Editing Mining (section)

== Techniques ==
[[File:SL500 01.jpg|thumb|Underground [[longwall mining]]]]
Mining techniques can be divided into two common [[Earthworks (engineering)|excavation]] types: [[surface mining]] and [[#Underground mining|sub-surface (underground) mining]]. Today, surface mining is much more common, and produces, for example, 85% of minerals (excluding petroleum and natural gas) in the United States, including 98% of metallic ores.<ref>Hartmann HL. ''Introductory Mining Engineering'', p. 11. [http://media.wiley.com/product_data/excerpt/11/04713485/0471348511.pdf First chapter] {{Webarchive|url=https://web.archive.org/web/20160415175613/http://media.wiley.com/product_data/excerpt/11/04713485/0471348511.pdf |date=2016-04-15 }}.</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 materials]]; and ''lode deposits'', where valuable minerals are found in veins, in layers, or in mineral grains generally distributed throughout a mass of actual rock. Both types of ore deposit, placer or lode, are mined by both surface and underground methods.{{Citation needed|date=January 2021}}

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>{{cite web |url=http://world-nuclear.org/info/inf27.html |title=In Situ Leach Mining (ISL) of Uranium |publisher=World-nuclear.org |access-date=2013-06-22 |archive-url=https://web.archive.org/web/20100817042715/http://www.world-nuclear.org/info/inf27.html |archive-date=2010-08-17 |url-status=dead }}</ref>

'''<big>Explosives in Mining</big>'''

Explosives have been used in [[surface mining]] and [[Underground hard-rock mining|sub-surface mining]] to blast out rock and ore intended for processing. The most common explosive used in mining is [[ammonium nitrate]].<ref name="Bajpayee-2004">{{Cite journal |last1=Bajpayee |first1=T.S. |last2=Rehak |first2=T.R. |last3=Mowrey |first3=G.L. |last4=Ingram |first4=D.K. |date=January 2004 |title=Blasting injuries in surface mining with emphasis on flyrock and blast area security |url=http://dx.doi.org/10.1016/j.jsr.2003.07.003 |journal=Journal of Safety Research |volume=35 |issue=1 |pages=47–57 |doi=10.1016/j.jsr.2003.07.003 |pmid=14992846 |issn=0022-4375}}</ref> Between 1870 and 1920, in Queensland Australia, an increase in mining accidents lead to more safety measures surrounding the use of explosives for mining.<ref>{{Cite journal |last=Wegner |first=Jan Helen |date=2010-06-22 |title=BLASTING OUT: EXPLOSIVES PRACTICES IN QUEENSLAND METALLIFEROUS MINES, 1870-1920: Blasting out |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1467-8446.2010.00301.x |journal=Australian Economic History Review |language=en |volume=50 |issue=2 |pages=193–208 |doi=10.1111/j.1467-8446.2010.00301.x |access-date=2023-04-03 |archive-date=2023-02-21 |archive-url=https://web.archive.org/web/20230221022152/https://onlinelibrary.wiley.com/doi/10.1111/j.1467-8446.2010.00301.x |url-status=live }}</ref>  In the United States of America, between 1990 and 1999, about 22.3 billion kilograms of explosives were used in mining quarrying and other industries; Moreover "[[coal mining]] used 66.4%, nonmetal mining and quarrying 13.5%, metal mining 10.4%, [[construction]] 7.1%, and all other users 2.6%".<ref name="Bajpayee-2004" />

