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C-1980-007 TR-120 <br />PAR Comments - MLT <br />10-Mar-2010 <br />Page 3 of 4 <br />Applicable Rules <br />MLRB Rules governing the design and construction of the RPE East Coal Mine Waste Bank are <br />4.09.1 (Disposal of Excess Spoil), 4.09.2 (Valley Fill), 4.09.3 (Head of Hollow Fill), and 4.10 <br />(Coal Mine Waste Banks). <br />? The location selected for the RPE East (in No Name Gulch) complies with 4.09.1(4). <br />? Placement, compaction, cover and grading described in Section 4.0 comply with <br />4.09.1(7). <br />? A toe buttress and keyway have been designed as required by 4.09.1(10) <br />? A subdrainage/underdrain system is proposed in Section 4.0 in accordance with <br />4.09.1(13), 4.09.2(2) and 4.09.3. In addition, a rock blanket comprised of ripped <br />sandstone bedrock will be provided. <br />? Foundation investigation and laboratory testing of foundation materials, as required by <br />4.09.1(14) has been addressed in Section 2.0 and Appendices A and B <br />? Compliance with 4.10.1(3) is provided in Section 4.5 Compaction <br />? No slopes are proposed to be steeper than 2h:1v, as required by 4.10.4(4) <br />? Haul Road stability is addressed in Section 4.7.2; Figures 4-1 and 4-2; Appendix D <br />(Drawing No. C-12); and Appendix H. The charts in Figures 4-1 and 4-2 were derived <br />from the nomographs presented in Appendix H, and will be used to determine the <br />maximum heights of roadway cut slopes and embankments that may be constructed under <br />various configurations, ensuring that a factor of safety of 1.5 or greater is maintained. <br />When necessary, as described in Section 4.7.2, site-specific soil parameters will be <br />determined. This section describes the methodology that will be followed to ensure <br />compliance with the requirements of Section 4.03. <br />4. Inspection of fill during construction is required by 4.09.1(11) and 4.10.2. I was unable <br />to locate, in the TR-120 application, a description of field inspection activities and <br />reporting that are proposed for the RPE East. Please incorporate inspection and <br />reporting details into Volume IOC that comply with the requirements of the sections <br />listed above, or reference another place in the Permit where the information may be <br />found. <br />5. A minimum static safety factor of 1.5 is required by 4.10.4(2). The "Permit Design" <br />configuration modeled in Figures 2-9 and 2-10 of the original application resulted in a <br />static Factor of Safety of 1.82 and a seismic Factor of Safety of 1.58. These factors may <br />be reduced slightly by the change in friction angle for the refuse material, but are still <br />likely to exceed the requisite values. Please revise the Permit Design model runs of <br />Figures 2-9 and 2-10 to reflect the change in refuse friction angle derived from the <br />LRP investigation.