Texas Natural Resources Code - NAT RES § 134.093. Backfilling, Grading, and Compacting: Insufficient Overburden

(1) that is carried out at the same location over a substantial period;

(2) that transects the coal deposit;

(3) in which the thickness of the coal deposit relative to the volume of the overburden is large; and

(4) for which the operator demonstrates that the overburden and other spoil and waste materials at a particular point in the permit area or otherwise available from the entire permit area are insufficient, considering volumetric expansion, to restore the approximate original contour.