=== Artisanal ===
{{Excerpt|Artisanal mining}}

=== Surface ===
{{main|Surface mining}}
[[Surface mining]] is done by removing surface vegetation, dirt, and bedrock to reach buried ore deposits. Techniques of surface mining include: [[open-pit mining]], which is the recovery of materials from an open pit in the ground; [[quarry]]ing, identical to open-pit mining except that it refers to sand, stone and clay; [[strip mining]], which consists of stripping surface layers off to reveal ore 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 placer deposits, because they are shallowly buried, are mined by surface methods. Finally, [[landfill mining]] involves sites where [[landfill]]s are excavated and processed.<ref>[http://www.enviroalternatives.com/landfill.html Landfill Mining] {{Webarchive|url=https://web.archive.org/web/20170523045629/http://www.enviroalternatives.com/landfill.html |date=2017-05-23 }} Landfill Mining, Preserving Resources through Integrated Sustainable Management of Waste, Technical Brief from the World Resource Foundation</ref> Landfill mining has been thought of as a long-term solution to [[methane emissions]] and local pollution.<ref>{{Cite journal|date=2012-03-01|title=Landfill mining: A critical review of two decades of research|journal=Waste Management|volume=32|issue=3|pages=513–20|doi=10.1016/j.wasman.2011.10.015|pmid=22083108|issn=0956-053X|last1=Krook|first1=Joakim|last2=Svensson|first2=Niclas|last3=Eklund|first3=Mats|bibcode=2012WaMan..32..513K }}</ref>

{{wide image|Tagebau_Garzweiler_Panorama_2005.jpg|1000px|[[Garzweiler surface mine]], [[Germany]]}}

=== High wall ===
[[File:Mega HIghwall Mining ADDCAR 16.jpg|thumb|Coalburg Seam highwall mining at ADDCAR 16 Logan County WV]]
High wall mining, which evolved from auger mining, is another form of surface mining. In high wall mining, the remaining part of a coal seam previously exploited by other surface-mining techniques has too much overburden to be removed but can still be profitably exploited from the side of the artificial cliff made by previous mining.<ref>{{Citation|url=https://oilprice.com/Energy/Coal/Coal-Mining-And-The-Highwall-Method.html|title=Coal Mining and the Highwall Method|last1=Drum|first1=The Oil|date=November 26, 2010|publisher=A Media Solutions|access-date=September 6, 2021|archive-date=September 6, 2021|archive-url=https://web.archive.org/web/20210906001207/https://oilprice.com/Energy/Coal/Coal-Mining-And-The-Highwall-Method.html|url-status=live}}</ref> A typical cycle alternates sumping, which undercuts the seam, and shearing, which raises and lowers the cutter-head boom to cut the entire height of the coal seam. As the coal recovery cycle continues, the cutter-head is progressively launched further into the coal seam. High wall mining can produce thousands of tons of coal in contour-strip operations with narrow benches, previously mined areas, trench mine applications and steep-dip seams.{{Citation needed|date=January 2021}}
[[File:Myslowice kopalnia Myslowice 07.jpg|thumb|upright|[[Mysłowice]] coal mine shaft tower, [[Upper Silesian Coal Basin]]]]

=== Underground mining ===
{{anchor|Underground Mining}}
{{main|Underground mining (hard rock)|Underground mining (soft rock)}}
[[File:Kilianstollen Zug.jpg|thumb|[[Mantrip]] used for transporting miners within an underground mine]]
[[File:Caterpillar Highwall Mine HW300.jpg|thumb|Caterpillar Highwall Miner HW300 – Technology Bridging Underground and Open Pit 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, and the extraction method or the technique used to reach the mineral deposit. [[Drift mining]] uses horizontal access tunnels, [[slope mining]] uses diagonally sloping access shafts, and [[shaft mining]] uses vertical access shafts. Mining in [[Underground mining (hard rock)|hard]] and [[Underground mining (soft rock)|soft]] rock formations requires different techniques.<ref>{{Cite conference |last=Harraz |first=Hassan Z. |date=2010 |title=Underground mining Methods |url=http://rgdoi.net/10.13140/RG.2.1.2881.1124 |doi=10.13140/RG.2.1.2881.1124}}</ref>

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]] mining, 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]], in which supporting pillars are removed as miners retreat, allowing the room to cave in, thereby loosening more ore. Additional sub-surface mining methods include [[underground mining (hard rock)|hard rock mining]], bore hole mining, drift and fill mining, long hole slope mining, sub level caving, and [[block caving]].{{Citation needed|date=January 2021}}