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Y !, 2000 Responses to Conrnrenu TR~32 Because aJ the limited urea in which it seems topsoil cart be salvaged, representative site-speclftc depth measurements jrmrt dre Elk Creek Mirte facilities area are needed to determine available mpsoil depths and to prepare the topsoil removal plan (Rules 2.05.4(2)(e) and 4.06.1). OM/ nary need to request a variance from topsoil rernocal for those areas where OMI cannot selvage topsoi/due to the steep slope ar poor qualih~ of materiel. There is a discrepancy in the proposed disturbed area acreage. The response to Comment 7 says 17 acres will be disturbed and on revised page 2.04-98 it says the E!k Creek Mine surface facilities will disturb approximately 23.7 acres. Please clarify the correct ncrenge and revise the permit pages if necessary. Response: A copy of the revised and updated soils baseline section (Section 2.04.9) prepared for PR-04, which addresses soil suitability, is included with these responses for the DMG's reference. As noted in the previous response, supplemental site-specific soil sampling has been completed. Based on the sampling results (included with these responses for insertion in Exhibit 2.04-ES), suitable soil material depths range from 4 to 24 inches in the Elk Creek Mine facilities areas. Based on the available soils information, OMI anticipates that they can salvage an average of approximately 14 inches of soil material from the soil recovery areas shown on the Facilities Details -Elk Creek Mine Disturbance Limits and SoilNegetation Details Map, (Map 2.05-M3). Soil salvage depth will vary consistent with natural variability in soil depths within these areas, with a maximum recovery depth of approximately 4 feet. A topsoil recovery variance will not be required since OM- plans to recover all reasonably available suitable soil material from [he areas shown on Map 2.05-M3. The apparent discrepancy in disturbance acreages noted by the DMG is a reflection of the distinction noted in the previous response to Comment 7 of 17 acres of "new" surface disturbance. The total disturbed acreage figure of 23.7 acres included previously disturbed areas that would be redisturbed by the proposed activities. OMI has reviewed updated maps for the proposed activities and has updated and checked disturbance acreage figures (or consistency (please refer to Table 2.05-TI (pg. 2.05-55) for corrected acreages). 8. OMI presented an estimated topsoil mass balance in the response to queslian 8 ushrg nn average salvage depth of /2 inches of topsoil for 7.0 acres. The topsoil ntnss balance needs to 6e boxed on site- specifrc darn to project volumes of topsoil to be snlvnged. The depth ojtopsoil to be replaced should be based on the field data. As stated in the permit application ao topsoil was sahnged in many other wrens of the mine and there is mr inherent topsoil shortage. Therefore, if there are nbundnnt topsoil materials in the Elk Creek drairrnge, there may be an opportunih~ to enhance dte reclamation of the overburden materials proposed ns a plant growth medium in pre-law disturbance areas with topsoil jrorn the Elk Creek drainage. Please explain n•hy sail recovery beyond jour jeer becomes a concern to the sire drnireage. kesoonse: The topsoil balance for this area is necessarily an estimate based on soil depth and suitability variations. Based on the supplemental site-specific sampling results and the revised and updated soil recovery boundary, OMI projects recovery of an average of approximately 14 inches of soil for several soil recovery areas totaling approximately 7.1 acres. Projected soil recovery volume from these areas to be stockpiled in the North Elk Creek soil stockpile is approximately 13,400 cy (7.1 acres x 43,560 x (14inches/12inches) recovery deplh/27). OMI is committed to recover all reasonably available suitable soil material within the designated soil recovery areas (refer to Map 2.05-M3). Because soil recovery will occur primarily within or in close proximity to the Elk Creek drainage and given limited topographic variation within the restricted drainage valley, soil recovery beyond the 4-foot maximum proposed recovery depth could adversely impact localized drainage patterns. As a practical matter, available drilling and sampling information in this area indicate that soil depths are generally limited to 4 Feet or less, with the material becoming excessively clayey or rocky with depth. Given that there is a suitable soil material shortage for the overall mine area due to historical pre-law disturbance where soil materials were not salvaged, and assuming an average soil material recovery depth of 14 inches for the Elk Creek Mine facilities area, OMI is proposing that approximately 8 W'N'Pd: NMSAJMrMmn w Cnnurcnrt VlYtu~/v