits to all other minerals where necessary. UNFC 2009 was crafted in such a way that it supports the African Mining Vision and hence, it was easy for Africa to consider its immediate adoption. Even though this is the case, Africa organized several regional meetings on Harmonization, Adaptation, Implementation and Development of the framework in line with the AMV. In this case, it was proposed that the UNFC 2009 will be the benchmark which will be supported by the African Minerals Resources Classification and Management System (UNFC- AMREC) and that this will be used in reporting Uranium and other mineral deposits at national level in Africa. It is following this development that this paper will tackle the genesis of AMREC and Pan African Reserve and Resources (PARC) Codes for reporting of these minerals. Emphasis will be put on how the AMREC- PARC Code will be used to report Uranium deposits. UNDERSTANDING UNFC 2009- AMREC AND PARC AND THEIR RELATIONSHIPS The United Nations Framework Classification for Fossil Energy and Mineral Reserves and Resources 2009 (UNFC-2009) is a universally acceptable and internationally applicable scheme for the classification and reporting of fossil energy and mineral reserves and resources. It is currently the only classification in the world to do so. The UNFC-2009 reflects conditions in the economic and social domain, including markets and government framework conditions, technological and industrial maturity and the ever present uncertainties. It further provides a single framework on which to build international energy and mineral studies, analyze government resource management policies, plan industrial processes and allocate capital efficiently . UNFC 2009 has mainly three classes which are abbreviated as E,F,G and they mean: E: Economic and Social Viability F: Feasibility and field project status, and: G: Geological knowledge. UNFC 2009 Classes classifies each and every mineral deposit using these three classes which have categories and subcategories. On the other hand, as a way of simplifying Mineral Reporting tasks and making sure that UNFC 2009 is adopted with an African consideration as supported by several continental strategies for development, a plan to set up an African Minerals Resource Classification (AMREC) was born. Spearheaded by the African Minerals Development Centre (AMDC), AMREC is the continental framework that will harmonize, adapt, and develop the UNFC 2009 according to the principles of the Africa Mining Vision (AMV) . Further do the development of AMREC, a proposal to develop a Pan African Resources Code (PARC), which will be a code for transparent financial reporting was discussed and agreed. Both AMREC and PARC were in line with the UNFC 2009 provisions which greatly support the AMV 2009. DISCUSSION AND CONCLUSION Mineral Resource reporting is very crucial and vital to any resource rich country. Most countries in Africa lack capacity in areas such as interpretation and usage of the available reporting frameworks which are normally used for commercial purposes. As is the case, the submitted reports are used for commercial purposes and national (public) purposes. On the part of public usage, the reports can enable the State make exploration and exploitation plans. The reports can also be used by some other international institutions to raise awareness of a particular country’s resource and investment potential. Such institutions includes the United States Geological Surveys (USGS) which produces mineral potential, exploration results and production records of almost every member states. Failure to report correctly leads to misinforming the potential investors or any other interested party (stakeholders). The African Mining Vision (AMV) supports the idea of public resource reporting and the linkages which exists to frameworks such as UNFC 2009 and AMREC-PARC, addresses this need. Currently, most African States are using UNFC 2009- AMREC to report Uranium reserves and resources for easy development of a Country Preparedness Matrix and hence plan for a strategic exploitation of the Yellow Cake. After considering the African challenges at hand, and the need to have a user friendly resource reporting framework, this paper highly commends in adoption of the three frameworks thus UNFC 2009- AMREC/PARC. 1-- (United Nations. Economic Commission for Europe, 2014) ((UNECA), 2nd October, 2017) 2-- (United Nations. Economic Commission for Europe, 2014) ((UNECA), 2nd October, 2017) Bibliography (UNECA), U. N. (2nd October, 2017). Workshop on African Mineral Resource Classification . Ethiopia, Addis Ababa: UNECA. United Nations. Economic Commission for Europe. (2014). United Nations Framework Classification for Fossil Energy and Mineral Reserves and Resources 2009 Incorporating Specifications for Its Application. US: University of Minnesotae.

Speaker: Mr Cassius Chiwambo (Chief Mining Engineer)

176 Exploration successes in the Tim Mersoi basin (Niger): a case study

INTRODUCTION The Madaouela Uranium Project consists of a string of seven deposits located within the Tim Mersoi Basin, near the town of Arlit. Since 2008, GoviEx Uranium Inc (GoviEx) has been exploring for, and defining the mineral resources at the Madaouela Uranium Project. GoviEx has to date delineated a total resource of 117Mlbs of U (46 Mtonnes of ore at a grade of 0.115% eU) in the Measured, Indicated and Inferred categories [1]. On 25 January 2017, GoviEx received its MADAOUELA I mining permit, after completing an ESIA and a Feasibility Study as required by Niger regulation. After Goviex acquired the licences, there was an intense period of delineation and validation of the previous work, followed by exploration along a perceived redox front towards the south. This led to the discovery and the delineation of a number of deposits to the south culminating with the Miriam deposit, broadly along the same trend [2,3,4,5] HISTORY The CEA (Commissariat à l’Energie Atomique) conducted drilling operations using drilling grids of 800 m over large areas, and down to 100 m over two contiguous mineralized zones termed Marianne and Marilyn. The discovery of the Marilyn deposit was then drilled locally at 50 m and less spacing, and an underground mining test was implemented for detailed sampling mineralogical studies, processing tests and investigations into the global rock quality from a mining perspective. CEA also discovered the other deposits that are the current active mines in the area (the Somaïr and Cominak operations), and subsequently ceased exploration work on Madaouela in 1967. [1] The Japanese Power and Nuclear Fuel Development Corporation (“PNC”) conducted additional uranium exploration work up to 1992 and produced a report on the feasibility of the Madaouela deposit in 1993, which was later updated in 1999. Historical mineral resources/reserves were stated at 5 to 15 Mlb U3O8, depending upon the cut-off used.[1]A total of 5 exploration licences were granted in 2007 and exploration and development activities have been ongoing since 2008. GEOLOGY The Tim Mersoi Basin is defined by fluvio-deltaic sedimentary packages that host significant uranium mineralisation. A combination of structural, paleogeographic, paleo-hydrologic and sedimentary factors controlled the location of these deposits [6]. , The main deposits occur within the Carboniferous Guezouman Formation and are differentiated on their gross morphology - a thin carpet type (basal deposit) which occurs right at the base of the Guezouman Formation- controlled by sedimentological features -organic accumulation at crossbed foresets and sulfide accumulation. It is also found within the basal conglomerate - the Teleflak which consists of pebbles from the Air basement, clay and phosphatic nodules. The other type, is described as having Christmas tree morphology (Roll front) with thick mineralised accumulations, up to 25m, and appears to be controlled by fractures. Geological control is a combination of structurally controlled paleochannels - the N70 direction, with the associated development of the UA formation (feldpathic sandstone) within some of these channels and thickening of the Guezouman Formation. The mineralisation occurs at the contact between the reduced Talak Formation (dark mudstone) and the Guezouman Formation, a fluvio-deltaic sandstone and siltstone. [6] The Miriam deposit is different to the others as it can be described a more of a classic roll front with Christmas tree like structures believed to be controlled by N140 expansion fractures, as opposed to carpet like morphology of the other deposits. These fractures can be seen on aerial photographs and aeromagnetic data, and are significant in the search for other Miriam type roll front deposits. Proximity to the N40 Madaouela Fault may be an essential control as the N140 fractures are more like riedel type fractures, located between the Izeretagen and Madaoulea Faults. The other type occurs further up the stratigraphy, within the Madaouela Formation, near or at the contact with the Permian Tarat Formation, host to the nearby SOMAIR mine. This is more of classic roll front, associated with thin mudstones, and occur as stacked lenses. Uranium mineralization typically occurs as coffinite and uraninite associated with molybdenum-rich and titanium-rich coffinite as interstitial grains in kaolinite-illite-chlorite-carbon-calcite cement to quartz-feldspar matrix of the sandstone. Sulfide minerals are associated with the uranium minerals, typically pyrite, nickeline, molybdenite and gersdorffite. Radiogenic galena is present associated with early phase uranium paragenesis. Some surficial oxidation has occurred at La Banane and other localities with near surface-surface carnotite, umhoite and tyuyamunite occurring in calcite cemented shale in fractures. CURRENT STATUS OF EXPLORATION The discovery of the Miriam deposit represents the continuity of exploration which started from the Marianne-Marilyn deposit which have been re-discovered by reopening some old holes drilled by CEA-Cogema. The GoviEx geologists had suggested that at a certain stage it should be possible to encounter redox front of the Akouta model (Cominak). So, a grid of 400X400m has been defined on the basis of redox observation from surface geological formations, and structure. Unfortunately, no rich intersects were recorded but the scintillometric logs, and chips colors clearly show the possibility for a local redox front, albeit at low grade. These results encouraged the Goviex team to define the 200X200m grid and defined an important mineralization at 200ppm cut off, showing interesting continuities at an average depth lower than 100m and some rich intercepts suggesting the possibility of a “low grade openpitable” deposit. Following up on this, the Miriam deposit was then drilled out to a 25 x 25m grid to define the known resource.[5] For the La Banane deposit, this was purely a greenfields discovery following step out from the main trend to test the hypothesis that parallel redox fronts exist to the east of the one that runs through the Marianne to Miriam deposits within the Guezouman Formation. The work started by regional strip mapping along 800m lines to identify the geological structure and favorable redox zone in the eastern part of Madaouela fault. This was followed with the reopening of a few historical holes to verify the historical radiometric data and was followed up by drilling on an initial 3200m spacing grid with 1600m infill along sections, followed by further infill as anomalies were being identified. The redox interpretation was conducted mainly on rock chip observations (grain coating, colours of matrix, clay, organic matter, hematite, limonite) and the scintillometer anomalies. [3] Further additional anomalies have been identified within the Guezouman (Marianne-Marilyn however the largest number of mineralized intercepts occur in the Madaouela arkosic channels. The geological continuity of mineralization within the Madaouela was confirmed by closing up the drill spacing, and several elongated mineralized bodies 300-400m were delineated. GoviEx finally infilled drilling at 100m spacing to control extension and to carry out the correct sequential correlation and to sustain the geological model. [1,2] CONCLUSIONS This case study demonstrates that the geology of the Tim Mersoi basin is still largely unknown. The basin is large and has a complex geology but is similar to other sedimentary basins elsewhere in the world known to host uranium. Current discoveries and exploration activity indicates potential for further development in the region. ACKNOWLEDGMENTS The work completed and discoveries within the Goviex tenure was led by Dr Henri Sanguinetti, Ibrahim Aouami and Tiemogo Mahaman. REFERENCES [1] SRK Consulting, 2015. NI 43-101 An Updated Integrated Development Plan For The Madaouela Project, Niger. Report issued to GoviEx Uranium Inc. [2] Randabel, J., Major D., Aouami, I., Sanguinetti H., Garba, M., Korgom, F.2015 The Madaouela Uranium Project The Newest Mine In Niger ?. IAEA Technical Meeting on Uranium Deposits Associated with Sedimentary Environments. September 2015. [3] Sanguinetti, H., Tiemogo, M, Awouami, I., Bowell,R., GuibalD. 2012.The Discovery of Uranium Mineralisation in the Madaouela Formation – A Transitional Term Between Carboniferous and Permian Sedimentation, Madaouela Uranium Project, Tim Mersoi Basin, Niger. AUSIMM Uranium Conference. [4] Sanguinetti, H., Tiemogo M, Awouami, I., GuibalD. 2012. Exploration and Resources Estimation at the Madaouela Uranium Deposit, Niger. AUSIMM Uranium Conference. [5] Sanguinetti, H., Tiemogo M, Awouami, I., Guibal, D., Bowell, R., Gleeson, P., 2013 The MIRIAM case, a new type of uranium deposit within the Carboniferous sandstone hosted Uranium Mineralization of the Arlit Agadez province, Tim Mersoi Basin, Niger. AUSIMM Uranium Conference. [6] Cazoulat, M., 1985, Geologic environment of the uranium deposits in the Carboniferous and Jurassic sandstones of the Western margin of the Aïr mountains in the Republic of Niger, in : Geological environments of sandstone-type uranium deposits, IAEA TECDOC 328, Vienna, p. 247-263.

