Mine safety is carefully monitored at the Cleveland Salt Mine. Huge fans direct fresh air into the farthest working sections and blow exhaust gases back out. Miners use other machines to scale loose salt from roof and walls to prevent rock falls. As in any mining operation, workers brace the roof with bolts spaced a few feet apart. But Wilczynski says salt is different.
Salt always has a small amount of movement to it.
It's almost impossible to stop, because it's kind of an elastic type of rock. Whereas other stuff will just fail quickly because it's brittle, salt is more of a ductile thing. Because of salt's tendency to bend rather than break, miners leave about half the salt behind. Between the rooms, huge salt pillars support the roof of the mine. This room and pillar system of mining rock salt has its roots in prehistory.