Favorable results from laboratory and pilot-scale heap-leach tests have prompted BHP Billiton to move
forward on a government-approval application that could lead to construction of a demonstration plant
at its Olympic Dam copper-uranium mine in South Australia. (Photo courtesy BHP Billiton)
BHP Billiton reported in late July that laboratory and pilot-scale trials of heap leaching as an alternative process for extracting metals from ore mined at its Olympic Dam copper-uranium mine in South Australia have shown promising results. To further test heap leaching at a larger and more integrated scale, the company has lodged an application for assessment by the Australian federal and South Australian governments to construct and operate a demonstration plant on the existing mining lease at Olympic Dam.
If BHP Billiton receives the required approvals, and also subject to internal company approvals, construction of the demonstration plant could begin in the second half of 2015, followed by a projected trial period of 36 months beginning in late 2016.
Prior to September 2012, BHP Billiton spent several years investigating a huge expansion project for Olympic Dam. Project design included a new open-pit mine that would have eventually consumed the existing underground mine. Production would have increased from 180,000 metric tons per year (mt/y) to 750,000 mt/y of refined copper, plus associated uranium oxide, gold and silver. The existing smelter would have been expanded, and new concentrator and hydrometallurgical plants would have been constructed, along with new waste rock and tailings storage facilities and major infrastructure projects.
Capital costs to develop the expansion were estimated at about $30 billion.
In September 2012, BHP Billiton announced that it was abandoning the high-cost plan and would investigate alternative, less capital-intensive designs. The company's current plan for a heap-leach demonstration plant is a result of those investigations.
In BHP Billion's fiscal year ended June 30, Olympic Dam produced 184,400 mt of copper cathode, 121,300 oz of gold, and 4,000 mt of uranium (payable metal in concentrate).