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Continued. <br />• Crushed ore should be placed within the entire PSSA as soon as possible to <br />buttress the spent ore lift within the PSSA in order to provide stability to the spent <br />ore and protect the liner system in the PSSA. To achieve the minimum operational <br />factors of safety, crushed ore needs to be placed throughout the base of the PSSA <br />to an elevation of at least 9,378 feet. <br />• However, due to displacement of water within the existing pool resulting from <br />placement of ore within the PSSA, the water level within the PSSA is estimated to <br />rise to approximate elevation 9,386 feet following placement of ore throughout the <br />PSSA. This estimate assumes 35% porosity of ore and a current pool elevation of <br />9,378 feet. This estimated elevation provides 64 vertical feet of freeboard within the <br />PSSA (below elevation 9,450 feet) or approximately 144 million gallons additional <br />water capacity within the ore voids (assuming the PSSA is filled with ore to 9,450 <br />feet). It is recommended that the ore placement methodology take into <br />consideration the estimated elevation of the water level resulting from ore placement <br />in the PSSA. <br />• Crushed or spent ore is to be placed in the PSSA should commence from the lowest <br />elevation side of the PSSA and proceed upslope. Ore should not be placed on <br />downward sloping surfaces for stability reasons. Detailed methodology for safely <br />placing material within the PSSA is currently under development jointly between <br />CC&V, Amec Foster Wheeler and Ames Construction. <br />• Erosion of DCF within the PSSA should be repaired as soon as possible and prior to <br />placement of material within the PSSA so that a rising pool does not submerge the <br />eroded DCF. The exposed geomembrane must be inspected for defects prior to <br />covering with additional DCF. As geomembrane upslope of the PSSA is covered <br />with DCF, the risk of erosion of exposed DCF will be reduced. <br />5.0 References <br />AMEC Earth and Environmental, Inc. (AMEC), 2011. "Cripple Creek & Victor Gold <br />Mining Company, Squaw Gulch Valley Leach Facility Design", report prepared for <br />Cripple Creek & Victor Gold Mining Company, September 1, 2011. <br />Colorado Division of Reclamation, Mining and Safety (DRMS), 2015. "Design Standard <br />of Care for Slope Stability/Geotechnical Analyses", Memorandum dated July 15, <br />2015. <br />Rocscience, 2010. Slide Version 6.0 Users Manual. Toronto, Ontario, Canada. <br />Spencer, E. 1967. A method of analysis of the stability of embankments assuming <br />parallel inter -slice forces. Geotechnique. Vol. 68, No.1, pp. 190-198. <br />Page 6 of 7 <br />