Reclamation efforts, including but not limited to backfilling, grading, topsoil replacement, and revegetation, on all land that is disturbed by surface mining activities shall occur as contemporaneously as practicable with mining operations, except when such mining operations are conducted in accordance with a variance for concurrent surface and underground mining activities issued under Sec. 785.18 of this chapter. [48 FR 24652, June 1, 1983, as amended at 56 FR 65635, Dec. 17, 1991]