Mining

Mining is the extraction of valuable minerals or other geological materials from the earth, usually (but not always) from an ore body, vein, or (coal) seam. Materials commonly recovered by mining include bauxite, coal, copper, diamonds, iron, gold, lead, manganese, magnesium, nickel, phosphate, platinum, rock salt, silver, tin, titanium, uranium, and zinc. Other highly useful materials that are mined include clay, sand, cinder, gravel, granite, and limestone. Any material that cannot be grown from agricultural processes must be mined. Mining in a wider sense can also include extraction of petroleum and natural gas.

Mining techniques

Mining techniques can be divided into two basic excavation types:

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1. Surface mining

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:*Open-pit mining

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:*Quarrying

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:*Strip mining

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:*Placer mining

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:*Mountaintop removal

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2. Sub-surface mining

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:*Drift mining

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:*Slope mining

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:*Shaft mining

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:*Hard rock mining

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:*Borehole mining

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