Plutonic

Overview

Plutonic gold mine is located 180km north-east of Meekatharra in the state of Western Australia.

The gold deposit was discovered in the 1987-1989 period by Great Central. Plutonic mine has been in operation since August 1990. It started as an open pit mining operation. It was subsequently transitioned to an underground mining operation in 1995. Barrick Gold Corporation the present day owner acquired the mine in 2001 by acquiring Homestake Mining Company.

Plutonic is an underground mining operation that produces gold through a cyanidation process.

As of December 2011, proven and probable reserves were estimated at 2.688 Mt at 4.59 g/t for 402, 000 ounces gold.

In 2011, Plutonic produced 115,000 ounces of gold at a total cash cost of $934 per ounce^..

Location

Plutonic gold mine is located 180km north-east of Meekatharra in the state of Western Australia. It is connected by rail and roads to the region’s main cities.

Western Australia occupies the whole western part of the continent. Its economy is largely driven by extraction and processing of a diverse range of mineral and petroleum commodities. The state contributes an estimated 58 percent of Australia's Mineral and Energy Exports.The gold deposit was discovered in 1988.

Geology & Mineralization

Mineralization consists of a number of discrete lodes hosted within mafic volcanics in an Archean succession of ultramafic and mafic volcanics and sediments. Gold mineralization is associated with sulphide and oxides – arsenopyrite, chalcopyrite, scheelite.

The lodes present as multiple stacked lodes having a thickness of 1 meter to 10 meters.

As of December 2011, proven and probable reserves were estimated at 2.688 Mt at 4.59 g/t for 402, 000 ounces gold.

Mining & Operation

Plutonic mine has been in operation since August 1990. It started as an open pit mining operation. It was subsequently transitioned to an underground mining operation in 1995.

Underground mining methods employed in mining the gold lodes are room and pillar for thicker mineralized areas – support pillars are progressively mined on retreat; and, long hole open stoping for steep dipping ore shoots. Backfilling mining is also employed in mining of the underground reserves.

Processing

Plutonic processing plant was designed at rates up to 2 million tonnes per year.

Ore processing is carried through ore crushing and grinding (SAG and ball mills) circuit followed by a carbon-in-leach & carbon-in-pulp cyanidation circuit (CIL/CIP). The resulting pregnant solution is transferred to adsorption tanks and a gold recovery circuit; its end product is then smelted and refined to gold bars.

In 2009, the mine was accredited by the International Cyanide Management Institute.

Tailings are discharged in a combination of in-pit and surface tailings storages. A paste fill plant was inaugurated in 2003.

Gas-fired power plant provides 16.5 Mw by using 4 X Wartsila 18V34SG engines. Gas is sourced via a lateral connected to the North West Shelf to Perth pipeline. A secondary diesel-fired power station is also on site and used as supplemental power source.

Personnel accommodation is provided in a camp located 2 km west of the processing plant.

In 2011, Plutonic produced 115,000 ounces of gold at a total cash cost of $934 per ounce.

Environment & Community

Rehabilitation of waste dumps and the tailings storage facility closure is ongoing.

The company successful managed six priority flora and one scheduled animal and conservation habit.