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The secret city beneath our feet: Inside Detroit’s epic salt mines

The history of the Detroit Salt Mines

Detroit salt mine workers (Detroit Salt Company)

DETROIT – If the residents of Detroit ever tried to dig a hole to China like I did when I was a kid, you probably wouldn’t have made it to China, but you might have eventually reached the secret salty city below the streets of Detroit.

ClickOnDetroit readers frequently submit questions about the salt mines through our 4YI form, so we decided to take a deep dive into the epic salt mines below our feet.

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Michigan Basin Map (Detroit Salt Company)

According to the Detroit Salt Company, 400 million years ago, ocean water flooded into a large basin, an area known as the Michigan Basin. As the water evaporated it left behind large deposits of salt. These deposits were covered by dirt that was pushed by glaciers over the years. All of you sciencey folks out there, the Salt Company says this: “The basin was an arid area of Michigan’s lower peninsula separated from the ocean by a natural bar of land. As the basin continued to sink lower into the earth, salt-laden ocean water repeatedly poured into the depression, where it gradually evaporated, forming miles of salt beds.”

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The salt rock was first discovered in 1895. The only issue is that the deposits were located beneath hundreds of feet of stone and glacial drift. By 1906, the Detroit Salt and Manufacturing Company was ready to do, what seemed to be, the impossible.

Construction crews had consistent challenges come their way. Aside from the stone and glacial drift, there was also the presence of hydrogen sulfide gas. Six men were killed during the dig. This endeavor would ultimately bankrupt Detroit Salt and Manufacturing Company before reaching the buried treasure.

Detroit salt (Detroit Salt Company)

Detroit Salt reports that the company was eventually reorganized and able to finish the 1,060-foot shaft in 1911 with their new name, Detroit Salt Company. Two years later, with new management, the Watkins Salt Company, the company was able to sink the shaft another 100 ft. and miners were able to begin work on a second salt bed.

Productivity significantly improved, so much so that their competitor International Salt Company began to notice their success. To maintain their hold on the Midwest, the company strategically purchased the Detroit mine.

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By 1914, the mine was producing 8,000 tons of rock salt each month. The salt produced was mostly used for leather and food processing industries. New technology only pushed the mine further as physical demands of miners were reduced. More mine workers, more money, electric locomotives, mechanical shovels, and electric power were the keys to continued success.

In 1922, Detroit Salt explains, the company began to dig a deeper and larger second shaft. The goal was to increase the rate of hoisting rock salt to the surface. Within three years the second shaft was in operation. Due to narrow shaft openings, all of the machinery had to be lowered down piece by piece and reassembled once inside.

Detroit salt mine worker (Detroit Salt Company)

The mine remained in use until 1983, when International Salt closed the doors. Two years after the closure in 1985, Crystal Mines Inc. purchased the mine as a potential storage site. However, in 1997, the Detroit Salt Company, LLC, bought the mine back from Crystal Mines and began salt production in the fall of 1998.

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Although the salt was used in leather production and food industries, road salt is currently the only product the mine provides.

In 2010, The Kissner Group purchased the Detroit Salt Company, LLC and the Detroit Mine, Detroit Salt says. Both companies now work together to provide the continent with a line of ice-melting products.

With the latest mining techniques, the mine is one of the safest, modern, and efficient mines in the world.

While many remember touring the salt mines decades ago, they are no longer available due to safety regulations. Try not to be salty about it.

Fun fact: the Detroit salt mines are featured and can be viewed in MINILAND Detroit, a Lego display with replicas of loved landmarks from Detroit at Legoland Discovery Center in Great Lakes Crossing.

Detroit salt mine replica at Legoland Discovery Center (Legoland Discovery Center)

Do you have a memory of touring the salt mines? Let us know in the comments below.