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Brock Bowles <br />BOW2: Revised Page B -7 demonstrates that for a peak flow of 54.47 a flow depth of 1.16 ft. <br />(1.2 ft.) will be required, which will allow for 0.8 feet of freeboard. No changes will be needed <br />to the current Pond F flume configuration. <br />Rule 4.10.4(2) <br />11. DRMS: BRL is proposing to excavate the ridge of material back to a slope of 1.5H: 1V. It is <br />apparent, from the contour lines shown on Figure 1 , that coal mine waste (CMW) will be placed <br />only part way up the cut slope, and that a portion of the slope will remain permanently exposed. <br />TR -72 does not provide a prediction of the long -term stability of this slope. As referenced in TR- <br />44, Buckhorn Geotech determined that a cut slope of 2H:1V into the native soils (for CMWDA <br />No. 4) would provide a factor of safety of 1.50. Please address the question of Tong -term <br />stability of the permanent cut slope. <br />BOW -2: DRMS Rule 4.03.3(d) allows for road cuts to be 1.5h:1v in unconsolidated material or <br />up to 0.25h:1v in rock. While the cut is not related to a road, the same theory can be applied; <br />that a cut slope of 1.5H:1V is considered stable, and a geotechnical stability analyses is not <br />required. <br />Please feel free to call me if you have any questions. <br />Sincerely, <br />° .Ycgr rvm-a C 4-L <br />Tamme Bishop, P.E. <br />Project Engineer <br />- 4 - May 22,2012 <br />Enclosures: <br />TR -72 Application Form <br />Volume II: Maps 15 -3, 21 -3 <br />Volume IX: Pages 1, 11, , Figures 1, 2, & 3, Appendix A, and pages App. B -4, 7, 9 &18i <br />