Heap Biooxidation Of Sulfidic Gold Concentrates

GeoBiotics has developed a biooxidation technology (patents pending) which involves coating refractory precious metal sulfide concentrates onto a support material and biooxidizing the sulfides in a heap configuration. The concentrates are produced from low or high grade sulfidic refractory ores or existing mine tailings. The process has been found to achieve high gold recoveries asso­ciated with stirred tank biooxidation, but at the low operating and capital costs associated with whole ore heap biooxidation. Improved gold recoveries of up to 98% after biooxidation are reported for 4 representative mines or deposits. The sulfide flotation concentrates were studied using 3 and 6 in. diameter columns or 3 in. drained vats. The refractory sulfide concen­trates biooxidize rapidly in 3 to 12 weeks with substantial increases in subsequent gold recovery.