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drainage or East Salt Creek, and no significant effects are expected. A full suite analysis of mine <br />discharge water presented in Table 6 of the 2002 AHR shows a total dissolved solids (TDS) value <br />of 1810 mg/l, compared to TDS values of 3000 to 4000 mg/1 documented for East Salt Creek, at <br />monitoring sites SW -1 and SW -8, in Table 4 of the AHR. Following the conclusion of mining, all <br />culverts and diversions will be removed, and a network of ephemeral drainages in geomorphic <br />balance with adjacent areas will be reconstructed on the disturbed area. Following successful <br />vegetation establishment, it is expected that surface water hydrologic characteristics of the reclaimed <br />area will approximate pre -mining conditions. <br />In association with RN -06 and TR -15, the operator prepared a mass balance evaluation <br />to assess the effects of irrigation season mine water discharge on the salinity (conductivity) of East <br />Salt Creek water downstream from the point where discharge water enters the stream. The <br />evaluation included data from the 2001 through 2005 irrigation seasons. During four of the five <br />years, conductivity levels were reduced due to dilution by lower conductivity mine discharge water. <br />During one of the 5 years (2005) there was a slight, but insignificant (0.2%; 0.004 mmho) increase. <br />Over the five year period, there was an over-all 10.9% reduction in irrigation season conductivity on <br />East Salt Creek downstream of the mine, resulting from minewater discharge. These results confirm <br />that mine discharge is not causing a deleterious increase in stream salinity levels. <br />IV. Topsoil — Rule 4.06 <br />Soils resource information, including soil series descriptions, and evaluation of mine bench <br />materials for use as plant growth medium is provided in Section 4.4 of the permit application. <br />Information on topsoil management is provided in Sections 2.3 and 3.2, and information on topsoil <br />replacement is provided in Section 3.3. <br />No topsoil was stripped prior to mine bench and haul road construction, as this disturbance <br />occurred prior to the enactment of the Surface Mining Control and Reclamation Act (SMCRA). <br />Topsoil was salvaged from subsequently disturbed areas including the sediment pond, riprap <br />stockpile, and office facility areas, and, with the exception of one small area addressed below, will <br />be salvaged from approved disturbance areas where construction has not yet been initiated. <br />Figure 2.2-2 (Surface Facilities Map), shows site specific mapping of soils at an Order I or <br />II level of intensity. The mapping indicates that soils in the vicinity of the sediment pond and riprap <br />stockpile were Rivra Gravelly Sandy Loam Variant, and Nihill Loam, and office facility soils were <br />Glendive Sandy Loam. Soils to be affected by the proposed McClane to Munger haul road are <br />mapped as Glendive Sandy Loam, and a small area of Rivra Gravelly Sandy Loam. A small area <br />affected by the Haul Road segment at the junction with the state highway is mapped as Havre Loam, <br />saline phase. <br />Twelve (12) to eighteen (18) inches of soil were salvaged from the sediment pond and riprap <br />stockpile area, and 24 inches of soil were salvaged from the office area. <br />Information in Tables 4.4-1 through 4.4-6 documents the suitability of affected soil types <br />by horizon. Upper horizons of the affected soil types are generally good growth media, with the <br />exception of the Havre Loam, which exhibits SAR values in excess of 40 within each sampled <br />horizon below a depth of 1.5 inches. <br />Because no topsoil was salvaged initially, portions of the reclaimed mine bench access/haul <br />road may not be topsoiled upon final reclamation, and the mixed soils and overburden material in <br />