Mining 20381 226036206 2008-07-16T15:22:58Z Ctbolt 571072 /* External links */ removed 'link to 19th century mining'. Local and narrow perspective on a general and worldwide article. {{globalize}} {{dablink|This article is about mineral extractions. "Mining" can also refer to the installation of explosive devices. See [[Mine]] for other meanings, or [[Myna]] for the various birds so called. <br>"Miner" redirects here. For other meanings, see [[Miner (disambiguation)]].}} [[Image:Chuquicamata-002.jpg|thumb|right|[[Chuquicamata]], the largest and second deepest [[open-pit mining|open pit]] [[copper]] mine in the world, [[Chile]].]] [[Image:GarbuttMine.gif|thumb|right|Break time underground, [[Colorado]], ca. 1900]] '''Mining''' is the extraction of [[value (economics)|valuable]] [[mineral]]s or other [[geology|geological]] materials from the earth, usually (but not always) from an [[ore]] body, [[vein (geology)|vein]] or (coal) seam. Materials recovered by mining include [[bauxite]], [[coal]], [[copper]], [[gold]], [[silver]], [[diamond]]s, [[iron]], [[precious metal]]s, [[lead]], [[limestone]], [[magnesite]], [[nickel]], [[phosphate]], [[oil shale]], [[Sodium chloride|rock salt]], [[tin]], [[uranium]] and [[molybdenum]]. Any material that cannot be grown from [[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]]). ==History== {{globalize}} 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 set [[fire]] and break rock.<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]] the mine dates around 4,100 BC, [[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 Aug. 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 Aug. 27, 2007, [http://www.peaceparks.org/story.php?mid=168&pid=148].</ref> Mines of a similar age in [[Hungary]] and are believed to be sites where [[Neanderthal]]s may have mined [[flint]] for weapons and tools. [[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>Shaw, I. (2000). ''The Oxford History of Ancient Egypt''. New York: Oxford University Press, p. 108.</ref> Quarries for [[turqoise]] and [[copper]] were also found at "Wadi Hamamat, Tura, Aswan and various other Nubian sites"<ref>Shaw, I. (2000). ''The Oxford History of Ancient Egypt''. New York: Oxford University Press, p. 168.</ref> 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]]. ===Europe=== [[Image:Georgius Agricola.jpg|thumb|150px|left|Agricola, author of ''De Re Metallica'']] [[Image:Archscrew2.jpg|right|thumb|200px|Drainage wheel from Rio Tinto mines]] Mining in Europe has a very long pedigree, examples including the silver mines of [[Laurium]], which helped support the Greek 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, and included using it to remove overburden and rock debris, as well as washing [[comminuted]] or crushed ores, and driving simple machinery. [[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]]. The [[Celts]], for example, who were native to [[Great Britain|Britain]], had [[Mining in Roman Britain|mined]] minerals for centuries,<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]]. Mining in the [[Medieval]] period is best known through the work [[De Re Metallica]] (1556) of [[Georg Agricola]], who described many different mining methods then used in German or Saxon mines. Use of water power in the form of [[water mill]]s was extensive, and were employed in crushing ore, raising ore from shafts and ventilating galleries by giant [[bellows]]. [[gun powder|Black powder]] was first used in mining in [[Banská Štiavnica]], [[Kingdom of Hungary]] present-day [[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> In 1762, the world's first mining academy was established in the same town. ====Britain==== Britain's gold mines were located in Wales at [[Dolgellau]] and [[Dolaucothi Gold Mines|Dolaucothi]]. Romans discovered the Dolaucothi [[vein (geology)|vein]] after the [[Roman conquest of Britain|invasion]], in about 74 AD, and a settlement was soon set up in the Cothi Valley protected by a [[fort]]. They used [[hydraulic mining]] methods on a large scale to prospect for the veins of ore, especially a now redundant 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 attacked by [[fire-setting]] to heat the rock, which would then 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. [[Image:the_golden_wheel_from_Dolaucothi.png|thumb|200px|right|The Dolaucothi Golden Wheel]] 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. Alternatively, the veins may have been trenched, keeping the upper part open to the air. At deeper levels, [[stoping]] will have been necessary. 