312 IAC 25-6-114 Underground mining; backfilling and grading; previously mined areas

Sec. 114. (a) A remining operation on a site that contains a preexisting highwall must comply with section 112 of this rule, except as provided under this section. (b) Section 112(a)(2) of this rule does not apply to a remining operation if the volume of reasonably available spoil is demonstrated, in writing, to the director to be insufficient to completely backfill the reaffected or enlarged highwall. The highwall must be eliminated to the extent technically practicable as follows: (1) Spoil generated by the remining operation and any other reasonably available spoil shall be used to backfill the area. Reasonably available spoil in the immediate vicinity of the remining operation shall be included within the permit area. (2) The backfill shall be graded to a slope which is compatible with the approved postmining land use and that provides adequate drainage and long term stability. (3) A highwall remnant shall be stable and shall not pose a hazard to the public health and safety or to the environment. The operator shall demonstrate to the director that the highwall remnant is stable. (4) Spoil placed on the outslope during previous mining operations shall not be disturbed if the disturbance will cause instability of the remaining spoil or will otherwise increase hazards to public health, safety, or the environment.