Salt has become an inexpensive and readily available commodity that is taken for granted by most people. But in older times, wars were fought over salt, and huge taxes were also levied on it. In some places, salt was in such high demand that it was minted into coins that were as valuable as gold and functioned as the basic currency for ancient civilizations. Where salt was scarce it was traded ounce for ounce with gold–for as the Roman statesman Cassiodorus observed, "Some seek not gold, but there lives not a man who does not need salt." Because everyone, rich and poor, craves salt, rulers going back at least as far as the Chinese emperor Yu in 2200 B.C. have tried to control and tax it. Salt taxes helped finance empires throughout Europe and Asia, but also inspired a lively black market, smuggling rings, riots, even revolutions.
Pure salt consists of the elements sodium and chlorine. Its chemical name is sodium chloride and its formula is NaCl. Its mineral name is halite. This is the salt we eat. The basic components of salt are, by themselves, potentially dangerous. Sodium will ignite immediately if it comes into contact with water, and chlorine is poisonous if ingested or inhaled. In combination, though, the two elements form sodium chloride.
Salt is one of the main building blocks of our bodies, and is essential in maintaining their functions. Each of us contain from113 to 227 grams of salt. In the body, salt is as important to humans as water or air. It helps maintain the normal volume of blood in the body and also helps keep the correct balance of water in and around the cells and tissues. Salt plays an important part in the digestion of food and is essential in making the heart beat correctly. It is also necessary for the formation and proper function of nerve fibres, which carry impulses to and from the brain. Sodium, together with calcium, magnesium and potassium, helps regulate the body's metabolism.
The sodium in salt, in combination with potassium, regulates the acid-alkaline balance in our blood and is also necessary for proper muscle functioning. When we don't get enough sodium chloride, we experience muscle cramps, dizziness, exhaustion and, in extreme cases, convulsions and death.
For years, many " researchers" have claimed that salt threatens public health, mostly by contributing to high blood pressure. Recently, though, other researchers have begun to change salt's reputation, by publishing results of unbiased scientific studies . A recent review of salt studies conducted over the past two decades concluded that there's no reason for doctors to recommend reducing sodium intake for people with normal blood pressure. It may be that most of us are protected from excessive salt by our kidneys, which regulate the body's sodium level and eliminate any excess.
All salts come from a sea, but are processed in different ways. The oceans that once covered the earth left a generous supply of salt beds and underground deposits, often hidden hundred of metres below the surface. There are two basic methods for removing salt from the ground: room-and-pillar mining and solution mining. In room-and-pillar mining, shafts are sunk into the ground, and miners break up the rock salt with drills. The miners remove chunks of salt, creating huge rooms that are separated by pillars of salt. The room-and-pillar method requires that about half the salt be left behind as pillars. In solution mining, a well is drilled into the ground, and two pipes are lowered into the hole. The pipes consist of a small central pipe inside a larger pipe. Hot water is pumped down, into the salt deposit, dissolving it and producing a brine, which is either shipped as a liquid or evaporated in special devices called vacuum pans to form solid salt.
Only about five percent of the world's annual salt production ends up as seasoning at the dinner table. The vast majority, pours into chemical plants, where it leads the five major raw materials utilized by industry: salt, sulphur, limestone, coal and petroleum. Salt pickles cucumbers, preserves meat and canned food, cures leather, makes glass and rubber and wood pulp. Salt has some 14,000 uses, more than any other mineral. Regrettably, by far most of the salt consumed by humans today is a refined, "dead" salt; a pure chemical substance, with all benefits of the natural salt removed.
(Source: http://himalayansalt.com.au/saltfacts.htm)
