Method of biotreatment for solid materials in a nonstirred surface bioreactor

A method of biotreating and recovering metal values from metal-bearing refractory sulfide ore using a nonstirred surface bioreactor, said process comprising the steps of:

• a. producing a concentrate of metal sulfide particles from the refractory sulfide ore,
• b. coating the surface of a plurality of coarse substrates having a particle size of greater than about 0.3 cm with the metal sulfide particles to be biotreated and thereby forming a plurality of coated coarse substrates, said metal sulfide particles to be biotreated having a particle size of less than about 250 μm;
• c. forming a nonstirred surface reactor by stacking said plurality of coated coarse substrates into a heap or placing said plurality of coated coarse substrates into a tank, said reactor having a void volume greater than or equal to about 25% and a surface area of greater than or equal to 100 square meters per cubic meter of reactor space;
• d. biooxidizing the metal sulfide particles on the plurality of coarse substrates;
• e. contacting the biooxidized metal sulfide particles with a metal lixiviant to thereby dissolve metal values from the biooxidized metal sulfide particles;
• and
• f. recovering precious metal values from the lixiviant.