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Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, [1] is a surface mining technique that extracts rock or minerals from the earth. Open-pit mines are used when deposits of commercially useful ore or rocks are found near the surface where the overburden is relatively thin. In contrast, deeper mineral ...
Power shovels are used principally for excavation and removal of overburden in open-cut mining operations; they may also be used for the loading of minerals, such as coal. They are the classic equivalent of excavators, and operate in a similar fashion. Other uses of the power shovel include: Close range work. Digging very hard materials.
A box cut (box pit) is a small open cut built to supply a secure and safe entrance as access to a slope to an underground mine. Generally the box cut is sunk until sufficiently unweathered rock is found to permit the development of the decline. [ 1 ]
In-situ leach for uranium has expanded rapidly since the 1990s, and is now the predominant method for mining uranium, accounting for 45 percent of the uranium mined worldwide in 2012. [2] Unlike open-pit and underground mining, in-situ leaching does not rely on burial depth as a criterion but is based on the properties of the uranium deposit.
In Australia, bauxite is mined using an open-cut method. [4] This is possible because most bauxite in Australia can be found at or relatively close to the surface and is easily accessible by this method. [2] Open cut mining involves first removing the area above the bauxite ore called the overburden.
The mine works as an open cut operation and Mount Fubilan has been reduced to a deep pit in the ground in the course of the excavation of the Ok Tedi Mine. By 31 December 2004, 8,896,577 tonnes of copper concentrate (containing 2,853,265 tonnes of copper metal and 7,035,477 troy ounces or 218.8278 tonnes of gold metal) had been mined.
The Mexican Mining Chamber (Camimex) opposes the ban on open-pit mining, saying such a prohibition would cause a 1% contraction in the country's GDP and threaten some 200,000 jobs.
As such they tend to be tabular, flat and really large, covering many square kilometres of the Earth's surface. However, at any one time the area of a deposit being worked for the nickel ore is much smaller, usually only a few hectares. The typical nickel laterite mine often operates as either an open cut mine or a strip mine. [citation needed]