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Contingency inflows, including 12 hours of draindown and the 100 -year, 24 hour design <br />storm event, also will be contained. The maximum anticipated PSSA storage volume, <br />including all contingency flow is approximately 92 million gallons, which represents only <br />52 percent of the maximum available PSSA capacity, and 65 percent of the 80 percent <br />PSSA capacity. <br />The water balance results are presented in Appendix 9, Volume V of this document. <br />7.2.6 Surface Water Diversion System <br />A surface water diversion system has been designed for the SGVLF area. The diversion <br />system has been designed for the maximum limits of the construction; however during <br />the three -year construction period for Phase I temporary diversion will be used to control <br />upgradient storm water flows and direct these flows away from the construction area. <br />The diversions have been sized to divert upgradient surface water flows around the <br />facility including flows from the SGOSA. The diversions have been designed to carry <br />peak flows from a 100 -year, 24 -hour storm event of 3.5 inches. Temporary (Phase I) <br />operation and post- operation diversion designs are included in Appendix 9, Volume V. <br />Surface water diverted around the SGVLF will be routed to sediment ponds designed to <br />contain twice the runoff from a 25 -year, 24 -hour storm event with freeboard. A <br />temporary pond will be constructed for Phase I followed by construction of the operation <br />and post- operation pond as part of Phase II. The design also includes the ability to pump <br />water from the sediment pond to prevent overtopping. The sediment ponds are designed <br />as excavations into native ground with no liner, so some infiltration of storm water into <br />the foundation is expected. <br />7.2.7 Geotechnical Analysis <br />7.2.7.1 Settlement Analyses <br />Settlement analyses were conducted by AMEC to evaluate the settlement of the SGVLF <br />and PSSA embankment under the design. For the PSSA, the analyses evaluated <br />settlement of the embankment and not the natural ground settlement along the base, as <br />the base will be placed on bedrock. The results of the PSSA embankment analyses <br />indicated that the maximum anticipated settlement along the PSSA embankment will <br />likely range from 0.6 to 9 inches. These settlements are considered minor and are not <br />anticipated to damage the PSSA liner system. <br />Cripple Creek & Victor Gold Mining Company <br />Cresson Project Mine Life Extension 2 <br />7 -15 <br />