Sodium Chloride

Two ways of removing salt from the ground are room and pillar mining and solution mining. In the room and pillar method, shafts are sunk into the ground and miners use techniques such as drilling and blasting to break up the rock salt. The salt is removed in such a way that empty rooms remain that are supported by pillars of salt.

In solution mining, water is added to the salt deposit to form brine. Brine is a solution of sodium chloride and water that may or may not contain other salts. In one technique, a well is drilled in the ground and two pipes (a smaller pipe placed inside a larger one) are placed in it. Fresh water is pumped through the inner pipe to the salt. The dissolved salt forms brine which is pumped through the outer pipe to the surface and then removed.