The Oil Drum

Gail:
Generally, though it depends on how thick the coal is, you aren't going to strip much above a hundred feet of overlying rock, or that order of magnitude. In the Utah case they are mining in under a mountain, so while the cover starts out very shallow it increases as the mine gets further under the hill that is developing from the valley where the coal came to the surface. The reports are stating that the drill is located over where the miners are thought to be, and at this point, some 3.4 miles into the mine, the ground is some 1,500 ft above the seam.

When strip mining you generally have enough land to contain all the mining, but the rock immediately over the operating strip is moved into the strip that has just had the coal removed. This leaves it in the piles that are the usual picture of strip mining, but after a few more strips have been taken, these piles are graded out back to the original contour, and the topsoil, which has been saved in a separate pile, is then replaced, together with other features that were agreed when the reclamation plan was originally submitted. (Note that they don't go back to original contour with mountain-top removal which is a special case, but still have to fit to a pre-approved plan).