2012-02-28_REVISION - M1980244 (65)

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Cripple Creek & Victor Gold Mining Company Squaw Gulch Valley Leach Facility Design 1998). In March 2000, Golder developed a design report for Phase IV titled, "Cresson Project; Valley Leach Facility Expansion, Phase IV Design," which was presented as Volumes V, VI, and VII of Amendment No. 8 to Permit M- 1980 -244 filed with the OMLR (CC &V 2000). In March 2008, Smith Williams Consultants Inc. (SWC) developed a design report for Phase 5 titled, "Cripple Creek & Victor Gold Mining Company, Cresson Project Valley Leach Facility Phase 5 Extension Design" which was presented as Amendment No. 9 to Permit M- 1980 -244 filed with the OMLR (CC &V 2008). Pertinent data used as part of the previous designs, which have been approved by the MLRB and OMLR, have been included as part of the VLF design in Squaw Gulch. Surveying and development of the digital topography for the VLF was performed by Foresight West Surveying, Inc. (Foresight). The design features, consistent with those submitted previously as part of the existing VLF design, have been selected and developed through the integration of state -of- the -art methods, design criteria, and site - specific conditions to minimize the potential for releases to the environment. 1.4 Design Criteria AMEC completed the engineering design for the VLF using the design criteria presented in the following paragraphs. Geometric design criteria for the VLF are presented in the following table, which includes a maximum ore depth over liner of 800 feet. Parameter Maximum ore depth over liner Nominal ore angle of repose slope Overall operational ore side slope against upsloping ground Overall operational ore side slope against downsloping ground Overall operational ore side slope above Squaw Gulch VLF PSSA embankment Overall operation ore side slope above mill Maximum lift height Project No.: 74201125G0 Page 5 1 September 2011 Value 800 feet 1.4H:1V 1.6H:1V 2.5H:1V 2.5H:1V 2.0H:1V 100 feet amec'G