Abstract
Kazakhstan possesses impressive stocks of gold. But production of gold is for about 20 tons annually. It does not meet requirements of the Republic. The reason of this situation is in low extraction ofgold because of the absence of reliable technology and the raised persistence of the Kazakhstan deposits ores. The use of traditional methods of ores processing frequently does not give desirable results. Widelyknown methods of biooxidation also are not effective because of specific toxicity of the Kazakhstan oresin relation to acidophilic microorganisms. In this connection working out of original methods of biooxidation of the ore, based on native strains use, remains an actual problem. Earlier searches of acidophilicmicroorganisms – active oxidizers gold-bearing minerals on a number of deposits of Kazakhstan havebeen carried out. Active strains of acidophilic bacteria were isolated and investigated and their effectiveassociations are received. Now parameters of biochemical technology of gold extraction from Bolshevikdeposit ore are investigating. The purpose of the present research was a choice of the optimal degree ofgold-bearing Bolshevik deposit ore crushing for effective extraction of gold. The technology has beenbased on two-stage bio-leaching. On first stage a biooxidation of crushed ore with two perspective associations of acidophilic bacteria were conducted. On the second stage the chemical extraction of goldwith thiosulfate solution takes place. As a result of the given research the conclusion will be drawn onnecessity of super thin crushing of ore that will allow saving power expenses. In work traditional microbiological and hydromet-allurgical methods are used.Key words: biochemical leaching, bacterial association, thiosulfate, gold