Engineering & Mining Journal

FEB 2013

Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr

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P R O C E S S I N G S O LU T I O N S The press statement pointed out that, although the current copper commodity market is primarily supplied by treating chalcopyrite ores typically grading greater than 0.8% copper by the conventional process, there are few unexploited worldclass orebodies with greater than 0.8% copper head grades and the next generation of mines will be closer to 0.6%. This head grade is likely to be uneconomic using the conventional process due to increasing power costs, unless the price of copper increases significantly. Over the past 20 years, major companies have tried to develop low-cost hydrometallurgical processes for such chalcopyrite ores, notably for heap leaching. Thus far, none seem to have been put into production. According to the company, HyperLeach has excellent prospects for being a breakthrough technology in chalcopyrite heap leaching. In addition to chalcopyrite, Alexander claims HyperLeach has been shown to be effective for treating nickel ores, concentrate and mattes; treating molybdenite ores, concentrates and flotation tailings; removing zinc from lead concentrates; reducing arsenic in copper flotation concentrates and removing impurities from copper concentrates. www.e-mj.com It noted that HyperLeach can also be used as a pre-treatment for MetaLeach's AmmLeach technology to provide synergism between the processes. HyperLeach solubilizes and mobilizes target metals from sulphides, with AmmLeach leaching the target metals selectively. This combination allows processing of a whole orebody from the oxide cap through the transition zone to the sulphide basement using the same plant by moving from AmmLeach to HyperLeach as the orebody is mined. Iron Ore Processing System Boosts Bellzone Project Jersey-based mining company Bellzone Mining plc is currently developing two iron ore assets in Guinea, West Africa: Forecariah and Kalia. A 15-year mining license was recently granted to the company for the Forecariah site, with output expected to reach 4 million metric tons per year by 2014. The Forecariah license will be held in a joint venture between Bellzone and Chinese group CIF. The partners have an offtake agreement with Glencore for Forecariah's output. The equipment currently on site there comprises a crushing and screening plant. However, the fines produced from this plant have less iron content, which adversely affects the quality of the material and its suitability for resale. Bellzone has selected CDE Global to develop a tailored iron ore wet processing system that will effectively remove the ultra-fine fraction to ensure that the remainder of the crushing and screening plant fines have a high enough iron content to be sold directly. CDE said it quickly identified the need for low-grade fines to be efficiently separated at 1 mm to produce a +1 mm product, which can go direct to port, with the finer fraction passing to the CDE Evowash to remove the gangue, therefore upgrading the entire fraction to a saleable product. The effective removal of contaminants, according to CDE, will consistently maintain a +58% Fe level from the low-grade fines stock, and an efficient process producing minimal waste ensures that a high product yield is maintained. An Aquacycle Thickener water recirculation system will also be incorporated to effectively recover process water, further enhancing efficiency and maintaining a compact footprint. FEBRUARY 2013 • E&MJ; 87

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