Salt of the Earth

Image Source: Winsford Salt Mine

With Britain facing its coldest winter for 27 years, the UK is running short of a geological resource that is largely overlooked – rock salt.

Almost all of the UK’s halite (or rock salt) comes from a single salt mine, Winsford, in Cheshire operated by Salt Union. Normally, Winsford can supply up to 100,000 tonnes a week, but with its reserves near exhausted , it can only provide about 30,000 tonnes from mining operations.

Some local authorities are having to prioritise what roads to grit, others are using table salt rather than rock salt. The UK is urgently importing rock salt from Spain, Tunisia and Italy as the cold weather continues.

Rock salt used to have only limited uses, adding more salt to weak salt brines which are evaporated for table salt, and salt licks for cattle. It was only in the 1950s when rock salt was started to be used to grit roads that production really took off.

Rock salt use is highly variable and it ironic that after a string of warm winters (and the promise of global warming) the Winsford mine has been diversifying in order to survive. It has two contrasting uses for the huge underground caverns that it creates. One end of the former mineworkings are used to store archive records. The dry, temperature controlled conditions are ideal for storing paper documents including the National Archive. The other end of the mine is being used to store hazardous waste.

Image Source: Minosus