Engineering & Mining Journal

JUN 2018

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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REGIONAL NEWS - AUSTRALIA/OCEANIA JUNE 2018 • E&MJ 25 www.e-mj.com SCALPING www.kpijci.com The Mackay project PFS is based on extraction of brine-hosted SOP min- eralization from a single aquifer unit in the lake that begins approximately 40 cm below ground surface. Brine will be extracted from an extensive network of shallow trenches and fed into a series of solar evaporation ponds. Potassi- um-bearing salts will precipitate in the ponds and be wet harvested and pumped to the process plant. The trench network and feed chan- nel are planned to have a total length of 546 km and an average depth of 4.5 m, resulting in 8.5 million m 3 of excavat- ed material. The depth of the trenches will vary to allow sufficient volume and gradient for the brine to flow naturally along the trench network southward to the feed channel. Brine will be trans- ferred along the feed channel to the solar evaporation ponds with the assistance of two pumping stations. The brine will advance through a se- ries of five ponds designed to precipi- tate potassium-bearing salts in the final pond. The salts will be wet harvested and pumped to the process plant. The plant flowsheet will include flotation, decom- position, and SOP conversion. The pro- duction process is estimated to have an overall potassium recovery of 80%. Once approved, project construction and commissioning are estimated to take 36 months. Production ramp-up to 70% of production is expected in the first 12 months of operation before reaching the full production target of 426,000 mt/y. Cadia Starts Deposition of Tailings Into Old Open Pit In early May, Newcrest began depositing tailings into the Cadia Hill open pit fol- lowing the completion of the construction and commissioning work for the pipeline infrastructure. After a short ramp-up pe- riod, Newcrest said it expects Cadia to return to full production rates before the end of the current financial year. On April 23, Newcrest announced it had received approval from the New South Wales (NSW) Department of Plan- ning and Environment to use the first 200 meters (m) of the old Cadia Hill open pit as a tailings storage facility. Newcrest said it continues to review and determine the cause of the North- ern Tailings Facility (NTF) embankment slump. A prohibition notice issued by the NSW Resources Regulator on depositing tailings in the NTF remains in place. Newcrest Managing Director and Chief Executive Officer Sandeep Biswas said, "I again applaud the efforts of our people at Cadia who have worked hard to safely re- store the operation to normal production. It has been a significant additional chal- lenge to acquire and build the required infrastructure in such short time. "Today's announcement is a true testament to the dedication and com- mitment of our people, the support we have received from the state govern- ment and local government authorities, and the constructive engagement and support we have received from the Cadia district community." Heron Prepares to Reclaim, Reprocess Tailings Heron Resources Ltd. awarded two con- tracts for supplying equipment and min- ing services for the reclamation of tailings for reprocessing at its Woodlawn zinc-cop- per project in New South Wales, Austra- lia, which is currently under construction and due to commence commissioning at the end of 2018. The Woodlawn Project includes both reprocessing of 9.5 million metric tons (mt) of historic tailings from the previous operations (1978-1998), in addition to the processing of fresh ore from underground mining. Heron's tailings reprocessing opera- tion includes reclamation by hydraulic mining reclamation; using an IsaMill for fine grinding; and sequential differential flotation of copper, lead and zinc to con- centrates. The mining reclamation rates for the tailings ore will be at a rate of 190 mt per hour (mt/h) using remote-con- trolled water cannons. Heron has con- tracted with National Pump & Energy Pty Ltd. (NPE), one of Australia's leading pumping equipment providers for the hy- draulic mining equipment. Alongside NPE, Heron has awarded a mining services contract to Paragon Tail- ings Australia Pty Ltd. to provide process design, mining planning, construction supervision and support, operator train- ing and personnel to support the tailings reclamation operations. Formed in 2016, Paragon has a track record in hydraulic mining both internationally and within Australia, with the principals having more than 30 years of operational experience with this form of mining.

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