A.K. Sarangi, Uranium Corporation of India Ltd., Jaduguda, India and Mr. P.S. Parihar, report that India’s uranium exploration programme started in 1948-1949 after the formation of the Indian Atomic Energy Commission. Initially, the emphasis of exploration focussed on the existing mineral belts and geologically favorable areas of the sub-continent. The maiden effort in the Singhbhum copper belt (Singhbhum Shear Zone (SSZ)) became a major success story, where a uranium-bearing stretch containing over 50 anomalies was discovered in early 1950s. Since then, uranium exploration concepts and practices have undergone many changes with increased knowledge on the geology of the terrain along with global development of exploration tools.
A total of 12 low-grade, small to medium size uranium deposits have been established in the SSZ. Presently, seven mines and two mills are producing uranium from this Province. Apart from the SSZ, potential for uranium deposits has now been recognized in other Proterozoic and Phanerozoic basins of India [3, 41]. These include:
- Umra (metamorphite type), Rajasthan;
- Tummalapalle (carbonate type), Andhra Pradesh;
- KPM-Wahkyn-Tyrnai-Umthongkut-Gomaghat (sandstone type), Meghalaya;
- Bodal-Jajawal (metamorphite type), Chhattisgarh;
- Lambapur-Peddagattu-Chitrial-Koppunuru (unconformity type), Andhra Pradesh;
- Rohil (metasomatite type), Rajasthan;
- Gogi (unconformity type), Karnataka.
A number of smaller deposits are also reported from other parts of India.
Uranium Resources in India
Nearly 160,000 tU are reported contained in 40 small to medium size deposits in the country [41]. Six major uranium provinces have been identified, which are the Singhbhum Shear Zone (metamorphite type), Southern Cuddapah (carbonate type), Northern Cuddapah (unconformity type), Mahadek Basin (sandstone type), North Delhi Fold Belt (metasomatite type) and Bhima Basin (unconformity type). A number of occurrences have also been established in other promising areas.
Of the total identified uranium resources in India, the Cuddapah Basin (Proterozoic) in Andhra Pradesh accounts for 51 per cent, the Singhbhum Shear Zone (SSZ) (Proterozoic) in Jharkhand hosts 29 per cent, the Mahadek Basin (Phanerozoic) in Meghalaya hosts 11 per cent, the North Delhi Fold Belt (Proterozoic) in Rajasthan hosts 4 per cent, the Bhima Basin (Proterozoic) in Karnataka hosts 2 per cent, and the remaining uranium occurs in other Proterozoic basins of the country. Uranium deposits of India are of low grade (less than 0.1% U).
Classification of Uranium Resources in India
Uranium resource estimation and reserve categorization in India is generally done following the Indian Bureau of Mines (IBM) guidelines proposed in 1981 [42]. These guidelines are based on the concept of McKelvey system [43] and are comparable with the CRIRSCO Template. In 2003, the IBM made it mandatory to report mineral resources adopting the UNFC-1997 system. Currently, discussions are in progress to adopt the UNFC-2009 for uniform reporting of all resources, including petroleum. However, reporting of uranium continues to be in earlier guidelines of the IBM.
Uranium resources are also classified as per the NEA/IAEA classification scheme under the categories identified and undiscovered resources. Identified resources are normally not reported in cost categories in India. With globalization of the Indian nuclear sector, there is a greater need for the Indian uranium industry to align its current system of resource/reserve estimation with global practices, reporting procedures, and associated risks. Accordingly, the uranium industry is attempting to orient its system of resource/reserve reporting procedures in line with global developments. Efforts are being made to assess different uranium exploration projects in the framework of UNFC-2009 Class/Sub-class system. It has been appreciated that the inherent granularity in the UNFC-2009 Class/Sub-class scheme shall help to classify the projects on the basis of their mineable status.
In India, two Government agencies – the Atomic Minerals Directorate for Exploration and Research (AMD) and the Uranium Corporation of India Ltd. (UCIL) – under the Department of Atomic Energy are engaged in exploration and mining of uranium, respectively. The geological details (G axis) of almost all deposits discovered so far by the AMD have been extensively studied (G1/G2/G3). The technical feasibility studies (F axis) by UCIL are carried out on a case-by-case basis as more and more geological details emerge during the exploration. As the uranium is exclusively used by the Government of India, the economic consideration (E axis) towards development of uranium deposits is not related to internal market-based production. Financial viability of Indian uranium deposits is to some extent related to national production scenarios reviewed time to time.
Aligning uranium deposits in the Singhbhum Shear Zone to the UNFC-2009 Class/Sub-class system More than 46,000 tU resources have been established in the Singhbhum Shear Zone, a major uranium Province in India. All the deposits in the Province are of <0.1% U grade. Presently, seven deposits are being mined.
