What is Salt mine?
[[Image:Wieliczka salt mine danilowicz.jpg|thumb|right|Salt mine in [[Wieliczka]], in [[Poland]]]] A '''salt mine''' is a [[Mining|mine]] where [[salt]] is taken from the earth. Very often, this is done in the [[mountain]]s. It is different from a [[salt evaporation pond]], where salt is taken from [[salt water]]. Getting salt from different layers of [[Rock (geology)|rock]] in a mountain used to be a very dangerous job. The [[Ancient Rome|Romans]] used to sentence [[prisoner]]s to this kind of [[Labour (economics)|labour]]. Usually the salt is mixed with rock that has [[chloride]]s and [[sulfate]]s. Empty salt mines are used very often as a storage area, for example, for unused radioactive elements (from [[Nuclear power plant|nuclear]] [[power plant]]s). Salt mines are empty if there is no salt left to take, or if taking the salt that is left would be too expensive. {{geo-stub}} [[Category:Mining]]