Salt

Salt (sodium chloride) can be extracted by pumping water into underground salt deposits in a process called solution mining. The salt water (brine) is brought to the surface where the water and impurities are removed to produce table salt.

Salt mining can cause buildings to fall down due to subsidence if the mine below them collapses. Air pollution can result from the burning of fossil fuels to provide the energy needed for mining.

In hot countries they can make salt by simply allowing shallow pools of sea water to dry out (by evaporation) in the sun.