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



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.

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    • OPENING SESSION Boardroom A

      Boardroom A


      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, [6] KAZATOMPROM, Kazatomprom Announces Further Production Cuts, December 4, 2017, [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, and-key-lake-operations-an. [9] CAMECO CORP., Cameco Announces Operational Changes in Saskatchewan and the United States, April 21, 2016, operational-changes-in-saskatchewan-and-the-united-states. [10] PALADIN ENERGY LTD, 2016 Annual Report and Financial Statements, August 24, 2016, 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 PM
      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) [2] NUCLEOELÉCTRICA ARGENTINA S.A. , Web pages (2017) [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) [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) [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) /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
        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, [8] REPUBLIC OF TURKEY MINISTRY OF ENERGY AND RESOURCES, Electric Consumption data,
        Speaker: Dr Banu Bulut Acar (Hacettepe University Nuclear Engineerin Department)
      • 10
        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), [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), [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),
      • 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), [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)
    • 3:40 PM
    • 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
        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
        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). INTERNATIONAL ATOMIC ENERGY AGENCY, New 'Comprehensive' Approaches to Uranium Mining and Extraction (2011), 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). 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, (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)
    • 5:40 PM
      Welcome Reception

      Untill 20:00

    • 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
        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
        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.
      • 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), [4] BASOV, V., These 10 mines have the world's most valuable ore (2017), [5] The Ux Consulting Company, LLC, [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), [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,, 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
        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)
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        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
        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 AM
    • Applied Geology and Geometallurgy of Uranium and Associated Metals
      Conveners: Dr Alexander Boytsov (Uranium One Group), Mr Christian Polak (AREVA MINES)
      • 34
        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
        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 ( 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
        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
        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
        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
        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)
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        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:>. 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:>. Access in: 26 February of 2018. [4] NATIONAL SYSTEM OF THE ENVIRONMENT (SISNAMA), official website. Available in:>. 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:>. 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:>. 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:>. Access in: 26 February of 2018. [9] ESTADÃO, “Urânio contamina água na Bahia”, 22 August of 2015, official website. Available in:,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:>. 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:,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))
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        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)
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        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. (2017) [3] LITMANEN, T, JARTTI, T & RANTALA, E., Citizens’ attitudes toward mining in Finland (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), [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. (2012). [12] New Uranium Production Cycle Assessment Service Makes its Debut (2010). [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 PM
      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
        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
        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, 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, 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, A note on Tirukocha Fault, SSZ, India (in preparation)
      • 47
        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 M3



      Conveners: Mr Dennis Amos MWALONGO (Tanzania Atomic Energy Commission), Dr Gabi Schneider (Namibian Uranium Institute)
      • 48
        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
        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
        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., [6] ANGLE software for quantitative gamma-spectrometry, [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,
        Speaker: Prof. Slobodan Jovanovic (University of Montenegro, Centre for Nuclear Competence and Knowledge Management (UCNC))
      • 51
        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
        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)
    • 3:40 PM
    • Health, Safety, Environment and Social Responsibility M3



      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
        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. Accessed February 2018. [2] (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
        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] [2] Environmental Safety Report PJSC PIMCU 2015 ( [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 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.( lectures/Plenary_lecture_at_INAE-CAETS_Convocation_at_New_Delhi.pdf) [2] [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:// [5] SARANGI,A.K.(2014). se/pp/unfc_egrc/egrc5_apr2014 /1May/13_Sarangi_IndiaUraniumUNFC.pdf [6] [7] [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)
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        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)
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        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)
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        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))
    • Advances in Exploration
      Conveners: Mr Luis LOPEZ (CNEA (Argentina)), Martin Fairclough (International Atomic Energy Agency)
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        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), [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), [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), [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), [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),
        Speaker: Dr Mark Mihalasky (U.S. Geological Survey)
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        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 ( (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).
    • Uranium Newcomers
      Conveners: Dr Brett Moldovan (IAEA), Mr Dennis Amos MWALONGO (Tanzania Atomic Energy Commission)
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        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/ [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, [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 AM
    • 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]- [3]- Resources, Production and Demand Paladin Energy Denison Mines Mantra Resources OECD NEA & IAEA, 2016. [4]- Daily Mail Reporter “mail online” 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 PM
      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] [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. [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
        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. 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. 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.)
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        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)
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        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, [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)
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        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 co