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C-1981-019 TR-81 <br />PAR - mlt <br />16 Feb 2009 <br />Page 6 of 7 <br />8. The original Jul-2006 S&W Study concluded that no rock toe buttresses or key-way cuts <br />are required for the South Taylor valley fills. Section 4.09.1(10) requires that, "where the <br />slope in the disposal area is steeper than 2.8h:1v... keyway cuts or rock toe buttresses <br />shall be constructed to stabilize the fill. Where the toe of the spoil rests on a downslope, <br />stability analyses shall be performed in accordance with 2.05.3(6)(b), (c) and (d) to <br />determine the size of the rock toe buttresses and keyway cuts. Paragraph (10) contains no <br />language that would limit these requirements to "final" slopes. The temporary fill <br />outslope proposed for the East Taylor valley fill is 2.5h: Iv, which is steeper than 2.8h: 1v. <br />Please address the keyway cut 1 rock toe buttress requirements of Rule 4.09.1(10), <br />revising the Oct-2009 study and permit documents as appropriate. <br />9. A bedrock buttress is depicted at the southeastern toe of Section D-D' in the Oct-2009 <br />S&W Study and on Map 45. The mass was incorporated into the stability analysis for <br />this section, but no dimensions are presented on the height, slope, and length of this <br />structure. <br />Please modify the Oct-2009 S& W Study to include the design details, and modify the <br />plan and D D' cross-sectional views of Map 45 to include the location and dimensions <br />of the bedrock toe buttress. <br />Maps <br />10. Map 19B - Postmining Topography - South Taylor Area <br />a) Please add stationing tick-marks to the cross sections. <br />b) A portion of slope located approximately 1000' west of the "20" appears to be steeper <br />than 3H:1V. Section 2.05.4(2)(c) Backfilling Plan for South Taylor/Lower Wilson states <br />the Colowyo will grade all final slopes so that overall grades do not exceed 33% (3h:Iv). <br />Please review the proposed postmining topography to ensure that no slopes will exceed <br />33%. <br />11. Map 23A - Mine Plan - South Taylor Area <br />a) Cross Section locations are not shown on this map, but would be useful for comparison <br />with other permit maps. Please add ST sections A A ; B-B , C-C ; D-D' and E-E' as <br />they are shown on Map 19B, including stationing tick-marks. <br />b) Mining in the central portion of South Taylor pit is described as occurring "2008 - <br />2011", while subsequent years' mining are identified individually. Please delineate, by <br />individual year, the proposed mining sequence for 2010 - 2011. <br />12. Map 20B - Premining & Postmining Cross Sections - South Taylor Area <br />a) A dark blue "Fill Design" line appears on sections ST-B, ST-C and ST-D. This line is <br />not defined in the Legend. Please provide a description for the "Fill Design "line.