Metallurgical investigations into the extraction of gold and platinum group metals from a sample of ore from the Coronation Hill deposit, Australia

Abstract

70kg of mineralised material from Coronation Hill was submitted to Mineral Deposits by BHP Engineering. The material had been roll- crushed to -0.5mm (nominal), and expected assays were: 6.85g/T Au, 1.85g/T Ag, 0.71g/T Pt, and 1.34g/T Pd. The aim of the testing was to determine the susceptibility of the material to concentration and recovery of the precious metals by gravity, cyanidation, and CIP techniques. The original (-0.5mm) sample grind gave a poor gravity concentrate. When the ore was ground to 80%-75 micron, cyanide leach recoveries were 90% Au, 80%Pd, 25% Pt, and 10% Ag. A gravity concentration stage after ball milling but before leaching is recommended to remove coarse gold. Cyanide leach performance is not much improved by leaching >24 hours. CIP data were limited due to insufficient sample, but recovery of Au and Pd onto activated carbon was suitable.