Olympic Dam Mine, Roxby Downs, Stuart Shelf, South Australia, Australia
|Latitude & Longitude (WGS84):||30° 26' 24'' South , 136° 52' 22'' East|
|Latitude & Longitude (decimal):||-30.44000,136.87278|
|Köppen climate type:||BWh : Hot deserts climate|
A very large operating copper-gold-uranium mine. The ore deposit is located on Roxby Downs Station, about 25 kilometres west of the opal mining town of Andamooka (265 km north of Port Augusta).
Australia's largest reserve of copper and uranium ore is at Olympic Dam. Some sources report it to be also the world's largest Uranium resource. It was discovered in 1975 as the result of a drilling program conducted by Western Mining Corporation Limited, targeting geophysical targets. The mine is currently operated by BHP Billiton.
The deposit is essentially a iron oxide rich megabreccia formed in a Proterozoic granite, and is considered to be a classic example of an IOCG (Iron oxide-copper-gold) deposit.
There are extremely large volumes of mineralised rock in the ore body but at present only about 450 million tonnes of ore has been proven. This contains about 11 million tonnes of copper, 360 000 tonnes of uranium oxide, 2700 tonnes of silver, and 270 tonnes of gold. The top of the deposit is about 350 metres below ground level, so did not outcrop and underground mining is necessary. The deposit itself is about 7 kilometres long and 4 kilometres wide. It is the largest copper ore body in Australia and one of the world's largest uranium deposits. The mine itself is the biggest long term development project in South Australia and more than one billion dollars was spent on establishing it: this includes the construction of the nearby town of Roxby Downs which is home to about 3500 people.
Mining started in June 1988. By March 1996 more than 8500 tonnes of uranium oxide had been produced along with 370,000 tonnes of copper, 66 tonnes of silver, and 5 tonnes of gold. In 1999-2000 Olympic Dam produced 4089 tonnes of uranium oxide achieving $895 million in export revenue. Just over half the uranium (55%) has been sold to power utilities in Europe, about a quarter to Japan, and the remainder to Korea (11%) and the United States (8%). Olympic Dam has an expected life of 200 years.
A resources update (Sept 2007) was 6.7 billion tonnes of ore @ 0.87%Cu, 0.29kg/t U3O8, 0.3g/t Au and 1.6g/t Ag. In 2012 there were smaller but higher grade estimated reserves of 2.95 billion tonnes of ore grading 1.2% copper, 0.04% uranium, 0.5 g/t of gold and 6 g/t of silver.[Wikepedia]
Types of uraninite: (1) primary, small, cubic crystals, with oscillatory and sector chemical zoning, defect-free structure, contains Pb(IV) and REE; (2) zoned, coarser, sub-euhedral; (3) "Cobweb", hexagonal-octagonal habit, defect-free structure, also contains Pb(IV) and REE, plus inclusions of galena, Cu-Fe sulfides, and minerals of REE; (4) dominant, massive, highest-grade, micro-grain to aphanitic, forming larger aggregates and vein fillings, lower in Pb and REE but enriched in Ca; product of post-1590-Ma dissolution and reprecipitation. The late uraninite is possibly hydrothermal and formed at relatively low temperatures, that is, less than 250oC.
Similar granite-related Proterozoic iron-oxide copper-gold deposits in this area of South Australia are Prominent Hill and Carrapateena.
95 valid minerals. 1 (TL) - type locality of valid minerals.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
|Messinian - Lutetian|
5.333 - 47.8 Ma
Age: Cenozoic (5.333 - 47.8 Ma)
Stratigraphic Name: Watchie Sandstone
Comments: sedimentary siliciclastic; synthesis of multiple published descriptions
Lithology: Sedimentary siliciclastic
Reference: Raymond, O.L., Liu, S., Gallagher, R., Zhang, W., Highet, L.M. Surface Geology of Australia 1:1 million scale dataset 2012 edition. Commonwealth of Australia (Geoscience Australia). 
Mining Annual Review (1985): 369.
Econ Geol. (1992) 87:1-28
Econ Geol. (1995) 90:281-307
Lottermoser, B. G. (1995): Rare earth element mineralogy of the Olympic Dam Cu-U-Au-Ag deposit, Roxby Downs, South Australia; implications for ore genesis. Neues Jahrbuch für Mineralogie, Monatshefte 1995, 371-384.
Ehrig, K., McPhie, J., Kamenetsky, V. (2012) Geology and mineralogical zonation of the Olympic Dam iron oxide Cu-U-Au-Ag deposit, South Australia. Economic Geology Special Publication 16, pg. 237-267.
Kirchenbaur, M., Maas, R., Ehrig, K., Kamenetsky, V. S., Strub, E., Ballhaus, C., & Münker, C. (2016). Uranium and Sm isotope studies of the supergiant Olympic Dam Cu–Au–U–Ag deposit, South Australia. Geochimica et Cosmochimica Acta, 180, 15-32.
Macmillan, E., Cook, N.J., Ehrig, K., Ciobanu, C.L., Pring, A. (2016): Uraninite from the Olympic Dam IOCG-U-Ag deposit: linking textural and compositional variation to temporal evolution. American Mineralogist: 101: 1295-1320.
Ciobanu, C. L., Cook, N. J., Ehrig, K. (2017): Ore minerals down to the nanoscale: Cu-(Fe)-sulphides from the iron oxide copper gold deposit at Olympic Dam, South Australia. Ore Geology Review 81, 1218-1235.