Challenger (gold mine)
| Challenger Gold Mine | |||
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| General information about the mine | |||
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| Mining technology |
Open pit civil engineering |
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| Information about the mining company | |||
| Operating company | Dominion mining | ||
| Start of operation | 2002 | ||
| Funded raw materials | |||
| Degradation of | gold | ||
| Greatest depth | 700 m | ||
| Geographical location | |||
| Coordinates | 28 ° 58 '25.3 " S , 134 ° 22' 50.7" E | ||
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| Location | Coober Pedy | ||
| State | South Australia | ||
| Country | Australia | ||
Challenger is a gold mine in the Australian state of South Australia . It is operated by the Australian mining company Dominion Mining .
location
The mine is located in southwest South Australia, approximately 900 km northwest of Adelaide and 40 km west of Coober Pedy . It is connected to the Sturt Highway via a 180 km long track . The pit also has a runway through which Adelaide personnel are flown in.
history
The deposit was discovered in 1995 due to geochemical anomalies in the calcrete cover. In the vicinity of the deposit, abnormally high grades of several hundred mg / t (ppb) gold were measured, whereupon Dominion and the then joint venture partner Resolute Ltd. a drill program commenced and encountered high grade gold mineralization. In 2000, Dominion took over the part of the project from Resolute and started a feasibility study with positive results. The upper part of the deposit up to a depth of 125 m was mined from 2002 to 2004. The development of underground operations began in 2004 and full capacity was reached in mid-2005. The current life expectancy of the pit is another 7 years. However, there are promising exploration results that make longer-term mining likely. Challenger is with costs of about 310 AUD per ounce gold, the cheapest gold mine in Australia. The annual production currently stands at 110,000 ounces of gold.
geology
Challenger is located in the southwest of the archaic-Mesoproterozoic Gawler kraton . Adjacent rock to the ore bodies are granulite facial , partly migmatitic gneisses ( English Christie Gneiss - a garnet - biotite - cordierite - gneiss) with an age of 2.4 billion years. The deposit consists of several ore bodies, two of which (M1 and M2) are being mined. They are heavily folded bodies with about 40 ° to NE with bluish fat quartz as gangue and lollingite , arsenopyrite , pyrrhotite and solid gold as ore minerals. The average gold grades are 9 g / t, but can also be several 10 g / t locally. The deposit was formed before the peak metamorphosis, because under granulite facial conditions too few fluids are available to form a hydrothermal ore body. Presumably it is an archaic orogenic gold deposit, analogous to that in Western Australia, which was intensely metamorphically overprinted 2.4 billion years ago. During the Proterozoic , unmined mafic veins and lamprophyres intruded .
Dismantling and processing
The operational management was transferred from Dominion to the mining company HWE. The extraction originally took place in the main and the smaller EZE opencast mine. Approximately 120,000 ounces of gold were recovered from the main open pit, mainly from the M1 body and, to a lesser extent, the M2 body. A smaller body of the same name was mined in the EZE open-cast mine. Subsequently, mining of the M1 ore body began underground, down to the current depth of around 700 m. The deposit is accessed via a helix , from which stretches are driven into the M1 body every 20 m. The body with an M-shaped cross-section is drilled and blown from one sole to the next lower. In order to keep the contamination with secondary rock low, the blasting is largely adapted to the shape of the ore body, so that the mines also have an M-shaped cross-section. The parallel M2 ore body is currently being developed, which is being mined from the existing helix analogous to the M1 body. Further exploration work is ongoing to determine the potential of the two ore bodies at a greater depth and other neighboring ore bodies.
The ore is transported to the nearby processing facility with dump trucks. There it is broken up and ground in a ball mill, after which 60% of the gold it contains can be extracted gravitationally. The remaining 40% is removed from the ore by cyanide leaching . The tailings finally contain 0.2 g / t of the original 9 g / t gold in the raw ore. The gold is melted on site into bars with a purity of 98%. These are then sold.