Speaker: Mr Jerome Randabel (GOVIEX URANIUM INC)

15:40 Break

Thorium and associated resources

Conveners: Mr C.K. ASNANI (HINDU), Dr Michel CUNEY (CNRS - GeoRessources - CREGU - Universite de Lorraine)

177 Thorium as nuclear fuel: What, how and when?

INTRODUCTION Even though thorium is considered a sustainable fuel cycle option, due to the abundance of uranium and its relative ease of handling, serious attention has not been paid to develop a commercial thorium fuel cycle. Recently, the focus has been renewed toward thorium utilization because of the favourable aspects of thorium fuel [1]. Advantages of thorium include its relative abundance compared to uranium and its occurrence as a coproduct or byproduct from deposits mined for other minerals [2]. Other benefits of thorium include the better waste profile of the fuel cycle and non-proliferation advantages. For these reasons, research and development activities are currently being carried out on several types of advanced reactors that can use thorium. THORIUM AS A FUEL The thorium fuel cycle differs from the uranium fuel cycle in some ways. Natural thorium (Th) contains only trace amounts of fissile material, which are insufficient to initiate a nuclear chain reaction. In a Th-fueled reactor, 232Th absorbs neutrons to produce 233U eventually. The 233U either fissions in situ or is chemically separated from the used nuclear fuel and formed into new nuclear fuel. The sustained fission chain reaction could be started with existing 233U or some other fissile material such as 235U or 239Pu. Subsequently, a breeding cycle similar to, but more efficient than that with 238U-239Pu can be created [3, 4]. Thorium-based fuels exhibit several attractive nuclear properties relative to uranium-based fuels, such as efficient fertile conversion, and better neutron economy and breeding possibilities in thermal spectrum reactors. Thorium dioxide (ThO2) has a higher melting point, higher thermal conductivity, lower coefficient of thermal expansion, and higher chemical stability than U-Plutonium (Pu) fuel. In addition, thorium offers an advantage from the waste perspective. The production of Pu and minor actinides (neptunium, americium, curium), which are the major contributors to the radiotoxicity of the wastes in the uranium-plutonium cycle, is drastically reduced if actinides are recycled [5]. The 233U produced in thorium fuels is inevitably contaminated with 232U, a hard gamma emitter; therefore, heavily shielded facilities are required for handling it. As a result, thorium-based used nuclear fuels possess inherent proliferation resistance. Some of the unique features of the thorium fuel cycle often prove to be the significant challenges in its application. Initial fissile requirements for 235U, 233U, or Pu make thorium unsuitable for rapid expansion of nuclear energy. Thorium introduction could be preferred after a good stock of fissile material (in the form of either Pu or 233U) has been built up [6]. If thorium is used in an open fuel cycle (i.e., utilizing 233U in situ), higher burnup is necessary to achieve a favourable neutron economy. If thorium is used in a closed fuel cycle in which 233U is recycled, remote handling is needed because of the high radiation dose resulting from the decay products of 232U. PREVIOUS WORK ON THORIUM FUEL Research toward utilizing thorium as a nuclear fuel has occurred for over 50 years. Basic research and development, as well as the operation of test reactors with thorium fuel, has been conducted in Canada, Germany, India, Japan, the Netherlands, Norway, the Russian Federation, Sweden, Switzerland, the United Kingdom, and the United States. Light water reactors can be operated with thorium fuel. In the United States, thorium fuel was tested in pressurized water reactors (PWRs) at the Indian Point plant in New York initially (start up in 1962), but this reactor was later converted to a uranium fuel cycle. The Shippingport reactor in Pennsylvania, a “seed-blanket” PWR, operated with thorium fuel from 1977 to 1982. Boiling water reactors (BWR) offer design flexibility that can be optimized for thorium fuels. Thorium was used in a BWR at the Elk River Reactor in Minnesota, United States from 1963 to 1968. Thorium fuel was also tested at the 60 MWe BWR in Lingen, Germany until 1973. Heavy water reactors could offer excellent neutron economy and faster neutron energy, so they are considered better for breeding 233U. Conceptual design studies have indicated that thorium and uranium fuel concepts have many common design characteristics and that the thorium cycle could be used in a plant designed for the uranium cycle without substantial performance penalties. In Canada, Atomic Energy Canada Limited has more than 50 years of experience with thorium-based fuels. India is continuing the use of ThO2 pellets in pressurized heavy water reactors, used for neutron flux flattening of the initial core after start-up. There is no advantage in using thorium instead of depleted uranium as a fertile fuel matrix in fast breeder reactor (FBR) systems due to a higher fast fission rate for 238U and the fission contribution from residual 235U in this material. 232Th in the blanket can be advantageous in a mixed reactor scenario. India has a three-stage nuclear energy scenario in which FBRs play an important role. Thorium has been used in the blanket to breed 233U in a 40 MWt FBR test reactor near Kalpakkam, India. As a pilot study, the Kamini 30 kWt experimental neutron-source research reactor, adjacent to the FBR test reactor, uses 233U as fuel. High-temperature gas-cooled reactors (HTGRs) are thermal spectrum reactors moderated with graphite and cooled by helium. In Germany, reactors testing Th-based nuclear fuels have included the 15 MWe AVR (Arbeitsgemeinschaft Versuchsreaktor) and a 300 MWe Th high-temperature reactor. Other examples of experimental HTGRs using Th as fuel have included: (1) in the United States, the Peach Bottom high-temperature, graphite-moderated, helium-cooled reactor in Pennsylvania and the Fort St Vrain test reactor in Colorado; and (2) in the United Kingdom, the experimental 20 MWt Dragon reactor. In April 2013, Thor Energy of Norway commenced a test of two thorium-based fuels in the Halden research reactor in Norway. Fuel irradiation is being tested to determine if a mixed Th-Pu (“MOX”) fuel can be used in commercial nuclear power plants. Molten salt reactors (MSRs) offer attractive concepts for thorium utilization. In 1954, scientists at the Oak Ridge National Laboratory in Tennessee, United States, designed a 2.5 MWt MSR nuclear reactor with the intent to attain a high-power density for use as an engine in a nuclear-powered aircraft [7]. The Pratt and Whitney Aircraft Reactor No. 1 (PWAR-1) was a zero power MSR that was tested in Oak Ridge in 1957; the reactor used NaF-ZrF4-UF4 as the primary fuel and coolant [8]. THORIUM RESOURCES Thorium is part of the group of element referred to as the High Field Strength Elements (HFSE), which have a valence state greater than two (high charge) and small-to-medium-size ionic radii, thus producing a high electric field (high field strength). These attributes inhibit the ability of the HFSE, which include the rare earth elements (REEs), to achieve charge balance and fit into the structure of most common igneous minerals. As a result, thorium and other HFSE co-occur in anomalous concentrations in unusual rocks, such as carbonatites, alkaline igneous intrusive complexes and associated veins and (or) dykes, and massive magnetite-apatite bodies. Additionally, some moderate- to high-grade metamorphic rocks (amphibolite facies and higher) contain monazite, a REE-Th-phosphate mineral, as an accessory mineral. Monazite is the principal thorium mineral. Xenotime [YPO4] and thorite [(Th,U)SiO4] are other Th minerals in some REE-Th deposits, but are less common. Carbonatites host large tonnage REE deposits and commonly have associated enrichments in thorium [9]. Thorium and the REEs have a strong genetic association with alkaline igneous processes, particularly peralkaline magmatism [9]. Alkaline rocks typically have higher enrichments in REEs and Th than most other igneous rocks. Thorium-rich veins of uncertain origin also exist. Most of these types of vein deposits are interpreted to be related to concealed alkaline magmatism. Massive iron-oxide deposits of magmatic-hydrothermal origin can contain elevated concentrations of Th and REEs, usually in relatively small amounts. Heavy-mineral sands are sedimentary deposits of dense (heavy) minerals that accumulate with sand, silt, and clay in coastal and alluvial environments, locally forming economic concentrations of heavy minerals [10]. Expansive coastal deposits of heavy-mineral sands are the main source of titanium feedstock for the titanium dioxide (TiO2) pigments industry, through the recovery of the minerals ilmenite (Fe2TiO3), rutile (TiO2), and leucoxene (an alteration product of ilmenite). Heavy-mineral sands are also the principal source of zircon (ZrSiO4); it is often recovered as a coproduct. Other detrital heavy minerals produced as coproducts from some deposits are sillimanite/kyanite, staurolite, garnet, and monazite, as a source of REEs and thorium. Globally, the important thorium resources occur as minor minerals within a variety of REE deposits and some heavy-mineral sands. Significant REE deposits of all deposit types also represent the largest thorium deposits. Actively mined REE ore deposits are economic by their REE production, not for their Th content. Heavy-mineral sands operations are economic based on their production of titanium minerals (ilmenite and rutile) and zircon, but they also can often provide detrital monazite as a by-product, and sometimes xenotime. Thus, if a market develops for thorium in the future, mineral deposits that are economic as sources of REEs, including specific types of crystalline rocks and many heavy-mineral sands, can be evaluated as sources of byproduct or co-product thorium [1, 2]. FUTURE THORIUM UTILIZATION China in collaboration with the USA has extensive ongoing research on thorium utilization in MSR designs. This is a dual program involving an early solid fuel stream and advanced liquid fuel stream. In 2011, the China Academy of Sciences launched a research and development program on a liquid-fluoride thorium reactor, called the thorium-breeding molten salt reactor. Since 2008, CANDU Energy of Canada and the China National Nuclear Corporation have been cooperating in the development of thorium and recycled uranium as alternative fuels for new CANDU reactors. CANDU Energy (now part of SNC Lavalin) works on Advanced Fuel CANDU Reactor (AFCR) technology, which aims at thorium utilization. AFCR will be designed to use recycled uranium or thorium as fuel, thus reducing spent fuel inventories and significantly reducing fresh uranium requirements. Spent fuel from four conventional PWR reactors can fully supply one AFCR unit (as well as providing recycled plutonium for mixed oxide fuel (MOX)). In India, research on thorium utilization has been carried out since the 1950s. A three-stage nuclear energy program with uranium-fueled pressurized heavy water reactors, plutonium-fueled FBRs, and thorium-233U-based advanced heavy water reactors has been proposed as the long-term plan. A 500 MWe prototype fast-breeder reactor is in the final stages of completion. Additional 500 MWe FBRs are planned for immediate deployment and beyond 2025; also, a series of 1000 MWe FBRs with metallic fuel, capable of high breeding potential is proposed. The large-scale deployment of thorium is expected to occur in three to four decades after the commercial operation of FBR, with short doubling time when thorium can be introduced to generate 233U. REFERENCES [1] Van Gosen, B.S., and Tulsidas, Harikrishnan, 2016, Thorium as a nuclear fuel (Chapter 10), in Hore-Lacy, Ian, ed., Uranium for nuclear power—Resources, mining and transformation to fuel: Amsterdam, Elsevier Ltd., Woodhead Publishing Series in Energy, Number 93, p. 253–296. [2] Ault, Timothy, Van Gosen, Bradley, and Croff, Allen, 2016, Natural thorium resources and recovery—Options and impacts: Nuclear Technology, v. 194, no. 2, p. 136–151. [3] International Atomic Energy Agency (IAEA), 2005, Thorium fuel cycle—Potential benefits and challenges. Vienna, Austria, International Atomic Energy Agency Technical Document IAEA-TECDOC- 1450, 105 p. [4] World Nuclear Association (WNA), 2018, Thorium: World Nuclear Association. A accessed 29.03.18 at http://www.world-nuclear.org/information-library/current-and-future-generation/thorium.aspx [5] David, Sylvain, Huffer, Elisabeth, and Nifenecker, Hervé, 2007, Revisiting the thorium-uranium nuclear fuel cycle: Europhysics News, v. 38, no. 2, p. 24–27. [6] International Atomic Energy Agency (IAEA), 2012, Role of thorium to supplement fuel cycles of future nuclear energy systems: Vienna, Austria, International Atomic Energy Agency, IAEA Nuclear Energy Series NF-T-2.4, 157 p. [7] Rosenthal, M.W., 2009, An account of Oak Ridge National Laboratory’s thirteen nuclear reactors.:Oak Ridge National Laboratory Report ORNL/TM-2009/181, 80 p. Available at http://info.ornl.gov/sites/publications/Files/Pub20808.pdf. [8] Scott, D., Alwang, G.W., Demski, E.F., Fader, W.J., Sandin, E.V., and Malenfant, R.E., 1958. A zero power reflector-moderated reactor experiment at elevated temperature: Oak Ridge National Laboratory Report ORNL-2536. Available at http://energyfromthorium.com/pdf/ORNL-2536.pdf [9] Verplanck, P.L., Van Gosen, B.S., Seal, R.R, and McCafferty, A.E., 2014, A deposit model for carbonatite and peralkaline intrusion-related rare earth element deposits: U.S. Geological Survey Scientific Investigations Report 2010–5070-J, 58 p., http://dx.doi.org/10.3133/sir20105070J. [10] Van Gosen, B.S., Fey, D.L., Shah, A.K., Verplanck, P.L., and Hoefen, T.M., 2014, Deposit model for heavy-mineral sands in coastal environments: U.S. Geological Survey Scientific Investigations Report 2010–5070–L, 51 p., http://dx.doi.org/10.3133/sir20105070L.

