Minerals present in the CSA ore body are mainly chalcopyrite, with lessor cubanite, pyrite and pyrrhotite as well as very minor bornite, sphalerite and galena with traces of silver. Quartz, siltstone clasts, calcite, magnetite and chlorite form the gangue to the sulphide minerals.

Economic mineralisation at Cobar occurs mostly as narrow lenses with short strike lengths that are depth extensive. Lenses consist of vein or semi massive to massive chalcopyrite hosted by sub-vertical quartz chlorite shear zones within a siltstone unit. The Cobar Mineral Resource is reported within five ‘systems’: Western, Eastern, QTS North, QTS South and QTS Central.

The CSA mine operates a conventional long hole open stop mining method with all extracted ore being hauled along drives to a crusher underground. Once the ore is crushed it is transported to the surface via the No.2 shaft using a friction winder. The ore is then processed to produce copper concentrates, which are transported via rail network to Wollongong for export.

The mine has two shafts that are referred to as the No.1 and No.2 shafts. The No.2 shaft comprises the mine’s primary operational haulage shaft. The No.1 shaft was not operational at the time of the incident as it was undergoing substantial refurbishment and was in the process of being extended to a depth of 1500 metres with the objective of bringing the shaft into production.

The ore is processed on site using SAG and ball mills in closed circuit with hydro cyclones. Once ground, ore slurry is concentrated through a conventional flotation circuit. From here the concentrated slurry is thickened, filtered, dried and stockpiled. Concentrate is transported by rail in purpose built, fully enclosed, steel containers to Port Waratah (Newcastle) for storage and export shipment by ocean freight.

CSA Mine, an underground copper mine, which produces up to 1.1 million tonnes of copper ore and in excess of 185,000 tonnes of copper concentrate per annum.