OBJECTIVES

Heap bioleaching – the use of bacteria to extract metals from huge piles of generally low-grade ore – is now commercially used for gold ores and for leaching copper from copper oxides and secondary copper sulfide ores such as chalcocite.

Its application to other sulfides, particularly chalcopyrite (copper iron sulfide), pentlandite (iron nickel sulfide) or sphalerite (zinc sulfide), has been less successful. Industry interest in developing a viable heap bioleaching process for other sulfides is strong because it is a low-cost process for recovering metals from low-grade and difficult-to-process ores and mine wastes that minimises environmental impacts and enables operations to produce the final product on site.

The objective of this project is to broaden the application of heap bioleaching for whole ore processing through fundamental understanding of reaction chemistry and microbiology, leading to operational strategies to optimise processing, demonstration of the benefits of selected strategies and testing at heap scale with an industry partner.

INDUSTRY BENEFITS

• an improved understanding of heap leach chemistry and microbiology, and insights on a chalcopyrite heap leach “operating window”, which would complement the development of a heap leach model that could assist the copper industry to extend their heap leach capability
  
• demonstrated operational strategies for improving the rate and recovery in the heap bioleaching of copper from secondary sulfide ores such as chalcocite
  
• native Australian bioleaching bacteria with enhanced copper leaching ability over previously known strains available for evaluation and test work
  
• demonstrated technique for tracking different types of microbes in bioreactors to help manage the right mix of microbes in the microbial community needed for effective bioleaching.

RESEARCH TEAM
Dr Helen Watling (Project Leader)
Dr Alex Elliot
Ms Helen Fletcher
Dr David Maree
Dr Lesley Mutch
Ms Felicity Perrot
Dr Suzanne Rea
Mr Denis Shiers
Dr Elizabeth Watkin
Ms Melissa Corbett (PhD student)
Ms Carla Zammit (PhD student)
Mr Richard O’Rourke (Honours student)

RESEARCH COLLABORATION
CSIRO Minerals
Curtin University
CSIRO Land & Water
Hahn-Meitner Institut (Germany)

PROJECT DURATION
2005-2008