Speaker: Mr Harikrishnan Tulsidas (UNECE)

178 Black- Sand in Sudan for economics thorium fuel cycles

Sudan mining department is conducting project research involving the use of the thorium fuel cycle by tracing Alpha- radiation emitting from isotopes of uranium and thorium were found on the surface marine sediment on the Sudanese coast of the Red Sea at Port Sudan localities through the use of radio chemical procedure and Alpha particle spectrometry that activity concentration of 232U, 234U, 238U, 232Th, 230Th, 228Th were measured so based on that findings the national council for radiological and nuclear control in Sudan conducting a project research involving the use of the thorium fuel cycle to future nuclear industry in Sudan. The works on thorium cycle were conducted for both studying and investigating aspects of development of nuclear power and the methods of involving thorium into it as an additional resource (long-term outlook), and studying those useful qualities which can be introduced by the use of thorium in operating reactors (short-term outlook and medium-term aspect). This paper considers and evaluates the potential benefits that the thorium fuel cycle may offer as an alternative to the existing uranium fuel cycle.

Speaker: Dr Abdalla Hamed (Sudan University for Science & Technology)

179 Thorium resources in China: Spatial distribution, genetic type and geological characteristics

INTRODUCTION Thorium is a radioactive element and widely distributed in nature with average content of 10.5 ppm in the upper crust of the earth [1]. The thorium resource has been regarded as a potential energy source nowadays as more nations are looking for more clear energies to reduce carbon dioxide emissions caused by the traditional oil, gas and coal power plants. Several test reactors designed in the United States, Europe, Japan, Russia, and India has successfully generated electricity using thorium fuel sources [2], although till now it is still in experimental stage. The specialized and systematic exploration and evaluation of thorium resource have not been carried out in China yet. However, at least 90 Th-bearing deposits or occurrences have already been reported till now during the exploration of other resources (e.g. U, REE, Nb). In recent years, some reconnaissance work for the thorium resource have been carried out in China, and by the literature research, comprehensive analyses as well as geological investigation for some representative deposits, we have roughly summarized the spatial distribution, genetic type and geological characteristics of the thorium deposits in China. SPATIAL DISTRIBUTION The thorium deposits have been recognized in all the first-level tectonic units in China, from north to south, including the Central Asian Orogenic Belt, North China Craton and Tarim Block, Central China Orogen (Kunlun-Qilian-Qinling-Dabie Orogenic Belt), Yangtze Craton, South China Block as well as the Tibet-Sanjiang Orogenic Belt. Most of these Th deposits or occurrences are concentrated in the following tectonic subunits: (1) the northern margin of the North China Craton, represented by the well-known Bayan Obo Th-Fe-REE deposit [3], and the Saima U-Th-Nb-REE deposit [4]; (2) the Central Asian Orogenic Belt, represented by the Ba’erzhe (or Balingyao) U-Th-REE-Nb deposit [5]; (3) Central China Orogenic Belt, represented by the Huayangchuan U-Th-Nb deposit [6]; (4) South China (including Yangtze Craton and South China Block), including a series of placer Th deposits and several hydrothermal type Th deposits (e.g., Xiangshan U-Th ore field); (5) Mian’ning-Dechang metallogenic belt in Southwestern China, represented by the Maoniuping, Muluozhai and other similar Th-REE deposits [7]. GENETIC TYPE Most of the Th deposits in China have other commodities, including uranium, rare earth elements, high-field strength elements (Nb, Ta, Zr). According to the geological and geochemical features, the major genetic types of the Th deposits identified in China so far mainly include: (1) the magmatic type, (2) hydrothermal type, and (3) placer type, which have different ore element assemblages. The magmatic type deposits can be further divided into: (a) alkaline silica-undersaturated nepheline syenite-related Th-U-Nb-REE mineralization system, as exemplified by the Saima deposit in northeastern China at the northern margin of the North China Craton [4]; (b) alkaline silica-oversaturated granite-related Th-U-Nb-REE deposit, Ba’erzhe deposit in the eastern Central Asian Orogenic Belt [5] and Boziguo’er [8] in Xinjiang Province at the southwestern margin of the Central Asian Orogenic Belt are both examples of this type; (c) carbonatite-related Th-U-REE deposit, represented by the world-known Bayan Obo Th-Fe-REE deposit (first largest REE and Th deposit in the world [4]) and a series of Th-REE deposits (including Maoniuping, the third largest REE deposit in the world) in the Mian’ning-Dechang metallogenic belt in southwestern China [7]. The hydrothermal type Th deposits are those typically related to hydrothermal fluid activities and are relatively uncommon as compared to the magmatic type Th mineralization systems. This is consistent to the relatively stable geochemical behavior of the thorium element but still some hydrothermal type Th deposits have been recognized, including the Zoujiashan U-Th deposit in the Xiangshan ore field, South China [9] and Xinshuijing U-Th deposit in the Longshoushan metallogenic belt in northwestern China [10]. The placer type monazite deposit is the most common Th deposit type not only in the world but also in China. The placer monazite deposits are widespread in South China (in both the Yangtze Craton and South China Block) where the river systems are well developed, which is favorable for the formation of this type of Th mineralization. The exact examples of the placer type Th deposits include the Juanshui monazite placer in the Mufushan area in Central Yangtze Craton and several similar ones along the southeastern coastal areas. SUMMARIZED GEOLOGICAL FEATURES OF EACH TH DEPOSIT TYPE For the magmatic type Th deposits, main summarized geological features include: (1) they all show intimate spatial-temporal and genetical relationship with the host magmatic rocks, no matter they are peralkaline nepheline syenite (Saima), peralkaline granite (Ba’erzhe) or carbonatites (Bayan Obo); (2) the mineralization are commonly controlled by the morphology of the causative plutons or the contact zone between the magmatic rocks and host rocks, although local fracture zones or faults are also favorable locations for ore mineral precipitation. For instance, the Th-U-REE orebodies are mostly concentrated along the contacts between the nepheline syenite and host marbles in the Saima deposit [4]; (3) the major ore minerals are commonly refractory accessory minerals, including zircon, thorite, pyrochlore, monazite, xenotime, F-, CO32--bearing REE minerals (bastnaesite, synchysite, parisite), etc.; (4) although the mineralization are mostly related to the magmatic fractionation crystallization process, the enrichment and overprint of volatile-rich fluids sometimes also play an important role in the formation of the polymetallic mineralization. For example, the mineralization stage of the Saima deposit includes the magmatic crystallization stage, skarn mineralization stage and later hydrothermal type pitchblende vein stage [4]; (5) they were mostly formed in post-collisional or within-plate extensional tectonic settings, although the formation age can be varied form Neoproterozoic (Bayan Obo), Late Paleozoic (Boziguo’er), Mesozoic (Saima and Ba’erzhe) or Cenozoic (Maoniuping). The representative geological characteristics of the hydrothermal type Th deposits mainly are: (1) they are strictly controlled by liner structures including faults or fracture zones; (2) most of these systems are intimately related to the alkali metasomatism, with the typical alteration assemblage of albite + hematite + chlorite + carbonate, such as in the Xiangshan and Xinshuijing deposits; (3) the major Th minerals are thorite, uranothorite, but some fine-grained Th-phosphate aggregates have also been recognized in certain deposits, suggesting the low-temperature conditions [10]. The placer type Th deposits in China have the following features: (1) they can be further divided into the river/stream placer, beach placer or off-shore placer subtypes according to different sedimentary environments; (2) the major ore minerals are dominated by monazite, together with other heavy minerals including ilmenite, rutile, magnetite, xenotime, zircon, et al. resulting from weathering of the solid source rocks, which are mostly granites. CONCLUSIONS 1. Thorium deposits have been recognized in all the first-level tectonic units in China but are mostly concentrated in the northern margin of the North China Craton, the Central Asian Orogenic Belt, South China and Mian’ning-Dechang metallogenic belt. 2. The major genetical types of the Th mineralization systems recognized in China are magmatic type, hydrothermal type and placer type. 3. The magmatic type Th deposits are mostly located at the craton margins or in the collision belts, and are genetically related to alkaline syenite, alkaline granite or carbonatite magmatic activities during different geological times, and sometimes overprinted by the post-magmatic hydrothermal fluid processes. The hydrothermal type ones are commonly controlled by faults, fractures or breccias, while the placer Th deposits are mostly located in South China in both the coastal areas and inland river systems. REFERENCES [1] RENÉ, M., Chapter 9 Nature, Sources, Resources, and Production of Thorium. http://dx.doi.org/10.5772/intechopen.68304 (2017). [2] VAN GOSEN B. S., GILLERMAN, V.S., ARMBRUSTMACHER, T.J., Thorium deposits of the United States-Energy Resources for the future? U.S. Geological Survey Circular 1336 (2009). [3] SMITH, M.P., et al., A review of the genesis of the world class Bayan Obo Fe-REE-Nb deposits, Inner Mongolia, China: Multistage processes and outstanding questions. Ore Geology Reviews, 2015, 64(1): 459-476. [4] CHEN, Z.B. et al., Saima alkaline rocks and relevant metallogenesis. Atomic Energy Press, Beijing (1996), 1-300. [5] QIU, Z.L., et al., Zircon REE, trace element characteristics and U-Pb chronology in the Ba’erzhe alkaline granite: Implications to the petrological genesis and mineralization. Acta Petrologica Sinica, 2014, 30 (6): 1757-1768 (in Chinese with English abstract). [6] HUI, X.C., et al., Research on the occurrence state of uranium in the Huayangchuan U-polymetallic deposit, Shanxi Province. Acta Mineralogica Sinica, 2014, 34(4): 573-580 (in Chinese with English abstract). [7] XIE, Y.L., et al., Chapter 6 Rare Earth Element deposits in China. Economic Geology, 18, 115-136 (2016). [8] HUANG, H., et al., Geochronology, geochemistry and metallogenic implications of the Boziguo’er rare metal-bearing peralkaline granitic intrusion in South Tianshan, NW China. Ore Geology Reviews, 61: 157-174. [9] JIANG, Y.H., Trace element and Sr-Nd isotope geochemistry of fluorite from the Xiangshan uranium deposit, Southeast China. Economic Geology, 2006, 101: 1613-1622. [10] ZHONG, J., et al., Major and trace element migration and metallogenic processes of the Xinshuijing U-Th deposit in the Longshoushan metallogenic belt, Gansu Province. Geology in China, 2016, 43(4): 1393-1408 (in Chinese with English abstract).

Speaker: Dr Jun Zhong (Beijing Research Institute of Uranium Geology)

180 Effect of Caustic Soda Fusion Temperature on Malaysian Xenotime

Xenotime is mineral rich in rare earth element (REE), mostly contain phosphate mineral which is a rich with yttrium source. Alkaline fusion method was used to devote the study of the preparation of thorium and rare earth. This method could minimize radioactive waste volume, using diluted acid for dissolution and recover phosphate as by product. The method studied included caustic soda fusion, solid and liquid separation and leaching process. The raw material used was a concentrate containing about 60% to 75% total rare earth oxides, 1 to 2% thorium oxide, and 23 to 26% phosphorus pentoxide. Different ratio of Xenotime mineral and NaOH (1:0; 1:1; 1:2 and 2:1) was studied and undergo fusion at different temperature (400, 500, 600 and 700 °c). The resulting powder was analyzed by X-ray diffraction (XRD), X-ray Fluoresce (XRF), particle size analysis (PSA), Field Emission Scanning Electron Microscope (FESEM), Raman Spectrometry and Simultaneous Thermal Analysis (STA). It is possible to extract almost 90% of thorium, rare earths and phosphate by these processes.

Speaker: Dr Roshasnorlyza HAZAN (MALAYSIAN NUCLEAR AGENCY)

Uranium Production by the In Situ Leaching (ISL) Process

Conveners: Dr Alexander Boytsov (Uranium One Group), Dr Peter Woods (IAEA)

181 Experience of plasma-pulse action for ISL uranium wells

While processing deep production horizons of the uranium deposit Inkai being developed using the technology of drill hole in situ leaching (ISL) it is essential to support high rates of pumped off well sites, to increase terms of interrepair working cycles of production wells, to keep the opportunity for reduction of number and duration of repair and renewal operations (RRO).

Speaker: Ms Olga Gorbatenko (Inkai Joint Venture)

182 THE RESULTS OF LABORATORY AND FIELD IN SITU LEACHING TESTS AT THE NYOTA URANIUM DEPOSIT (UNITED REPUBLIC OF TANZANIA)

