SECTION 460:20-45-39. Backfilling and grading: thin overburden

  In surface coal mining which is carried out at the same location over a substantial period of time where the operation transects the coal deposit and where the thickness of the coal deposit relative to the thickness of the overburden is large and where the operator demonstrates that the spoil and other waste materials available from the entire permit area are insufficient, giving due consideration to volumetric expansion, to restore the disturbed area to its approximate original contour, the operator shall, at a minimum:

(1)   Use all available spoil and waste materials to attain the lowest practicable grade, but not more than the angle of repose; and

(2)   Meet the requirements of Sections 460:20-43-38(a) (2) through 460:20-43-38(j) of this Chapter.

(3)   Thin overburden requirements apply when the final thickness of the swelled overburden is less than 80 percent of the sum of the overburden thickness and coal thickness prior to coal removal and when surface mining activity cannot achieve approximate original contour.