Mining is the extraction of valuable geological materials and minerals from the surface of the Earth. 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. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water.
A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to manage their safety risks and reduce their environmental impact.
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 above-ground mining structures are referred to as a "pit head". In Australia, "colliery" generally refers to an underground coal mine.
Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique that extracts rock or minerals from the earth using a pit, sometimes known as a borrow pit.
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.
Mining in the engineering discipline is the extraction of minerals from the ground. Mining engineering is associated with many other disciplines, such as mineral processing, exploration, excavation, geology, metallurgy, geotechnical engineering and surveying. A mining engineer may manage any phase of mining operations, from exploration and discovery of the mineral resources, through feasibility study, mine design, development of plans, production and operations to mine closure.
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. In the United States, mine reclamation is a regular part of modern mining practices. Modern mine reclamation reduces the environmental effects of mining.
Mountaintop removal mining (MTR), also known as mountaintop mining (MTM), is a form of surface mining at the summit or summit ridge of a mountain. Coal seams are extracted from a mountain by removing the land, or overburden, above the seams. This process is considered to be safer compared to underground mining because the coal seams are accessed from above instead of underground. In the United States, this method of coal mining is conducted in the Appalachian Mountains in the eastern United States. Explosives are used to remove up to 400 vertical feet of mountain to expose underlying coal seams. Excess rock and soil is dumped into nearby valleys, in what are called "holler fills" or "valley fills".
Drift mining is either the mining of an ore deposit by underground methods, or the working of coal seams accessed by adits driven into the surface outcrop of the coal bed. A drift mine is an underground mine in which the entry or access is above water level and generally on the slope of a hill, driven horizontally into the ore seam.
A spoil tip is a pile built of accumulated spoil – waste material removed during mining. Spoil tips are not formed of slag, but in some areas, such as England and Wales, they are referred to as slag heaps. In Scotland the word bing is used. In North American English the term is mine dump or mine waste dump.
The Office of Surface Mining Reclamation and Enforcement (OSMRE) is a branch of the United States Department of the Interior. It is the federal agency entrusted with the implementation and enforcement of the Surface Mining Control and Reclamation Act of 1977 (SMCRA), which attached a per-ton fee to all extracted coal in order to fund an interest-accruing trust to be used for reclamation of abandoned mine lands, as well as established a set environmental standards that mines must follow while operating, and achieve when reclaiming mined land, in order to minimize environmental impact. OSMRE has fewer than 500 employees, who work in either the national office in Washington, DC, or of the many regional and field offices.
The health and environmental impact of the coal industry includes issues such as land use, waste management, water and air pollution, caused by the coal mining, processing and the use of its products. In addition to atmospheric pollution, coal burning produces hundreds of millions of tons of solid waste products annually, including fly ash, bottom ash, and flue-gas desulfurization sludge, that contain mercury, uranium, thorium, arsenic, and other heavy metals. Coal is the largest contributor to the human-made increase of carbon dioxide in Earth's atmosphere.
The following outline is provided as an overview of and topical guide to mining:
Mining in New Zealand began when the Māori quarried rock such as argillite in times prior to European colonisation. Mining by Europeans began in the latter half of the 19th century.
Environmental effects of mining can occur at local, regional, and global scales through direct and indirect mining practices. Mining can cause erosion, sinkholes, loss of biodiversity, or the contamination of soil, groundwater, and surface water by chemicals emitted from mining processes. These processes also affect the atmosphere through carbon emissions which contributes to climate change.
Mining in the United States has been active since the beginning of colonial times, but became a major industry in the 19th century with a number of new mineral discoveries causing a series of mining rushes. In 2015, the value of coal, metals, and industrial minerals mined in the United States was US$109.6 billion. 158,000 workers were directly employed by the mining industry.
Coal was discovered in Kentucky in 1750. Since the first commercial coal mine opened in 1820 coal has gained both economic importance and controversy regarding its environmental consequences. As of 2010 there were 442 operating coal mines in the state, and as of 2017 there were fewer than 4,000 underground coalminers.
The Hobet 21 Coal Mine in West Virginia was operational between 1974 and 2015. Straddling the border of Boone County and Lincoln County in the Appalachian Mountains, the Hobet 21 mine was one of the largest mountaintop-removal coal mining operations in West Virginia. Originally owned by Fil Nutter, the mine used both underground mining and strip mining techniques, and later even more intensive surface mining using a dragline. Increasing productivity and profitability encouraged workers to successfully strike for their health plan in 1993, which resulted in unusually thorough coverage for mine workers at this time. The Hobet mine was incorporated into Arch Coal in 1997, along with several other mines, following booming coal demand. The mine was sold two more times: to Magnum Coal in 2005 and to Patriot Coal in 2008. Patriot Coal subsequently went bankrupt in 2015, and the Hobet site was passed into a Virginia-based conservation firm who continued to mine the land while reclaiming and planting trees to offset carbon emissions for other companies.
Environmental justice and coal mining in Appalachia is the study of environmental justice – the interdisciplinary body of social science literature studying theories of the environment and justice; environmental laws, policies, and their implementations and enforcement; development and sustainability; and political ecology – in relation to coal mining in Appalachia.
Environmental issues in Appalachia, a cultural region in the Eastern United States, include long term and ongoing environmental impact from human activity, and specific incidents of environmental harm such as environmental disasters related to mining. A mountainous area with significant coal deposits, many environmental issues in the region are related to coal and gas extraction. Some extraction practices, particularly surface mining, have met significant resistance locally and at times have received international attention.
