GOLD RECOVERY FROM A SULFIDE BEARING GOLD ORE BY PERCOLATION LEACHINGWITH THIOUREA

Percolation leaching with a thiourea solution was investigated for pro cessing a low-grade gold sulphide deposit (Bousquet V) belonging to th e mining company Lac Minerals Ltd. Certain leaching parameters, such a s percolation rate, thiourea concentration, oxidizing agent (H2O2, Fe3 +) and granulometry were studied. To limit the phenomena of thiourea d ecomposition and to optimize gold extraction, it was necessary to main tain the leaching potential between 420 mV and 450 mV (S.H.E.). The ma ximum gold extraction in leaching the Bousquet V ore, after 75 days, v aried between 76% (H2O2) and 83% (Fe3+), with thiourea consumption dep ended on the Tu/oxidizing agent concentration ratio and the nature of the oxidizing agent used. Acid consumption varied with ore granulometr y (100 kg/t for - 9.54 mm/ + 1.63 mm; 80 kg/t for - 19.04 mm/ + 1.63 m m).