INTRODUCTION Uranium deposit Nyota is located in the southern part of the United Republic of Tanzania. The geological setting of the deposit and its hydrogeological properties allow to consider part of the Resources as potentially amenable for mining by in-situ leaching (hereafter referred to as “ISL”). In 2015-2016 Uranium One Group conducted a range of studies for evaluating of the possibility of uranium ISL mining at the deposit. The studies consisted of laboratory core leaching, hydrogeological pumping tests and a field ISL test, carried out without processing of pregnant solutions. The ISL test aimed at determining the main ISL process parameters which are used for calculation of ISL mining parameters. The main ISL parameters are the following: uranium recovery, average uranium content in pregnant solutions, specific lixiviant consumption and liquid-to-solid ratio. DESCRIPTION The Nyota uranium deposit is a part of the Mkuju River Project located in Tanzania, some 470 km south-west of Dar es Salaam. The deposit is associated with a series of the Lower Triassic continental sediments of the Karoo Supergroup which are presented by poorly lithified gravelites, sandstones and siltstones. There are three basic mineral forms that represent uranium mineralization: meta-autunite, meta-uranocircite and phosphuranylite. The minerals form a dense interspersed yellowish-green color in the mica-hydrogoethite cement and on the surface of detrital grains. Ore-hosting rocks are of low CO2 content therefore they are considered as non-calcareous. Ore bodies are outlined with 0.01% uranium grade. Within the bodies ore grade varies from >0.01 to 1.8%. Within the central part of the deposit ore bodies are detected at shallow depths – from the surface to the depth of 60-70 m; within the northern part uranium mineralization detected at the depth of 150-170 m. Groundwater level depths are ranging from 1-2 m within river valleys to 40-50 m at watersheds. So uranium mineralization is partly located above groundwater level and partly below. Ore hosting aquifer is unconfined and has neither overlying nor underlying regional aquitards. As of 31.12.2016 Proven & Probable reserves of the Nyota deposit were estimated at 25,8 ktonnes of uranium and Measured & Indicated resources were estimated at about 48 ktonnes of uranium [1]. The existing development plan of the deposit provides for conventional open pit mining with hydrometallurgical processing of ore. Due to the recent uranium falling market Uranium One Group is considering another mining opportunities in addition to the open pit mining method. The geological and hydrogeological setting of the deposit gave Russian experts an idea of possibility of uranium mining by in situ leach method. In 2015-2016 Uranium One Group conducted researches to evaluate an amenability of uranium mineralization for ISL mining. The studies consisted of laboratory core leaching tests, hydrogeological tests and ISL field test. Laboratory tests were conducted on core samples obtained during drilling works in 2015. The boreholes location provided core sampling in the central, the north-eastern and the southern parts of the deposit. Core samples were disintegrated to the size of natural sand grains (0.5-1.5 mm) and averaged. Laboratory tests were conducted in two modes: static and dynamic leaching. The main objectives of static leaching were to determine an amenability of uranium to dissolve in leaching solutions; to select an appropriate composition of the leaching solution; and to determine a degree of homogeneity of the samples in terms of leaching. In static tests 10 g subsamples were leached in flasks at a constant liquid-to-solid ratio which was set to 10. Based on the results of preliminary leaching tests, the sufficient test duration was defined as 24 hours. A series of preliminary tests also revealed that sulphuric acid is the most efficient lixiviant. Therefore, further static tests were all carried out using solutions with sulphuric acid concentration 5, 10 and 20 g/l. The overall number of static tests was 222 (71, 73 and 78 respectively). The testing results showed that: a) uranium mineralization is easy to leach, b) all the samples are of the same type in terms of leachability and c) uranium recovery for the entire sample batch is independent of uranium head grade and equals to 100%. In dynamic tests filtration of leaching solutions through the core material was modelled. For this purpose leaching solutions were pushed upwards through the column loaded with core subsamples (200 g). Pregnant solutions were collected as samples of equal volumes (25 ml) from the overflow and then analyzed for uranium content, acid concentration and pH. Tests duration varied from 3 to 26 hours. The results of the dynamic leaching tests are as follows: uranium recovery 85-99%, average uranium content in pregnant solutions 69-1270 mg/l, sulphuric acid specific consumption 4-60 kg/kgU, liquid-to-solid ratio 1-4. These results are considered as positive. Hydrogeological studies consisted of single and cluster pumping tests which were conducted in hydrogeological wells drilled in 2015. The pumping tests conducted in line with the ordinary technique – pumping at a constant discharge rate and monitoring of groundwater levels at drawdown stage and recovery stage after pumping was stopped. Considering the possibility of the deposit development by both open pit and in-situ leaching, hydrogeological studies were conducted to evaluate hydrogeological properties of the upper part of uranium hosting aquifer. For that purpose well screens were installed in hydrogeological wells at depth interval 6-83 m. Estimation of hydrogeological properties showed that uranium mineralization is within the aquifer presented by sandstones of nonuniform permeability distribution. Hydraulic conductivity of the sandstones determined in cluster pumping tests is 25-63 m2/day, which means that the aquifer is permeable in general. The results of hydrogeological and laboratory leaching tests show that uranium mineralization is located in permeable sediments and can be dissolved by sulphuric acid solutions. These results allow execution of an ISL field test. ISL field testing was executed using the two-spot scheme, invented in Russia [2]. There are only two operating wells – the injection and the recovery ones. The flowrate of the recovery well should be greater than that of the injection well, and the ratio of these flowrates should be maintained constant throughout the test. Such a proportion of the flowrates maintains hydrodynamic isolation of a geological medium involved in ISL test that ensures movement of the solutions from the injection to the recovery well and only within the sampling volume. Planar area of the sampling volume can be calculated using a formula, with the distance between the injection and the recovery wells and the ratio of their flowrates indicated. There is no time variable in the formula so it means that the volume is stable in time. These features of the testing scheme allow reliable estimations of uranium reserves within the sampling volume, and uranium recovery in field tests as well. Maintaining of the stable sampling volume of the geological medium is the main advantage of the two-spot testing scheme. Pregnant solutions which are moving towards the recovery well are diluted by fresh groundwater when they are pumped off. The degree of dilution of pregnant solutions is controlled by flowrates ratio of the recovery and the injection wells. The pregnant solutions from the recovery well are sampled and then pumped into a discharge well. There is no processing of pregnant solutions and uranium recovery provided. The discharge well is usually located far enough from the test site in order to avoid an influence of the discharge on the test. The main objective of the ISL test is a determination of ISL parameters as follows: uranium recovery, average uranium content in pregnant solutions, specific consumption of a lixiviant and liquid-to-solid ratio. Taken together these parameters are usually used for evaluation of an amenability of deposits or ore bodies for ISL mining in terms of geology and hydrogeology. Two-spot tests were widely implemented at the deposits of the former USSR, Mongolia and they are currently applied in Russia and China. Duration of ISL tests vary from 2 to 6 months, with the average of 3 months. Thus, two-spot testing is a comparatively cheap and prompt exploration method which allows to evaluate deposits for ISL mining. Site selection for the ISL field test was based on the results of exploration drilling. Eventually it was decided to conduct the test in the southern part of the deposit, where uranium mineralization occurs below the groundwater table. There are two ore bodies detected within the selected test site. The upper ore body is within the depth of 25-35 m, the lower one is within the depth of 43-50 m. The ore bodies are divided by a layer of 8-10 m thick with uranium grade far below 0.01%. The upper ore body is more sustained in thickness within the test site and has a higher productivity than the lower ore body. For these reasons it was decided to conduct the ISL test only on the upper ore body. The test site has the following geological and hydrogeological setting (for the upper ore body): 9.6 m average thickness of the ore body, 0.078% average uranium grade, 13.2 kg/m2 average productivity, the aquifer is unconfined, groundwater table depth – 18 m, the upper boundary of the ore body is at the depth of 27 m, discharge flowrates of the injection and the recovery wells are about 2 m3/h, the ore body has neither overlying nor underlying aquitards which is typical of the entire deposit. The following parameters were set out for the test: the distance between the injection and the recovery wells – 6 m, screening interval – 25-35 m for the whole thickness of the ore body, the recovery and the injection flowrates ratio – 5. Concentration of sulpuric acid was initially planned to be 15 g/l, but almost in the beginning of the test it was increased to 30 g/l and maintained at this level throughout the test. The test duration was 10 months. During the test groundwater level monitoring was conducted both in 5 monitoring wells and 2 operating wells, the injection and discharge flowrates were monitored, leaching and pregnant solutions were sampled. In leaching solutions sulphuric acid concentration and pH were analyzed, in pregnant solutions uranium content, sulphuric acid concentration and pH were analyzed. RESULTS AND DISCUSSION On the test completion the actual flowrate ratio of the recovery and the injection wells was 5.1 that is very close to the design value. Uranium content in pregnant solutions throughout the test was typical for leaching with rapid increase of values in the beginning up to maximum 170 mg/l and the following slowly decreasing values. By the test completion uranium content in pregnant solutions was 125 mg/l. Average uranium content in pregnant solutions was increasing throughout the test. By the test completion it was 109 mg/l. Sulphuric acid specific consumption was always decreasing during the test as it normally happens. By the test completion specific consumption was 70 kg/kgU. Liquid-to-solid ratio varied linearly during the test and was equal to 2.2 when the test was stopped. According to the requirements of actual guidance documents, ISL two-spot testing should be conducted until leaching process is completed. ISL process completion sets in when uranium content in pregnant solutions decreases to the minimum industrial values (10-15 mg/l). Only completed ISL tests give reliable uranium recovery and other process parameters which can be used for further feasibility analysis. Taking into account that uranium content at the end of the test was still 125 mg/l, the test should be regarded as not carried out up to the end. Its results cannot be used directly for any estimations as they are not supposed to characterize ISL process in full. In this case ISL parameters can be estimated by their extrapolation beyond the test time frame. Extrapolation is available if the ISL parameters’ trends clearly appeared during the test. The results available show that these trends appeared, so they were used for the parameters extrapolation. Liquid-to-solid ratio value which is typical for ISL mining or which is often used in ISL development plans – is 4. So the other test parameters were extrapolated to the above mentioned value of liquid-to-solid ratio. According to uranium leaching dynamics liquid-to-solid ratio of 4 could have been achieved by the 458-th day of the test. By that time uranium recovery could be about 85%. By the end of the test actual sulphuric acid specific consumption achieved the level values which were not expected to change significantly even if we had completed the test. So the final sulphuric acid specific consumption shall be on the same level as it was at the end of the test – 70 kg/kgU. Average uranium content in pregnant solutions shall be definitely higher than minimum industrial level of 10-15 mg/l, and it is expected to be about 60-90 mg/l. ISL tests results are usually assessed by comparison with their criterion quantities. The results are considered positive if all the parameters’ values meet their criterion quantities which are as follows: uranium recovery >50%, average uranium content ≥20mg/l, sulphuric acid specific consumption <150-200 kg/kgU and liquid-to-solid ratio < 10. The extrapolated results tally with their criterion quantities. Consequently the studies conducted by Uranium One Group displayed the principal possibility of applying of uranium ISL mining at the Nyota deposit. The described ISL test at the Nyota deposit is the first one ever carried out in Africa and it yielded encouraging results. On the basis of this, it can be concluded that ISL mining is quite applicable there making mining business more economically efficient and environmentally friendly. REFERENCES 1. Uranium One official site // The Mkuju River Project, uranium resources and reserves chart (http://www.uranium1.com/our-operations/#tanzania). 2. Grabovnikov V.A. Laboratory and field tests in ISL exploration of metal deposits, 1995 (in Russian).

Speaker: Dr Alexey Yastrebkov (Uranium One Group)

183 EFFECTIVE AND ENVIRONMENTALLY COMPLIANT IN SITU RECOVERY OF SEDIMENTARY HOSTED URANIUM

This paper reviews recent advancements in 1. Development of in-situ recovery (ISR) projects for uranium including  dedicated exploration/delineation methods and field tests for gathering determining data,  efficient lab tests and assays of core samples, including up-scaling methodology applied to (1D) column leach tests for a reliable feasibility study of (3D) field ISR, 2. Planning and optimization of ISR processing comprising  wellfield hydrology,  leaching chemistry,  monitoring and process control,  economics,  environmental compliance, 3. Post-mining measures for ISR aquifer restauration in accordance to regulatory re-quirements including  conceptual methodology (combining test procedures and model predictions) for ISR project development and permit procedure,  monitoring and optimization. The effective and environmentally compliant ISR of uranium will be demonstrated for recent ISR projects operated by Heathgate Resources in the Frome Basin, South Australia.

