Name: Olympic Dam mine.

Location: The mine is located 560 km north-west of Adelaide, in South Australia.

Controlling Company: BHP Billiton.

Brief History: Olympic Dam was acquired in 2005 as part of the WMC Resources acquisition. Copper production began in 1988. Nominal milling capacity was raised to nine-million tonnes a year in 1999. In 2002, an optimisation project was completed on the mine. A new copper solvent extraction plant was commissioned in 2004.

Brief Description: The Olympic Dam site includes an underground mine and an integrated metallurgical processing plant.

Products: Copper cathode and uranium oxide. The mine also refines gold and silver bullion.

Geology/Mineralisation: Olympic Dam is a large polymetallic deposit of iron oxide/copper/uranium/gold mineralisation.

Reserves: Proven and probable reserves of sulphide as at June 30, 2015, were estimated at 484-million tonnes, grading 1.95% copper, 0.59 kg/t of uranium, 0,74 g/t of gold and 4 g/t of silver.

Resources: Mineral resources of sulphide as at June 30, 2015, were estimated at 10.1-billion tonnes, grading 0.78% copper, 0.25 kg/t of uranium, 0.30 g/t of gold and 1 g/t of silver.

Mining Method: Long-hole open stoping with cemented aggregate fill.

Major Infrastructure and Equipment: The underground mine extracts copper uranium ore and hauls the ore using an automated train and trucking network feeding underground crushing, storage and ore-hoisting facilities.

The processing plant consists of two grinding circuits through which high-quality copper concentrate is extracted from sulphide ore through a flotation extraction process. The operation includes a fully integrated metallurgical complex with a grinding and concentrating circuit; a hydrometallurgical plant, incorporating solvent-extraction circuits for copper and uranium; a copper smelter; a copper refinery and a recovery circuit for precious metals.

Prospects: The focus at Olympic Dam is to transform the existing operation to lower the cost of production safely and sustainably. BHP Billiton is progressing a prefeasibility study to examine potential future optimisation and expansion opportunities.

In addition, BHP has received approval from the Australian and South Australian governments in 2015 to build a site-based heap-leaching demonstration plant, as part of the company’s efforts to identify an alternative, less capital-intensive process for extracting metals from ore mined underground. Construction of the demonstration plant is subject to ongoing, off-site demonstration and testwork outcomes and board approvals.

Contact: Investor relations for Australia and Asia Tara Dines.

Contact Details:
BHP Billiton,
tel +61 3 9609 3333,
fax +61 3 9609 3015, and
email Tara.Dines@bhpbilliton.com.