Where does rock salt come from?

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(Free-Press-Release.com) January 27, 2012 -- Rock salt, the common name for halite, is different to the salt you might find on your table – although it is similar in many ways. As the name suggests it is a rock rather than a mineral.

Used predominantly to grit roads in harsh winter weather, rock salt can be found throughout the world, including lake beds, inland seas, and bays.

Although over consumption has led to the advertising of some of the dangers of salt more generally, in reality, we need it to live.

It is one of the oldest food sources known to man and has been mined for thousands of years, dating back to Xiechi Lake in China around 6000BC.

Grit salt, as it is now known, was used for preservation. Freezing salt was one of the major food preservatives.

Obtaining the rock salt is traditionally carried out through mining operations, rather than sea extraction. In Britain, this originally began in 1844 when rock salt was discovered in Winsford, Cheshire in 1844.

Although miners were actually searching for coal rather than road salt, nineteenth century mining methods led to a million tonnes of rock salt being mined in the coming half century.

Mining methods were difficult in this era - using shovels, hand picks and explosives used to excavate the rock salt. The Winsford mine is still open today, making it the oldest working grit salt mine.

These rock salt mines vary in depth – from 100 metres to a mile or more. Within the mines are networks of pathways for the areas that rock salt has already been extracted from.

These pathways are used as roads for mining vehicles and miners to move around the grit salt shafts.

Amazingly, the UK's road salt mines have 140 miles of tunnels – which is about the same distance as travelling from London to Brussels.

Pneumatic drills are used for digging into the working face of the mines in order to bore into the grit salt.

However, care must be taken to ensure that the mine is stable by leaving substantial pillars of rock salt to support the mine roof.

This method has been carried out for hundreds of years, and at the Winsford road salt mine you can see the pillars left by the original 19th century miners.

All the rock salt is treated with caking agents, to stop the pieces coagulating. This is also a way of ensuring it can be held in local storage depots until it is needed during bad weather.

Nearly 90 per cent of the UK’s grit salt was produced in Cheshire at the end of the 19th century.

Rock salt is used in many different applications ranging from food to chemicals. A major use for grit salt de-icing, which is why it is also known as grit salt and road salt.

It has also been used throughout history for preservation purposes, including preserving mummies in ancient Egypt.

The world's oceans contain a huge amount of salt.

For more on information on rock salt, road salt and grit salt, visit http://www.icethaw.co.uk.

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