Heap leaching of refractory gold ore by integrating enhanced bio-oxidation of pyrite and chloride-based gold leaching

Gold occurs in association with pyrite and arsenopyrite in the Carlin-type gold deposit, with little gold being contained in carbonaceous materials. Extracting this gold requires pretreatment, such as pressure oxidation or roasting, to remove carbonaceous materials and sulphides, followed by the application of alkali cyanide or thiosulphate solution to leach gold. These processes are energy-intensive and may generate potentially harmful substances to the environment. With decreasing ore grade and more stringent environmental regulations, these processes may become financially and environmentally unviable. The proposed research project aims to develop a heap leaching process as an alternative to treat this type of refractory gold ore. This process involves bio-oxidation of pyrite as pretreatment to expose gold, followed by chloride-based leaching of gold. This project will bring both economic and environmental benefits to Barrick, given that the proposed process involves neither energy-intensive unit operations nor chemicals of significant environment concern.

Faculty Supervisor:

Wenying Liu

Student:

Monserrat Rebolledo

Partner:

Barrick Gold Corporation

Discipline:

Engineering

Sector:

Life sciences

University:

University of British Columbia