Low grade uranium deposits of India – a bane or boon

Abstract Uranium resources of the world is estimated to be 5.5 million tonnes and the proven resources in India forms 3% of the world resources. The biggest uranium deposit is the Olympic dam deposit in Australia, which contains nearly 2.45 million tonnes of 0.023% U3O8, while the highest average grade of nearly 21% is established in the McArthur river deposit, Canada. Another very high grade deposit, the Cigar lake deposit, is also in Canada with an average grade of nearly 18%. Most of the uranium deposits established in India so far falls under the category of low grade. These low grade uranium deposits are distributed mainly in Singhbhum Shear Zone, Jharkhand; in parts of Chhattisgarh; Southern parts of Meghalaya; Cuddapah Basin, Andhra Pradesh; in parts of Karnataka and Aravalli- and Delhi Supergroups, Rajasthan and Haryana. These deposits are mainly hydrothermal vein type, stratabound type and unconformity related. The Singhbhum Shear Zone, Jharkhand hosts seventeen low grade vein type uranium deposits, aggregating about 30% of Indian uranium resources. The stratabound uranium mineralisation hosted by Vempalle dolostone extends over 160 km belt along southwestern margin of Cuddapah Basin in Andhra Pradesh and accounts 23% of the Indian resources. Though the dolostone hosted Tummalapalle uranium deposit was established in the early nineties, because of techno -economic constraints, the deposit remained dormant. As a consequence of the development of an innovative pre ssure alkali leaching process, the deposit became economically viable and a mine and mill are being constructed here. Recent exploration inputs are leading more such strata-bound low grade uranium deposits in the extension areas of Tummalapalle. Nearly 10 blocks have been identified within a 30 km belt which are being actively explored and a large uranium deposit has already been proved in this province. The deposit at Tummalapalle and adjoining areas is likely to emerge as one of the larger deposits in the world. The northern parts of Cuddapah basin in Andhra Pradesh is the host for unconformity related low grade uranium deposits. Four low grade low to medium tonnage deposits viz. Lambapur, Peddagattu, Chitrial and Koppunuru have been established in this province along the contact between basement granite and Proterozoic sedimentary rocks. This province also holds promise for large tonnage-high grade mineralization in the deeper unexplored parts of the basin. The North Delhi Fold Belt in the states of Rajas than and Haryana is the host for albitite/vein type uranium mineralization. A 320 km long NE-SW trending zone of deep seated fractures is the locus of mineralization and the mineralization is caused by soda metasomatism. A low grade uranium deposit is already established at Rohil associated with albitites and vast areas in this zone is open for exploration. The Cigar lake deposit, one of the two very high grade deposits in the world, though discovered in the year 1991 remains unexploited because of it high grade and requirement of remote handling and high end mining technology. The Mc Arthur deposit is being mined by raisebore mining method and the entire operation is carried out by 750 employees. Because of the high grade nature of the ore, it is diluted with barren rocks to bring the grade into manageable level before the beneficiation. The Rossing uranium deposit in Namibia, the biggest opencast mine for uranium, is of low grade and produces nearly 8% of the global output. As a result of the massive minin g and beneficiation operation, the employment of manpower is also very high compared to the high grade deposits. India, being a developing country with a high rate of unemployment, should treat the low grade deposits as an opportunity for employment. The operation of Rossing mine in Namibia is a shining example of as to how a low grade deposit could be economically exploited in the national interest and still be among the top five countries in terms of production. Inspite of mining the low grade resources, uranium mining industry in India provides direct and indirect employment to thousands of people and still operates in profit mode. Environmental concerns and radiation exposure to mining and milling personnel is negligible in the case of low grade deposits. The new mines, which are going to be opened in Tummalapalle, Andhra Pradesh; KPM (Domiasiat), Meghalaya; Gogi, Karnataka; Rohil, Rajasthan etc. will create substantial direct and indirect employment opportunities and transform the economy of these regions.