View source for Mining

{{About| the extraction of geological materials from the Earth|the municipality in [[Austria]]|Mining, Austria|the siege tactic|Mining (military)|name of the [[China|Chinese]] emperor|Daoguang Emperor}}

[[Image:Simplified world mining map 1.png|thumb|350px|right|Simplified world mining map (click to enlarge)]]
[[Image:Simplified world mining map 2.png|thumb|350px|right|Another simplified world mining map (click to enlarge)]]
[[Image:Chuquicamata-002.jpg|thumb|250px|right|[[Chuquicamata]], [[Chile]], site of the largest circumference and second deepest [[open-pit mining|open pit]] [[copper]] mine in the world.]]

'''Mining''' is  the extraction of [[value (economics)|valuable]] [[mineral]]s or other [[geology|geological]] materials from the earth, usually from an [[ore]] body, [[vein (geology)|vein]] or ([[coal mining|coal]]) seam. Materials recovered by mining include [[base metals]], [[precious metals]], [[iron]], [[uranium]], [[coal]], [[diamond]]s, [[limestone]], [[oil shale]], [[Sodium chloride|rock salt]] and [[potash]]. Any material that cannot be grown through [[agriculture|agricultural]] processes, or created [[Chemical synthesis|artificially]] in a [[laboratory]] or [[factory]], is usually mined.  Mining in a wider sense comprises extraction of any [[non-renewable resource]] (e.g., [[petroleum]], [[natural gas]], or even [[fossil water|water]]).

Mining of stone and metal has been done since [[Prehistory|pre-historic]] times. Modern mining processes involve [[prospecting]] for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desired materials and finally reclamation of the land to prepare it for other uses once the mine is closed. 

The nature of mining processes creates a potential negative impact on the environment both during the mining operations and for years after the mine is closed. This impact has led to most of the world's nations adopting regulations to moderate the negative effects of mining operations. Safety has long been a concern as well, though modern practices have improved safety in mines significantly. 

==History==
===Prehistoric mining===

[[Image:TimnaChalcolithicMine.JPG|thumb|Chalcolithic copper mine in Timna Valley, [[Negev Desert]], [[Israel]].]]
Since the beginning of civilization, people have used [[Rock (geology)|stone]], [[ceramic]]s and, later, [[metal]]s found on or close to the [[Earth|Earth's]] surface.  These were used to manufacture early [[tool]]s and [[weapon]]s, for example, high quality [[flint]] found in northern [[France]] and southern [[England]] were used to create [[Flint (tool)|flint tools]].<ref>Hartman, Howard L. ''SME Mining Engineering Handbook'', Society for Mining, Metallurgy, and Exploration Inc, 1992, p3.</ref> Flint mines have been found in [[chalk]] areas where seams of the stone were followed underground by shafts and galleries. The mines at [[Grimes Graves]] are especially famous, and like most other flint mines, are [[Neolithic]] in origin (ca 4000 BC-ca 3000 BC). Other hard rocks mined or collected for axes included the [[greenstone]] of the [[Langdale axe industry]] based in the [[English Lake District]].

The oldest known mine on archaeological record is the "Lion Cave" in [[Swaziland]]. At this site, which by [[radiocarbon dating]] proves the mine to be about 43,000 years old, [[paleolithic]] humans mined mineral [[hematite]], which contained [[iron]] and was ground to produce the red [[pigment]] [[ochre]].<ref>Swaziland Natural Trust Commission, "Cultural Resources - Malolotja Archaeology, Lion Cavern," Retrieved August 27, 2007, [http://www.sntc.org.sz/cultural/malarch.asp].</ref><ref>Peace Parks Foundation, "Major Features:  Cultural Importance." Republic of South Africa:  Author.  Retrieved August 27, 2007, [http://www.peaceparks.org/story.php?mid=168&pid=148].</ref>  Mines of a similar age in [[Hungary]] are believed to be sites where [[Neanderthal]]s may have mined [[flint]] for weapons and tools. {{Citation needed|date=March 2010}}

===Ancient Egypt===
[[Ancient Egypt]]ians mined [[malachite]] at [[Maadi]].<ref>Shaw, I. (2000). ''The Oxford History of Ancient Egypt''.  New York:  Oxford University Press, pp. 57-59.</ref> At first, [[Egyptians]] used the bright green malachite stones for ornamentations and pottery.  Later, between 2,613 and 2,494 BC, large building projects required expeditions abroad to the area of Wadi Maghara in order "to secure minerals and other resources not available in Egypt itself."<ref name="Shaw">Shaw, I. (2000). ''The Oxford History of Ancient Egypt''.  New York:  Oxford University Press, p. 108.</ref>  Quarries for [[turquoise]] and [[copper]] were also found at "Wadi Hamamat, Tura, Aswan and various other Nubian sites"<ref name="Shaw"/> on the [[Sinai Peninsula]] and at [[Timna]]. 

[[Mining in Egypt]] occurred in the earliest dynasties, and the [[gold mine]]s of [[Nubia]] were among the largest and most extensive of any in [[Ancient Egypt]], and are described by the Greek author [[Diodorus Siculus]]. He mentions that [[fire-setting]] was one method used to break down the hard rock holding the gold. One of the complexes is shown in one of earliest known maps. They crushed the ore and ground it to a fine powder before washing the powder for the [[gold dust]].

===Ancient Greece and Rome===
{{See also|Mining in Roman Britain}}

[[Image:Dolaucothimap4.jpg|thumb|250px|right|Ancient Roman development of the [[Dolaucothi Gold Mines]], Wales.]]
Mining in Europe has a very long history, examples including the silver mines of [[Laurium]], which helped support the Greek [[City-state|city state]] of [[Athens]]. However, it is the [[Ancient Rome|Romans]] who developed large scale mining methods, especially the use of large volumes of water brought to the minehead by numerous [[aqueduct]]s. The water was used for a variety of purposes, including using it to remove overburden and rock debris, called [[hydraulic mining]], as well as washing [[comminuted]] or crushed ores, and driving simple machinery.  

