Permeability Restoration and Lowering of Uranium Leakage from Leached Ore Beds.
U S Pat 4 270 802 1981 Jun; :
The permeability of a uranium ore bed is restored, after in situ mining of uranium with an alkaline leach solution containing peroxide or dissolved oxygen, by injection of an (nh4)2so3 or nh4hso3 solution. The sulfite solutions react with free oxygen in the leached ore formation and break up gas bubbles that block passage of the leach solution. Such solutions also decrease ground water contamination by uranium to <2 mg/l. Thus, an ore bed was leached for 54 days with a solution containing 1 g/l nh4hco3 and 0.5 G/l h2o2 and the permeability had decreased to 0.05 Darcy. A solution of 2 g/l nh4hso3 was injected for 5.5 Days and the permeability increased to 0.525 Darcy.
U.S. Pat. 4,270,802, June 2, 1981; Chem. Abstr. 94:69,235P