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. They were used extensively in the [[copper]] mines at [[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]]. [[Lead]] and [[silver]] were widely exploited during the Roman period, in [[Wales]], the [[Mendips]] and [[Pennines]]. A lead-silver mine at [[Charterhouse, Somerset]] for example, was guarded by a small [[fort]] and was next to the mine workings and settlement for the miners. Lead pigs have been found at several localities in Britain, and mining was so successful, that the Spanish complained about over-production depressing the market. The silver was valuable bullion, while the lead found numerous applications, especially in roofing and plumbing. There were many iron mines in [[Roman Britain]]. The index to the Ordnance Survey Map of Roman Britain lists 33 iron mines: 67% of these are in the [[Weald]] and 15% in the [[Forest of Dean]]. The majority of mine workers were [[Slavery in antiquity|slaves]]. The work conditions were poor, and up to 12% of miners died every year.<ref>[http://www.romans-in-britain.org.uk/raw_mining.htm ''The Romans in Britain: mining'']</ref> ===North America=== In [[North America]] there are ancient, prehistoric [[copper]] mines along [[Lake Superior]].<ref>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>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>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> 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>West, G.A. (1970). ''Copper: its mining and use by the aborigines of the Lake Superior region''. Westport, Conn: Greenwood Press, pp. 119-120.</ref> While the early French explorers that encountered the sites made no use of the metals due to the difficulties in transporting it,<ref>West, G.A. (1970). ''Copper: its mining and use by the aborigines of the Lake Superior region''. Westport, Conn: Greenwood Press, p. 51.</ref> 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> [[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 tools 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 Aug. 27, 2007, [http://www.cerrilloshills.org/Coalition/document.html].</ref> [[Image:TamarackMiners CopperCountryMI sepia.jpg|thumb|245px|Miners at the [[Tamarack Mine]] in [[Copper Country]], Michigan, USA in 1905.]] Mining in the [[United States]] became prevalent in the 19th century. As with the [[California Gold Rush]] in the mid 1800s, mining for minerals and precious metals alongside [[ranching]] was very important 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. According to the NAICS classification system, there are ten industries that are classified as belonging to the Mining division. Over 2008, the three riskiest industries within the Mining division are expected to be: Oil and Gas Extraction, Coal Mining and Other Metal Ore Mining. These three industries combined account for around 2.3% of America's gross domestic product. <ref> [http://www.ibisworld.com/newsletter/issues/us/07sep/news.htm: September 2007, Case Study: The Riskiest Industry in the US], ''IBISWorld''</ref> ==Procedure== ===Steps of process=== # [[Prospecting]] or [[Mineral exploration|Exploration]] to find and then define the extent and value of [[ore]] where it is located ("ore body") # Conduct [[mineral resource classification|resource estimation]] to mathematically estimate the size and grade of the deposit # 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. # Conduct a [[feasibility study]] to evaluate the financial viability, technical and financial risks and robustness of the project and make a decision as whether to develop or walk away from a proposed mine 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, milling and infrastructure costs, finance and equity requirements and a cradle to grave analysis of the possible mine, from the initial excavation all the way through to reclamation. # Development to create access to an ore body and building of mine plant and equipment # The operation of the mine in an active sense # [[Land rehabilitation|Reclamation]] to make land where a mine had been suitable for future use ===Techniques=== [[Image:Minecart toilet.jpg|thumb|A minecart toilet, used in [[Bisbee, Arizona]].]] Mining techniques can be divided into two basic [[Earthworks (engineering)|excavation]] types: {| cellspacing="0" border="0" bgcolor="white" | valign="top" | :1. [[Surface mining]] ::*[[Open-pit mining]]: removal from an open pit ::**[[Quarry]]ing: building materials