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object Cresson Project ade by gFM ob No 043-2251 <br />~~~~ odified VLF Boundary hecked by ,~L ate 7/29/04 <br />®~~~ Stability Analyses pproved by gL heel No 2 of 5 <br />• A conservative design coefficient of 0.14g (which is equal to the approved Peak Ground Acceleration <br />[PGA] for the Cresson Project) was used in the slope stability models, which is consistent with that <br />used for Amendment No. 8 (CC&V 2000). <br />RESULTS: <br />The analyses were performed using Spencer's method. Both circular and non-circulaz failure surfaces were <br />considered in the analyses. Excluding surficial "infinite slope" or veneer-type failure surfaces, the minimum <br />factors of safety for static and pseudostatic loading are presented in Table 2. Results of the stability analyses are <br />presented in Attachments 2 and 3 for static and pseudo-static conditions, respectively. <br />TABLE 2 -Summary of Stability Analyses <br />Section Analyzed Static Conditions Pseudo-Static Conditions <br />0.14 <br />Critical active/passive wedge failure FS = ].7 FS = 1.5 <br />alonggeomembreneinterface (P2-3S2sli) (P2-3Plsli) <br /> Non-circular surface Non-circulaz surface <br />Critical failure through ore slope FS = 1.5 FS = 1.2 <br /> (P2-3S3.sli) (P2-3P3.sli) <br /> Circulaz surface Circulaz surface <br />CONCLUSIONS: <br />One cross-section, intersecting the existing Phase II liner system and the proposed modified VLF boundary, was <br />' analyzed. The analyses were performed considering the maximum final ore stacking geometry (590 ft over the <br />liner system and 1.6H:1 V ore slope). Both circulaz and non-circulaz seazch routines were used to define critical <br />failure surfaces. <br />The modified VLF boundary is considered stable for static and dynamic loading conditions. Excluding veneer or <br />infinite slope failures through the ore slope, the static factor of safety is approximately 1.5 and the pseudostatic <br />factor of safety is approximately 1.2. <br />Cripple Creek & Victor Gold Mining Company (CC&V). 2000. Amendment No. 8 to Office of Mined Land <br />Reclamation, Permit M-80-244. Volume N. March. <br />Rocscience (2003). Slide 5.004, 2D limit equilibrium slope stability for soil and rock slopes, copyright 1989- <br />2003, Rocscience, Inc. <br />Phacen-tilFXT-Stahility dnr. <br />