Processing the minerals extracted from mining tends to take a lot of water, but that could soon change through a raft of new approaches being proposed by researchers at the JKMRC, University of Queensland.

An increased emphasis on saving water in mineral processing operations has led the mining industry to consider alternative processing technologies based on dry or near dry processing. JKMRC Director Professor Tim Napier-Munn said there were potential environmental and economic benefits to be gained from dry processing technology.

There is the potential to cut costs through a reduction in the use of chemicals, currently used in wet processes such as mineral flotation, and an environmental spin-off was likely through much less tailings effluent if any being generated from near-dry processing. Processes which already operate largely or entirely without water include crushing, grinding, screening, and shape sorting. "If dry processing is to replace conventional mineral processing in applications where water is scarce, unavailable, or difficult to recycle, new research will be required to assist with the replacement of existing water-dependant technology," Professor Napier-Munn said. He said the JKMRC was well-positioned to undertake research into some relatively new fields of minerals engineering to advance the use of dry processing, and had already reviewed the options. One of these options is selective mineral liberation in blasting, a potential method of removing waste prior to conventional processing. Other areas for research include improving the energy efficiency of dry grinding, reviewing the opportunities for using ore sorting devices prior to the mineral concentration process, and using electrical separation for fine particle concentration.

The Ultrasort JK Pycnometer is a sorting device recently developed in Australia for dry processing of minerals.

JKMRC Principal Research Fellow, Dr Peter Holtham, said the major drawback with current dry processing technology was related to scale. "Dry processing is sometimes an inherently low throughput process, which is inappropriate for the high tonnages required for the economic viability of most mineral processes," Dr Holtham said. "There are other problems to address, such as electrical separation being only suitable for processing fine particles, and that most dry processes use energy relatively inefficiently."

Renewed interest in the development of dry processing techniques in the European coal industry bode well for the minerals sector in countries like Australia. The European Union is funding research on the efficiencies of dry coal processing in four European centres looking at pneumatic jigging, dry cyclone separation, pneumatic tabling and dry dense medium separation.

Professor Napier-Munn said it was just a matter of time before Australia starts taking the initiative to adopt a similar research goal to reduce water reduction in the minerals processing sector.