pit mine ::*[[Strip mining]]: stripping surface layers ::**[[Mountaintop removal mining|Mountaintop removal]]: deep strip mining ::*[[Placer mining]]: mining sand and gravel deposits | valign="top" | :2. [[Underground mining|Sub-surface mining]] ::*Types of access shafts: ::**[[Drift mining]]: Horizontal access tunnel ::**[[Slope mining]]: Sloping access shaft ::**[[Shaft mining]]: Vertical access shaft ::*Types of extraction ::**[[Shrinkage Stope mining]]: mining upward in a room ::**[[Room and pillar]]: removing ore from rooms ::***[[Retreat mining]]: removing pillars which support rooms ::**[[Long wall mining]]: Grinding a long ore surface ::*[[Underground mining (hard rock)|Hard rock mining]]: mining hard materials ::*[[Bore hole mining]] ::*[[Drift and Fill mining]] ::*[[Long Hole slope mining]] ::*[[Sub level Caving]] ::*[[Block Caving]] |} [[In-situ leach]] is a particular mining technique that is used to mine minerals ([[potash]], [[potassium chloride]], [[sodium chloride]], [[sodium sulfate]] and [[uranium oxide]]) which dissolve in water. == Extractive metallurgy == The science of [[extractive metallurgy]] is a specialized area in the science of metallurgy that studies the extraction of valuable metals and minerals 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). {{seealso|biomineralization}} ==Environmental effects== {{Nofootnotes|date=August 2007}} [[Image:2008-05-23 Haus Ecke Kamp und Johowstrasse.JPG|thumb|House in [[Gladbeck]], Germany, with fissures caused by gravity erosion due to mining]] Environmental issues can include [[erosion]], formation of [[sinkhole]]s, loss of [[biodiversity]], and contamination of [[groundwater]]s and surface water by chemicals from the mining process and products. Modern mining companies in some countries are required to follow environmental and rehabilitation codes, ensuring the area mined is returned to close to its original state. In some countries with pristine environments, such as large parts of [[Australia]], this is impossible despite the best intentions. Some mining methods have devastating environmental and public health effects. Mining can have adverse effects on surrounding surface and ground water if protection measures are not exercised. The result can be unnaturally high concentrations of some chemical elements, notably arsenic and sulfuric acid, over a significantly large area of surface or subsurface. Coal mining releases approximately twenty toxic chemicals, of which 85% is said to be managed on site. Combined with the effects of water and the new 'channels' created for water to travel through, collect in, and contact with these chemicals, a situation is created in which massive contamination can occur. In well-regulated mines, hydrologists and geologists take careful measures to mitigate any type of water contamination that could be caused by mines. In modern American mining, operations must, under federal and state law, meet standards for protecting surface and ground waters from contamination, including [[acid mine drainage]] (AMD). To mitigate these problems water is continuously monitored at coal mines. The five principal technologies used to control water flow at mine sites are: diversion systems, containment ponds, groundwater pumping systems, subsurface drainage systems, and subsurface barriers. In the case of AMD, contaminated water is generally pumped to a treatment facility that neutralizes the contaminants.<ref>[http://itech.fgcu.edu/faculty/ndemers/Miningconference/mcindex.htm First International Conference on Mining Impacts to Human and Natural Environments (March 15, 2008)]</ref> [[Image:Iron hydroxide precipitate in stream.jpg|thumb|right|Iron hydroxide precipitate stains a stream receiving acid drainage from surface coal mining.]] Some examples of environmental problems associated with mining operations are: :'''[[Ashio Copper Mine]]''', [[Ashio]], [[Japan]] was the site of substantial pollution at end of the nineteenth century :[[Acid mine drainage]], exemplified by the cases of the '''[[Berkeley Pit]]''', and the '''[[Wheal Jane|Wheal Jane Mine]]''' :Dissolution and transport of dissolved metals and heavy metals by run-off and ground waters, an example being the '''[[Britannia Beach, British Columbia|Britannia Mine]]''', a former copper mine near Vancouver, British Columbia. '''Tar Creek''', an abandoned mining area in [[Picher, Oklahoma]] that is now an [[United States Environmental Protection Agency|Environmental Protection Agency]] [[Superfund (environmental law)|superfund]] site. Water in the mine has leaked through into local [[groundwater]], contaminating it with metals such as [[lead]] and [[cadmium]].