MMG Rosebery 14 July 2015 History of Rosebery
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MMG Rosebery 14 July 2015 History of Rosebery 1893 • Tom McDonald discovered alluvial gold with boulders of zinc-lead sulphide. 1920 • Rosebery and Hercules Mines purchased by the Electrolytic Zinc Company of Australasia Limited. (EZ). 1927 • Construction of Rosebery Mill begins. 1936 • Production started in February – Mill capacity was 15 tonnes/hour. 1961 • Mill capacity was 30 tonnes/hour. 1963 • Murchison Highway completed. 2003 • Breakthrough of surface decline allowing trucking of ore to surface. 2004 • Transition from Pasminco to Zinifex Ltd., becoming one of Australia’s leading companies in mining and producing zinc, lead, copper, gold & silver. 2008 • Zinifex Ltd and Oxiana merged into OZ Minerals. 2009 • MMG – Minerals & Metals Group. 2011 • 75 years of continuous mining and milling at Rosebery. 2 Overview Location: Tasmania, Australia Ownership: 100% MMG Mine: Underground (sublevel open stope – Transverse, Longitudinal and slashing stoping) Throughput: 0.95 Mtpa, mine, crush, grind, float Product: Zinc concentrate, Lead concentrate, Copper 2014 Revenue by commodity concentrate, Dore gold/silver. 3% 16% 12% Mine Life 2023 17% 52% Copper Gold Silver Zinc Lead 3 Site Layout – Proximity to township 3 1. Portal. 2. Concentrator. 6 3. Filter Plant & Train Loading 2 1 Station. 5 4 4. Administration Building. 5. Old 3 Level Open cut. 7 6. Waste Rock Dump. 7. Rosebery1 Hospital. Geology – Volcanogenic Massive Sulphide (VMS) deposit Characteristics of VMS Deposits Trilobite Size <1Mt to 50Mt to giant deposits (500Mt) e.g. Kidd Creek, Brunswick 12, Neves Corvo Polymetallic, Rosebery -Zn, Pb, Cu, Host Au, Ag Stacked Deposits, Repetition through rock sequence Occur as clusters within belts (3 to 6 km separation) Mt Read Volcanics of Tasmania, Iberian Pyrite Belt, Green Tuff Belt of Japan Present day analogue of VMS deposits are Black Smokers 5 Geology – Volcanogenic Massive Sulphide (VMS) deposit Size - >50Mt of massive to disseminated sulphide. Mineralogy - Sphalerite, Galena, Pyrite, Chalcopyrite, Electrum (Au containing Ag). Orientation – Orebodies strike NNE and dip at 43° to east. Host Package – Sequence of felsic volcaniclastics. Structure – Strong cleavage between two large reverse faults, Mt Black and Rosebery faults. Rosebery Y lens Orebody Mine Overview – Surface Underground Interaction 6 5 > One of the longest and deepest mines in operation currently in Australia (1,500 metres). > Mining areas (K, N&P, W, Y&X). > Mining – Ore: Zinc (Zn), Lead (Pb), Copper (Cu), Gold (Au) & Silver (Ag). Mine Overview - Current Production Areas Metallurgy flow sheet 9 Crushing and Grinding > The Rosebery crushing circuit consists of a Primary Jaw Crusher and a Secondary Cone Crusher. > During Crushing the ore size is reduced from around 650mm to P80 of 20mm. > The Grinding Circuit consists of 2 x Primary Ball Mills and 3 x Secondary Ball Mills. Secondary crusher Primary ball mill 10 Gravity Gold > Gravity gold is recovered from the grinding circuits using 2x Knelson Concentrators. > Gold Concentrates are leached in an Intensive Leach Reactor (ILR). > Then recovered from the pregnant leach solution by electrowinning and thereafter the gold sludge is smelted. 11 Gold pour Gold Doré bar Flotation > The recovery sequence for sulphide minerals in the Flotation Circuit is Chalcopyrite (Cu) → Galena (Pb) → Sphalerite (Zn). > Payable gold and silver is recovered with the copper and lead concentrates. Copper float cells Lead float bubbles 12 Filtration > Concentrates are pumped to the Filter plant where they are filtered using Larox Filters. > The filters produce a dry concentrate that is then transported via rail to Burnie. Lead Larox filter Zinc concentrate 13 Concentrate Shipment > From Burnie, concentrates are shipped to final destination by sea. Zinc concentrate being offloaded at Nrystar in Risdon Tailings – Dams > Tailings is disposed of in the Bobadil Tailings Storage Facility (TSF) that is situated approximately 4km from the processing plant. > The tailings slurry is pumped into an open flume that transports the material to the Tailings Storage Facility. Marketing Products: Zinc concentrate Lead concentrate Copper concentrate Gold Doré Production: 2015 guidance (metal in concentrate) Zinc: 80 - 85 kt contained zinc Lead: 22 - 24 kt contained copper Product sales: • Life of Mine/Life of Smelter contract with Nyrstar for 100% of produced concentrate. • Concentrate is transported by rail to Burnie Port. • Rosebery Zn and Pb is sold on FOB basis at the Burnie Port. • Zinc is transported to Hobart, Lead to Port Pirie, Copper on the open market and Gold Doré to Perth Mint. • MMG have exported some quantities of zinc concentrate in the past when Nyrstar 16 offtake fell below production. Marketing Zinc Concentrate > Relatively high Zn grade (+54%), with relatively low Fe and acceptable impurity content. > Precious metals content close to payability thresholds. > Attractive Zn concentrate in China / Asian markets. Lead Concentrate > Relatively high Pb and Ag grade, along with high Zn grades and low impurity levels. > Attractive contract with payments for contained Zn, Pb, Au & Ag. Copper concentrate > A complex concentrate with high precious metals and high impurities - limits buyers. > Currently selling under a Frame contract to a trader for blending with cleaner materials. This enables the value of high precious metals and copper to be realised. Dore’ concentrate > Transported to Perth Mint for refining, containing approximately 60% gold and 30% silver. 17 18 .