The Asia Miner

SEP-OCT 2014

The ASIA Miner - Reporting Important Issues to Mining Companies in the Asia Pacific Region

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September/October 2014 | ASIA Miner | 55 RISING energy, infrastructure and environmental costs are driving a new paradigm of precision mining. Mining is at the beginning of a period of transition for which the drivers are larger than our industry and refective of the growing global economy and increasing needs to bring the burgeoning population to an acceptable standard of living. In the last 10 years demand for minerals has steepened considerably over historical trends. In the future, companies will have to meet this in- creasing demand by more effectively mining lower-grade and more diffcult deposits. The solution is to raise productivity and lower production costs. The pursuit of productivity begins with increasing effciency of mining operations. During the last decade of the mining boom we have seen in- creased capacity from increased investment, but little increase in effciency. Some argue that we have lost focus on productivity, while pursuing volume through investment in larger machinery and mines. The main productivity drivers vary internationally. In Australia they gener- ally include labour, mining methods and work processes. The challenge in increasing short-term productivity is to drive mining processes, including equipment, towards achieving their theoretical optimal operating mode. The long-term challenge is opening new mines using more productive processes and methods and, where applicable, transitioning older mines. In practice, this may mean adopting new paradigms, some of which feel like a return to the past. For example, in the 1800s it was not feasible to mine large quantities of waste to extract small high-value ore bodies. The 1900s saw a transition to massive mines where movement of waste be- came a larger component of the process. Rising energy, infrastructure and environmental costs are driving a push towards a new paradigm of precision mining focusing on minimizing move- ment and processing of waste. Also, new mining methods will exploit a range of emerging technologies to mine, sort and select ore as close to the working face as possible. Intelligent equipment and new methods will enable work to take place in mining environments considered unsafe for humans and challenging for current methods. Machines may work on walls too steep for humans to safely tackle. Remotely operated or automated equipment won't demand the same expensive luxuries such as fresh air, workplace amenities and alternative escape routes. Ore bodies will be more accurately mapped and identifed before mining. In- formation-transmitting sensors embedded in the ore will enable it to be tracked, sorted and processed in the most effcient way. In surface mines at depths below 400 metres and perhaps shallower, ultra-large trucks will be replaced by conveyor or hydraulic transport systems that will reduce the cost of moving materials from up to 80% of total mining cost down to 10-15%. We already have much of the technology needed for the transition – CRCMining has delivered a number of step-change technologies like the universal dig and dump dragline, shovel load and assist program, cave tracking technology and Oscillating Disc Cutter. These and other innovative projects in the pipeline are indications of exciting times ahead as industry drives towards satisfying global market demand with new pro- ductivity levels. - From the CSIRO's resourceful magazine A NEW cost-effective technology to treat mining wastewater and re- duce sludge by up to 90% has been used for the frst time at a com- mercial mine. The Virtual Curtain technology was used to remove metal contaminants from wastewater at a Queensland mine and the equiv- alent of around 20 Olympic swimming pools of rainwater-quality water was discharged. Sludge is a semi-solid by-product of wastewater treatment and reducing the amount produced has huge environmental and economic benefts. "Our treatment produced a fraction of the sludge that a conventional lime- based method would have and allowed the mine water to be treated in a more environmentally sound way," says CSIRO scientist Dr Grant Douglas. "Reducing the amount is benefcial because the costly and timely steps involved to move and dispose it can be reduced." Given the Australian mining industry is estimated to generate millions of tonnes of wastewater each year, the technology opens a signifcant op- portunity for companies to improve water management practices and be more sustainable. "The technology can produce a material high in metal value, which can be reprocessed to increase a miner's overall recovery rate and partially offset treatment costs," Dr Douglas says. Virtual Curtain utilizes hydrotalcites, which are minerals sometimes found in stomach antacids, to simultaneously trap a variety of contaminants, in- cluding arsenic, cadmium and iron, in one step. Dr Douglas and his team developed the technology after discovering hydrotalcites could be formed by adjusting the concentrations of common wastewater contaminants, aluminium and magnesium, to an ideal ratio and then increasing the pH. "By using contaminants already present in wastewater we have avoided the need for expensive infrastructure and complicated chemistry to treat it," he says. "If required, the treated water can be purifed more effciently via reverse osmosis and released to the environment or recycled back into the plant. It has huge benefts for mining operators in arid regions such as Australia and Chile. "It is a more effcient and economical way to treat wastewater and is en- abling the mining industry to reduce its environmental footprint and extract wealth from waste." A new paradigm for mining By CRCMining CEO Professor Paul Lever Turning mine wastewater into rainwater The new treatment in progress to remove a range of metal contaminants.

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