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ArN <br />amec <br />February 5, 2010 <br />Mr. Timm Comer <br />Manager, Environmental Resources <br />Cripple Creek & Victor Gold Mining Co. <br />P.O. Box 191 <br />Victor, CO 80860 <br />Re: Phase 5 PSSA Ore Slope <br />Dear Timm: <br />AMEC Earth and Environmental (AMEC) has prepared this letter for the Cripple Creek & Victor Gold <br />Mining Company (CC&V) addressing the ore slope above the Phase 5 Pregnant Solution Storage Area <br />(PSSA) embankment. <br />In the Phase 5 design report (dated March 21, 2008), the ore slope above the Phase 5 PSSA <br />embankment was listed in the Design Criteria as being 2.0 Horizontal (H) : 1 Vertical (V). However, as <br />shown in Figure 1 (attached), the ore slope above the Phase 5 PSSA embankment can be increased to <br />1.6H:1 V while still meeting the minimum acceptable Factor of Safety (FOS) for the Valley Leach Facility <br />(VLF), as outlined in Amendment No. 9. The minimum acceptable FOS values for the VLF are 1.3 (static) <br />and 1.0 (pseudostatic). <br />A steeper ore slope shown in Figure 1 meets the stability requirements because the foundation along the <br />floor of the PSSA is relatively flat, as shown in the cross-section on Figure 1. The flatter PSSA floor <br />reduces the driving forces along the geomembrane/Soil Liner Fill interface, thereby increasing stability. In <br />addition, the Phase 5 PSSA embankment is buttressed by the natural ground, increasing the stability of <br />the embankment. <br />The details of the stability analyses are attached to this letter. Please note that Figure 1 reflects the latest <br />ore stacking configuration, and is in full compliance with the ore height restrictions set forth in Amendment <br />No. 9. The stability analyses were completed using the same design parameters and material properties <br />that were used for the Phase 5 design, and are consistent with previous amendments for the VLF. <br />If you have any questions or comments, please contact me at (303) 433-0262. <br />Sincerely, <br />AMEC Earth & Environmental, Inc. X° 7 <br /> <br /> <br /> V ° <br />ohn F. Lupo, Ph.D., P.E. <br />° <br /> <br />Principal Engineer o <br />° -s3 • - <br /> e? <br /> m <br /> <br />AMEC Earth & EmAmmt itta9, Ittcw <br />304 Inventess Wft Sautha Sadfe 490 <br />ErKWwoad, Cabrado 801112 <br />Tel: (303)433-MM <br />Fa)c (303) 43 2 vam-anwc-curn <br />S1PROJECTSt1125E CCV COA1e - conespondencekore slcpe letter.doc