What is "pitheads"

Usage examples of "pitheads".

Here in Wenshar, the southernmost of the Middle Kingdoms on the borders of the desert, even the few hardy herds of cattle grazing the patches of scrub that passed for oases were chivvied in to closer pastures near the foothill towns, and the silver miners strung lines of rope from their dwellings to the pitheads, lest the burning sand-winds rise while they were between one point and another, and the darkness come on so swiftly that they would be lost.