Salt mining

Salt mining extracts underground salt deposits by excavating rock salt or dissolving it underground and pumping the resulting brine to the surface.

Room and pillar mining: An underground mining method that extracts material in rooms while leaving pillars to support the roof. This method creates underground rooms and supporting pillars in bedded rock-salt deposits.
Halite: The mineral form of sodium chloride, commonly known as rock salt. Halite is the principal mineral extracted in underground salt mines.
Rock salt: A natural mass of halite mined and used in solid form. Excavated salt can be crushed and sold as rock salt.
Wieliczka Salt Mine: A historic salt mine near Kraków, Poland, worked from the thirteenth century into the twentieth. Its extensive excavated chambers illustrate centuries of rock-salt mining.
Solution mining: The extraction of soluble underground minerals by injecting water and pumping the resulting brine to the surface. Salt deposits can be dissolved underground instead of excavated as solid rock.
Sedimentary basin: A region where sediments accumulate and may become thick layers of sedimentary rock. Ancient basins contain many of the bedded salt deposits mined today.
Vacuum salt: High-purity salt produced by evaporating purified brine under reduced pressure. Brine from solution mining can be refined into vacuum salt.
Khewra Salt Mine: A major rock-salt mine in Punjab, Pakistan, within the Salt Range. Its workings expose a large deposit of Himalayan salt.
Brine: Water containing a high concentration of dissolved salts. Solution mining brings salt to the surface in this liquid form.
Diapir: A mass of relatively buoyant rock that rises through overlying layers and deforms them. Salt can rise into diapirs, producing thick deposits that may be mined.

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