Most people think salt is simply to add flavour to meals and to be used as a food preservative. However, only 6% of all salt manufactured goes into food. We use salt in over 14,000 different ways from making products such as paper, plastic, glass, polyester and rubber to household soap, bleach, dyes and detergents. Another common use of salt is to treat icy roads and paths in winter, this is because salt has a lower freezing point than water. Everyone uses salt, whether its directly or indirectly.
Salt can be obtained from either the sea or from underground salt deposits. There are many different types and grades of salt and a number of different methods to produce it. White salt is produced by evaporating “solution-mined” brine in pressure vessels. The brown rock salt we use for gritting roads come from mining ancient deposits.
Large earth moving equipment is used to extract rock salt. This is done by using a drill-and-blast mining technique in deep salt deposits, holes are then drilled into the face and explosives are used to break the salt into smaller pieces. Loaders and trucks transport the salt to the crusher which then reduces it in size and loads it onto a conveyor belt to be transported to a mill. This method of extraction leaves the salt with insoluble impurities, for example, reddish clay. This sort of salt doesn’t need to be pure as it is used to put on roads during freezing periods of weather.
The Wieliczka Salt Mine is one of the most valuable monuments of spiritual culture and material in Poland. Each year this attraction is visited by more than one million tourists from around the world. In Poland, salt mines are believed to have positive effects on the human respiratory system. A Polish doctor in 1843 documented how salt mine workers didn’t seem to suffer from the same respiratory problems as the general population, he believed this was because the salt helps reduce inflammation and mucus.
The largest salt mine in Europe is in a town called Slanic in Romania, this town is famous for the “Unirea Salt Mine”. This salt mine is a health spa formed of 14 rooms which are a sanatorium for the treatment of respiratory diseases. This mine welcomes both patients and tourists.
The worlds largest salt mine is located in Western Canada, Ontario. This salt mine produces 7,250,000 tonnes of salt each year!