Uranium deposit at Tummalapalle
The ore body is fairly continuous over the entire strike length of 6.6 km and uniformly extending downdip upto a depth of 275m. Two parallel ore bands, designated as hangwall lode and footwall lode with average width of 3.2 m and 2.5 m respectively are tabular, stratabound and non-transgressive in nature with little variation in grade and thickness along strike as well as in dip direction. These two bands are separated by a lean zone of 1.5 m to 3 m width. The host rock is quite competent. The radioactive minerals identified in the ore zone are pitchblende, coffinite, U-Ti complex. Pitchblende, which is the major contributor of radioactivity, occurs as fine grained aggregates intimately associated with pyrite in carbonate and phosphatic matrix. Coffinite is fine grained and associated with pyrite. Other associated minerals are pyrite, chalcopyrite, molybdenite and collophane. The gangue minerals are dolomite, quartz and microcline.
The mined out ore, after conventional crushing and grinding (80% passing 74-micron) will be thickened, repulped and subsequently subjected to alkali leaching by sodium carbonate and sodium bicarbonate solution. Leaching will be carried out in leaching tanks / autoclaves in series with a nominal residence time of 6.5 hrs at 130 0C and 6.0-8.0 Kg/Cm2 pressure. The leached slurry will be filtered and the washed cake in the form of slurry will be disposed in tailings impoundment facility. The leached filtrate, after clarification and precoat filtration will be subjected to precipitation with the addition of sodium hydroxide. The final product, at a pH of 12 or above will precipitate as Sodium diuranate (SDU). A study to treat the barren liquor to regenerate sodium carbonate and sodium hydroxide before recycling has been taken up. The plant is being designed to process 3000 T/day.
The technology proposed for mining and processing of low grade ore at Tummalapalle is the result of extensive research work involving Bhaba Atomic Research Center (BARC), Atomic Minerals Directorate for Exploration & Research (AMD) and Uranium Corporation of India Ltd. (UCIL) of Department of Atomic Energy, Govt. of India. This has helped in expanding the uranium reserve base leading to substantial rise in uranium production soon. The work at site is expected to start by mid 2007.
The mine is envisaged to produce 3000 T/day.
