312 IAC 25-6-142 Prime farmland; special performance standards; soil replacement

Sec. 142. (a) The minimum depth of soil and soil material to be reconstructed for prime farmland shall be sufficient to create in the reconstructed final soil, a root zone of sufficient depth to support the approved postmining land use and, as described in the approved plan submitted under 312 IAC 25-4-102, that will have the capability of achieving levels of yield equal to, or higher than, those of nonmined prime farmland in the surrounding area. (b) The minimum depth of soil and substitute soil material to be reconstructed shall be forty-eight (48) inches, or a lesser depth equal to the depth to a subsurface horizon in the natural soil that inhibits or prevents root penetration, or a greater depth if determined necessary by the director to restore the original soil productive capacity. A soil horizon inhibits or prevents root penetration if its physical or chemical properties or water supplying capabilities cause the horizon to restrict or prevent penetration by roots of plants common to the vicinity of the permit area and if these properties or capacities have little or no beneficial effect on soil productive capacity. (c) The operator shall replace and regrade the soil horizons or other root zone material to a uniform depth and in a manner that avoids excessive compaction. (d) The operator shall replace the B horizon, C horizon, or other suitable material specified in section 141(c)(2) of this rule to the thickness needed to meet the requirements of subsection (b). In an area where the B horizon or C horizon is not removed, but may have been compacted or otherwise damaged during the mining operation, the operator shall engage in deep tilling or other appropriate means to restore premining capabilities. (e) The operator shall replace the topsoil or other suitable soil materials specified in section 141(c)(2) of this rule as the final surface soil layer. This surface soil layer shall equal or exceed the thickness of the original surface soil layer as determined by the soil survey, and be replaced in a manner that protects the surface layer from wind and water erosion before it is seeded or planted. (f) The operator shall apply nutrients and soil amendments as needed to quickly establish vegetative growth.