<ref>[http://www.health.state.ok.us/PROGRAM/envhlth/sites/ottawa.html Ottawa County, Oklahoma Hazardous Waste Sites<!-- Bot generated title -->]</ref> :Long-term storage of tailings and dust, which can be easily blown off site by wind, an example being '''Scouriotissa''', an abandoned copper mine in [[Cyprus]]. :Erosion of exposed hillsides, mine dumps, tailings dams and resultant [[siltation]] of drainages, creeks and rivers, the prime example being the giant [[Ok Tedi Mine]] in [[Papua New Guinea]]. :In areas of wilderness mining may cause habitat destruction and destruction or disturbance of [[ecosystems]], and in areas of farming it may disturb or destroy productive grazing and cropping lands. In urbanised environments mining may produce [[noise pollution]], dust pollution and visual pollution. Although such issues have been associated with some mining operations in the past, modern mining practices have improved significantly and are subject to close environmental scrutiny. {{Fact|date=April 2008}} Modern mining practises aim to lessen environmental impacts from mining, and the ultimate aim is to return the local environment to as close to pristine as is possible. {{Fact|date=April 2008}} In many cases, the most significant environmental impact longer-term is visual, with pits and mine dumps prominent landscape features. {{Fact|date=April 2008}} To ensure completion of [[reclamation]] (restoring mine land) most governments and regulatory authorities around the world require that mining companies post a bond to be held in escrow until productivity of reclaimed land has been convincingly demonstrated. Since 1978 the mining industry has reclaimed more than 2 million acres (8,000 km²) of land in the United States alone. This reclaimed land has renewed vegetation and wildlife in previous mining lands and can even be used for farming and ranching. For further reading on reclamation of former mining sites, please see [[Restoration ecology]]. ==Mining industry== {{Limitedgeographicscope}} ===Overview=== 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, mostly publicly-listed companies. See [[:Category:Mining companies]] for a list. However, 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 dependent on public investment. The mining sector is typically large and multi-national companies sustained by mineral production from their mining operations. ===Employment=== ====United States==== Miners today do more than just dig in the Earth's subsurface. There are many different jobs, direct and indirect, in the mining industry, ranging from engineers and lab technicians to geologists and environmental specialists. Beyond employment directly linked to mine-site activity, the modern mining industry also employs many other professionals, including accountants, lawyers, sales representatives, public relations specialists, not to mention thousands of men and women involved who manufacture the machines and equipment necessary to mine minerals. Employment in the mining industry offers highly competitive wages and benefits, especially in rural or remote areas. According to the [[Bureau of Labor Statistics]] (BLS), wages for coal miners are 30% higher than the wage earned by the average American. Employees possessing at least a bachelor's degree in mining or geological engineering can earn a median pay of over $80,000 annually. The US Bureau of Labor Statistics estimates that 675,000 are employed in the natural resources and mining sector. Estimated employment by selected specific commodity (including mine, mill, smelter, and quarry workers) listed below is from [http://minerals.usgs.gov/minerals/pubs/mcs/ US Geological Survey Mineral Commodity Surveys]: * Crushed Stone - 79,700 workers * Copper - 7,000 * Cement - 18,000 * Sand and Gravel - 38,300 * Gold - 7,600 * Aluminum - 56,000 * Iron Ore - 4,400 * Platinum Group Metals - 1,600 * Salt - 4,100 * Phosphate Rock - 2,900 The mining industry has an experienced but aging workforce with a mean average age of 50 years and median of 46 years. Indeed, while the industry will require new employees to meet future demand, the largest dilemma currently facing mine operators is finding employees to fill vacancies left by a generation of miners, mine engineers, senior managers, technical experts and others who are set to retire between 2005 and 2015. However, the industry is struggling