Abstract: A method and apparatus are described for recovering gold from aqueous slurries of refractory gold ores containing sulfidic and/or carbonaceous matter. The method entails pretreating an ore slurry with chlorine in a multi-compartment autoclave operated at an elevated pressure. The chlorine used in this pressure chlorination pretreatment can be in either the gaseous or liquid state. Following the removal of residual chlorine from the pretreated ore slurry, said slurry is transferred to a conventional cyanide leach/carbon adsorption circuit to recover the gold values.