Gypsum, mirabilite, and epsomite are all highly soluble — exposed to humidity, rain, or contact with water, they dissolve.

This is why the primary question that archaeology has asked about the mining operation — what were the minerals used for — remains incompletely answered more than six decades after systematic research began.

What can be said with confidence is that these minerals were valuable enough to justify extraordinary effort.

The repeated, sustained nature of the mining operation — documented across nearly three millennia of torch fragments and mining marks and artifacts — establishes beyond reasonable doubt that the minerals served important purposes.

People do not go miles underground in total darkness for three thousand years to collect something that does not matter.