Almost World's largest salt mine is under Lake Erie at Cleveland, OH

Both Cargill and Morton have salt mines under Lake Erie. Evidently it is the Cargill mine that is the worlds largest.
(Satellite)

Street View, Jul 2021

Street View, Aug 2019

The Sifto salt mine in Goderich, ON, is the world's largest underground salt mine.

They mine under the lake because then they have to deal with only one land owner, Ohio State.

Ben H

The working face of the Morton mine is three miles under the lake and 2000' under. It produces 1.3m tons/year. Most of it is used to de-ice roads. They have retired the continuous mining machines. They now bore 23' holes for explosives and use huge front loaders to carry the salt-rock chunks to a crusher. The crushed salt is conveyed to an elevator. [Wired] Judging from the satellite image, there are loading facilities for both rail cars and ships.

A map of the salt deposit illustrates why there are multiple salt mines along the Great Lakes.

Pinterest and Yahoo

I learned about the "world's largest salt mine" from this post.

Tim Carson shared
Keith Diver Brown The largest salt mine in the world. [The blog comment is correct: Goderich has the largest. Thus I added "almost" to the title.]
Gary Wagner post
Dropped down a 250' hole then backed down a tunnel under Lake Erie 2 miles for 9 yds of grout.
Gary Wagner They dropped me down in a man cage after the mixer...They told me to keep backing up till you see something....
Rob McIntosh Hazard pay?
Gary Wagner We're mixer drivers Rob. Everyday is a hazard!
Randy Jongsma Any of you guys been on a barge in the water or ride the train in a mixer?
Chuck Gould Randy Jongsma train
Gary Wagner Yeah, Rode one out to Kelly's Island on lake erie in mid april.....too cold for this old duff!
[7 years ago]

1

2

3

(new window)  (source)

Cleaveland

They do have leaks, but it is from aquifers, not the lake. The mine closed in 2013 because they detected movements of a few hundredths of an inch in the height of some of the tunnels. [Cleaveland] It remained closed for four years. I could not find anything about what they did to fix the problem.

Bill Kloss posted three photos with the comment: "Interlake's newbuild Mark W. Barker loading salt in Cleveland.    8/12/2022"

Stephen Parker: Any idea where they are taking it to?

Justin Olsen: Stephen Parker Green Bay

1

2

3

It didn't take long to get to Green Bay.Jacky Pierce-Breech shared

Chuck Zentmeyer posted
Mark Barker in Green Bay shortly after it started discharging salt.
Terri Moore: Salt? Already? Planning on a short career?
Dave Nobbe: Salt Yes, short career no. It can handle a variety of cargoes but It was designed and built to handle a salt contract ...note the seventh paragraph..
 https://doorcountypulse.com/mark-barker-the-ship-named.../

1 of 5 photos posted by Lance Aerial Media
The Mark Barker filling up with Salt today at Cargill