Editing Salt mining (section)

== History ==
[[File:Salzbergwerk, Deutschen Museum.JPG|thumb|left|Diorama of an underground salt mine in Germany.]]
[[File:Slanic Salt Mine.jpg|thumb|upright|Inside [[Salina Veche]], in [[Slănic|Slănic, Prahova]], Romania. The railing (lower middle) gives the viewer an idea of scale.]]

Before the advent of the modern [[internal combustion engine]] and earth-moving equipment, mining salt was one of the most expensive and dangerous of operations because of rapid dehydration caused by constant contact with the salt (both in the mine passages and scattered in the air as salt dust) and of other problems caused by accidental excessive sodium intake. Salt is now plentiful, but until the [[Industrial Revolution]], it was difficult to come by, and salt was often mined by slaves or prisoners. Life expectancy for the miners was low.

The earliest found salt mine was in [[Hallstatt]], Austria where salt was mined, starting in 5000BC.<ref name=Kern>{{Cite book |title=Kingdom of Salt: 7000 Years of Hallstatt. |last=Kern |others=Vienna: Natural History Museum |year=2009 |isbn=9783903096080 |publication-date=2009}}</ref>

As salt is a necessity of life, pre-industrial governments were usually keen to exercise stringent control over its production, often through direct ownership of the mines. Whereas the collection of most [[tax]]es generally required at least the grudging cooperation of the upper classes, ownership of salt mines could provide monarchs with a lucrative source of income for which they did not need to rely on the goodwill of other strata of society such as the [[nobility]] to remit to the monarch. For example, [[Poland|Polish]] king [[Casimir the Great]] relied on salt mines for over a third of his revenue in the [[14th century]].

Ancient China was among the earliest civilizations in the world with [[Salt in Chinese history|cultivation]] and trade in mined salt.<ref name=Harris>{{Cite book |title=Studies in the History of Tax Law |last=Harris |first= Peter |others=Hart Publications |year=2017 |isbn=978-1509908370 |volume=8 |publication-date=August 10, 2017 |page=518}}</ref> They first discovered natural gas when they excavated rock salt. The Chinese writer, poet, and politician [[Zhang Hua]] of the [[Jin dynasty (265–420)|Jin dynasty]] wrote in his book ''[[Bowuzhi]]'' how people in [[Zigong]], [[Sichuan]], excavated natural gas and used it to boil a rock salt solution.<ref name="deng">{{Cite book |title=Ancient Chinese Inventions |last=Deng |first=Yinke |year=2011 |page=41 |isbn=978-0521186926}}</ref> The ancient Chinese gradually mastered and advanced the techniques of producing salt. Salt mining was an arduous task for them, as they faced geographical and technological constraints. Salt was extracted mainly from the sea, and salt works in the coastal areas in late imperial China equated to more than 80 percent of national production.<ref name=Höllmann>{{Cite book |title=The Land of the Five Flavors: A Cultural History of Chinese Cuisine |last=Höllmann |first=Thomas O. |publisher=Columbia University Press |year=2013 |isbn=978-0231161862 |publication-date=November 26, 2013 |page=33}}</ref> The Chinese made use of [[Salt crystal|natural crystallization]] of salt lakes and constructed some [[Salt evaporation pond|artificial evaporation basins]] close to shore.<ref name=Harris/> In 1041, during the [[Song dynasty]], a well with a diameter about the size of a bowl and several dozen feet deep was drilled for [[salt production]].<ref name="deng"/> In Southwestern China, natural salt deposits were mined with [[Borehole|bores]] that could reach to a depth of more than {{cvt|1,000|m}}, but the yields of salt were relatively low.<ref name=Höllmann/> Salt mining played a pivotal role as one of the most important sources of the Imperial Chinese government's revenue and state development.<ref name=Höllmann/>

Most modern salt mines are privately operated or operated by large multinational companies such as [[K+S]], [[AkzoNobel]], [[Cargill]], and [[Compass Minerals]]. 
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