A plan for the return of coal processing waste to abandoned underground workings, if applicable, shall include: A description of the design, operation, and maintenance of any proposed coal processing waste disposal facility, including: Flow diagrams, All necessary drawings and maps; A description of the source and quality of waste to be stowed, area to be backfilled, percent of the mine void to be filled, method of constructing underground retaining walls, influence of the backfilling operation on active underground mine operations, surface area to be supported by the backfill, and the anticipated occurrence of surface effects following backfilling; A description of the source of the hydraulic transport mediums, method of dewatering the placed backfill, retainment of water underground, treatment of water if released to surface streams, and the effect on the hydrologic regime; A description of the ground water monitoring program. All of the above requirements shall also apply to pneumatic backfilling operations, except where the operations are exempted by the regulatory authority from requirements specifying hydrologic monitoring.