Manager Hydrometallurgy and Pyrometallurgy, Glencore TechnologyEducation - B.Eng (Chemical – Hons I) University of Newcastle, Australia Professional Memberships - AusIMM Chartered Professional Current Position Technology Manager – Hydrometallurgy and Pyrometallurgy Experience Over 15 years experience in hydrometallurgy, pyrometallurgy and mineral processing
Economic recovery and upgrade of metals from middling and tailing streams
As mine head grades decline and orebodies become more complex, traditional mineral processing techniques and flowsheets to achieve saleable concentrate from these ores becomes more difficult. Mines with lower quality concentrates or concentrates with penalty elements are at particular threat. The economics of these operations are far more susceptible to metal price and the availability of other, cleaner concentrates. Additional value may be realised through improved recovery by the inclusion of low grade middling concentrates at the expense of lowering the overall concentrate grade. The most cost effective way to reduce impurity levels is to do so as early as possible in the mining value chain. Established technologies such as fine grinding and fine particle flotation are well established as effective methods in mineral processing unit operations. What is normally overlooked is how a hydrometallurgical process could also be integrated to achieve higher concentrate upgrade at the mill. In the base metals environment, this is mainly because hydrometallurgical processes are associated with production of metal or use of expensive and toxic precipitating agents once the minerals of interest are solubilised. These “back-end” processes can be very expensive particularly with power constraints and the high capital cost associated with low metal tonnes. Glencore Technology has recent experience in the treatment of middling and low grade concentrate streams as well as tailings streams to compliment a concentrator flowsheet in a refractory gold and base metals setting. The value proposition is the isolation of a low grade or tailings stream for treatment and upgrading the stream to an equal or higher grade than the bulk of the metal production and mixing it in for sale. This allows plants to operate on a more favourable part of the grade-recovery curve while avoiding the expense of metal production. For existing operations this is particularly attractive since it can be added on with no process interruptions. Two case studies are examined showing flowsheets and costings to arrive at the value proposition of the GT low grade treatment flowsheet.