Detroit Salt Mines

Did you know there is an entire city UNDER Detroit MI, comprised entirely of salt? Discovered in 1895, the first mining operations started in 1906. This vast complex covers over 1500 acres and over 100 miles of roads underground stretching from Dearborn to Allen Park. During its heyday, there was an entire city of miners, support staff, and other workers scurrying around under Detroit, around 1200 ft below.

The main shaft

The Detroit Salt & Mining Company dug the original 6’x6’ shaft 1060 feet down to the 1st salt layer through various rock, stone, and other impediments. That is the equivalent of sinking the height of the Chrysler building into the earth! This was quite the feat in 1906, and the company ended up going bankrupt before the shaft was even complete due to the high costs, and loss of at least 6 lives. It is still considered one of the greatest engineering feats in Michigan history. After a re-org following the bankruptcy, the new Detroit Salt Company was able to finish the shaft in 1910 and began operations carving out the vast layers of salt.

A few years later the mine was sold to the Watkins Salt Company. The original shaft was sunk another 100 feet into a deeper salt bed that proved to be more pure, and increased the company’s productivity with the higher purity salt.

The mine was producing 8000 tons of salt a month by 1914, and had employed modern electric locomotives on tracks, mechanical shovels, and other modern (for the time) methods of extracting the salt.

The sheer size and scale of these mines is enormous. Here are a few pictures to see the scale of the operation.

Every single item that was too big to fit the 6’x6’ shaft had to be disassembled, and lowered in pieces, and then re-assembled again in one of the workshops deep inside the mine. What went down never came back up, and that included the donkey labor they employed, at what I assume was a shortened life span for these animals as well as all the various equipment and resources needed for such a vast operation.

The mine operated all the way up until 1983 when salt prices and product margins were too small to remain profitable. The mine was sold to Crystal Mines, LLC a few years after the closure as a potential storage site. In 1997 the mine was sold to the Detroit Salt Company, LLC, which began salt production again in 1998, and are still producing salt at the time of this article.

The salt they produce now-a-days is mainly for road deicing salt, and other snow melt in bulk and bagged rock salt.  The blue coloring you see above is added and used to identify deicer on the roads.