The Romans used hydraulic mining methods on a large scale to prospect for the veins of ore, especially a now obsolete form of mining known as [[hushing]]. It involved building numerous [[aqueducts]] to supply water to the minehead where it was stored in large [[reservoirs]] and tanks. When a full tank was opened, the wave of water sluiced away the overburden to expose the bedrock underneath and any gold veins. The rock was then attacked by [[fire-setting]] to heat the rock, which would be quenched with a stream of water. The [[thermal shock]] cracked the rock, enabling it to be removed, aided by further streams of water from the overhead tanks. They used similar methods to work [[cassiterite]] deposits in [[Cornwall]] and [[lead]] ore in the [[Pennines]]. 

The methods had been developed by the Romans in [[Spain]] in 25 AD to exploit large [[alluvial]] gold deposits, the largest site being at [[Las Medulas]], where seven long aqueducts were built to tap local rivers and to sluice the deposits. [[Spain]] was one of the most important mining regions, but all regions of the [[Roman Empire]] were exploited. They used [[reverse overshot water-wheel]]s for dewatering their deep mines such as those at [[Rio Tinto Group|Rio Tinto]]. In Great Britain the natives had [[Mining in Roman Britain|mined]] minerals for millennia ,<ref>[http://news.independent.co.uk/uk/this_britain/article2169254.ece The Independent, 20 Jan. 2007: ''The end of a Celtic tradition: the last gold miner in Wales'']</ref> but when the [[Roman Empire|Romans]] came, the scale of the operations changed dramatically. 

The Romans needed what Britain possessed, especially [[gold]], [[silver]], [[tin]] and [[lead]]. Roman techniques were not limited to surface mining.  They followed the ore veins underground once opencast mining was no longer feasible. At [[Dolaucothi]] they stoped out the veins, and drove [[adit]]s through barren rock to drain the stopes. The same adits were also used to ventilate the workings, especially important when [[fire-setting]] was used. At other parts of the site, they penetrated the [[water table]] and dewatered the mines using several kinds of machine, especially [[reverse overshot water-wheel]]s. These were used extensively in the [[copper]] mines at [[Rio Tinto Group|Rio Tinto]] in Spain, where one sequence comprised 16 such wheels arranged in pairs, and lifting water about {{convert|80|ft|m}}. They were worked as treadmills with miners standing on the top slats. Many examples of such devices have been found in old Roman mines and some examples are now preserved in the [[British Museum]] and the [[National Museum of Wales]].<ref>[http://www.romans-in-britain.org.uk/raw_mining.htm ''The Romans in Britain: mining'']</ref>

===Medieval Europe===
[[Image:Georgius Agricola.jpg|thumb|150px|right|Agricola, author of ''[[De Re Metallica]]'']]
Mining as an industry underwent dramatic changes in [[Middle Ages|medieval Europe]]. The mining industry in the early Middle Ages was mainly focused on the extraction of copper and iron.  Other precious metals were also used mainly for gilding or coinage.  Initially, many metals were obtained through [[open-pit mining]], and ore was primarily extracted from shallow depths, rather than though the digging of deep mine shafts.   Around the 14th century, the demand for weapons, armor, stirrups, and horseshoes greatly increased the demand for iron.  Medieval knights for example were often laden with up to 100 pounds of plate or chain link armor in addition to swords, lances and other weapons.<ref>A culture of Improvement.  Robert Friedel. MIT Press. 2007. Pg.81</ref> The overwhelming dependency on iron for military purposes helped to spur increased iron production and extraction processes. 

These new military applications coincided with a population explosion throughout Europe in the 11th-14th centuries which enriched the demand for precious metals in order to fill a currency shortage.<ref>Medieval Science and Technology: Original Essays.Medieval Iron and Steel – Simplified
Hall, Bert http://www.the-orb.net/encyclop/culture/scitech/iron_steel.html</ref>   The silver crisis of 1465 occurred when the mines had all reached depths at which the shafts could no longer be pumped dry with the available technology.<ref>http://mygeologypage.ucdavis.edu/cowen/~GEL115/115CH7.html</ref> Although the increased use of [[bank notes]] and the use of credit during this period did decrease the dependence and value of precious metals, these forms of currency still remained vital to the story of medieval mining. Use of water power in the form of [[water mill]]s was extensive; they were employed in crushing ore, raising ore from shafts and ventilating galleries by powering giant [[bellows]]. [[gun powder|Black powder]] was first used in mining in [[Banská Štiavnica|Selmecbánya]], [[Kingdom of Hungary]] (present-day [[Banská Štiavnica]], [[Slovakia]]) in 1627.<ref>Heiss, A.G. & Oeggl, K. (2008). Analysis of the fuel wood used in Late Bronze Age and Early Iron Age copper mining sites of the Schwaz and Brixlegg area (Tyrol, Austria). ''Vegetation History and Archaeobotany'' 17(2):211-221, Springer Berlin / Heidelberg, [http://dx.doi.org/10.1007/s00334-007-0096-8].</ref> Black powder allowed blasting of rock and earth to loosen and reveal ore veins, which was much faster than [[fire-setting]], in which rock was exposed to heat and then doused with cold water. Black powder allowed the mining of previously impenetrable metals and ores.<ref>The use of Firesetting in the Granite Quarries of South India Paul T. Craddock The Bulletin of the Peak District Mines Historical Society, Vol. 13 Number 1. 1996</ref> In 1762, the world's first mining academy was established in the same town. 
  
