There is a level at which the Mammoth Cave mining story becomes a question about human motivation that transcends the specific archaeological details.

Why did people go miles underground in total darkness for three thousand years?

The easy answer is the minerals.

But the easy answer stops too soon, because it does not account for the depth of the penetration.

If the goal was simply gypsum, gypsum was available in cave passages much closer to the entrance.

The mineral-bearing passages begin within the first mile or so of the Historic Entrance.

Ancient miners did not have to go 2.5 miles — or farther — to reach usable gypsum deposits.