Flinders University, BHP Billiton to develop technique for cost-effective recovery of copper from low grade ores

Image credit: www.bhp.com

Flinders University has teamed up with mining giant BHP Billiton to work on a new technique for extracting low-grade copper in an affordable and sustainable way that could extend the life of some of the world’s largest and oldest mines.

Image credit: www.bhpbilliton.com

Funded by a three year $785,000 Australian Research Council Linkage grant, the research will also draw on the expertise of leading minerology researchers Professor Joel Brugger (Monash University) and Dr Benjamin Grguric (South Australian Museum) and focus on exploiting a normal ore body process known as ‘supergene enrichment’.

“This groundwater process happens naturally in the top parts of many copper deposits and converts primary copper sulfide minerals, which are expensive to mine and treat, into copper metal,” Flinders University Professor of Chemical Minerology Dr Allan Pring explained.

“This means low-grade ore is naturally upgraded into high-grade deposits.”

He said the phenomenon had been observed at a number of historically important copper deposits in South Australia (Moonta, Kapunda and Burra) which helped to establish the State’s economy in the 19th century.

“Before we can adopt that process in a large or commercial way, we have to understand the chemistry of these reactions and this can only be done by extensive laboratory experiments using special flow-through equipment my research group has developed at Flinders,” Professor Pring added.

Deputy Vice-Chancellor (Research), Professor Robert Saint, said the research builds on the ‘exciting fundamental and applied scientific research’ carried out at Flinders University.

“Researchers at Flinders are capitalising on emerging and traditional technologies to find new and more environmentally friendly ways to benefit a range of industries,” Professor Saint said.

“For example, several Chemical and Physical Sciences projects are making great inroads using the latest in microscopy and synchrotron X-ray spectromicroscopy to create future solutions for mining and other sectors.”

Future Fellow Associate Professor Sarah Harmer, who is studying the interaction between bacteria and mineral surfaces using advanced synchrotron spectromicroscopy techniques, said the new ARC project is strategic but with a definite applied outcome in mind.

“We are not setting out to improve the recovery of copper by a few percentage points. We are aiming to provide a new and innovative approach to the problem,” Ms Hammer remarked.

She said supergene zones occur at the top of ore deposits and just below the water table.

“Mild oxidazing reactions take place causing the primary ore minerals, such as chalcopyrite, to be replaced by more copper-rich, less refractory minerals,” Associate Professor Harmer continued.

“These processes are driven by coupled dissolution-reprecipitation (CDR) reactions and in many CDR reactions, the reaction mechanism, rather than intensive properties such as pressure and temperature, control the nature of the products and the overall reaction process. This project will explore the mechanism and controls on these reactions to see if they can be utilised in the mining industry to economically extract copper from low grade ores.”

The research team believes that this not only would extend the life of jobs and infrastructure at remote mine sites but reduce spending on the development of new mine sites.