Why is salt important?

A) Humans and animals

All humans and animals need salt. We have salt in every cell of our body. Adults need about 250 g in their body to maintain a normal amount of blood and to be able to digest food.

B) Industries

Salt is used in many ways, in thousands of products. It is used for preserving food, especially meat, but the largest amount is used in the Chemical Industries including those associated with tanning, dyeing, bleaching, soap, glass, the glazing of pottery and fertilizers.

What is Rock Salt?

Sea water is salty and when it evaporates it leaves the salt behind. Some countries which have a coastline, evaporate sea water in shallow pools along the coast. Other countries, like Pakistan, Iran, Turkmenistan, India and Chin, have deposits of rock salt. These are rocks made of salt which are deep underground and a long way from the coast.

Millions of years ago horizontal belts of salt were deposited when ancient oceans evaporated. Then erosion of the land led to layers of sedimentary rocks burying the salt deposits and they turned into rock. Earth movements then lifted all these rocks high above sea level.

The map shows the location of the Khewra Salt Mine which is the most important salt mine in Pakistan. Although this salt has been mined for hundreds of years, it is estimated that there is still 220 million tons of rock salt. At present 325,000 tons are mined every year.

The rock, 99% pure salt, is mined underground at 17 levels and the total length of the tunnels is over 40 kilometers.

Two-thirds of the output goes to chemical industries in Pakistan, the rest is for human and animal consumption, for making lamps, vases and other ornaments and for export.


Source: Geography Today 2