2017-02-03_REVISION - C1980004 (6)

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No topsoil was stripped prior to mine bench and haul road construction, as this disturbance occurred prior to the enactment of the Surface Mining Control and Reclamation Act (SMCRA). Topsoil was salvaged from subsequently disturbed areas including the sediment pond, riprap stockpile, and office facility areas, and, with the exception of one small area addressed below, will be salvaged from approved disturbance areas where construction has not yet been initiated. Figure 2.2-2 (Surface Facilities Map), shows site specific mapping of soils at an Order I or II level of intensity. The mapping indicates that soils in the vicinity of the sediment pond and riprap stockpile were Rivra Gravelly Sandy Loam Variant, and Nihill Loam, and office facility soils were Glendive Sandy Loam. Soils to be affected by the proposed McClave to Munger haul road are mapped as Glendive Sandy Loam, and a small area of Rivra Gravelly Sandy Loam. A small area to be affected by the proposed realignment of the access road segment at the junction with the state highway is mapped as Havre Loam, saline phase. Twelve (12) to eighteen (18) inches of soil were salvaged from the sediment pond and riprap stockpile area, and 24 inches of soil were salvaged from the office area. Information in Tables 4.4-1 through 4.4-6 documents the suitability of affected soil types by horizon. Upper horizons of the affected soil types are generally good growth media, with the exception of the Havre Loam, which exhibits SAR values in excess of 40, within each sampled horizon below a depth of 1.5 inches. Because no topsoil was salvaged initially, portions of the reclaimed mine bench access/had road may not be topsoiled upon final reclamation, and the mixed soils and overburden material in the bench and outslopes would be used as plant growth medium for final reclamation. Section 4.4.5.4 summarizes evaluation of the surficial and subsurface bench materials required by the Division through stipulations attachedto the 1982 and 1985 permit approvals. Analyses submitted in response to the stipulations demonstrated that the material would be suitable for plant growth, and that no special handling would be required. Upon final reclamation, topsoil will be re -spread to a minimum depth of 24 inches in the office area, and 4 to 8 inches on other post -law disturbance areas and approximately 1 acre of the mine bench. Sediment that has been removed from the sedimentation pond during particular sediment cleanout events in the past has been demonstrated to be suitable plant growth material, and has been allowed to be placed in the topsoil stockpile. Pond cleanout material will be approved for use as topdressing on pre -law disturbance areas only upon submittal of chemical and physical analyses demonstrating its suitability. During periods of active mining, coal fines are a significant component of sediment delivered to the pond, and the sediment cleanout material is not a suitable plant growth medium at such times. The following stipulation is necessary. STIPULATION NO. 27 SEDIMENT REMOVED FROM THE SEDIMENT POND MAY BE USED AS A TOPDRESSING OR TOPSOIL SUPPLEMENT PURSUANT TO RULE 4.06.2(4)(a), UPON SUBMITTAL OF CHEMICAL AND PHYSICAL ANALYSES DEMONSTRATING THAT THE MATERIAL IS EQUAL TO OR MORE W