Process of leaching precious metals

A method of extracting at least one precious metal from a precious metal-containing material, comprising the steps of:

• leaching a precious metal-containing material with a substantially cyanide-free and ammonia-free aqueous lixiviant containing dissolved thiosulfate, copper and an organic compound that serves as a copper ligand, thereby to form a leachate;
• and
• extracting the precious metal from the leachate;
• wherein the lixiviant is provided with a dissolved oxygen content above a natural level produced by gas-liquid interchange under open air conditions.

A method of extracting at least one precious metal from a precious metal-containing material, comprising the steps of:

• leaching a precious metal-containing material with a cyanide-free and substantially ammonia-free aqueous lixiviant containing dissolved thiosulfate, copper, and an organic compound that serves as a copper ligand, thereby to form a leachate;
• and
• extracting the precious metal from the leachate;
• wherein the leaching step is carried out at a temperature above 30° C. up to the boiling point of the lixiviant under ambient atmospheric conditions.