Detroit is known for cars and music. Natural resources? Not so much. Yet each day, 30 or so miners descend nearly 1,200 ft. beneath the city to extract salt from remnants of ancient seas that extend below much of the Great Lakes — and form one of North America’s robust salt reserves.
For more information, see:
Steven Gray, Detroit’s Salt Mine : What Lies Beneath, Time, July 12, 2010.
Underground Economy : The Big Salt Mine in Detroit photo essay.
The Giant Salt City 1200ft Beneath Detroit from Environmental Graffita. Note works best with Mozilla Firefox.
Detroit’s Salt Mine from Atlas Obscura
Daniel Duggan, “Detroit’s underground rock salt mine sold”, Crain’s Detroit Business, October 18, 2010.