Valley fill
Valley fill means a fill structure consisting of any material, other than organic material, that is placed in a valley where side slopes of the existing valley, measured at the steepest point, are greater than 20 degrees, or where the average slope of the profile of the valley from the toe of the fill to the top of the fill is greater than 10 degrees.
Source
30 CFR § 701.5
Scoping language
As used in this chapter, the following terms have the specified meanings, except where otherwise indicated: