Abstract: The cobaltiferous ores were studied by the process mineralogy for their main composition， ore particle size distribution， contents of primary elements and mineral dissemination characteristics. The results showed that the main content of the sulfide ores was carrollite that most of them were in monomer form， while a part of them were intergrowth with other ores. The copper ores were composed of chalcopyrite， bornite， chalcocite， covellite. The ferric sulfide is pyrite primarily. The cobaltiferous ores were comprised of 163% cobalt， 105% copper， 1500% sulfur and 124% iron. Shaking flask experiments were used to test the leaching efficiency of the cobaltiferous ores using ZY101 bacteria which was cultured with good anticobalt properties in the lab. The results showed that the cobalt bioleaching efficiency by bioleaching was 8571% which was 6326% higher than that by chemical leaching with high iron solution. So it was more suitable that recovery of cobalt by bioleaching than by chemical leaching， and ZY101 was favored for cobalt leaching because of its high leaching efficiency and cobalt tolerance.

Key words: cobaltiferous ores, process mineralogy, carrollite, bioleaching, chemical leaching