(a) Under the following conditions, the requirements in Chapter 4, Section 2(b)(iv), requiring the elimination of highwalls shall not apply to operations which affect land disturbed by previous coal mining operations which were not reclaimed in accordance with the requirements of Chapter 4, Section 2(b) (i.e., State Program requirements): - (i) Where the volume of all reasonably available spoil is demonstrated in writing to the Administrator to be insufficient to completely backfill the reaffected or enlarged highwall, and this condition is documented in writing by the Administrator, the highwall shall be eliminated to the maximum extent technically practical in accordance with the following criteria:
- (A) All spoil generated by the remining operation and any other reasonably available spoil shall be used to backfill the area. Under this Section, "reasonably available spoil" means spoil located in the immediate vicinity of the remining operation, which shall be included in the permit area, that is accessible and available for use and that when rehandled will not cause a hazard to public safety or significant damage to the environment.
- (B) The backfill shall be graded to a slope which is compatible with the approved postmining land use and which provides adequate drainage and long-term stability.
- (C) Any portion of highwall that remains after backfilling and grading of the remining permit area shall be stable and not pose a hazard to the public health and safety or to the environment. The operator shall demonstrate to the Administrator that the remaining highwall is stable.
(b) For revegetation success standards, as a minimum, the vegetative ground cover shall not be less than the ground cover existing before redisturbance and shall be adequate to control erosion.