In order to encourage advances in mining and reclamation practices, and to allow post-mining land use for industrial, commercial, residential, recreational, or public purposes, the commissioner may, with the approval of the Secretary of the United States Department of the Interior, authorize departures in individual cases on an experimental basis from the environmental performance standards established under AS 27.21.210. The commissioner may authorize these departures if
(1) the experimental practices are, during and after the surface coal mining operation, potentially more protective of the environment than, or at least as protective of the environment as, those required by this chapter and regulations adopted under it;
(2) the surface coal mining operation for which the departure is authorized is not larger than necessary to determine the effectiveness and economic feasibility of the experimental practices; and
(3) the experimental practices do not reduce the protection afforded public health and safety below that provided by law or regulation.