Concept
Overburden
Related concepts (7)
Surface mining
Surface mining, including strip mining, open-pit mining and mountaintop removal mining, is a broad category of mining in which soil and rock overlying the mineral deposit (the overburden) are removed, in contrast to underground mining, in which the overlying rock is left in place, and the mineral is removed through shafts or tunnels. In North America, where the majority of surface coal mining occurs, this method began to be used in the mid-16th century and is practiced throughout the world in the mining of many different minerals.
Mine reclamation
Mine reclamation is the process of modifying land that has been mined to ecologically functional or economically usable state. Although the process of mine reclamation occurs once mining is completed, the planning of mine reclamation activities occurs prior to a mine being permitted or started. Mine reclamation creates useful landscapes that meet a variety of goals ranging from the restoration of productive ecosystems to the creation of industrial and municipal resources.
Tailings
In mining, tailings or tails are the materials left over after the process of separating the valuable fraction from the uneconomic fraction (gangue) of an ore. Tailings are different from overburden, which is the waste rock or other material that overlies an ore or mineral body and is displaced during mining without being processed. The extraction of minerals from ore can be done two ways: placer mining, which uses water and gravity to concentrate the valuable minerals, or hard rock mining, which pulverizes the rock containing the ore and then relies on chemical reactions to concentrate the sought-after material.
Open-pit mining
Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique of extracting rock or minerals from the earth from an open-air pit, sometimes known as a borrow. This form of mining differs from extractive methods that require tunnelling into the earth, such as long wall mining. Open-pit mines are used when deposits of commercially useful ore or rocks are found near the surface.
Coal mining
Coal mining is the process of extracting coal from the ground or from a mine. Coal is valued for its energy content and since the 1880s has been widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from iron ore and for cement production. In the United Kingdom and South Africa, a coal mine and its structures are a colliery, a coal mine is called a 'pit', and the above-ground structures are a 'pit head'. In Australia, "colliery" generally refers to an underground coal mine.
Underground hard-rock mining
Underground hard-rock mining refers to various underground mining techniques used to excavate "hard" minerals, usually those containing metals, such as ore containing gold, silver, iron, copper, zinc, nickel, tin, and lead. It also involves the same techniques used to excavate ores of gems, such as diamonds and rubies. Soft-rock mining refers to the excavation of softer minerals, such as salt, coal, and oil sands. Accessing underground ore can be achieved via a decline (ramp), inclined vertical shaft or adit.
Mining
Mining is the extraction of valuable geological materials from the Earth and other astronomical objects. Mining is required to obtain most materials that cannot be grown through agricultural processes, or feasibly created artificially in a laboratory or factory. Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. The ore must be a rock or mineral that contains valuable constituent, can be extracted or mined and sold for profit.