Development of Hydrometallurgical Technology for Treatment of Oxidized Gold-Bearing Ores of Kochkovskoe Deposit

"A study was made of chemical and material compositions of the oxidized gold-bearing ore of the Kochkovskoe deposit. It was demonstrated that examined ore consisted mainly of quartz, carbonate and feldspar with a gold content of 2.2 g/t and a silver content of 6.1 g/t. By means of agitation leaching tests it was founded that about 79-80 % of gold can be extracted from ore using cyanide leaching solutions. The achieved high-speed dissolution rate of gold was due to its presence in a finely dispersed state (less than 2.73 µm), which was confirmed by the research of Uralmekhanobr. It was proposed that the ore can be processed by heap leaching process using cyanide leach solutions. Technological studies on the modeling of the heap leaching process were initially carried out in percolators with a capacity of 5 kg on agglomerated ore. It was preliminary established that agglomeration should be carried out at a cement consumption of 12-16 kg/t, with the moisture content in pellets reaching up to 10-12 %. The best percolation leaching results can be obtained with ore crushed to the size of -20 mm. The maximum extraction of gold to the solution was 79-80 % while the L:S ratio reached 1.2-1.4:1.In cooperation with the research center of OJSC ""Berezovsky mine"" a semi-industrial heap leaching test was accomplished. The result of a test performed was an extraction of 78.5 % of Au and 21 % of Ag from ore to a pregnant solution. This extraction degree was achieved at a L:S ratio 0.9: 1. On the ground of results obtained, a technical regulation was developed for design of the heap leaching plant with the capacity of 500 thousand tons of ore per year.INTRODUCTION The ore of the Kochkovskoe deposit represents an important reserve of gold in the Zabaikal region. Of the upmost interest are oxidized ores, the processing of which can be carried out by heap leaching (HL) with cyanide solutions. The purpose of this work was to study the composition and to develop a technology for heap leaching of oxidized ore."