to meet that demand due to current low enrollment levels in mining education programs at American colleges and universities. Mining is regulated under a comprehensive federal safety law (Federal Mine Safety and Health Act) that is administered by the Department of Labor's Mine Safety and Health Administration (MSHA). Currently under federal law, and enforced by MSHA each U.S. miner must have an approved worker training program in health and safety issues, including at least 40 hours of basic safety training for new underground miners with no experience; 24 hours for new miners at surface mines with no experience; plus eight hours of annual refresher training for all miners. ==Safety== ===United States=== 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. Mining ventilation is often seen to be a safety concern for many miners and their families. Poor ventilation of the mines causes exposure to harmful gases, heat and dust inside sub-surface mines. These can cause harmful physiological effects, even 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> Methane gas is a common source of ignition for explosions in coal mines and can propagate into the more violent [[coal dust]] explosions. Explosions can be prevented or mitigated by eliminating ignition sources, minimizing methane concentrations and coal dust accumulations, generalized rock dusting, and by using passive and active barriers to suppress propagating explosions.<ref name=NIOSH_Vent/> High temperatures and humidity may result in heat-related illnesses, including heat stroke which can be fatal. Dusts can cause lung problems, including [[silicosis]], [[asbestosis]] and [[pneumoconiosis]] (also known as miners lung or [[black lung]] disease). A ventilation system is set up to course 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. In the United States, the main fans at coal mines are required to be above ground. Air flows in one direction only, making circuits through the mine such that each main work area receives a supply of fresh air. Mining is regulated under the federal [[Mine Safety and Health Act]] by MSHA, which employs nearly one safety inspector for every four coal mines. Underground coal mines are thoroughly inspected at least four times annually by MSHA inspectors. In addition, miners can report violations, and request additional inspections. Miners with such concerns for their work safety cannot be penalized with any threat to the loss of employment. '''Immediately reportable accidents and injuries are:''' # A death of an individual at a mine; # An injury to an individual at a mine which has a reasonable potential to cause death; # An entrapment of an individual for more than thirty minutes; # An unplanned inundation of a mine by a liquid or gas; # An unplanned ignition or explosion of gas or dust; # An unplanned mine fire not extinguished within 30 minutes of discovery; # An unplanned ignition or explosion of a blasting agent or an explosive; # An unplanned roof fall at or above the anchorage zone in active workings where roof bolts are in use; or, an unplanned roof or rib fall in active workings that impairs ventilation or impedes passage; # A coal or rock outburst that causes withdrawal of miners or which disrupts regular mining activity for more than one hour; # An unstable condition at an impoundment, refuse pile, or culm bank which requires emergency action in order to prevent failure, or which causes individuals to evacuate an area; or, failure of an impoundment, refuse pile or culm bank; # Damage to hoisting equipment in a shaft or slope which endangers an individual or which interferes with use of the equipment for more than thirty minutes; and # An event at a mine which causes death or bodily injury to an individual not at the mine at the time the event occurs. Additionally, the Mine Safety and Health Act authorizes the [[National Institute for Occupational Safety and Health]] (NIOSH), part of the [[Centers for Disease Control and Prevention]] under the [[U.S. Department of Health and Human Services]] to develop recommendations for mine health standards for the Mine Safety and Health Administration; administer a medical surveillance program for miners, including chest X-rays to detect pneumoconiosos (black lung disease) in coal miners; conduct on-site investigations in mines; and test and certify personal protective equipment and hazard-measurement instruments.