Speaker: Dr Horst Maerten (Heathgate Resources Pty Ltd)

184 GROUNDWATER CONTAMINATION AND SELF-PURIFICATION AT URANIUM PRODUCTION BY THE IN SITU LEACHING PROCESS

INTRODUCTION An important condition of uranium mining industry development is environmental monitoring and ecological security of field development.Тhe well in situ leaching (ISL) method has a less impact on the environment than traditional underground and open-pit mining methods. The uranium extraction is carried out by the technological wells system construction that open a productive horizon containing the ore body. Injection wells are supplied with leaching solutions capable to dissolve selectively uranium containing minerals. The sulfuric acid ISL method is the most widespread in the world. The productive solution is extracted to the surface by the pumping wells and goes into the processing complex for the uranium sorption extraction. Thus, mining is carried out without lifting ore to the surface through selective dissolution of uranium minerals directly in the interior of the earth. At the same time, the deposit development is not accompanied by the formation of overburden and tailing dumps, drainage of underground aquifers, formation of waste waters of hydrometallurgical plants, etc. However, during the field development by the ISL method there is a contamination of underground waters with petrogenic and technogenic substances due to the leach solution injection and its interaction with the host rock [1-3]. To conduct the monitoring of the productive horizon state and to assess the geoecological effects of ISL, it is wise to use mathematical modeling methods. This is due to the process complexity occurring during the ISL and their high inertia, lack of information on the productive horizon state, the high cost of the observation well construction. The report presents a mathematical model of uranium sulfuric acid leaching and software for forecasting the groundwater state during the deposits development by the ISL method. The results of the epigenetic and predictive modeling of the change in the productive horizon state during the development of the Khokhlovsk uranium deposit by the ISL method are presented. METHODS AND RESULTS At sulfuric acid ISL, sulfuric acid goes into the productive aquifer together with the working solution. An oxidizer can also be added to the working solution. As a result of the interaction of the leaching solutions with uranium-bearing and rock-forming minerals, a sufficiently large number of different chemical elements pass into the technological solutions. According to their characteristics and ecological significance, all polluting components can be divided into three groups. The first group includes the radionuclides of uranium and thorium series (U-234, U-235, U-238, Th-230, Th-232, Th-228, Ra-228, Ra-226). The second group involves items passing to processing solutions in amounts exceeding permissible limits (Be, Al, Fe, V, Cd, Zn, Pb, Ti, Tl, Ni - 1-3 orders of magnitude, Na, Ca, Mg - several times). The third group consists of elements whose concentration in the technologicalg solution does not exceed the acceptable limits (Co, Mo, Sr, Se, Hg, Ag, Sb, Te, Cu). From the point of view of groundwater pollution monitoring, only the elements in the first two groups are of interest. The movement of polluting components in the aquifer occurs as a result of convective mass transfer, hydrodynamic dispersion and molecular diffusion. In solutions, pollutants migrate in the form of ions, neutral molecules and complex compounds. The form, in which there is a polluting component in the liquid phase, is conditioned by the geochemical conditions. The geochemical situation is determined by the following main factors: hydrogen index pH, oxidation-reduction potential Eh, solution ionic strength, and the presence of a large number of complex agents [4]. In the ISL process, the geochemical state of the productive horizon within the technological units varies significantly. At sulfuric acid ISL, the pH values within the technological unit decreases, and Eh increases compared to the reservoir waters. This can change the oxidation degree of polyvalent elements, such as iron and uranium, as a result their migration properties are changed. Contaminants can be also in the form of complex compounds. The main ligand at sulfuric acid leaching is sulfate ion. In the form of complex compounds, the components can increase their migratory ability or form sulfate insoluble compounds. It is not possible to describe the migration of all components of the ISL process in details. Therefore, when creating a model, it is necessary to determine the main physical and chemical processes to choose a limited number of minerals, components, the descriptions of which are sufficient for adequate modeling of the pollutants migration. In this paper we present a model describing the main hydrodynamic processes and physical and chemical processes that determine the pollutants behavior in uranium sulfuric acid ISL [5]. Among hydrodynamic processes are filtration of solutions within porous medium and hydrodynamic dispersion. Physical and chemical processes include complexation, diffusion, homophase and heterophase oxidation-reduction and acid-base processes, sorption, mineral precipitation-dissolution, solution components coprecipitation. The following components contained in technological solutions in significant quantities and determining the geochemical environment - Fe3 +, Fe2 +, Al3 +, Ca2 +, H +, OH-, K +, Na +, Mg2 +, S2-, SO42- are considered in the model as well as radioactive contaminants (U4+, UO22+, Ra2+, Th4+). The model does not examine the components of the third group as they are contained in the ISL process in a small amount and do not affect the geochemical situation. Also, some of the elements of the second group contained in a small amount in technological solutions are not taken into consideration. This is due to the fact that they precipitate in the form of hydroxides during acid neutralization as a result of interaction with the host rock and don’t extend beyond technological units. Based on the created mathematical model, problem-oriented software was developed to predict the pollutants migration within underground water and the effect evaluation on the environment as a result of uranium mining by the ISL method [6]. The software allows to carry out calculations taking into account actual operating modes of technological wells, working solution compositions, hydrogeological structure of productive horizon and regional groundwater flow. The software is developed in C ++ programming language and intended for the use on personal computers (PC) with Microsoft Window XP-10 operating systems. Interaction with geological and technological databases is carried out through SQL inquiries. DISCUSSION AND CONCLUSIONS Groundwater contamination and self-purification of the productive horizon after the uranium mining is considered on the example of the central part of the Khokhlovsk uranium deposit. Khokhlovsk deposit belongs to the Zauralsk uranium ore region. The deposit development is carried out by Dalur, which is a part of the ARMZ uranium holding. The simulation was carried out on the basis of the deposit hydrogeological model constructed with the help of a mining and geological information system based on the data of exploration and technological wells geophysical investigation [7]. The information on working solution compositions and technological well operating modes was imported from the technological database of the mining complex information system [7]. Epigonous simulations have been carried out since the beginning of operation up to the present but forecast calculations for a twenty-year period after the uranium mining completion. The simulation results show that having started the operation, the acid content in the technological solutions within the operating unit region increases. After attaining a value of several grams per liter less then acid concentration in the leaching solutions, the acid content is terminated. Similarly, the oxidation and reduction potential Eh which values increase from 100-200 mV to 350-450 mV during the ISL process, behaves. The total iron content also increases during ISL process reaching values about of 1 g/l. The uranium content in the technological solutions increases, reaches the maximum values and decreases as the ore body is worked out. The ion sulfate content in the process solutions of the operating unit is increased by reaching values of 15-20 g/l to the mining completion. The contents of aluminum, potassium, sodium, magnesium are increased as well. Thus, the total mineralization of technological solutions increases to 30-40 g/l. During ISL process, most of the technological solutions remain within the operating unit region. This is due to the rates equality of the working solution injection and productive solution pumping out both for separate operational unit and the entire field. When the process solutions leave the operating unit region, the acid neutralization and formation of uranium and other pollutants insoluble compounds take place. As a result, the area of uranium distribution goes beyond the outline of the technological units for distances not exceeding 20-30 meters. The sulphate ion having the highest migration capacity extends beyond the block outline for the maximum distances of 80-100 meters. To confirm the adequacy of the ISL process description by the created model, the simulated and actual time dependences of the uranium concentration, two and trivalent iron, sulfuric acid and sulfate ion in productive solutions were compared. The comparison was carried out both for individual pumping and observation wells, and for operational unit and the entire field. A good coincidence of simulation results with real data confirms the adequacy of the proposed model and the correctness of the software operation. Having completed the field development neutralization of the acid and increase in the pH of the residual process solutions have been occuring for several years due to the interaction with the host rock. As a result, insoluble hydroxides of uranium, iron, aluminum are formed and their concentration in residual solutions decreases. At the same time, insoluble sulphate containing minerals (gypsum, alunite, jarosite, etc.) are formed. For 20 years the total mineralization of residual technological solutions has decreased from 30-40 g/l to 7-10 g/l. Having completed the operation, the lens of residual solutions remains within the operating unit region as a result of the very low rate of groundwater regional movement in the productive horizon of the Khokhlovsk uranium deposit. The simulation results show that in the case of uranium ISL, the groundwater contamination region is local and situated mainly within the boundaries of the operational units. The main indicator of pollution is sulphate ion because its content in processing solutions with sulfuric acid ISL much more exceeds the concentrations of other components, and it has high migration ability. According to its distribution in the underground waters it is possible to evaluate the area of the productive horizon pollution. Having completed the uranium mining, there is self-cleaning of the productive horizon in some decades. The pollutant concentration reduction occurs in the result of the interaction of residual technological solutions with rock-forming minerals, formation of new minerals and dilution with groundwater waters. The self-cleaning process speed depends on the mineralogical composition of the ore-bearing rocks of the productive horizon and the intensity of water exchange. In the case of a low groundwater movement speed, the self-cleaning process takes place within a region slightly beyond the boundaries of technological units. REFERENCES [1] INTERNATIONAL ATOMIC ENERGY AGENCY, Мanual of acid in situ leach uranium mining technology, IAEA-TECDOC-1239, Vienna (2001). [2] BELETSKY, V.I., BOGATKOV, L.K., VOLKOV, N.I. et al., Reference book on uranium geotechnology, Energatomizdat, Moscow (1997) (In Russian). [3] SOLODOV, I. N., KAMNEV, E. N. (Ed.), Geotechnology of uranium (Russian experience), KDU: University Book, Moscow (2017) (In Russian). [4] SOLODOV I.N., KOCHKIN B.T. Influence of geostructural and geochemical factors on the distribution of technogenic sulfuric acid brines in the aquifer containing the uranium Bukinay deposit (Kazylkum), Geology of ore deposits. 38 (1996) 87 (In Russian) [5] TEROVSKAYA, T.S., NOSKOV, M.D., KESLER, A.G. Mathematical modeling of polluting components migration formed during sulfuric acid well in situ leaching of uranium, Izvestiya VUZ. Fizika. 57 (2014) 83 (In Russian). [6] TEROVSKAYA, T.S., NOSKOV, M.D., KESLER, A.G. Geoecological modeling system for productive of productive stratumstate at ranium mining by in situ leaching method, Izvestiya VUZ. Fizika. 58 (2017) 123 (In Russian). [7] NOSKOV, M.D., GUTSUL, M.V., ISTOMIN, A.D., KESLER, A.G., NOSKOVA, S.N., CHEGLOKOV, A.A. Software package for uranium mining managing by the method of in situ leaching method, Vestnik of the National Research Nuclear University "MEPhI" 2 (2013) 95 (In Russian).

