The Prominent Hill Mine is a major copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

, silver

Silver

Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...

 and gold

Gold

Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

 mine in north west South Australia

South Australia

South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...

, 130 km south-east of Coober Pedy

Coober Pedy, South Australia

Coober Pedy is a town in northern South Australia, 846 kilometres north of Adelaide on the Stuart Highway. According to the 2006 census, its population was 1,916 . The town is sometimes referred to as the "opal capital of the world" because of the quantity of precious opals that are mined there...

, which has been developed by Oxiana Limited

Oxiana Limited

Oxiana Limited was an Australia-based copper and gold miner and exploration company. The company's operations were located in Laos, Australia, Cyprus and the Philippines...

, later to become OZ Minerals

OZ Minerals

OZ Minerals is an Australian mining company, formed from the merger of Oxiana Limited and Zinifex in 2008.In 2009, Chinese state owned China Minmetals proposed a purchase of the heavily indebted company. The Chinese proposal was one of three high profile moves by Chinese firms to acquire stakes in...

. The deposit is an iron oxide copper gold

Iron oxide copper gold ore deposits

Iron oxide copper gold ore deposits are important and highly valuable concentrations of copper, gold and uranium ores hosted within iron oxide dominant gangue assemblages which share a common genetic origin....

 style mineralisation.

The mine has cost A$1.15 billion to develop, and it is projected to produce 100,000 tonnes of copper and 115,000 oz of gold in concentrates a year.

History

Oxiana Limited decided to develop the mine in August 2006, having first got involved in the project in 2003 and having bought its partner, Minotaur Exploration Limited in 2005.

The mine went into production in February 2009. The development includes an open-pit mine, a conventional grinding and flotation processing plant, construction of a permanent village to accommodate the workforce and construction of a haulage road, power line and bore field. Studies for underground development are underway.

Resources of the deposit are 152.8 Mt at 1.18 % Cu, 0.48 g/t Au and 2.92 g/t Ag plus 38.3 Mt at 1.17 g/t Au of non-sulfide ore.

In contrast to the Olympic Dam deposit, an iron oxide copper gold deposit of similar age about 200 km to the southeast of Prominent Hill, uranium

Uranium

Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...

 values do not exceed 150 ppm and therefore uranium recovery is not economical.

The mine was part of the sale of its assets by OZ Minerals

OZ Minerals

OZ Minerals is an Australian mining company, formed from the merger of Oxiana Limited and Zinifex in 2008.In 2009, Chinese state owned China Minmetals proposed a purchase of the heavily indebted company. The Chinese proposal was one of three high profile moves by Chinese firms to acquire stakes in...

 to Minmetals Australia Pty Ltd

China Minmetals

China Minmetals Corporation is a Chinese metals and mineral trading company. It is a state-controlled corporation existing under the laws of the People's Republic of China, is a diversified metals and mining company based in Beijing, China...

 but was blocked by the Australian Government

Government of Australia

The Commonwealth of Australia is a federal constitutional monarchy under a parliamentary democracy. The Commonwealth of Australia was formed in 1901 as a result of an agreement among six self-governing British colonies, which became the six states...

, citing national security concerns. Wayne Swan

Wayne Swan

Wayne Maxwell Swan is the Deputy Prime Minister of Australia and an Australian politician. He has been an Australian Labor Party member of the Australian House of Representatives from 1993 to 1996, and then re elected in 1998 till today , representing the Division of Lilley, QLD...

, Treasurer of Australia

Treasurer of Australia

The Treasurer of Australia is the minister in the Government of Australia responsible for government expenditure and revenue raising. He is the head of the Department of the Treasury. The Treasurer plays a key role in the economic policy of the government...

, stated that Prominent Hill could not be included in the sale as it was within a sensitive military area and the sale of the other OZ Minerals mines went only ahead after Prominent Hill was excluded.

Ore from Prominent Hill travels to customers via the Adelaide–Darwin railway, which passes within 116 km of the mine to the Port of Darwin

Darwin, Northern Territory

Darwin is the capital city of the Northern Territory, Australia. Situated on the Timor Sea, Darwin has a population of 127,500, making it by far the largest and most populated city in the sparsely populated Northern Territory, but the least populous of all Australia's capital cities...

.

Geology and mineralogy

The deposit is located in the Gawler Craton

Gawler craton

The Gawler Craton covers approximately 440,000 square kilometres of central South Australia. Its Precambrian crystalline basement crustal block was cratonised ca. 1550-1450 Ma...

 and it is hosted mainly in a fault zone where Hiltaba-Suite granite

Granite

Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...

s overthrust

Thrust fault

A thrust fault is a type of fault, or break in the Earth's crust across which there has been relative movement, in which rocks of lower stratigraphic position are pushed up and over higher strata. They are often recognized because they place older rocks above younger...

 a Mesoproterozoic

Mesoproterozoic

The Mesoproterozoic Era is a geologic era that occurred between 1600 Ma and 1000 Ma . The Mesoproterozoic was the first period of Earth's history with a respectable geological record. Continents existed in the Paleoproterozoic, but we know little about them...

 volcano-sedimentary sequence. The age of the mineralisation is about 1.58 billion years. It consists of a breccia

Breccia

Breccia is a rock composed of broken fragments of minerals or rock cemented together by a fine-grained matrix, that can be either similar to or different from the composition of the fragments....

 containing host rock clasts (dolomite

Dolomite

Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....

, sandstone

Sandstone

Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

, andesite

Andesite

Andesite is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and dacite. The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende. Magnetite,...

) which is intensively hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

, chlorite

Chlorite group

The chlorites are a group of phyllosilicate minerals. Chlorites can be described by the following four endmembers based on their chemistry via substitution of the following four elements in the silicate lattice; Mg, Fe, Ni, and Mn....

 and sericite

Sericite

Sericite is a fine grained mica, similar to muscovite, illite, or paragonite. Sericite is a common alteration mineral of orthoclase or plagioclase feldspars in areas that have been subjected to hydrothermal alteration typically associated with copper, tin, or other hydrothermal ore deposits...

 altered. Major sulfide mineral

Sulfide mineral

The sulfide minerals are a class of minerals containing sulfide as the major anion. Some sulfide minerals are economically important as metal ores. The sulfide class also includes the selenides, the tellurides, the arsenides, the antimonides, the bismuthinides, the sulfarsenides and the sulfosalts...

s are pyrite

Pyrite

The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...

, chalcopyrite

Chalcopyrite

Chalcopyrite is a copper iron sulfide mineral that crystallizes in the tetragonal system. It has the chemical composition CuFeS2. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs scale. Its streak is diagnostic as green tinged black.On exposure to air, chalcopyrite...

, bornite

Bornite

Bornite is a sulfide mineral with chemical composition Cu5FeS4 that crystallizes in the orthorhombic system .-Appearance:Bornite has a brown to copper-red color on fresh surfaces that tarnishes to various iridescent shades of blue to purple in places...

 and chalcocite

Chalcocite

Chalcocite, copper sulfide , is an important copper ore mineral. It is opaque, being colored dark-gray to black with a metallic luster. It has a hardness of 2½ - 3. It is a sulfide with an orthorhombic crystal system....

.

Sources

• The Australian Mines Handbook: 2003-2004 Edition, Louthean Media Pty Ltd, Editor: Ross Louthean

External links

• Place Names Search Results - Prominent Hill Geoscience Australia
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