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<br />calculated values that were hypothesized to exist at the time of the recent slope <br />failure, with two assumed ground water profiles. The lower ground water profile <br />(elevation 7270 ft) is based on calculated failure surfaces with upper failure limits <br />close to the observed main scarp. The higher ground water (elevation 7470 ft) levels <br />are based on the "steam plume" observed coming from the main scarp a few days <br />after the failure (see photograph on Fig. E-5). <br />The pre-failure slope topography used is that shown on Fig. 3. The <br />subsurface profile for the limestone and sandstone are a simplified version of the <br />information presented in the cross-sections from 2001 Reclamation Plan <br />Amendment by Banks and Gesso. The fault, scarp, and surface fracture locations <br />are based on our mapping. <br />The estimated and back-calculated strength parameters for the materials are <br />used in the analysis are summarized in the following table. <br />0 TABLE 1 <br />SLOPE STABILITY MATERIAL PROPERTIES <br />Material Ground Water <br />Level Friction Angle <br />(Degrees) Cohesion <br />(psf) <br />Granite Both 45 2000 <br />Shale Both 18 750 <br />Limestone Lower 33 1000 <br />Sandstone Lower 28 100 <br />Limestone Upper 40 1000 <br />Sandstone Upper 35 100 <br />We analyzed both slopes under three conditions after back calculating <br />strength parameters for the two assumed water levels: pre-failure with ground <br />water (used to back calculate the strength parameters), pre-failure dry, and post <br />failure with ground water to calculate the stability of the current slopes. The back <br />calculated strength parameters used in the stability analysis are not unique, but are <br />a set of strength parameters that are representative of the conditions modeled by <br />TRANSIT MIX AGGREGATES 18 <br />PIKEVIEW QUARRY SLOPE <br />CTLIT PROJECT NO. CS17341-125 <br />S:%CS17000-174991CS17341.0 0 011 2 512. Reports%CS1 7 341-1 2 5-R1-Final.doc