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Evolution Ownership
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.

Location
~35km north west of Cloncurry, Queensland, Australia

Local Communities
Cloncurry, Mt Isa

History

  • March 1998: Glencore commenced commercial production as an open pit mine
  • 2009: Glencore announced a $589 million project to transition the operations to underground shaft mining
  • 2011: Trucking ore from underground commenced in December 2011 upon completion of the Ernest Henry open pit
  • 2014: Hoisting operations commenced from a new kilometre-deep underground shaft in June 2014
  • 2016: Evolution and Glencore announces an agreement where Evolution will have a 30% economic stake in the mine and be entitled to 100% of Ernest Henry gold production, subject to an agreed life of mine and block model

Style of mineralisation
Iron oxide copper-gold deposit

Contained metals
Copper, gold, silver

Measured, Indicated and Inferred Resources (at 31 Dec 2015)
1.4Moz Au, 431Kt Cu

Ore Reserves (as at 31 Dec 2015)
1.0Moz Au, 184Kt Cu

Year commenced operations
1998

Mining Method
Underground

Gold Production
CY2015: 65kt Cu & 88koz Au (in concentrate)

Processing Method
Ernest Henry’s concentrator is a conventional single-line processing circuit producing a bulk copper-gold sulphide flotation concentrate.

Nominal treatment rate
~6.4Mtpa

Geology
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.

Mining
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.

Processing
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.

Fact Sheet
Ernest Henry fact sheet – available shortly