Evolution has acquired an economic interest in Glencore’s Ernest Henry operation, for A$880 million and an obligation to meet a proportion of future production costs. For detailed information please read the Investor presentation.
~35km north east of Cloncurry, Queensland, Australia
Cloncurry, Mt Isa
Style of mineralisation
Iron oxide copper-gold deposit
Copper, gold, silver
Measured, Indicated and Inferred Resources (at 31 Dec 2016)
89.80Mt at 0.60g/t gold for 1.72Moz
26.94Mt at 1.17% copper for 315kt
Ore Reserves (as at 31 Dec 2016)
59.45Mt at 0.50g/t gold for 964koz
17.82Mt at 1.02% copper for 182kt
Year commenced operations
Underground – sub level cave
CY2015: 65kt Cu & 88koz Au (in concentrate)
Ernest Henry’s concentrator is a conventional single-line processing circuit producing a bulk copper-gold sulphide flotation concentrate.
Nominal treatment rate
The Ernest Henry iron oxide copper-gold deposit is located in the Cloncurry district within the Eastern Succession of the Mt Isa Inlier. The orebody is hosted within the Mt Fort Constantine volcanics, a sequence of intensely altered felsic to intermediate metavolcanics (dacite, andesite and basalt) and metasedimentary rocks that are Paleoproterozoic (1740Ma) in age. The orebody has no natural surface outcrop and lies beneath 50m of Phanerozoic cover comprising of clays, gravels and sands. The Ernest Henry deposit is a breccia pipe plunging approximately 45° to the south-southeast and is bounded between northeast trending ductile shear zones.
The operation is an underground mining operation employing sub-level caving ore extraction method. There is also an underground primary crusher and ore handling system. Ore is brought to surface via a 1km hoisting shaft with a hoisting capacity in excess of 6Mt ore p.a. The operation also has an effective and sophisticated above and below ground water management system.
Copper and gold are recovered from the ore using traditional grinding and flotation methods in the concentrator. Magnetite is liberated during this process and the magnetite extraction plant allows it to be recovered from the concentrator tailings stream.
The plant has a current processing rate of ~6.4Mt p.a. (8.5Mt p.a. capacity and scalable to ~11Mt p.a.). The concentrator incorporates grinding (four mills), conventional flotation and dewatering. A single copper-gold-silver concentrate is produced by a rougher and a three stage cleaning circuit. The Concentrate is treated at Glencore’s Mt Isa smelter (~150km trucking distance) and metal is refined at Glencore’s Townsville refinery.