Gold recovery from Mastra ve Kaletaş (Gümüşhane) ores

SUMMARY Gold Recovery from Mastra ve Kaletaş (Gümüşhane) Ores Gold ores can be processed by different methods based on their mineralogical and metallurgical characteristics. Cyanidation process is traditionally used to treat gold ores since times much than century. In this study, Mastra and Kaletaş gold ores were mineralogically investigated in order to determine their ore processing characteristics. Gravity tests and cyanide leach tests were carried out for Mastra ore. Diagnostic leach tests, cyanidation, roasting + cyanidation and flotation tests were investigated for Kaletaş. Amenability of Mastra (Gümüşhane) gold ore to gravity recovery using a Falcon and Knelson Concentrator were examined. In Falcon gravity tests, a concentrate (Cons.l) with a grade of 262 ppm Au was produced at 81 % recovery and 7.2 % yield. In the Knelson gravity test, a concentrate containing 771.95 ppm Au was produced at 47.15 % recovery and 1.58% yield. In the cyanide leach test, the gold recovery for Mastra and Kaletaş are 90-95 % and 65-70 % respectively. In flotation tests for Kaletaş ore, apart from zinc, consistently unsatisfactory recoveries for gold, copper and iron was obtained despite the production of concentrates with a gold content of 20-30 ppm. Roasting of the Kaletaş ore was carried out as a pretreatment step prior to cyanidation at different temperatures. As the temperature increased only a limited improvement in the extraction of gold was noted and highest gold recovery was obtained in the cyanide leaching of the calcine produced at 550°C. It could be estimated from the diagnostic leaching data that the refractoriness of the ore is caused by fine dissemination and association of gold particle within carbonates and oxides (-13%), sulfides (-13%) and silicates (-2%). Key Words: Gold, Refractory Gold, Mastra, Kaletaş, Cyanide Leach, Gravity, Flotation, Roasting, Diagnostic Leach VI