Gift on deposit

In the middle of the 17th century, the people of Cheshire, southeast of Liverpool in northern England, were envious of neighbouring towns that were getting rich mining the coal that lay beneath their feet.  So they began to dig too.  But they didn’t find coal.

Under the town of Cheshire lies an almost incomprehensibly huge deposit of salt.  

It was left behind 220 million years ago in the Triassic period when the dinosaurs were king.  England lay beneath a tropical sea then, and over millions of years as it evaporated, the salt, mixed with sand blown in from eastern deserts, was left behind.

People have been using the brine that bubbled to the surface in Cheshire since at least 600 BC.  By the industrial period, though, this method produced paltry results next to the riches delivered by digging up coal.  So they started to dig, and opened the first salt mine in 1690.  Today the salt is mined by huge machines that can take a single bite and spit out a chunk 16 feet wide and 20 feet deep.  It works 24/7, pulverizing 20,000 tonnes a day, enough to fill and re-fill 2000 gritters day in and day out.  50 million tonnes have been taken out in the last 50 years.

Despite this, the salt is no where near being depleted.  Huge caverns created by the excavated materials are now used for storage, some for government records going back as far as the 16th century, some for toxic waste.  25 truckloads arrive each day, 100,000 tonnes  annually.  They don’t expect all the room ever to be filled.  The rooms where waste will be stored for the next 100 years have already been assigned for the purpose.  

The mine itself is already so big that there are street lights and maps to guide workers around the what is the size of a town.

The dinosaurs would, no doubt, be amazed.

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About Terry Sissons

Terry Sissons is the author of The Big Bang to Now: All of Time in Six Chunks, and this blog is a dialogue about the universe and what’s happened in the last 13 billions years.
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