Responding to the global efforts for finding a common code and terminologies for representation of mineral resources and the gradual acceptance of UNFC-2009 by various countries, an attempt has been made to place all known deposits (mines/deposits/occurrences) in the Singhbhum Shear Zone of India (Figure 11) under UNFC-2009 Class and UNFC-2009 Sub-class categories.
Uranium Deposits and Occurrences of the Singhbhum Shear Zone, India
The deposits with active mining in the Singhbhum Shear Zone (Jaduguda, Bhatin, Narwapahar, Bagjata, Turamdih, Banduhurang and Mohuldih) (Figure 11) are considered as “on production” with categories E1.1, F1.1, G1,2. These deposits account for about 57 per cent of the total known uranium resources in the area and 15 per cent of the total known resources of the country. The resources reported around existing operating mines, such as the Banadungri-Singridungri extensions of the Narwapahar and Jaduguda Deposits, are grouped under the UNFC-2009 Class of “potentially commercial projects”, because they may emerge as production centres under changed socio-economic considerations in the foreseeable future. These deposits may be categorized as E2, F2.2, G1,2,3 (Table 10). Nearly 10 per cent of the resources of the SSZ fall under this class.
Resources identified in deposits, such as the Bangurdih, Garadih, Nimdih, Rajgaon, Kanyaluka and other deposits of the Singhbhum Shear Zone, which require separate infrastructure and independent considerations for mining and processing, may be placed under the UNFC-2009 Sub-class “development unclarified”. The economic viability of these deposits warrants very favorable socio-economic consideration. These deposits are not reasonable prospects for economic extraction in the foreseeable future, and thus may be categorized as E3.2, F2.2, G1,2,3. These quantities are estimated to be 33 per cent of the resources in the SSZ.
Tummalapalle and its adjoining area in the southern Cuddapah Basin report more than 70,000 tU of carbonate type resources. Host rock characteristics and the lower grade of these deposits make them economically less attractive. But considering their large tonnage, extraction is expected to be sustainable in some part of these deposits. Implementation of the project at Tummalapalle is underway for a part of the indicated resources; studies are in progress for Tummalapalle extension blocks. UNFC-2009 code of E1.2, F1.2, G1,2 for 17 per cent of the resources of the basin at Tummalapalle; E2, F2.1, G1,2,3 for 18 per cent of the resources for extension of Tummalapalle; and E2, F2.2, G1,2,3 for the remaining resources of the adjoining area has been proposed (Table 11).
The unconformity related deposits in the northern Cuddapah Province are also of low grade resources. Project activities are in progress for the development of some of these deposits. The geological aspects of these deposits are fairly well understood. A UNFC-2009 code of E2, F2.1, G1,2,3 has been proposed for some of the northern Cuddapah uranium deposits.
Uranium resources in the North Delhi Fold Belt Province are also of low grade and the national economic considerations could permit extraction in future, subject to favorable findings in feasibility studies. Geological characteristics of these resources are fairly well established. A UNFC-2009 code of E2, F2.2, G1,2,3 is proposed for the North Delhi Fold Belt resources.
Uranium resources in the Bhima Basin are of medium grade and unconformity related. Implementation of the mining/extraction in this area is subject to some more technical studies and favorable socio-economic consideration. The geological aspects of the deposit have been fairly well understood and a UNFC-2009 code of E2, F2.1, G1,2 has been proposed for the Bhima Basin resources.
The sandstone type deposits in the Mahadek Basin in the state of Meghalaya are of low to medium grade and amenable for open pit mining. Geological aspects of these deposits have been adequately studied. A UNFC-2009 code of E2, F2.1, G1,2 is proposed for the resources at KPM (Domiasiat), which accounts for about 47 per cent of the basin, and E3.3, F2.3, G2,3 for remaining resources (Wahkyn-Tyrnai-Umthongkut-Gomaghat - II and others of the Mahadek Basin) is proposed.
Exploration Projects
Quantities estimated in several exploration projects totaling to 84,800 tU [3] have been assigned UNFC-2009 codes of E3.2, F3, G3,4.
Conclusion
The advantages of applying UNFC-2009 lies in its simplicity to quantify the judgment in a coded manner, which can be best understood and uniformly interpreted by professionals. It also provides a linkage to business processes and decision making. In the Indian uranium industry, although it has not yet become mandatory to report the status of project using the UNFC-2009 system, the usefulness has been aptly realized by the professionals. However, it may not be complex to report the status of all mines/deposits/occurrences in this system while maintaining the existing system of reporting, since the industry is appropriately structured and well-regulated. The industry has a large base of experts/professionals to address complex issues on uranium exploration and mining in the country.
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