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David Berry -19- June 20, 1996 <br />properties derived for the slope stability of the proposed <br />coal mine waste bank at this site are reasonable based on well <br />developed SPT correlations. However, we were not certain <br />about the characteristics of the coal mine waste; to ensure <br />correct material properties thus, laboratory testing was <br />performed on these materials. <br />Moreover, we performed the stability analysis considering a <br />conservative saturation condition of all of the foundation <br />materials (materials "2" to "4"). In the case of the Mancos <br />Shale, reduced strength was modeled instead of the actual <br />high-strength field conditions to account for possible <br />saturation. Groundwater saturation therefore has been <br />accounted for in this stability analysis. <br />Structures with a calculated 1.5 factor of safety have 50 <br />percent more strength than required for static stability. The <br />calculated factor of safety for this proposed coal mine waste <br />bank shows it has 54 percent more strength than at equilibrium <br />conditions (F.S. = 1.00). The relatively high long-term <br />factor of safety requirement of 1.5 for coal mine waste banks <br />is met in this analysis using reasonable material properties <br />and conservative groundwater conditions. Based on the <br />foregoing, we do not believe that further laboratory analysis <br />are required. <br />71. See item 27 above. No response at this time regarding <br />stability of reclamation. <br />72. The DMG questions the reclamation plan as it relates to the <br />reclamation of the haul road from old State Highway 133 to the <br />portal area. This issue is discussed on page 2.05-23. Based <br />on the DMG's comments the discussion of the haul road <br />reclamation was expanded on the enclosed and revised pages <br />2.05-23 and 23i. <br />73. The operator is aware of the DMG's concern regarding yellow <br />sweetclover. However, it has been noted at the nearby Blue <br />Ribbon Mine that yellow sweetclover seemed to serve as a <br />useful nurse crop and initial erosion control and was <br />eventually supplanted over a period of 2-3 years by the <br />perennial species. This experience led to it's inclusion in <br />the two Bowie seed mixes. The operator wishes to maintain its <br />presence. <br />74. The operator accepts the Division's suggestion of a species <br />diversity standard that requires four perennial species to be <br />present in excess of 38 relative cover. This number is <br />actually consistent with the baseline community values. Five <br />species exceeded 38 relative cover in the Juniper Woodland <br />community and three species exceeded 3~ relative cover. BRL <br />