The widespread adoption of agricultural innovations such as the iron [[plowshare]], as well as the growing use of metal as a building material, was also a driving force in the tremendous growth of the iron industry during this period.  Inventions like the arrastra were often used by the Spanish to pulverize ore after being mined.  This device employed animal power and utilized mechanical principles similar to that of the ancient Middle Eastern technology of grain [[threshing]].<ref>"The Spanish Tradition in Gold and Silver Mining." Otis E. Young ''[[Arizona and the West]]'', Vol. 7, No. 4 (Winter, 1965), pp. 299-314 (''Journal of the Southwest'') Stable URL: http://www.jstor.org/stable/40167137.</ref>

Much of our knowledge of Medieval mining techniques comes from books such as [[Biringuccio]]’s ''[[De la pirotechnia]]'' and probably most importantly from [[Georg Agricola]]'s ''[[De re metallica]]'' (1556).  These books detail many different mining methods used in German and Saxon mines.  One of the prime issues confronting medieval miners (and one which Agricola explains in detail) was the removal of water from mining shafts.  As miners dug deeper to access new veins, flooding became a very real obstacle.  As a result the mining industry became dramatically more efficient and prosperous as the use of various mechanical and animal driven pump systems were implemented.

===North and South America===
[[Image:TamarackMiners CopperCountryMI sepia.jpg|thumb|245px|Miners at the [[Tamarack Mine]] in [[Copper Country]], Michigan, U.S. in 1905.]]
In [[North America]] there are ancient, prehistoric [[copper]] mines along [[Lake Superior]].<ref name="Lankton91">Lankton, L. (1991). ''Cradle to Grave:  Life, Work, and Death at the Lake Superior Copper Mines''. New York:  Oxford University Press, p. 5-6.</ref><ref name="west70">West, G.A. (1970). ''Copper:  its mining and use by the aborigines of the Lake Superior Region''.  Westport, Conn:  Greenwood Press.</ref>  "Indians availed themselves of this copper starting at least 5000 years ago,"<ref name="Lankton91"/> and copper tools, arrowheads, and other [[Cultural artifact|artifacts]] that were part of an extensive native trade network have been discovered.  In addition, [[obsidian]], [[flint]], and other minerals were mined, worked, and traded.<ref name="west70"/>  While the early French explorers that encountered the sites made no use of the metals due to the difficulties in transporting it,<ref name="west70"/> the copper was eventually traded throughout the continent along major river routes.  In [[Manitoba]], Canada, there also are ancient [[quartz]] mines near Waddy Lake and surrounding regions.<ref>Bruno, L. & Heaman, L.M. (2004). Structural controls on hypozonal oroganic gold mineralization in the La Rouge Domain, Trans-Hudson Orogen, Saskatchewan. ''The Canadian Journal of Earth Sciences'', Vol. 41, Issue 12, pp. 1453-1471.</ref> 

In the early colonial history of the Americas, "native gold and silver was quickly expropriated and sent back to Spain in fleets of gold- and silver-laden galleons"<ref>Vaden, H.E. & Prevost. G. (2002). ''Politics of Latin America:  The Power Game''. New York:  Oxford University Press, p. 34.</ref> mostly from mines in Central and South America.  [[Turquoise]] dated at 700 A.D. was mined in [[pre-Columbian]] America; in the Cerillos Mining District in [[New Mexico]], estimates are that "about 15,000 tons of rock had been removed from Mt Chalchihuitl using [[stone tool]]s before 1700."<ref>Maynard, S.R., Lisenbee, A.L. & Rogers, J. (2002).  Preliminary Geologic Map of the Picture Rock 7.5 - Minute Quadrangle Sante Fe County, Central New Mexico. New Mexico Bureau of Geology and Mineral Resources, Open-File Report DM-49.</ref><ref>The Cerrillos Hills Park Coalition, (2000).  Cerrillos Hills Historic Park Vision Statement. Public documents:  Author.  Retrieved August 27, 2007, [http://www.cerrilloshills.org/Coalition/document.html].</ref>  

Mining in the [[United States]] became prevalent in the 19th century, and the [[General Mining Act of 1872]] was passed to encourage mining of federal lands.<ref>McClure R, Schneider A. [http://www.seattlepi.com/specials/mining/26875_mine11.shtml The General Mining Act of 1872 has left a legacy of riches and ruin]. ''Seattle PI''.</ref> As with the [[California Gold Rush]] in the mid 19th century,  mining for minerals and precious metals, along with [[ranching]], was a driving factor in the [[Westward Expansion]] to the Pacific coast. With the exploration of the West, mining camps were established and "expressed a distinctive spirit, an enduring legacy to the new nation;" Gold Rushers would experience the same problems as the Land Rushers of the transient West that preceded them.<ref>Boorstin, D.J. (1965). ''The Americans:  The National Experience''. New York:  Vintage Books, pp. 78-81.</ref>  Aided by railroads, many traveled West for work opportunities in mining.  Western cities such as [[Denver, Colorado|Denver]] and [[Sacramento, California|Sacramento]] originated as mining towns.

==Mining methods and procedures==
===Steps of mine development===
[[File:Cut and fill schematic.png|thumb|300px|right|Schematic of a [[Underground mining (hard rock)|cut and fill mining operation in hard rock]].]]
The process of mining from discovery of an ore body through extraction of minerals and finally to returning the land to its natural state consists of several distinct steps.  The first is discovery of the ore body, which is carried out through [[prospecting]] or [[Mineral exploration|exploration]] to find and then define the extent, location and value of the ore body.  This leads to a mathematical [[mineral resource classification|resource estimation]] to estimate the size and [[ore grade|grade]] of the deposit.  

This estimation is used to conduct a pre-feasibility study to determine the theoretical economics of the ore deposit. This identifies, early on, whether further investment in estimation and engineering studies is warranted and identifies key risks and areas for further work. The next step is to conduct a [[mining feasibility study|feasibility study]] to evaluate the financial viability, technical and financial risks and robustness of the project.  