Speaker: Prof. Mikhail Noskov (Seversk Technological Institute of National Research Nuclear University MEPhI)

185 A URANIUM ISOTOPIC PERSPECTIVE ON THE FORMATION OF ROLL-FRONT MINERAL DEPOSITS AND IMPLICATIONS FOR POST MINING REMEDIATION

‘INTRODUCTION’ Roll front deposits are an important global source of economic uranium ore, commonly mined using in situ leach (ISL) methods. The simplified conceptual model for roll front formation calls for the reductive precipitation of U(VI) to U(IV)s as oxygen-rich groundwater interacts with subsurface reductants such as iron minerals, sulfide and anaerobic microbes, forming reduced U minerals such as uraninite and coffinite. While this model captures the broad mechanisms of roll front formation it does not directly address why roll fronts form in only some reducing sediments, the timescale of formation and whether some roll fronts are actively accumulating U and/or migrating. These questions are of geologic interest but more importantly affect the economic and environmental decisions related to ISL mining. In the USA, the primary concern with ISL mining is the fate of remnant aqueous U(VI) in the mined formation after the cessation of mining and active remediation (e.g. reverse osmosis). In many existing mines at least some portions of the aquifer have U(VI) concentrations in excess of the pre-mining aquifer concentrations and it is unknown how far downgradient this U(VI) will migrate before it is reduced to U(IV) and precipitated. This so-called natural attenuation of residual aqueous U is an important component of designing the lifecycle strategy for ISL mines. There are very few direct constraints on the kinetics of U sorption and reduction reactions that can be directly applied to roll fronts, however, some guidance on this topic comes from recent studies of U remediation across contamination sites in the US Dept of Energy complex [1-4]. There are, however, significant differences in the hydrology and groundwater chemistry (e.g. organic carbon activity) in typical roll front deposits compared to the (primarily) vadose zone studies. Recent observations from groundwater and minerals in roll front deposits show a remarkable variation in the isotopic ratio of 238U/235U[5-8]. The observations of U isotopes in groundwater combined with the theory that fractionation of the 238U/235U is largely due to reduction of U(VI) to U(IV) should make it possible to quantify the extent of U reduction in the subsurface both before and after mining activities. Modeling the extent of U reduction has been complicated by (1) deviations in the extent of isotopic fractionation from theoretical models and (2) heterogeneities in the isotopic composition of ore minerals. It remains unclear what processes affect the magnitude of isotope fractionation and give rise to heterogeneous mineral compositions. One suggestion is that biotic and biotic U reduction will yield different isotopic effects and that mixtures of these two mechanisms could explain the variations[9, 10] The purpose of this contribution is to investigate if a 2-dimensional spatial analysis of U and U isotope distributions in a roll front can resolve the aforementioned problems with interpreting the U data from associated groundwater. We demonstrate that the spatial distribution of U, and the U isotope ratios are not random but a result of reactive transport that can be approximated to a pipe flow model and that this information can be used to place constraints on the formation and migration timescales of the roll front. Geologic and Hydrogeologic settings: The Smith Ranch-Highlands uranium mine is located 50 miles northeast of Casper Wyoming, USA on the southern edge of the Powder River Basin. The U ore is concentrated in fluvial sandstones of the Paleocene Fort Union Formation. Regionally the strata dip to the East at <0.5° and groundwater flow is mostly in the same direction at 2-3 m/yr [11]. Uranium is concentrated at redox boundaries (roll fronts) that are typically 2-8 meters wide and at depths of 61-366 meters. Uranium typically occurs as uraninite (UO2) and coffinite (U(SiO4)0.9(OH)0.4) coatings on sand grains and is commonly associated with pyrite and carbonaceous matter, the presumed uranium reductants [12-14]. METHODS AND RESULTS We collected 3 cores through a single roll front in the expected mineralized zone along the depositional axis of the roll front. The cores are spaced approximately 10 meters from one another and are about 6-9 meters in total length. The sediments range from silt and clay-rich horizons to coarse quartz arkose sands. The coarse sediments contain lignite fragments that show some rounding from fluvial transport. Preliminary visual analysis of the core is consistent with a fluvial deltaic type depositional environment. The cores were divided into 0.15-0.3 m sections in the core barrel and packaged in two food grade vacuum bags, evacuated and heat sealed for shipping to the laboratory. Each core hole was logged for gamma radiation, resistivity, and conductivity. In the lab the cores were scanned with a handheld NaI gamma detector to identify sections of low and high radioactivity. Core sections were opened inside an O2-free anaerobic chamber where an aliquot was preserved inside a glass bottle sealed with a rubber septum and the remainder was stored in gas impermeable Mylar bags. Samples of ~5 grams were transferred to degassed 15 ml centrifuge tubes and leached successively with a KCl solution (pore water leach), NaHCO3 solution (adsorbed U fraction) and HCl solution to extract the precipitated UO2 fraction without sampling significant U from silicate minerals such as zircon. The acid leachates were then analyzed for U concentrations, 234U/238U and 235U/238U in the Center for Isotope Geochemistry at Lawrence Berkeley National Laboratory. Results: The cores are numbered 1-3 from upgradient to downgradient for description purposes. The sediments are quartz rich (SiO2 85.1-95 wt%) with large, pink potassium feldspar. Using the ternary chemical classification Na2O-K2O-FeO+MgO all of the core samples plot within the arkose field. Uranium is the only trace element with consistent enrichment above average upper continental crust, with most trace elements between 0.1 and 1 times the upper continental crust. The concentrations of U in the U mineral leachate fraction vary from approximately 0.5 ppm to 1000 ppm. In each core there is a zone of high U concentration that tail to lower concentrations above and below giving a generally convex concentration profile when compared to depth. The 235U/238U ratios vary by approximately 2‰ amongst the analyzed samples and show a convex relationship compared to the sample depth. The 235U/238U values are slightly enriched in the highest U concentration samples but are depleted in the lower concentration samples. In the axis of the roll front, defined by the highest U concentrations there is a decrease in the maximum 235U/238U ratio in the cores further downgradient. The 234U/238U are reported relative to secular equilibrium (SE) as activity ratios (AR): 234U/238Usample/234U/238USE. The 234U/238UAR vary from 0.771 to 2.257 but most samples cluster between ~0.84 and 1.65. In contrast to the 238U/235U and U concentrations the activity ratios show a concave pattern when compared to sample depth with the lowest 234U/238UAR coincident with the highest U concentrations. The highest 234U/238UAR values are generally toward the top and bottom of the cores, however, some of the highest values occur within 0.6 m of the lowest 234U/238UAR in the most upgradient core. The NaHCO3 leachate is assumed to represent the adsorbed U component. The spatial distribution of 238U/235U (described as 238U) and 234U/238UAR in the adsorbed component are similar to the reduced fraction described above, though the absolute values are distinct. For comparison of the two components we describe ∆238U (238Ureduced-238Uads) and 234U/238UAR (% difference). Samples of the adsorbed component are both enriched and depleted ∆238U compared to the reduced component, however most of adsorbed fractions are depleted in ∆238U compared to the reduced fraction (range of ∆238U -1.63 (-0.6 exclude outlier) to +0.26). All samples have 234U/238U enrichment in the adsorbed fraction varying from 16-271%. Most samples with [U]>10 ppm have 234U/238U enrichments less that 75%, while most samples with [U]<10 ppm have enrichments greater than 75%. ‘DISCUSSION AND CONCLUSIONS’ The distributions of U and U isotope ratios in the studied roll front appear to have a systematic distribution, which is distinct from earlier isotopic observations that lacked the resolution to capture this phenomena[5, 7, 9] (but recognized by [15]). In order to understand the distribution of U and U isotope values we constructed a simplified 2 dimensional reactive transport model. The model is constrained by the observed reservoir hydraulic conductivity and the spatial observations of U and U isotopes. First the fluid velocities are set at the maximum value coincident with the high U concentration zone and calculated above and below using a no slip boundary condition at the top and bottom of the domain (i.e. pipe flow model). The model dos not consider hydrodynamic dispersion or chemical diffusion. The U reduction rate is assumed to be a pseudo-zero reaction with at rate that is characterized by the width of the roll front 0.1 µmol L-1 yr-1. The reaction order is reasonable if U reduction is catalyzed by enzymes or by mineral surfaces. The distribution of U and U isotopes is solved: v dU/dx=-R Where x is distance (m), v is fluid velocity (m/yr), U uranium concentration in mol L-1 and R is the precipitation rate mol yr-1. The simulation of uranium reduction over the model domain yields a convex distribution of 238U with the most enriched solids in the center of the domain and more depleted values toward the upper and lower boundaries similar to the observed pattern in the SRH cores. This model is a single-pass analytical solution and does not integrate U addition over the lifetime of the redox boundary, meaning that we cannot directly investigate the concentration profiles. The model uses a single 238U/235U isotopic fractionation factor and yields U solids that are both enriched and depleted in 238U(s) compared to the starting solution composition. Thus, we can explain enriched and depleted 238U(s) occurring in close proximity to each other solely based on advective transport and a single reduction reaction. The model does make an additional prediction that the change in 238U(s) with distance should be smallest in the high flow zone and greatest as you approach the low flow zone adjacent to the zero flow boundaries, which we observe in our dataset, though not to the extremes predicted in our model. In one other roll front deposit extreme values of 238U -4‰ in mineralized sands, which would be consistent with similar effects as the model presented above[7]. Preliminary Conclusions: The U isotopic compositions of roll front ores can vary substantially over the meter scale and larger. These variations can be largely explained by advective transport during roll front ore deposition without significant changes in the mechanisms of U mineralization. These findings also suggest that large changes in hydraulic conductivity in the reservoir may affect the ISL mining and remediation efficiencies. REFERENCES [1] FOX, P.M., DAVIS, J.A., ZACHARA, J.M., The effect of calcium on aqueous uranium (VI) speciation and adsorption to ferrihydrite and quartz, Geochimica et Cosmochimica Acta (2006). [2] CHARLES JOHN BOPP, I.V. et al., Uranium 238U/235U Isotope Ratios as Indicators of Reduction: Results from an in situ Biostimulation Experiment at Rifle, Colorado, U.S.A., Environmental Science & Technology 44 15 (2010) 5927. [3] DRUHAN, J.L. et al., Sulfur Isotopes as Indicators of Amended Bacterial Sulfate Reduction Processes Influencing Field Scale Uranium Bioremediation, Environmental Science & Technology (2008). [4] LOVLEY, D.R., TECHNOLOGY, E.P.E.S., 1992, Bioremediation of uranium contamination with enzymatic uranium reduction, ACS Publications . [5] BASU, A. et al., Isotopic and geochemical tracers for U (VI) reduction and U mobility at an in situ recovery U mine, Environmental Science & Technology 49 (2015) 5939. [6] BROWN, S.T. et al., Isotopic evidence for reductive immobilization of uranium across a roll-front mineral deposit, Environmental Science & Technology 50 12 (2016) 6189. [7] MURPHY, M.J., STIRLING, C.H., KALTENBACH, A., Fractionation of 238U/235U by reduction during low temperature uranium mineralisation processes, Earth and Planetary Science Letters 388 (2014) 306. [8] BOPP, C.J., IV, LUNDSTROM, C.C., JOHNSON, T.M., GLESSNER, J.J.G., Variations in 238U/235U in uranium ore deposits: Isotopic signatures of the U reduction process?, Geology 37 7 (2009) 611. [9] BHATTACHARYYA, A. et al., Biogenic non-crystalline U(IV) revealed as major component in uranium ore deposits, Nature Communications 8 (2017) 1. [10] STYLO, M. et al., Uranium isotopes fingerprint biotic reduction, Proceedings of the National Academy of Sciences (2015) 201421841. [11] Smith Ranch Site, Smith Ranch Site, http://www.nrc.gov/info-finder/materials/uranium/licensed-facilities/smith-ranch.html. [12] DAHLKAMP, F.J., “Uranium deposits of the world”, (2010). [13] Cameco Resources, License Renewal Application, Technical Report, Table of Contents - Chapter 10.0, Part 1 of 4., Cameco Resources, License Renewal Application, Technical Report, Table of Contents - Chapter 10.0, Part 1 of 4., (2012) pp. 1–302. [14] WOLDEGABRIEL, G. et al., Characterization of cores from an in-situ recovery mined uranium deposit in Wyoming: Implications for post-mining restoration, Chemical Geology 390 (2014). [15] DOOLEY, J.R., GRANGER, H.C., ROSHOLT, J.N., Uranium-234 fractionation in the sandstone-type uranium deposits of the Ambrosia Lake District, New Mexico, Economic Geology 61 8 (1966) 1362.

