Peak is a series of polymetallic high-grade ore bodies dominated by gold, copper and zinc, with Gold-rich ore sources in the Southern Corridor and Copper-rich ore sources in the Northern Corridor.
The Peak, New Occidental and Perseverance mines are accessed by means of a shaft and decline located at the Peak Mine site. The Peak mine site is also where the processing plant and administration buildings are located. The Chesney and New Cobar deposits are accessed by way of a decline at the base of the new Cobar open pit.
Significant infrastructure – replacement cost of plant and infrastructure of A$390M, including c$60M in underground mobile fleet, with a 750ktpa process plant located at the Peak mine site.
Metal recoveries are ~90% for gold and ~ 87% for copper. Gold and silver are recovered in a gravity circuit with Knelson concentrators to produce gold dore bars. Gold, silver and copper are also recovered as a copper concentrate in a conventional flotation circuit. A third method of gold and silver recovery is by cyanidation in a tank leach circuit. In addition to a copper concentrate, Peak has recently been producing a lead concentrate from the processing of high-grade gold/lead/zinc Chronos ore.
Peak consists of five underground operations currently producing gold and copper.
A copper-gold processing plant operates on site which handles the production from all five underground operations comprise the following:
The development of the Perseverance ore body began in 2002 with the initial production stope coming on-line in 2003. It is a relative high-grade deposit that contains most of the groups gold resource.
The Peak ore body was the first to be discovered in 1980. over one million ounces of gold was produced from this deposit between 1991 and 2002 when mining ceased. Mining was re- commenced in 2006. The surface decline was completed in 2007 that connected the underground workings between the Peak and New Occidental deposits.
This deposit has been mined on and off throughout the last century. Mining was recommenced in 2001 after 50 years. It is located three kilometres from the peak ore body but is linked via the decline.
The Chesney deposit has also been mined at different times in the past. It was brought back into production in 2009 and linked to the New Cobar deposit via a 700 metre decline. It has the best copper grading of all the Peak Mines.
This deposit was earlier worked as an open pit and when the open pit ceased in 2004 it had produced one million tonnes of ore. Underground mining began in 2004 and it continues as an important contributor to the group’s copper/gold processing plant.
The Cobar Peak Mines operation takes place by exploiting the five different deposits contained in the Greater Cobar Gold Field, a 10 kilometre long highly mineralised belt, that extend north from the Perseverance deposit to the Tharsis Mine located immediately north of the town of Cobar. The Cobar Gold Field is situated at the eastern extremity of the Cobar Basin and has produced more than 200,000 tonnes of copper and three million ounces of gold since mining began in the area in 1870.