A salt well is used to mine salt

Salt

In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...

 from subterranean

Subterranea (geography)

Subterranea refers to underground structures, both natural and man-made . Some subterranea include:* Bunker* Casemate* Catacombs* Caves** Ice caves* Cave dwellings, Cave house* Cave temple* Cellar* Cenote* Dungeon...

 caverns or deposits by the use of water

Water

Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 as a solution to dissolve the salt or halite

Halite

Halite , commonly known as rock salt, is the mineral form of sodium chloride . Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pink, red, orange, yellow or gray depending on the amount and type of impurities...

 deposits so that they can be extracted by pipe to an evaporation process that results in a brine

Brine

Brine is water, saturated or nearly saturated with salt .Brine is used to preserve vegetables, fruit, fish, and meat, in a process known as brining . Brine is also commonly used to age Halloumi and Feta cheeses, or for pickling foodstuffs, as a means of preserving them...

 or dry product for sale or use. In the 19th century, salt wells were a highly significant source of income for the operator and the government. Locating the underground salt deposits was usually based on locations of existing salt springs.