<ref>{{cite web|url= http://www.cdc.gov/niosh/topics/about.html |title=About NIOSH |accessdate=2007-10-28|publisher=United States National Institute for Occupational Safety and Health}}</ref> Statistical analyses performed by the [[United States Department of Labor|U.S. Department of Labor]]'s [[Mine Safety and Health Administration]] (MSHA) show that between 1990 and 2004, the industry cut the rate of injuries (a measure comparing the rate of incidents to overall number of employees or hours worked) by more than half and fatalities by two-thirds following three prior decades of steady improvement. ==Machinery== Heavy machinery is needed in mining for exploration and development, to remove and stockpile overburden, to break and remove rocks of diverse hardness and toughness, and to process the ore as well as for reclamation. Bulldozers, drills, explosives and trucks are important for digging into the land, especially in surface mining. Underground mining, like continuous mining, tends to be more technologically sophisticated because of the dangers and expense of subsurface tunneling. [[Tram]]s are used to transport miners, minerals and waste. Mining machinery manufacturers include [[Atlas Copco]], [[Joy Mining Machinery]], [[Bucyrus International]], [[Caterpillar Inc.|Caterpillar]], [[Komatsu Limited|Komatsu]], [[Volvo]], [[Hitachi Construction Machinery (Europe)|Hitachi]], [[Terex]], [[Dresser Industries]], [[Kawasaki Heavy Industries|Kawasaki]], [[Eimco Elecon India Limited]], and [[Liebherr]]. [[Image:Alaskan Trommel.jpg|thumb|right|Alaskan Placer Mining Trommel and Excavator at the Blue Ribbon Mine.]] [[Placer mining]] is a type of surface mining, usually for [[gold]], [[tin]], and other metals, and [[gemstones]]. Ore, typically unconsolidated gravels ([[alluvium]]), is fed into machinery that may consist of a hopper, shaking screen or [[trommel]] which frees the minerals from the gravels. The target minerals are then concentrated using [[sluices]] or jigs. ==Abandoned mines== {{Merge|Abandoned_mine|date=September 2007}} [[Image:Minedanger.jpg|thumb|right|Danger sign at an old Arizona mine.]] The number of abandoned mines in the [[United States]] remains an unknown, ranging "from the [[National Park Service]]'s tally of 2,500 on its lands, to the Mineral Policy Center's assessment of 560,000 abandoned mines on public and privately owned lands." <ref>;Kertes, N., (March, 1996). US abandoned mine count still a mystery - General Accounting Office report. ''American Metal Market'', Retrieved Aug. 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> Many of these abandoned mines are associated with abandoned neighboring towns often referred to as [[ghost town]]s. Experts strongly warn against entering or exploring old or abandoned mines. In the U.S., the estimation is that approximately 25% of the abandoned mine lands (AML) sites pose physical safety hazards.<ref>Greenley, M.N. (1999). National Reclamation of Abandoned Mine Lands. Presentation to the Society for Mining Metallurgy and Exploration: Author. Retrieved Aug. 27, 2007, [http://www.fs.fed.us/geology/amlpaper.htm]</ref> Old mines are often dangerous and can contain deadly gases. Since weather may have [[erosion|eroded]] the earth/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]]). Blackdamp is a deadly killer which provides no warning to any individual or group of individuals entering such an environment. Every year, dozens are injured or killed in recreational accidents on mine property. It is only fair to note, however, that the majority of the deaths are unrelated to mine exploration. Drownings in open quarries and ATV accidents on abandoned mine properties are the main cause of accidental death. The U.S. Department of Labor notes that since 1999, "more than 200 people have died in recreational accidents at surface and underground active and abandoned operations across the country." <ref> U.S. Department of Labor, (March, 2007). MSHA issues warning to children and adults to 'Stay Out and Stay Alive'. News Release: Author. Retrieved Aug. 27, 2007, [http://www.msha.gov/MEDIA/PRESS/2007/NR070319.asp]</ref> Due to these circumstances, MSHA ([[Mine Safety and Health Administration]]) launched the "Stay Out – Stay Alive" campaign, which is a national public awareness campaign aimed at warning and educating children and adults about the dangers of exploring and playing on active and abandoned mine sites. In the U.S., the Abandoned Mine Land Initiative, launched by the Western Governor's Association and the [[National Mining Association]] is also an effort focusing on reporting the number of high-priority AML sites.