This is when the mining company makes the decision to develop the mine or to walk away from the project. This includes mine planning to evaluate the economically recoverable portion of the deposit, the [[metallurgy]] and ore recoverability, marketability and payability of the ore concentrates,  engineering concerns, milling and infrastructure costs, finance and equity requirements and an analysis of the proposed mine from the initial excavation all the way through to reclamation. 

Once the analysis determines a given ore body is worth recovering, development begins to create access to the ore body. The mine buildings and processing plants are built and any necessary equipment is obtained. The operation of the mine to recover the ore begins and continues as long as the company operating the mine finds it economical to do so. Once all the ore that the mine can produce profitably is recovered, [[Land rehabilitation|reclamation]] begins to make the land used by the mine suitable for future use.

=== Mining techniques ===
[[Image:SL500 01.jpg|thumb|250px|Underground [[Longwall mining]].]]
Mining techniques can be divided into two common [[Earthworks (engineering)|excavation]] types: surface mining and sub-surface (underground) mining. 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.<ref>Hartmann HL. ''Introductory Mining Engineering'', p. 11. [http://media.wiley.com/product_data/excerpt/11/04713485/0471348511.pdf First chapter].</ref> Targets are divided into two general categories of materials: ''placer deposits'', consisting of valuable minerals contained within river gravels, beach sands, and other [[alluvium|unconsolidated material]]s; 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 ore deposit, placer or lode, are mined by both surface and underground methods.

Processing of placer ore material consists of gravity-dependent methods of separation, such as [[sluice]] boxes. Only minor shaking or washing may be necessary to disaggregate (unclump) the sands or gravels before processing. Processing of ore from a lode mine, whether it is a surface or subsurface mine, requires that the rock ore be crushed and pulverized before extraction of the valuable minerals begins. After lode ore is crushed, recovery of the valuable minerals is done by one, or a combination of several, mechanical and chemical techniques.

[[File:UMine.JPG|thumb|right|[[Uranium]] mine near [[Moab, Utah]].]]
Some mining, including much of the rare earth elements and [[uranium mining]], is done by less-common methods, such as [[in-situ leach]]ing: 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.<ref>http://world-nuclear.org/info/inf27.html</ref><ref>http://www.kazatomprom.kz/cgi-bin/index.cgi?p27&version=en</ref>

[[Surface mining]] is done by removing (stripping) surface vegetation, dirt, and if necessary, layers of bedrock in order to reach buried ore deposits. Techniques of surface mining include; [[Open-pit mining]] which consists of recovery of materials from an open pit in the ground, [[quarry]]ing or gathering building materials from an open pit mine, [[strip mining]] which consists of stripping surface layers off to reveal ore/seams underneath, and [[Mountaintop removal mining|mountaintop removal]], commonly associated with coal mining, which involves taking the top of a mountain off to reach ore deposits at depth. Most (but not all) placer deposits, because of their shallowly buried nature, are mined by surface methods. [[Landfill mining]], finally, involves sites where [[landfill]]s are excavated and processed.<ref>[http://www.enviroalternatives.com/landfill.html Landfill Mining] Landfill Mining, Preserving Resources through Integrated Sustainable Management of Waste, Technical Brief from the World Resource Foundation</ref>

[[Underground mining|Sub-surface mining]] consists of digging tunnels or shafts into the earth to reach buried ore deposits. Ore, for processing, and waste rock, for disposal, are brought to the surface through the tunnels and shafts. Sub-surface mining can be classified by the type of access shafts used, the extraction method or the technique used to reach the mineral deposit. [[Drift mining]] utilizes horizontal access tunnels, [[slope mining]] uses diagonally sloping access shafts and [[shaft mining]] consists of vertical access shafts. 

Other methods include [[shrinkage stope mining]] which is mining upward creating a sloping underground room, [[long wall mining]] which is grinding a long ore surface underground and [[room and pillar]] which is removing ore from rooms while leaving pillars in place to support the roof of the room. Room and pillar mining often leads to [[retreat mining]] which is removing the pillars which support rooms, allowing the room to cave in, loosening more ore. Additional sub-surface mining methods include [[underground mining (hard rock)|hard rock mining]] which is mining of hard materials, [[bore hole mining]], [[drift and fill mining]], [[long hole slope mining]], [[sub level caving]] and [[block caving]]
{{wide image|Tagebau_Garzweiler_Panorama_2005.jpg|1200px|[[Tagebau Garzweiler|Garzweiler]] open-pit mine, [[Germany]]}}

===Machinery===
[[Image:Bagger-garzweiler.jpg|thumb|300px|The [[Bagger 288]] is a [[bucket-wheel excavator]] used in [[strip mining]].]]
Heavy machinery is needed in mining for exploration and development, to remove and stockpile overburden, to break and remove rocks of various hardness and toughness, to process the ore and for reclamation efforts after the mine is closed. Bulldozers, drills, explosives and trucks are all necessary for excavating the land. In the case of [[placer mining]], unconsolidated gravel, or [[alluvium]], is fed into machinery consisting of a hopper and a shaking screen or [[trommel]] which frees the desired minerals from the waste gravel.  The minerals are then concentrated using [[sluices]] or jigs. 

Large [[diamond drilling|drills]] are used to sink shafts, excavate stopes and obtain samples for analysis.  [[Tram]]s are used to transport miners, minerals and waste.  Lifts carry miners into and out of mines, as well as moving rock and ore out, and machinery in and out of underground mines.  Huge trucks, shovels and cranes are employed in surface mining to move large quantities of overburden and ore.  Processing plants can utilize large crushers, mills, reactors, roasters and other equipment to consolidate the mineral-rich material and extract the desired compounds and metals from the ore.

