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Surface Water Management <br />The surface water management system for the SGOSA is based on a series of diversion <br />and conveyance structures designed to route flows from the 100 -year, 24 -hour <br />precipitation event. Some of these structures direct flows into detention basins prior to <br />sending the water to downgradient streams. The detention basins are designed so that the <br />most downgradient structures contain twice the 10 -year, 24 -hour precipitation event. <br />During operations, interim surface water management will occur using the best <br />management practices described in Section 10.0. The Storm Water Management Plan <br />contained in Appendix 12, Volume VI contains information on MLE2 drainage system <br />including specific channel locational changes as a result of the changes in the SGOSA <br />and the addition of the SGVLF. <br />Stability <br />The geotechnical stability analysis of the SGOSA was re- evaluated using the revised <br />SGOSA design although many of the input parameters were not changed from the <br />analysis submitted as part of MLE. In summary, this analysis used a peak ground <br />acceleration of 0.14 g for pseudo- static analysis for operations and 0.08 g for the pseudo - <br />static analysis for the post closure configuration, the same value used in previous <br />approvals at the Cresson Project. Other input parameters were derived from field <br />examinations, laboratory tests, use of accepted numerical assumptions for certain rock <br />types, and the proposed dimensions of the overburden fill during placement and upon <br />regrading. Material properties for overburden materials and native bedrock are based on <br />previous analyses. FOS for the SGOSA were derived for both static and pseudo- static <br />conditions. <br />The stability was analyzed for post - reclamation conditions and the results indicate that <br />the minimum static FOS was equal to or exceeded 1.3 and the minimum pseudo - static <br />FOS exceeded 1.2. The SGOSA is stable under both static and seismic loading <br />conditions as the computed factors of safety meet or exceed the prescriptive values of 1.3 <br />and 1.0, respectively. For additional details on the stability analysis for the SGOSA <br />please refer to Appendix 7, Volume IV. <br />5.7.2 East Cresson Overburden Storage Area ( "ECOSA ") <br />General <br />The ECOSA is an overburden storage area approved for construction as part of MLE <br />which has not yet been constructed. It will be located in the northeast portion of the mine <br />Cripple Creek & Victor Gold Mining Company <br />Cresson Project Mine Life Extension 2 <br />5 -19 <br />