C Cleveland

Since many of us in are in the midst of a cold winter blast, have you ever wondered where the salt comes from that's used to clear your roads? One source is the Cargill Salt Mine in Cleveland.



Millions of years ago, ancient seas dried up, leaving behind a bed of salt over 50-feet thick. Limestone and shale deposits buried the bed and retreating glaciers left the Great Lakes on top. This salt was accidentally discovered when drillers searching for oil found salt instead.

In the early 1800's, most of the salt used in Cleveland was brought in from Pennsylvania and New York. It proved to be a costly commodity given the demand but by 1863, thanks to chance discoveries, Ohio was the third largest salt producing state.

Fast forward to 1957, when International Salt Company (now owned by Cargill) acquires Whiskey Island, the peninsula in the Cuyahoga River 1.5 miles from downtown Cleveland. Whiskey Island is the surface entrance to a vast rock mining city under the city.


Salt mine seen above the bridge

From the highway that runs alongside it, the mine looks like any other industrial site in a busy, Great Lakes port. But working here is not at all like working in any other industrial job. To start their day, workers make a daily descent in an elevator cage that takes four minutes to carry them down 1793 feet to the the 9000 acre reserve.

There, the 400 miles of underground roads link the rooms of salt. Each room is 45 feet wide and 18-20 feet tall, separated by large safety pillars of salt. These pillars support more than 350 vertical feet of deposits above the galleries currently excavating the bed called F2-B. The rock salt removed after blasting one room can be up to 650 tons in weight. This room and pillar system has been used for centuries.



The salt mine produces almost 2 1/2 million tons of salt a year. Nightly, miners bore holes for explosives in the rock face and in the morning, the loose salt is dumped into machines that break it into smaller pieces. It's processed in an underground mill before it's taken to the surface, 20 tons at a time.

Salt isn't a rigid, break away type of rock and because of this, it has movement to it. Workers leave about half the salt behind in a room and close it off to increase ventilation.

You would think that cutting away large quantities of rock would cause some structural changes and you would be right. However, it's difficult to distinguish if the deformities in the area under Whiskey Island are from the loss of weight of salt being removed rather than merely representing natural variations in the rock unit's composition so I think we're safe for now.

No, sadly, they don't offer tours.