=== Extractive metallurgy ===
{{Main|extractive metallurgy}}
The science of [[extractive metallurgy]] is a specialized area in the science of metallurgy that studies the extraction of valuable metals from their ores, especially through chemical or mechanical means. [[Mineral processing]] (or mineral dressing) is a specialized area in the science of metallurgy that studies the mechanical means of crushing, grinding, and washing that enable the separation (extractive metallurgy) of valuable metals or minerals from their [[gangue]] (waste material).  Since most metals are present in ores as oxides or sulfides, the metal needs to be [[Redox|reduced]] to its metallic form.  This can be accomplished through chemical means such as [[smelting]] or through electrolytic reduction, as in the case of [[aluminum]]. [[Geometallurgy]] combines the geologic sciences with extractive metallurgy and mining.

==Environmental effects==
[[Image:Iron hydroxide precipitate in stream.jpg|thumb|upright|right|Iron hydroxide precipitate stains a stream receiving acid drainage from surface coal mining.]]
{{Main|Environmental issues with mining}}

Environmental issues can include [[erosion]], formation of [[sinkhole]]s, loss of [[biodiversity]], and contamination of soil, [[groundwater]] and [[surface water]] by chemicals from mining processes. In some cases, additional forest logging is done in the vicinity of mines to increase the available room for the storage of the created debris and soil.<ref>[http://ngm.nationalgeographic.com/2009/01/gold/larmer-text/6 Logging of forests and debris dumping]</ref> Contamination resulting from leakage of chemicals can also affect the health of the local population if not properly controlled.<ref>{{cite web |url=http://ngm.nationalgeographic.com/2009/01/gold/larmer-text/12 |title=The Real Price of Gold |publisher=National Geographic |date=2009-01 |first=Brook |last=Larmer }}</ref> 

Mining companies in most countries are required to follow stringent environmental and rehabilitation codes in order to minimize environmental impact and avoid impacts on human health.  These codes and regulations all require the common steps of [[Environmental impact assessment]], development of [[Environmental management]] plans, [[Mine closure planning]] (which must be done before the start of mining operations), and [[Environmental monitoring]] during operation and after closure.  However, in some areas, particularly in the developing world, regulation may not be well enforced by governments.  

For major mining companies, and any company seeking international financing, there are however a number of other mechanisms to enforce good environmental standards.  These generally relate to financing standards such as [[Equator Principles]], [[International Finance Corporation|IFC]] environmental standards, and criteria for [[Socially responsible investing]].  Mining companies have used this financial industry oversight to argue for some level of [[self-policing]].<ref name=RocksHardPlaces>Moody R. (2007). ''Rocks and Hard Places''. Zed Books.</ref> In 1992 a Draft Code of Conduct for Transnational Corporations was proposed at the [[Earth Summit (1992)|Rio Earth Summit]] by the UN Centre for Transnational Corporations (UNCTC), but the Business Council for Sustainable Development (BCSD) together with the International Chamber of Commerce (ICC) argued successfully for self-regulation instead.<ref>Abrahams D. (2005). [http://www.business-humanrights.org/Links/Repository/276544/link_page_view Regulations for Corporations: A historical account of TNC regulation], p. 6. UNRISD.</ref> 

This was followed up by the Global Mining Initiative which was initiated by nine of the largest metals and mining companies, and led to the formation of the [[International Council on Mining and Metals]] to "act as a catalyst" for social and environmental performance improvement in the mining and metals industry internationally.<ref name=RocksHardPlaces/> The mining industry has provided funding to various conservation groups, some of which have been working with conservation agendas that are at odds with emerging acceptance of the rights of indigenous people - particularly rights to make land-use decisions.<ref>{{cite journal |title=A Challenge to Conservationists: Can we protect natural habitats without abusing the people who live in them?
|url=http://www.worldwatch.org/node/565 |first=Mac |last=Chapin |date=2004-10-15 |accessdate=2010-02-18
|journal=World Watch Magazine |series= 6 |volume=17}}</ref> 

Ore mills generate large amounts of waste, called [[tailings]]. For example, 99 tons of waste are generated per ton of copper, with even higher ratios in gold mining{{Citation needed|date=July 2010}}. These tailings can be toxic. Tailings, which are usually produced as a [[slurry]], are most commonly dumped into ponds made from naturally existing valleys.<ref name=EPADesignDams>US EPA. (1994). [http://www.epa.gov/osw/nonhaz/industrial/special/mining/.../tailings.pdf Technical Report: Design and Evaluation of Tailings Dams].</ref> These ponds are secured by impoundments ([[dam]]s or [[embankment dam]]s).<ref name=EPADesignDams/> In 2000 it was estimated that 3,500 tailings impoundments existed, and that every year, 2 to 5 major failures and 35 minor failures occurred (citation needed); for example, in the [[Marcopper mining disaster]] at least 2 million tons of tailings were released into a local river.<ref name=StewardDams>TE Martin, MP Davies. (2000). [http://www.infomine.com/publications/docs/Martin2000.pdf Trends in the stewardship of tailings dams].</ref> Subaqueous tailings disposal is another option.<ref name=EPADesignDams/> The mining industry has argued that submarine tailings disposal (STD), which disposes of tailings in the sea, is ideal because it avoids the risks of tailings ponds; although the practice is illegal in the United States and Canada, it is used in the developing world.<ref>Coumans C. (2002). [http://www.wman-info.org/resources/technicalreports/Submarine%20Tailings%20Disposal%20Toolkit.pdf Mining’s Problem with Waste]. MiningWatch Canada.</ref>

