Surface mining activities shall be conducted to meet, at a minimum, the following standards: All spoil and wastes not required to achieve the approximate original contour of the mine plan area shall be hauled or conveyed, backfilled, or graded to the lowest practicable grade, to achieve a static factor of safety of 1.3 and cover all acid-forming and other toxic-forming materials; Haul or convey, backfill, and grade excess spoil and wastes only within the permit area and dispose of the materials in accordance with COMAR 26.20.26. Haul or convey, backfill, and grade excess spoil and wastes to maintain the hydrologic balance and to provide long term stability by preventing slides, erosion, and water pollution; Haul or convey, backfill, grade, and revegetate wastes and excess spoil to achieve an ecologically sound land use approved by the Bureau as compatible with the prevailing land uses in unmined areas surrounding the mine plan area; Eliminate all highwalls and depressions by backfilling with spoil and suitable waste materials; and Meet the revegetation requirements for all disturbed areas.