Man-Made Man-Made Caves of SaltCaves of Salt

An enormous salt mine has An enormous salt mine has been operating beneath been operating beneath Detroit for more than a Detroit for more than a

century.century.

Click here to see a drawing of an 1896 mine operation.

This bed of This bed of salt is salt is

hundreds of hundreds of millions of millions of years old years old

and contains and contains trillions of trillions of

tons of salt.tons of salt.

Detroit began using rock salt on icy Detroit began using rock salt on icy roads in 1940 and began selling salt roads in 1940 and began selling salt

to other cities for the same use.to other cities for the same use.

Click here to see some other uses for salt.

The mine spreads over The mine spreads over 1,400 acres under 1,400 acres under

Detroit and its suburbs.Detroit and its suburbs.

Electric trucks Electric trucks do much of the work.do much of the work.

Click here to see a conveyor Click here to see a drill truck Click here to see a shovel

The Process of Salt MiningThe Process of Salt Mining

The miners use a “room-and-The miners use a “room-and-pillar” method to get the salt.pillar” method to get the salt.

The black blocks represent pillars of salt.

A “room and pillar” mine.

Photo courtesy Detroit Salt Company

The blue grid represents the tunnels where the salt is mined.

Fifty miles of road carry Fifty miles of road carry construction equipment, trucks, construction equipment, trucks, and cars, which had to be taken and cars, which had to be taken apart to fit down the shaft.apart to fit down the shaft.

Photo courtesy Kansas Geological Survey

If the mine goes out of business, it If the mine goes out of business, it could be used to store important could be used to store important

items or become a museum.items or become a museum.

The Historic Wieliczka salt mine near Krakow, Poland, houses a fascinating museum.

The EndThe End

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An 1896 Mining OperationAn 1896 Mining Operation

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Early uses for salt included storing Early uses for salt included storing meat and fish and making ice cream.meat and fish and making ice cream.

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Giant chainsaw trucks cut grooves Giant chainsaw trucks cut grooves in the mine wall and huge in the mine wall and huge

conveyors move the salt blocks .conveyors move the salt blocks .

Underground salt mine conveyorPhoto courtesy of Kansas Geological Survey

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Drill trucks bore holes in the wall Drill trucks bore holes in the wall for dynamite.for dynamite.

Salt mine drill and transport.Photo courtesy of Kansas Geological Survey

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Shovel trucks Shovel trucks scoop up rock scoop up rock

salt, which salt, which then goes into then goes into dump trucks.dump trucks.

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