Abstract: Bacterial oxidation by mixed acidophilic bacteria and cyanide leaching experiments for a carbonaceous Carlintype gold deposit in Yunnan province were carried out. The results showed that the gold recovery of direct cyanide leaching is very low (129%). The sulfide minerals packing problem can be effectively solved by bacterial oxidation process， which greatly increases the gold recovery. But the prerobbing effect can’t be eliminated by this process. The absorption effect of carbonaceous substances can be effectively inhibited by carbon cyanide leaching， which can further improve gold recovery for bacterial oxidation residue. Through bacterial oxidation and carbon cyanide leaching process， the gold recovery can reach 8239% and the cyanide reagent is reduced by 4968%. So the bacteria oxidation and carbon cyanide leaching process is an effective method for carbonaceous Carlintype gold deposits. .

Key words: carbonaceous Carlintype gold deposit, bacterial oxidation, prerobbing effect, carbon cyanide leaching, gold recovery