the term biomining have been coined to refer to the use of microorganisms in mining processes as in the biooxidation of refractory gold minerals. the biooxidation of refractory gold ores presents similar characteristics when compared with roasting and pressure oxidation. almost without exception, microbial extraction procedures are more environmentally friendly. the isolated bacteria in this st...

The orthogonal array design has been used to determine the optimum conditions for gold recovery from Zarshuran refractory gold sulfide ore (Iran) by direct cyanidation and roasting-cyanidation. The Taguchi method was used as the experimental design to determine the optimum conditions of dissolution behavior of gold with cyanidation and roasting-cyanidation from Zarshuran refractory gold ore . T...

The term biomining have been coined to refer to the use of microorganisms in mining processes as in the biooxidation of refractory gold minerals. The biooxidation of refractory gold ores presents similar characteristics when compared with roasting and pressure oxidation. Almost without exception, microbial extraction procedures are more environmentally friendly. The isolated bacteria in this st...

The term biomining have been coined to refer to the use of microorganisms in mining processes as in the biooxidation of refractory gold minerals. The biooxidation of refractory gold ores presents similar characteristics when compared with roasting and pressure oxidation. Almost without exception, microbial extraction procedures are more environmentally friendly. The isolated bacteria in this st...

In this paper, gold leaching of a refractory sulfide concentrate by chloride–hypochlorite solution was investigated and effects of stirring speed, temperature and particle size on the leaching rate were reported. Experimental data for leaching rate of gold were analyzed with the shrinking–core model. Results were consistent with chemical reaction control mechanism in the first 1 h of leachin...

The Mouteh refractory pyrite concentrates at pulp densities of 1.5%, 3%, 4.5% and 6% were treated, using Thiobacillus ferrooxidans DSM 581 and the same bacteria adapted on the Mouteh pyritic concentrate. Compared with a non-adapted culture, use of an adapted inoculum of T. ferrooxidans increased bioleaching rate of iron by a factor of 1.940, 2.011, 1.859 and 1.559 for pulp densities 1.5%, 3%, 4...

Since early 2001, Kalgoorlie Consolidated Gold Mines (KCGM) has successfully operated an ultra fine grinding (UFG) circuit to supplement its roaster capacity for the treatment of the refractory gold flotation concentrate. A second UFG mill was installed in 2002 taking the total UFG capacity to over 20tph while grinding to 11-12 microns and achieving over 90% gold recovery. A development program...

Pyrite and arsenopyrite are known to be the most common gold-bearing sulfide minerals in refractory gold ores. Traditionally, these have been first oxidized by roasting, acidic pressure oxidation or bio-oxidation release gold, after which is dissolved subsequent cyanide leaching step. The chloride (chloride-bromide) solution presents an alternative cyanide-free media, able not only leach minera...

The effect of mechanical activation on the kinetics of ammoniacal thiosulfate leaching of a refractory oxide gold ore containing 2.8 ppm Au was investigated. The gold extraction of 99.81% was achieved by 16 h leaching of a sample mechanically activated for 60 minutes. The gold extraction observed for a similar reference sample without mechanical activation was only 55%. Studies revealed that le...

Double refractory gold concentrates were subjected a two-stage microbial process to destroy both sulfides and carbonaceous matter. In the first stage, the well-known sulfide biooxidation process, which utilizes chemolithotrophic bacteria was used to oxidize sulfides and in the second stage carbonaceous matter is destroyed using the bacterium Streptomyces setonii. After biooxidation of sulfides ...