Certification of mines with good practices occurs through the [[International Organization for Standardization]] (ISO) such as ISO 9000 and ISO 14001, which certifies an 'auditable environmental management system'; this certification involves short inspections, although it has been accused of lacking rigor.<ref name=RocksHardPlaces/>{{rp|183-4}} Certification is also available through [[Ceres (organization)|Ceres]]' [[Global Reporting Initiative]], but these reports are voluntary and unverified. Miscellaneous other certification programs exist for various projects, typically through nonprofit groups.<ref name=RocksHardPlaces/>{{rp|185-6}}

== Regulations and World Bank relationship ==
The [[World Bank]] has been involved in mining since 1955, mainly through grants from its [[International Bank for Reconstruction and Development]], with the Bank's [[Multilateral Investment Guarantee Agency]] offering [[political risk]] insurance.<ref>For an overview of the Bank and mining, see [http://www.pdac.ca/pdac/publications/papers/2001/pdf/Weber-Fahr(T-8).pdf Mining, Sustainability and Risk:World Bank Group Experiences].</ref> Between 1955 and 1990 it provided about $2 billion to fifty mining projects, broadly categorized as reform and rehabilitation, greenfield mine construction, mineral processing, technical assistance, and engineering. These projects have been criticized, particularly the Ferro Carajas project of Brazil, begun in 1981.<ref>See the 1995 ''World Development'' '''23'''(3) pp. 385-400.</ref> The bank established mining codes intended to increase foreign investment, in 1988 solicited feedback from 45 mining companies on how to increase their involvement.<ref name=RocksHardPlaces/>{{rp|20}}

In 1992 the bank began to push for privatization of [[government-owned corporation|government-owned mining companies]] with a new set of codes, beginning with its report ''The Strategy for African Mining''. In 1997, Latin America's largest miner [[Vale (mining company)|Companhia Vale do Rio Doce]] (CVRD) was privatized. These and other movements such as the Philippines 1995 Mining Act led the World Bank to publish a third report (''Assistance for Minerals Sector Development and Reform in Member Countries'') which endorsed mandatory environment impact assessments and attention to the locals. The codes based on this report are influential in the legislation of developing nations. The new codes are intended to encourage development through tax holidays, zero custom duties, reduced income taxes, and related measures.<ref name=RocksHardPlaces/>{{rp|22}} The results of these codes were analyzed by a group from the University of Quebec, which concluded that the codes promote foreign investment but "fall very short of permitting sustainable development".<ref>GRAMA. (2003). [http://migs.concordia.ca/documents/MIGS_Campbell_Feb07.pdf The Challenges of Development, Mining Codes in Africa And Corporate Responsibility]. In: ''International and Comparative Mineral Law and Policy:
Trends and Prospects''. Summarized in the [http://www.unites.uqam.ca/grama/pdf/AfricaCodes-Mining_Journal.pdf African Mining Codes Questioned].</ref> The observed negative correlation between natural resources and economic development is known as the [[resource curse]].

==Mining industry==
{{Expand section|date=October 2008}}
Mining exists in many countries but Australia and Canada have a reputation for domestic mining expertise, and London is known as the capital of global "mining houses" such as [[Rio Tinto]], [[BHP Billiton]], and [[Anglo American PLC]].<ref name=NAIndustryProfile>MacDonald A. (2002). [http://www.iisd.org/publications/pub.aspx?id=448 Industry in Transition: A Profile of the North American Mining Sector]. [http://www.iisd.org/pdf/2001/mmsd_na_mining_profile.pdf Free full-text].</ref> The US mining industry is also large but it is dominated by the coal and nonmetal minerals, and the various regulations have worked to reduce the significance of mining in the United States.<ref name=NAIndustryProfile/> In 2007 the total [[market cap]] of mining companies was reported at US$962 billion, which compares to a total global market cap of publicly traded companies of about US$50 trillion in 2007.<ref>Reuters. [http://www.reuters.com/article/idUSL2144839620070321 Global stock values top $50 trln: industry data].</ref> 

While exploration and mining can sometimes be conducted by individual entrepreneurs or small business, most modern-day mines are large enterprises requiring large amounts of capital to establish. Consequently, the mining sector of the industry is dominated by large, often multinational companies, most of them publicly listed. See [[:Category:Mining companies|Mining Companies]] for a list.  It can be argued that what is referred to as the 'mining industry' is actually two sectors, one specializing in exploration for new resources, the other specializing in mining those resources. The exploration sector is typically made up of individuals and small mineral resource companies ("juniors") dependent on venture capital. The mining sector is typically large and multi-national companies sustained by mineral production from their mining operations.  In addition to these two sectors, various other industries such as equipment manufacture, environmental testing and metallurgy analysis also rely on and support the mining industry throughout the world. Canadian stock exchanges have a particular focus on mining companies, particularly junior exploration companies through the [[TSX Venture Exchange]]; Canadian companies raise capital on these exchanges and then invest the money in exploration globally.<ref name=NAIndustryProfile/> Some have argued that below juniors there exists a substantial sector of illegitimate companies primarily focused on manipulating stock prices.<ref name=NAIndustryProfile/>

Mining operations can be grouped into five major categories in terms of their respective resources.  These are, oil and gas extraction, coal mining, metal ore mining, nonmetallic mineral mining and quarrying, and support activities for mining.<ref>United States Bureau of Labor 
http://www.bls.gov/oco/cg/cgs004.htm#nature</ref> Out of all these categories oil and gas extraction remains one of the largest in terms of its global economic importance.  Prospecting potential mining sites, a vital area of concern for the mining industry is now done using sophisticated new technologies such as seismic prospecting and remote-sensing satellites.

===Corporate classifications===
Mining companies can be classified based on their size and financial capabilities:

* '''Major''' companies are considered to have an adjusted annual mining-related revenue of more than US$500 million, with the financial capability to develop a major mine on its own.

* '''Intermediate''' companies have at least $50 million in annual revenue but less than $500 million.

