the colonel's take on mt coffin copper in qtry, page-5

Copper was the first metal to be used by man. It can occur naturally in its pure state (native copper) but is principally mined as the primary sulphide chalcopyrite (CuFeS2). The main oxidised ores are the copper oxide cuprite (Cu2O), and the carbonates azurite (Cu3(CO3)2(OH)2) and malachite (Cu2CO3(OH)2).

Copper is one of the most important and widely used metals of modern society due to its properties of:

high electrical conductivity
high thermal conductivity
resistance to corrosion
ability to form alloys with other metals such as brass (zinc), bronze (tin) and cupronickel (nickel).
The largest use of copper is in the electrical industry where copper wire and cable account for about half of the worlds copper production. Other major markets are the motor vehicle and construction sectors. Copper is also an integral part of the expanding information technology sector and is used in the manufacture of computers, mobile phones, fax machines and televisions.

Annual world mine production of copper metal in 2000 was 13.2 Mt of which about one-third comes from Chile. Australian mine production is 829 000 t and ranks among the worlds top five producers. South Australian production in 2001was 196 105 t, the bulk of which came from the Olympic Dam Mine, Australias largest producer and ranked about fifteenth in the world.

Copper mining has played a key role in the development of South Australia since European settlement in 1836. In particular, the discovery of rich copper deposits at Kapunda (1842), Burra (1845), KanmantooCallington (1846), Wallaroo (1859) and Moonta (1861) were vital to the early development and prosperity of the State. Copper mineralisation is widespread and found in most geological provinces (Fig. 1, (pdf ~ 160kb)).


Olympic Dam

The Olympic Dam copper, uranium, gold and silver deposit is one of the worlds largest known accumulation of metals, with reserves of 580 Mt of ore containing 12 Mt of copper, 0.35 Mt of uranium (U3O8), 350 t of gold and 2800 t of silver. Western Mining Corporation discovered the deposit in 1975. Underground mining commenced in 1988, and a major expansion program from 1997 to 1999 has lifted annual production capacity to ~9.2 Mt of ore yielding 200 000 t of copper, 4600 t of U3O8, 78 000 oz of gold and 850 000 oz of silver.

The deposit is within the Mesoproterozoic Hiltaba Suite Roxby Downs Granite (1588 Ma) beneath ~300 m of undeformed Adelaidean and Cambrian platform sediments of the Stuart Shelf. Mineralisation is hosted by a large, broadly zoned hydrothermal haematitegranite breccia complex comprising a barren core of haematitequartz breccia flanked by 12 km wide mineralised zones of haematite-rich breccias intermingled with altered granitic breccias (Fig. 2, (pdf ~ 140kb) and Fig. 3, (pdf ~ 90kb)).

Ore mineralisation mainly comprises disseminated and fragmental chalcocite, bornite, chalcopyrite, pitchblende and finely disseminated free gold, with sulphide veinlets developed locally.