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Wags Are Sitting on an Underground Secret in Cheshire
In 1820 John MacAdam discovered a new way to pave roads that did away with the need for massive rock foundations. Instead, he realised, all that was needed was a crust that would protect the soil underneath from wear.
He advised a layer of gravel that would be packed down into a solid surface by the normal passage of carts and wagons. In order to accelerate the packing down process with the advent of the much faster motor car, the macadam surface was sprayed with tar.
With a road surface that could take the traffic, the use of the combustion engine mushroomed. Road-building boomed, and has never stopped since.Which was extremely good news for Cheshire. Because along with the tar macadam road came the problem, in winter, of ice.
In Cheshire, where salt had been mined for centuries, a new industry was about to be born _ gritting. Until then the rock salt had been refined for use in the food and tanning industries. But, in its raw, unrefined, gritty, form, complete with a smattering of impurities, it was the ideal chemical to help prevent icy roads.
Salt lowers the freezing point of moisture on the roads. It is not a complete solution; it is useless below minus 10 centigrade, and only really kicks in above minus 5 centigrade.
But it is relatively cheap, and we have plenty of it. The Cheshire town of Winsford sits on top of a salt deposit that extends for more than 100kms. The need to keep roads ice free created an enormous new demand for rock salt, and now Winsford Salt Mine alone shovels out more than one million tonnes of rock salt a year.
More than two million tonnes of salt are spread on UK roads each year, mainly on motorways, trunk roads and main roads. Less than a third of other roads are salted. The cost is put at about 150 million GBP a year, but is estimated to prevent delays that would cost 2 billion GBP a year.
The figures quickly eclipse even present footballers' transfer fees. Before MacAdam made motoring a real possibility rock salt was mainly used for cattle licks. Now 98 per cent of all production is sprinkled on our roads. And it takes machinery that even Jeremy Clarkson would be proud of to excavate it.
The standard run-around down the mine is the CAT 990 shovel loader. Its 27-litre diesel engine cranks out 675 horsepower. It is 16 feet high, and 42 feet long with 10 foot high wheels filled with water to improve the ride. It can move 20 tonnes in one go. And if Wayne and Coleen are worried about safeguarding their wedding presents, read on.
Unlike depleted coal mines, old salt quarries have a useful, and profitable after-life. Salt is a natural dehumidifier - the reason it is used to cure meat by extracting moisture.
Down the mines a steady temperature and humidity of 55 per cent is ideal for long term storage of documents. Hospitals, councils, the police, and other large organisations stash some 400,000 boxes of paperwork there.
Another premier league level client is the National Archives. The Archives are responsible for the safe-keeping of the records of the UK government and the courts of law. Some are almost 100 years old. Others, like recent MI6 files are still too sensitive to be revealed.
The collection is constantly expanding. There are 100 miles of archives at its Kew headquarters and it grows at the rate of a mile a year. The solution to the quest for additional, top security storage was found in the Cheshire mine.
The climate is kind to paperwork, and deadly to paper-eating insects, but just as importantly, the miles of tunnels prove off-putting to even the most dedicated smash and grab merchant. Where else would you salt away your valuables?
About the Author Samantha is an expert Research and Theatre consultant. She is currently writing for Show and Stay and is very excited about the upcoming West End revival of Oliver!
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