Chesney

The Chesney Mine in Cobar, New South Wales, produces copper, gold, lead, zinc and silver. It makes up part of the Peak Gold operation at Cobar that is owned by Canadian listed mining company New Gold Inc. The minerals from all five underground mines owned by New Gold in the area are processed at the one central processing plant.

The Rich Mineral Field at Cobar has Been Mined Since 1870

The rich mineral deposits mined at the Chesney underground mine are part of the greater 10 kilometre long Cobar Gold Field that extends in a northerly direction from the Perseverance Mine to the Tharsis Mine. This particular gold field is located on the eastern margin of the greater Cobar Basin that has recovered more than 200,000 tonnes of copper and three million ounces of gold since as far back as 1870. The ore bodied presently being mined include the Chesney, Perseverance, New Cobar, New Occidental and Peak.

The Current Chesney Mining Commenced in 2009

The Chesney deposit has been mined on an intermittent basis over many years and it is accessed via a 700 metre decline from the New Cobar Mine. The ore body currently being mined was first brought into production in 2009. It is a gold/copper deposit and has grades higher than any of its neighbouring mines.

Peak Gold Mines Hold 845 Square kilometres of Mining and Exploration Leases at Cobar

Peak Gold Mines, the operator of the Chesney Mine commenced operations at Cobar 1992. When it brought the Chesney Mine into production in 2009, along with Perseverance Zone D, it expanded its production to near 100,000 ounces of gold and 15 million pounds of copper. The company holds 845 square kilometres of mining and exploration licences within the Cobar mineral field and will therefore be mining in the area for the long term.

Diamond Drilling Proves up New Deposits

Diamond drilling exploration is continually being undertaken underground to extend its known reserves for future development. In this way geologists are able to map the way forward. Mining engineers then have the job of accessing to new deposits.

Chesney Underground Mine Uses Long Hole Open Stoping Methods

Mining methods at the Chesney Underground Mine is carried out by long hole open stoping. This requires the establishment of levels every vertical 30 metres. To do this rows of fan pattern holes are drilled to a depth of 30 metres and blasted in sequence. A working space, or slot, is then created to facilitate removing the ore to create the stope. Other holes are then drilled and blasted to cause ore to fall into the gap that has been created so that it to can be removed. Once all the ore is removed the remaining hole, or stope, is filled with mullock, cement and/or sand. There is usually four stopes being worked in the mine at any one time. All openings and walls underground are re-inforced with the use of cable or rock bolts. Surfaces are supported by a coating of fibrocrete or steel mesh. The cable bolts go into the rock to a distance of six metres to ensure safety. Mining crews carry out all their own rock support, ore removal, blasting and drilling.

Concentrate Leaves Mine For Smelting or Further Refining

Once mined the ore is taken to an underground crusher by haulage trucks via the decline. After primary crushing it is taken to the surface by means of a hoisting shaft. Mill processing on the surface requires the crushed ore to be further crushed until it become fine particles. The individual minerals are then separated from the fine particles by means of floatation to form a concentrate of that particular mineral. This process is achieved in the concentrator plant that is under the charge of metallurgists. The concentrate of different metals is shipped out to be smelted or further refined.