Enhanced recovery of silver from Artvin-Kafkasor ore by microbial treatment

In the Artvin-Kafkasor ore deposit gold and silver are the main precious me tals and are associated with quartz and limonite. In the present investigat ion, a fungal culture isolated from a mine water was tested under laborator y conditions for its bioleaching potential for enhancing silver recovery pr ior to cyanidation. The silver recovery was expressed as both the silver di ssolved after biotreatment and that recovered after cyanidation following b iotreatment. Silver recovery increased as a function of fungal pretreatment time. After 40 days, silver recovery was about 83% (of which 15% was due t o direct microbial action). The recovery by cyanidation alone, on the other hand (as observed with the uninoculated control), was 53%. These results s uggest that the microbial action favours a more effective cyanidation by ch anging the physical properties of the ore.