2012-02-28_REVISION - M1980244 (104)

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portions of the High Grade Mill facilities will be approximately 211 gpm (77 tons of slurry per hour). The milling process that will be used at the Cresson Project will experience minimal water losses and require approximately 290 gpm in fresh water makeup. The majority of the water lost will be in the process that is returned to the VLFs in the agglomerated product. In addition, approximately 60 gpm from the mill leach circuit will be pumped to AGVLF or SGVLF and either injected into the barren pipeline or to a designated drip tube distribution system. Fresh water will be added to the mill circuit from the upgraded water line from the Altman station located in Grassy Valley downgradient of the Cresson Project. 6.6 Storm Water Control at the High Grade Mill Facilities Prior to construction of Phase 2 of the SGVLF, storm water from the High Grade Mill facilities platform will be directed along the surface to a sump. From the sump, the storm water will be pumped to the AGVLF. Any potential leaks or spills on the High Grade Mill platform surface will flow to the sump and any infiltration will be contained within the lined areas of the High Grade Mill platform. After Phase 2 of the SGVLF is completed and the liner system for the High Grade Mill platform is tied into the SGVLF liner system, storm water flows will be directed to the SGVLF. 6.7 Stability The geotechnical stability analysis of the SGOSA was previously discussed in Section 5.7.1. The High Grade Mill facilities platform and associated buildings and structures were also evaluated as part of the SGOSA analysis. The same parameters as previously discussed for the SGOSA were used for input into the High Grade Mill facilities platform including a peak ground acceleration of 0.14 g for pseudo- static analysis for operations and 0.08 g for the pseudo- static analysis for the post closure configuration. Use of a portion of the SGOSA as a platform for the High Grade Mill facilities added additional parameters to the stability analysis. A distributed load of 4,500 pounds per square foot was estimated to model the pressure of the overlying High Grade Mill buildings and structures on the platform. The stability analysis for the High Grade Mill facilities platform was conducted similarly to the stability analysis for the SGOSA. The minimum static FOS was determined to be equal to or exceed 1.7 and the minimum pseudo- static FOS exceeds 1.4 for the post - reclamation conditions. For the operational analyses, using a peak ground acceleration of 0.14g, the FOS for the High Grade Mill facilities platform under pseudo- static conditions exceeds 1.3. The High Grade Mill Cripple Creek & Victor Gold Mining Company Cresson Project Mine Life Extension 2 6 -13