An Integrated Geometallurgical Approach to Optimize Business Outcomes at the MKD5 Nickel Deposit, Mount Keith, Western Australia
Ben Grguric, Timothy Riley, 2005. "An Integrated Geometallurgical Approach to Optimize Business Outcomes at the MKD5 Nickel Deposit, Mount Keith, Western Australia", Wealth Creation in the Minerals Industry: Integrating Science, Business, and Education, Michael D. Doggett, John R. Parry
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The MKD5 nickel sulfide orebody at Mount Keith, Western Australia, is one of the world’s lowest-grade operating Ni mines and currently the largest Ni producer in Australia. The mineralogy and metallurgical properties of MKD5 low-grade, disseminated ores are complex and consequently have required detailed characterization combined with innovative processing and mining in order to achieve economic metal recoveries and concentrate quality. Most of this complexity relates to the effects of hypogene and supergene alteration of the ultramafic protore, and consequent modification of both gangue and sulfide mineral assemblages. A multidisciplinary approach has been taken in order to optimize the resource modeling, mining and processing of the MKD5 orebody, including the development and use of an integrated geometallurgical (GEOMET) model to predict key processing parameters, steps taken to minimize the impact of deleterious contaminants, and the development of a concentrate quality predictor. The design of the Mount Keith concentrator flow sheet presented significant technical difficulties, mainly relating to high pulp viscosities and reagent consumption which were a direct result of the tendency of the ore to generate high levels of slimes during comminution. This was overcome by the development of a unique, two-stage desliming circuit. The recovery improvements developed by a specialist team have resulted in a 13 percent increase in Ni recovery, and increased the net present value of the MKO by A$300 M.
Significant advances continue to be made which promise to enhance further the capacity, product quality, and cost effectiveness of the operation. These advances are once again the result of an interdisciplinary team-based approach. Such an approach is necessary in the current business environment given the rapid progress of mining and processing technology and is particularly important in the case of an operation such as that at Mount Keith, because of the very low grade nature of the resource.
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Global political and economic developments shape both the demand for minerals and primary metals and their supply. Overall, demand has moved broadly in step with economic activity over the past 30 years. Notwithstanding the collapse of the Soviet Union and Eastern Bloc countries, demand grew more rapidly in the second half of the period than the first. The performance of individual products within this general trend largely reflects the specific nature of their main end uses. The geographic center of demand has shifted away from the mature industrial economies of North America, Western Europe, and Japan toward the newly industrializing countries of the Pacific Rim, China, and India. Mine production rose with demand, but not always in precise step. New capacity was required not just to meet demand, even where that was static, but also to offset the continuing effects of ore depletion. There were also changes in the location of production in response to geopolitical forces, the depletion of ore reserves, and the changing economics of extraction and processing. The number of mines contracted, especially during the 1990s, and the scale of mining operations was increased in order to achieve the requisite cost savings. Prices fluctuated in response to changing balances between supply and demand, trending downward from the early 1970s until the early 2000s. Most products witnessed at least one sharp price spike during the period, usually with continuing repercussions. Prices picked up from 2003, but generally not back to their earlier peak in real terms. Profitability varied according to the products concerned. In many years the average rates of return on capital employed have been insufficient to cover the risks involved.