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Cripple Creek & Victor Gold Mining Company Squaw Gulch Valley Leach Facility Design <br />analyzed are shown on Drawings A700 and A710. The following material profile was <br />used in the models: <br />• Crushed Ore: Crushed ore that is placed in the VLF is totally underlain by the <br />composite liner. The ore slope within the VLF will vary, depending on location. In <br />the area upgradient of the PSSA embankment, the ore will be placed at the angle <br />of repose with bench offsets to provide an overall slope of 2.5H:1V. In areas with <br />downsloping foundations, the ore will be placed at the angle of repose with bench <br />offsets to provide an overall slope of 2.5H:1V. In other areas, with the exception of <br />above the mill, the slope of each lift of ore will be at the angle of repose with bench <br />offsets to provide an overall slope of the ore at 1.6H:1 V during operations. The <br />overall ore slope above the mill will be 2.0H:1 V during operations. <br />• Composite Liner: The composite liner will be installed below the crushed ore and <br />consists of a 1 foot -thick SLF overlain by a geomembrane. Though the PSSA <br />composite liner system consists of two geomembrane liners separated by a gravel <br />layer, the critical surface for stability is modeled through the interface represented <br />by the SLF and the lower geomembrane. <br />• Foundation Material: Based on the results of the geotechnical investigations, the <br />VLF foundation material consists of a relatively high strength foundation material <br />representing competent bedrock materials or granular native soils. <br />5.1.2.2 Geotechnical Material Design Parameters <br />The development of the conceptual stratigraphic model discussed above in Section <br />5.1.2.1 provides a framework on which to base the geotechnical analyses. Material <br />design properties used in the stability analyses are discussed below and summarized <br />on Drawings A700 and A710. <br />Crushed Ore. For the stability analysis, the crushed ore material was modeled with <br />an angle of internal friction of 40 degrees with no cohesion, based on testing <br />performed on Cresson ore material. The results of the testing performed on nominal <br />1%-inch minus Cresson ore was reported to the OMLR in a January 9, 1996, letter <br />from CC &V (1996b) titled, "Cresson Project: Permit M- 1980 -244: Procedures and <br />Materials for 1996 Construction." The results indicate a curvilinear failure envelope <br />with internal friction angles ranging between 45 degrees (under low normal stress) and <br />36 degrees (under high normal stress) in the stress range expected along critical <br />stability failure surfaces in the VLF. Weighting the internal friction angle to the normal <br />stress levels expected along critical failure surfaces results in an internal friction angle <br />of 38 to 40 degrees. The ore shear strength test results are presented in Appendix <br />B.S. Shear tests were also conducted in nominal % -inch ore materials. The test <br />results from the 3 / -inch ore resulted in an internal angle of friction of 39 degrees, which <br />is similar to the 1 -inch ore test results. These shear test results indicate that an <br />internal angle of friction between 38 to 40 degrees can be used for ore that is <br />nominally sized between 1 and 3 inches. These test results are within the range of <br />Project No.: 74201125G0 Page 28 <br />1 September 2011 <br />amec0 <br />