Speaker: Mr Shaun Brown (UC Berkeley and Lawrence Berkeley National Lab)

186 Actual problems of development and carrying out of repair and restoration works of underground uranium leaching wells

The article discusses the issues of complex problems of wells' development, at the stage of their construction, ERW, and the ways of their solution, methods and technology. The analysis of the causes of problems of well development. New advanced technologies and methodics have been introduced to improve well productivity both at the construction stage and at the stage of the ERW.

Speaker: Mr Armanbek Omirgali (JSC "NAC "Kazatomprom")

Friday, 29 June

CLOSING SESSION

Conveners: Dr Michel CUNEY (CNRS - GeoRessources - CREGU - Universite de Lorraine), Ms Olga Gorbatenko (Kazatomprom)

187 Sustainable Development of uranium production: Status, prospects, challenges

Recent WNA [1] and UxC [2] reports demonstrate similar approaches for uranium supply demand forecasts until 2035 in the reference case scenario. Both reports show uranium oversupply at least until 2023. About 10% of global requirements will be provided during this period from secondary sources. The share of the secondary sources will gradually decrease in time. Primary uranium has no alternatives in a long term perspective. According to the WNA report, uranium production is expected to increase in about 40% by 2035. Primary uranium production from existing mines will decrease by 30% in 2035 due to resources depletion and mines closure, while new planned mines will only compensate exhausted mines capacities. Both reports show, that during 2023-2026 uranium demand may exceed supply and new prospective mines from so-called supply pipeline, which development is not yet confirmed by companies plans, must start production during the next 10 years to fill the gap and ramp up to 30 ktU/y by 2035. Are uranium resources and mining capacities sufficient to meet future long-term NPP requirements? Despite depressed market, uranium production continued to grow steadily during the last decade and reached 62 ktU in 2016, which was a historical maximum since 1983. However, in 2017 it dropped back to 59 ktU. Kazakhstan provided the major historical input, increased uranium production six times during the last decade and keeps the world leadership since 2009. Its share comprised 40% of the world total in 2017, followed by Canada with 22% share. Kazatomprom keeps leadership in companies ranking with 21% share, followed by Orano, Cameco (both 16%) and Rosatom (Uranium One + ARMZ) with 14% share. In Situ Leach is the main uranium mining method. Its share in the world total production has increased from 20% in 2005 to 50% in 2016 and 2017. Kazakhstan contributed 40%, while five other ISL producing counties (Uzbekistan, Russia, USA, Australia, China) - 10% of the world total. ISL mining capacities will start to decline after 2028 and production from low cost ISL mines will sharply decline starting from 2022 due to resources depletion, while higher cost ISL production may partly replace it and only until 2028 [3]. Thus, uranium companies may face economic and technical challenges in new ISR projects development due to higher costs and resources availability. Statistics in ranking operating mines by costs and mining capacities show that 95% of mines with full cost below current spot price are located in Kazakhstan [3]. While keeping only 27% of total existing production capacities, they produce 40% of world total. All six Uranium One mines in Kazakhstan are in top 20 of low cost mines and five of them are in top 5. Today is the era of Kazakhstan, however in the new mines supply pipeline there are only seven small new ISL mines, and only one of them in Kazakhstan. Only 40% of 43 currently operating mines produce U at a cost below spot market price. That means than only companies with low cost production or favorable long term contracts may survive in current challenging uranium market. Low uranium prices do not boost production and force companies to to stop, revise or defer their exploration and development projects. In addition to low U prices, companies face technical constraints, political, social and environmental factors. These risks hamper development of several world class uranium projects in Canada, Australia, Africa, Russia and other countries. Kazakhstan has recently announces about 20% below contracts 2018 production, Cameco announced on McArthur stop in 2018. It may result in uranium production further drop in 2018 by at least 10%. However, the companies do not refuse from new mining projects, but focus more on their optimization and effective technologies development. Reliable and low cost uranium resources is a key factor for sustainable long-term production development. Global uranium resources are more than sufficient to ensure the long-term needs of nuclear industry. At the same time, the great share of resources belong to high cost categories and after 2020 uranium producers may face the shortage of low cost resources [4]. During the last decade the total global known uranium resources increased by 21%, however resources in low cost category <80$/kgU decreased by 48%. Kazakhstan nowadays is a world leader, but it may also face all above-mentioned challenges in future. Kazakhstan U resources amounted to about 1 MtU in 2015 [4], 70% of which are in low cost sandstone type, amenable for ISL. Remaining resources belong to lignite, vein and phosphate types. However, 95% of ISL amenable resources belong to operating and under construction mines. Kazakhstan plans to maintain current uranium mining capacities at a level of 65Mlbs until 2020, however actual uranium production during this period may be below capacities from 10 to 20% due to unfavorable uranium market. After 2020, Kazakhstan may face uranium production gradual decrease by 40% in 2030 and by 70% in 2035 due to resources mining depletion and old mines closure. In order to extend existing mining capacities for a long-term period, new uranium mines must start operation during the next five years, but potential for stand by uranium deposits development is limited. The history of uranium discoveries in Kazakhstan shows that almost all deposits in Kazakhstan for ISL mining with initial huge resource base (1,238 MtU) were identified between 1970 and 1990. Uranium exploration during the last decade was focused more on prognosticated resources conversion into measured and indicated categories. The exploration potential to discover new large uranium deposits amenable for ISR mining within the largest uranium provinces in Kazakhstan is far from being exhausted. Favorable transparent legislation must facilitate investments in uranium exploration, when the investor has a State guarantee to mine discovered resources and possess produced uranium under strict compliance with established national standards and regulations. REFERENCES [1] The Nuclear Fuel Report. World Nuclear Association, September 2017. [2] Uranium Market Outlook. Ux Consulting, Q1 2018 Report. [3] Uranium Production Cost Study. Ux Consulting, August 2017 Report. [4] OECD NUCLEAR ATOMIC ENERGY AGENCY, INTERNATIONAL ATOMIC ENERGY AGENCY, Uranium 2016: Resources, Production and Demand, A Joint Report by the OECD Nuclear Energy Agency and the IAEA (2016)

Speaker: Dr Alexander Boytsov (Uranium One Group)

188 A long term view on uranium resources, supply and demand

The need for a long-term view on uranium resources and supply was recognized early in the development of the civilian nuclear power sector. In 1965, a working group was formed to compile worldwide uranium resource estimates by the precursor to the Nuclear Energy Agency (NEA), and in co-operation with the International Atomic Energy Agency (IAEA) since the mid-1980s this group has been producing reports on global uranium supply and demand, currently every two years (“Red Book”). Over the course of its history, the “Red Book” has become recognized as an authoritative source of government-sponsored information on the uranium industry. More than 100 countries have contributed data to the 26 editions published to date. The Red Book summarizes information from various countries, analyzing the evolution of the market and developing conclusions about the evolution of the global uranium resource base, mine production and uranium demand.

Speaker: Dr Adrienne HANLY (IAEA)

189 Harmony - the future of electricity and nuclear delivering its potential

Nuclear power is in demand globally and growing at its fastest rate in 25 years, with new countries and new designs coming on line for the first time. However, to meet climate and development goals nuclear must grow faster still. Harmony is the nuclear industry's vision for the future of electricity and sets the goal of building 1000 GWe of new capacity and providing 25% of global electricity in 2050. What might be the consequences for fuel supply of such a nuclear programme? The 1250 GWe of nuclear capacity envisaged in 2050 would require about 200,000 tU annually, assuming similar fuel efficiencies to current reactors, and it would require nearly 4.5 million tU of cumulative consumption up to 2050. Sufficient uranium resources exist in the world to allow such a rapid expansion: the 2016 edition of the ‘Red Book’ identifies over 10 million tU of conventional and unconventional resources. More could undoubtedly be discovered with scaled-up exploration programmes. Of course, a very rapid expansion of the mining sector would also be needed to supply such an industry.

Speaker: Mr Serge Gorlin (World Nuclear Association)

10:00 Break

CLOSING SESSION

Convener: Prof. Jim Hendry (University of Saskatchewan)

190 Panel discussion

191 Chair's closing statement

Speaker: Dr Michel CUNEY (CNRS - GeoRessources - CREGU - Universite de Lorraine)