Prominent Hill Mine

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Prominent Hill is a copper -gold deposit in the Australian state of South Australia. Owned by the Australian mining company OZ Minerals (formerly Oxiana ). The first copper-gold concentrate was promoted in February 2009.

Location

The deposit is located in the center of South Australia about 130 km south-east of Coober Pedy and 130 km northwest of Olympic Dam. It is connected via a 40 km dirt road to the Sturt Highway, continues to have the mining complex on a runway, which is served in scheduled service by Alliance Air from Adelaide. About a purpose built 130 km high voltage transmission line it is connected to the Australian electricity network in Olympic Dam.

History

The deposit was discovered in 2001 by Minotaur Resources in a joint venture with Oxiana. Was preceded by reconnaissance work to smaller firms due to Geomagnetikdaten, which indicated a strong positive anomaly. Holes on this anomaly remained in the 1990s, however, unsuccessful. Minotaur combined these data with gravimetric data, which also who demonstrated an anomaly, but a bit offset from the magnetic. Minotaur then drilled in the overlap region and met with about 90 m cover a large ore body. In 2006 a feasibility study was completed, and Oxiana, which had taken over at this point Minotaur, opted for the exploitation of the deposit. In 2007 began the construction of the treatment plant and the digestion of the mine. The ore body has been found in about 90 m depth in early 2008 and promoted the first ore. The preparation was launched in October 2008 and produced copper-gold concentrate which is sold to smelters and Asian and Australian.

The originally planned life of the mining operation is 10 years. The construction of the mine cost 1.08 billion AUD. Currently, however, läft a feasibility study for underground mining, to decrease the lifetime of the mine could be increased to 20 to 30 years.

Geology

The deposit is part of the so-called iron oxide - copper -gold deposits (English Iron -Oxide- Copper - gold, IOCG ) and is very similar in many properties of the giant Olympic Dam deposit. It is located in the Gawler Craton in an approximately 1.585 billion years old volcano- sedimentary rock sequence. The volcanic rocks are part of the Gawler Range Volcanic ( GRV) - Hiltaba event. Thus, the deposit is approximately the same age as Olympic Dam, but the latter is in a granite of Hiltaba suite while Prominent Hill is linked to volcanic rocks. The host rocks of the deposit show virtually no metamorphic overprint.

There are three geological zones in the deposit: the skarn - granite package in the hanging wall of the ore body, the hanging- wall fault zone ( HWFZ - Fault zone at the contact with the hanging wall of the ore body ) and the volcano- sedimentary package, which consists of carbonate rocks, sandstones, greywacke and mafic to intermediate volcanics is. The skarns in the hanging wall of the ore body wearing a subökonomische magnetite Sulphidmineralisation. The Mesoproterozoic rocks of the Gawler Craton are superimposed at Prominent Hill of approximately 90 m thick Permian and Cenozoic sediments.

In the ore body itself is an extremely hydrothermally altered breccia, which occurs in the HWFZ and the vulkanosedimentären rocks. The alteration is essentially a hematite alteration. The copper minerals are limited to the hematite breccia. These breccias formed by hot hydrothermal fluids. There are channels on which the fluids flowing through the rock. The kupfervererzten areas consist of a crystalline hematite -sericite - fluorite - barite -carbonate matrix, which is interpreted as filling open spaces between the Nebengesteinsklasten. In addition, a zone with earthy hematite occurs which has no copper mineralization and is interpreted as a displacement of the country rock by hematite at lower temperatures. Outside the kupfervererzten breccia comes as Halo before a low-copper bis- free gold mineralization, which consists of hair-thin gold-bearing Karbonattrümchen.

Main mineral of the ore as described hematite, but no iron is obtained. The main copper minerals are chalcocite, bornite and chalcopyrite, subordinated to come pyrite, barite, fluorite, native gold and as pitchblende ore minerals ago. Unlike, however, at the Olympic Dam uranium levels are only about 50 to 100 g / t, so that a recovery of this metal is not worthwhile.

The current reserves of the deposit will be 79.2 million tons, but the ore body is open in several directions (including the depth ), so that one hopes to develop further proven resources in the future in civil engineering. The current resource base of the deposit contains 1.9 million tonnes of copper, 3.7 million ounces of gold and 15.8 million ounces of silver. The average ore grade is 1.24% copper, 0.58 g / t gold and 3.1 g / t silver. In the only gold fields gold deductibles will be around 1.1 g / t and copper levels below 0.3 %, but locally intervals up to 20 g / t gold observed.

Mining and processing

The deposit is developed in the open pit, which is expected to reach finally 1.5 x 1.2 km Size at a depth of 500 m. The rock is broken by blasting and connect with three Liebherr 996 backhoe and transported away 18 Caterpillar 793 dump trucks. Ore production is about 8 million tonnes per year. The ore is stockpiled according to the quality and sent with a planned throughput of 1,000 tonnes per hour into the treatment. The ore is broken up and milled in a plurality of stages. It is then subjected to flotation, purified, concentrated, and the concentrate is dehydrated in a press. The tailings are deposited in a circular Tailingsbecken. The concentrate is transported by road trains according to a loading dock on the Ghan and from there to Darwin. A small portion of the concentrate goes to the hut of Olympic Dam.

We distinguish several kinds of ores: Chalcosin - bornite, bornite - chalcopyrite, chalcopyrite - pyrite - gold mineralization and only. These are processed separately. Depending on the type of ore will concentrate different qualities give 54% copper ( chalcocite - bornite ), 34 % copper ( bornite - chalcopyrite ) and 25 % ( chalcopyrite - pyrite ). There will also be a copper-free only - gold concentrate. Gold grades are each lie at 10 to 15 g / t. The high- chalcocite - bornite concentrate will be produced first. In 2009, to 110,000 t to 120,000 t of copper and 75000-85000 ounces of gold in concentrate produced. The other types of ore to be processed later and will initially be stockpiled. The production will consequently decline in later years of production to 90,000 tonnes of copper per year.

Left

• Oz Minerals
• Prominent Hill at PIRSA

• Active Mine
• Open-cast mining
• Geology of Australia
• Copper mine in Australia
• South Australia
• Gold mine in Australia