Glencore’s AUD589 million investment in Ernest Henry Mining near Cloncurry in northwest Queensland, Australia, to transition from open-pit to underground operations has celebrated a significant milestone. It has commenced operations from a new 1-km-deep hoisting shaft.

Queensland Minister for Natural Resources and Mines the Hon. Andrew Cripps commemorated the milestone at an event at Ernest Henry attended by Glencore CEO Ivan Glasenberg, Head of Copper Telis Mistakidis and community leaders.

The operation will now begin to ramp up copper production from 3 million metric tons per year (mt/y) to 6 million mt/y in 2015, and similarly double metal production to 50,000 mt/y of copper and 70,000 oz/y of gold in concentrate over an extended mine life to 2026.

COO for copper assets in North Queensland Mike Westerman said Ernest Henry’s development strengthens the production profile and sustainability of Glencore’s regional copper operations. “Our assets in Mount Isa and at Ernest Henry accounted for around 14% of Glencore’s global copper production in 2013,” he said. “This investment in Ernest Henry has effectively added 14 years to the life of the mine to 2026. We’re pleased to have this opportunity to sustain production at a higher rate, continue to support around 500 employees plus contractors, and deliver ongoing benefits to the Cloncurry community and economy.”

The underground project commenced in December 2009 and has involved more than 50 km of underground development accessed by a 6-km decline; constructing associated infrastructure, including the underground primary crusher and 1.2 km of below surface and overland conveyors to transport ore to and from the hoisting system; installing a 75-m high permanent headframe to house the hoisting system and with a capacity to lift around 1,000 mt/hr; and reconfiguring the concentrator to align with the underground production rate.

Four production levels are operational using an innovative sublevel caving mining method and have trucked ore to the surface via the decline since December 2011 while the project was under way.

As of December 2013, Ernest Henry had total ore reserves underground of 74 million mt at 1.04% copper and 0.53 g/mt gold.