* '''Junior''' companies rely on [[equity (economics)|equity]] financing as their principal means of funding exploration.  Juniors are mainly pure exploration companies, but may also produce minimally, and do not have a revenue of US$50 million.<ref name=MEG-CorpClass>{{cite web|url= http://www.metalseconomics.com/pdf/PDAC%202009%20World%20Exploration%20Trends.pdf|title=Metals Economics Group World Exploration Trends Report|accessdate=2009-05-05|publisher=Metals Economics Group Inc.}}</ref>

==Safety==
[[Image:Minedanger.jpg|thumb|right|Danger sign at an old Arizona mine.]]
[[Image:Inclined Mine Shaft Entrace at Yarnbury.jpg|thumb|right|Abandoned mine entrance in [[Yorkshire]], [[England]], [[United Kingdom]]]]
Safety has long been a controversial issue in the mining business especially with sub-surface mining. While mining today is substantially safer than it was in the previous decades, [[mining accident]]s are often very high profile, such as the [[Quecreek Mine Rescue]] saving 9 trapped Pennsylvania coal miners in 2002. The [[Courrières mine disaster]], Europe's worst mining accident, caused the death of 1,099 miners (including many children) in Northern [[France]] on 10 March 1906. It seems that this disaster was surpassed only by the [[Benxihu Colliery]] accident in [[China]] on April 26, 1942, which killed 1,549 miners.<ref>{{fr icon}} {{cite news | title=Marcel Barrois | publisher=Le Monde | date=March 10, 2006 | url=http://www.lemonde.fr/web/article/0,1-0@2-3226,36-749532,0.html}}</ref>  As many as 20,000 Chinese miners die in accidents each year.<ref>"[http://www.time.com/time/magazine/article/0,9171,1595235,00.html Where The Coal Is Stained With Blood]". ''TIME''. March 2, 2007</ref> Mining ventilation is a significant safety concern for many miners. Poor ventilation of the mines causes exposure to harmful gases, heat and dust inside sub-surface mines. These can cause harmful physiological effects, including death. The concentration of methane and other airborne contaminants underground can generally be controlled by dilution (ventilation), capture before entering the host air stream (methane drainage), or isolation (seals and stoppings).<ref name=NIOSH_Vent>{{cite web|url= http://www.cdc.gov/niosh/mining/topics/topicpage30.htm |title=NIOSH Mining Safety and Health Ventilation |accessdate=2007-10-29|publisher=United States National Institute for Occupational Safety and Health}}</ref> 

Ignited [[Methane|methane gas]] is a common source of explosions in coal mines, or, the more violent [[coal dust]] explosions. Gases in mines can also poison the workers or displace the oxygen in the mine, causing asphixiation.<ref name=NIOSH_Vent/> For this reason, the MHSA requires that workers have gas detection equipment in groups of miners.  It must be able to detect common gases, such as CO, O2, H2S, and % Lower Explosive Limit.  Additionally, further regulation is being requested for more gas detection as newer technology such as nanotechnology is introduced.  

High temperatures and humidity may result in heat-related illnesses, including [[Hyperthermia|heat stroke]] which can be fatal. Dusts can cause lung problems, including [[silicosis]], [[asbestosis]] and [[pneumoconiosis]] (also known as miners lung or [[Coalworker's pneumoconiosis|black lung]] disease). A ventilation system is set up to force a stream of air through the working areas of the mine. The air circulation necessary for the effective ventilation of a mine is generated by one or more large mine fans, usually located above ground. Air flows in one direction only, making circuits through the mine such that each main work area constantly receives a supply of fresh air.

Since mining entails removing dirt and rock from its natural location creating large empty pits, rooms and tunnels, cave-ins are a major concern within mines. Modern techniques for timbering and bracing walls and ceilings within sub-surface mines have reduced the number of fatalities due to cave-ins, but accidents still occur.{{Citation needed|date=October 2008}}  The presence of heavy equipment in confined spaces also poses a risk to miners, and despite modern improvements to safety practices, mining remains dangerous throughout the world.

===Abandoned mines===
[[Image:Abandoned mine Yerington.JPG|thumb|right|Abandoned mine in Nevada.]]
[[File:Abandoned mines sign.jpg|thumb|Warning sign near [[Jerome, Arizona]] ]]
There are upwards of 560,000 abandoned mines on public and privately owned lands in the United States alone.<ref>Kertes, N., (March, 1996). US abandoned mine count still a mystery - General Accounting Office report. ''American Metal Market'', Retrieved August 27, 2007, [http://findarticles.com/p/articles/mi_m3MKT/is_n60_v104/ai_18131890]</ref><ref>People, Land, and Water (March, 2007). KEEP OUT! Old Mines Are Dangerous. ''Office of Surface Mining'':  U.S. Department of the Interior.  Retrieved Aug, 27, 2007, [http://www.peoplelandandwater.gov/osm/osm_03-20-07_keep-out-old.cfm]</ref> Abandoned mines pose a threat to anyone who may attempt to explore them without proper knowledge and safety training. Old mines are often dangerous and can contain deadly gases. Standing water in mines from seepage or infiltration poses a significant hazard as the water can hide deep pits and trap gases below the water.  Additionally, since weather may have [[erosion|eroded]] the earth and rock surrounding it, the entrance to an old mine in particular can be very dangerous. Old mine workings, caves, etc. are commonly hazardous simply due to the lack of oxygen in the air, a condition in mines known as [[blackdamp]].

