S.D. Codified Laws § 45-6B-42

Any area outside of the affected land shall be protected from slides, subsidence, or damage occurring during the mining operation and reclamation. All high walls shall be reduced to a slope not greater than the angle of repose upon abandonment of the mining operation, unless such a reduction would create conditions more detrimental than preserving the high wall. Prior to slope reduction, the operator shall take precautions to limit access to the high wall area and to warn the public of the high wall. Such precautions shall include fencing and posting of warning signs. If high wall reduction is deemed impossible, impractical, or aesthetically undesirable by the Board of Minerals and Environment, the board shall prescribe adequate fencing.