<ref>Western Governors Association and the National Mining Association, "Cleaning up Abandoned Mines: A Western Partnership." Retrieved Aug. 27, 2007, [http://www.westgov.org/wga/publicat/miningre.pdf]</ref> The initiative identifies, measures and reports on the progress of current reclamation cleanup programs on an annual basis. In the Americas region, the [[United Nations Environment Programme]] (UNEP) and the Chilean Copper Commission (COHILCO) co-hosted a workshop to address the problem of abandoned or "orphaned" mines.<ref>Chilean Copper Commission (COHILCO) and United Nations Environment Program: Division of Technology, Industry and Economics, (June, 2001). Abandoned Mines: Problems, Issues and Policy Challenges for Decision Makers. Summary Report: Author. Retrieved Aug. 27, 2007, [http://www.mineralresourcesforum.org/docs/pdfs/abandoned_report.pdf]</ref> Including a representative from the UN, ten countries were represented from North, Central and South America with an eleventh participant being Japan. == Records == * The deepest mine in the world: [[Savuka Mine]] in the [[North West Province]], [[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 ** The first mine declared the deepest in the world was [[TauTona]] in [[Carletonville]], [[South Africa]] at 3,581 meters. Plans exist to extend TauTona to a depth of 3,902 meters by July 2008, which will make it the deepest again.<ref name="TauTonaPlans" /> * The deepest open pit mine in the world: [[Bingham Canyon Mine]] in [[Bingham Canyon]], [[Utah]], [[USA]] at over 1,200 meters * The largest and second deepest open pit copper mine in the world: [[Chuquicamata]] in [[Chuquicamata]], [[Chile]] at 900 meters, 940.600 Tons of fine copper and 17.700 Tons of molybdenum * The largest underground mine: [[Codelco#El_Teniente|El Teniente]], in Rancagua, [[Chile]], 2400 kilometers of underground drifts, 418.000 Tons of copper yearly * The deepest mine in Europe: [[Pyhäsalmi Mine]] in [[Pyhäjärvi]], [[Finland]] at 1,444 meters * The second deepest mine in Europe: [[Boulby Mine]] [[England]] at 1,400 meters (shaft depth 1,100 meters) * Sweden's largest underground mine: [[Kirunavaara mine]] in [[Kiruna]], [[Sweden]], 450 kilometers of roads, 40 million tonnes of ore produced yearly, depth 1270 meters. * The deepest borehole in the world: [[Kola Superdeep Borehole]] at 12,262 meters. This, however, is not a matter of mining but rather related to [[scientific drilling]]. == See also == {| |-valign=top | | *[[Acid mine drainage]] *[[Biomining]] *[[Coal mining]] *[[Coal mining debate]] *[[Deepsea mining]] *[[General Mining Act of 1872]] *[[De re metallica]] *[[Deformation Monitoring|Deformation monitoring]] | width=60 | | *[[Gold mining]] *[[Industrial Revolution]] *[[Mineral Policy Institute]] *[[Mining engineering]] *[[Mine reclamation]] *[[Mine disaster]] *[[Mine rescue]] *[[National Institute for Occupational Safety and Health]] *[[National Mining Hall of Fame]] | width=60 | | *[[Landfill mining]] *[[Oil shale industry]] *[[Ore grade]] *[[Office of Surface Mining]]-<br> United States Mining Regulation Agency *[[Optical Granulometry]] *[[Photoanalysis]] *[[Quartz reef mining]] *[[Killhope Wheel]], Lead Mining Museum, Co. Durham, UK. |} ==References== === Citations === {{reflist|2}} === Bibliography === {{Commons2|Mining}} * Ali, Saleem H. (2003). Mining, the Environment and Indigenous Development Conflicts. Tucson AZ: University of Arizona Press. * Bhattacharya Jayanta (2003) ''Principles of Mine Planning'', Allied Publishers, New Delhi, India. 454 pages * Morrison, Tom (1992) ''Hardrock Gold: A Miner's Tale'' (ISBN 0-8061-2442-3) * Even-Zohar, Chaim (2007) ''[http://www.mine2mistress.com From Mine to Mistress]: Corporate Strategies and Government Policies in the International Diamond Industry ''(ISBN 0953733610) * 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 ''[http://alaska-freegold.com: Alaska Placer Mining]'' ==External links== {{Wiktionarypar|mining}} * [http://www.mining-journal.com/Mining_101.aspx Mining 101] * [http://www.mininglife.com/glossary/a.asp Glossary of terms] * [http://media.wiley.com/product_data/excerpt/11/04713485/0471348511.pdf Introduction to Mining] * [http://kids.mongabay.com/lesson_plans/lisa_algee/mining.html What is mining?] * [http://www.mininghall.com/minerals/mining.htm Mining] <!--===========================({{NoMoreLinks}})===============================--> <!--| DO NOT ADD MORE LINKS TO THIS ARTICLE. 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