===Hearing loss===
[[Miners]] utilize equipment strong enough to break through extremely hard layers of the Earth's [[crust (geology)|crust]]. This equipment, combined with the closed workspace that [[underground mining|underground miners]] work in, can cause [[hearing loss]].<ref name=sound>{{cite journal|last=Peterson|first=J.S.|coauthors=P.G. Kovalchik, R.J. Matetic|title=Sound power level study of a roof bolter|journal=Trans Soc Min Metal Explor|issue=320|pages=171–7|year=2006|url=http://www.cdc.gov/niosh/mining/pubs/pdfs/splso.pdf|format=[[Portable Document Format|PDF]]|accessdate=2009-06-16}}</ref> For example, a roof bolter (commonly used by mine roof bolter operators) can reach sound power levels of up to 115 dB.<ref name=sound/> Combined with the [[reverberant]] effects of underground mines, a miner without proper [[hearing protection]] is not only at a high risk for [[hearing loss]],<ref name=sound/> but is also going against [[Occupational Safety and Health Administration|OSHA]] standards<ref>{{Cite book | contribution = Appendix A: OSHA Noise Standard Compliance Checklist | contribution-url = http://origin.cdc.gov/niosh/docs/96-110/pdfs/96-110.pdf | title = Preventing Occupational Hearing Loss: A Practical Guide | editor-last = Franks | editor-first = John R. | pages = 60 | year = 1996 | publisher = U.S. Department of Health and Human Services}}</ref>.

== Records ==
As of 2008, the deepest mine in the world is [[TauTona]] in [[Carletonville]], [[South Africa]] at 3.9 kilometers,<ref name="TauTonaExtended">{{cite news |title=TauTona, Anglo Gold - Mining Technology |url=http://www.mining-technology.com/projects/tautona_goldmine/ |publisher=SPG Media Group PLC |date=2009-01-01 |accessdate=2009-03-02 }}</ref> replacing [[Savuka Mine]] in the [[North West Province (South Africa)|North West Province]] of [[South Africa]] at 3,774 meters.<ref name="TauTonaPlans">{{cite news |first=Brindaveni |last=Naidoo |title=TauTona to take ‘deepest mine’ accolade |url=http://www.miningweekly.co.za/article.php?a_id=98516 |publisher=Creamer Media's Mining Weekly Online |date=2006-12-15 |accessdate=2007-07-19 }}</ref> [[East Rand Mine]] in [[Boksburg]], [[South Africa]] briefly held the record at 3,585 meters, and the first mine declared the deepest in the world was also TauTona when it was at 3,581 meters.  The deepest mine in Europe is [[Pyhäsalmi Mine]] in [[Pyhäjärvi]], [[Finland]] at 1,444 meters. The second deepest mine in Europe is [[Boulby Mine]] [[England]] at 1,400 meters (shaft depth 1,100 meters).

The deepest open pit mine in the world is [[Bingham Canyon Mine]] in [[Bingham Canyon]], [[Utah]], [[United States]] at over 1,200 meters.  The largest and second deepest open pit copper mine in the world is [[Chuquicamata]] in [[Chuquicamata]], [[Chile]] at 900 meters, 940,600 tons of copper and 17,700 tons of molybdenum produced annually. {{Citation needed|date=October 2008}} <!-- [[Escondida]] mine now has larger annual production -->

The deepest open pit mine with respect to sea level is [[Tagebau Hambach]] in Germany, where the ground of the pit is 293 meters below sea level.

The largest underground mine: [[El Teniente]], in Rancagua, [[Chile]], 2,400 kilometers of underground drifts, 418,000 tons of copper yearly. <!-- (none of these are records: Sweden's largest underground mine is [[Kirunavaara mine]] in [[Kiruna]], [[Sweden]], 450 kilometers of roads, 40 million tonnes of ore produced yearly, depth 1,270 meters. --> The deepest borehole in the world is [[Kola Superdeep Borehole]] at 12,262 meters. This, however, is not a matter of mining but rather related to [[scientific drilling]].

== See also ==
*[[Mining engineering]]
*[[Outline of mining]]
*[[Landfill mining]]
*[[List of uranium mines]]
*[[Mineral industry]]
*[[Spoil tip]]

'''Region specific:'''
*[[Mining and metallurgy in medieval Europe]]
*[[Mining in the Upper Harz]]
*[[Mining in Cornwall and Devon]]
*[[Canadian Mining Hall of Fame]]
*[[National Mining Hall of Fame|National Mining Hall of Fame (USA)]]

==References==
{{Reflist|2}}

==Further reading==
* Ali, Saleem H. (2003) ''Mining, the Environment and Indigenous Development Conflicts''. Tucson AZ: University of Arizona Press.
* Ali, Saleem H. (2009) ''Treasures of the Earth: need, greed and a sustainable future''. New Haven and London: Yale University Press
* {{cite book |title=From Mine to Mistress: Corporate Strategies and Government Policies in the International Diamond Industry |last=Even-Zohar |first=Chaim |year=2002 |publisher=Mining Journal Books |isbn=0953733610 |pages=555}}
* Geobacter Project: [http://www.geobacter.org/press/2001-07-21-economist.pdf Gold mines may owe their origins to bacteria] (in [[Portable Document Format|PDF]] format)
* Garrett, Dennis ''Alaska Placer Mining''
* {{cite book |title=Principles of Mine Planning|edition=2nd |last=Jayanta |first=Bhattacharya |year=2007 |publisher=Wide Publishing |location= |isbn=81-7764-480-7 |pages=505}}
* Morrison, Tom (1992) ''Hardrock Gold: a miner's tale''. ISBN 0-8061-2442-3

==External links==
{{Wiktionary|mining}}
{{Commons category|Mining}}
* [http://kids.mongabay.com/lesson_plans/lisa_algee/mining.html What is mining?]
* [http://www.smenet.org Society for Mining, Metallurgy, and Exploration]
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{{Mining techniques}}
{{Technology}}
{{Caves}}

[[Category:Mining| ]]
[[Category:History of mining|*]]
[[Category:Occupational safety and health]]

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