Kanowna

Overview

Barrick has a strong presence in the Eastern Goldfields near Kalgoorlie-Boulder, 570 kilometres east of Perth in Western Australia. In addition to the Kalgoorlie Super Pit, there are currently three underground mines in production — Kanowna Belle, Raleigh, and Bullant, collectively “Kanowna”.

Kanowna Belle and Raleigh mines are mined by longhole stoping and underhand longhole bench stoping with paste fill methods.

Bullant utilizes retreat sublevel stoping as its mining method. Ore types in this region consist of both refractory and free milling, which are processed at the Kanowna Belle mill.

During 2011, Kanowna mine produced approximately 226,000 ounces of gold at a cash cost of $611 per ounce. Proven and probable mineral reserves as of December 31, 2011 were estimated at 832,000 ounces of gold. 

Location

The Kanowna mines are located in the Eastern Goldfields near Kalgoorlie-Boulder, 570 kilometres east of Perth in Western Australia.

Western Australia (WA) is a state of Australia, occupying the entire western third of the Australian continent. The first European to visit Western Australia was the Dutch explorer Dirk Hartog, who visited the Western Australian coast in 1616. Western Australia achieved self-government in 1890, and later federated with the other British colonies in Australia in 1901. Today Western Australia's economy mainly relies on mining, agriculture, and tourism, with the state supplying 46% of Australia's exports. Western Australia is the third-largest iron ore producer in the world.

Kanowna Belle is located on a depositional plain surrounded by low hills. The climate is semi-arid and has an average annual rainfall of 250 mm.

Geology & Mineralization

The underground mine at Kanowna Belle is in full production and all mined ore is now sourced from underground. The Kanowna Belle open-pit operated for six years to December 1998, producing over 1.1 million ounces of gold.

It is hosted in an Archean sequence of conglomerates and fragmental rocks, the Norseman-Wiluna Greenstone Belt, containing both felsic and mafic clasts in a sericite-carbonate altered felsic matrix. The rocks are associated with intrusions of quartz and feldspar porphyry.

Mineralization appears to be controlled by a planar shear zone, the Fitzroy Fault, striking northeast and dipping at 60 degrees to the southeast. Most of the mineralization (>80%) is contained in a zone parallel to and extending outward from the Fitzroy Fault. The deposit consists of a series of stacked lenses with astrike length of over 2,000 feet and to a vertical depth of over 2,000 feet.

Proven and probable reserves as of December 2011, were estimated at 5.27 million tonnes grading 5 g/t gold for 832,000 ounces.

Mining & Operation

There are three underground mines in production — Kanowna Belle, Raleigh, and Bullant.

Kanowna Belle and Raleigh mines are mined by longhole stoping and underhand longhole bench stoping with paste fill methods. Additionally, geotechnical driven mining sequence and a fill system is employed to minimize the impact of mining induced stress on the underground operations. Bullant utilizes retreat sublevel stoping as its mining method. Ore types in this region consist of both refractory and free milling, which are processed at the Kanowna Belle mill.

The mining fleet was provided by Atlas and consists of development drill rigs (Rocket Boomer 322S), two production drill rigs (Simba), a rockbolting rig (Boltec 335SH ), seven 50t mine trucks ( MT5000) and three scooptrams (ST1800). Ore is hauled to surface by using Caterpillar 775 haul trucks.

Processing

Ore types in this region consist of both refractory and free milling, which are processed at the Kanowna Belle mill.

Ore is screened and oversize ore is being crushed to 200 mm. Grinding is done in a two stage circuit consisting of SAG and ball mills. Next, ground material is treated by flotation. Flotation concentrates are washed and thickened then subjected to a two-stage self-sustaining roasting process. The final product is being subjected to cyanide leaching with gold captured by activated carbon in seven adsorption tanks. Loaded carbon is stripped and gold electrowinned on steel wool. Next step involves the production of gold dore bars by smelting.

Before disposal tailings are also subjected to cyanide leaching in a 750 cubic metre tank. Gold is recovered in a series of four adsorption tanks.

Environment & Community

A sulphur dioxide strategy is in place to prevent environmental contamination from roasting of refractory ores.