BHP Billiton, the world’s largest diversified resources company, is focused on developing bioleaching technology to recover metals from difficult-to-treat concentrates or low-grade ores.

A relatively inexpensive method – bio-assisted leaching – relies on using adapted microbial cultures that catalyse mineral leaching. These diverse bacterial cultures treat low-grade ores, which is important in the face of high-grade ore depletion. It also has an environmental upside: eliminating crushing, grinding and flotation in the production process reduces energy consumption.

Primary copper sulphide ores are notoriously difficult to leach in acid media due to the high content of chalcopyrite, a mineral that is refractory to acid leaching at ambient temperatures and pressures less than 100kPa.

Bio-assisted leaching at temperatures above 500C and up to 700C, overcomes the refractory nature of chalcopyrite, allowing relatively fast leach rates and increased copper recovery.

In addition to bio-assisted leaching, BHP Billiton has developed successful tank bioreactor leaching technologies to treat nickel and copper concentrates under the respective registered process trademarks of BioNIC™ and BioCOP™.

For more information: BHP Billiton,

Carolyn Steere, Tel: +61 3 9609 3670, Carolyn.Steere@BHPBilliton.com