Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain any material that cannot be grown through agricultural processes or created artificially in a laboratory or factory. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water.
Why mine?
Mining is a money making business. Not only do mining companies prosper, but governments also make money from revenues. Workers also receive income and benefits.
Mining Techniques
Mining techniques can be divided into two common excavation types: surface mining and sub-surface (underground) mining. Today, surface mining is much more common, and produces, for example, 85% of minerals (excluding petroleum and natural gas) in the United States, including 98% of metallic ores.
Targets are divided into two general categories of materials: placer deposits, consisting of valuable minerals contained within river gravels, beach sands, and other unconsolidated materials; and lode deposits, where valuable minerals are found in veins, in layers, or in mineral grains generally distributed throughout a mass of actual rock. Both types of the ore deposit, placer or lode, are mined by both surface and underground methods.
Some mining, including much of the rare earth elements and uranium mining, is done by less-common methods, such as in-situ leaching: this technique involves digging neither at the surface nor underground. The extraction of target minerals by this technique requires that they be soluble, e.g., potash, potassium chloride, sodium chloride, sodium sulfate, which dissolve in water. Some minerals, such as copper minerals and uranium oxide, require acid or carbonate solutions to dissolve.
Exploration
A mining operation begins with prospecting and exploration -- stages with long periods of investment and high risk of failure. However, prospecting and exploration are necessary forms of investment and insurance for the future of any mining company. Success in mineral exploration or the acquisition of high -potential mineral properties by negotiation determines the survival of mining companies and industrial nations.
