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<br />before the western edge of the Hole can even be exposed. Therefore, it does not <br />appear that instability of the mountainside will be created by excavating the Hole, <br />although small scale instability of individual benches within the Hole may occur." <br />HIGHWALL CONDITIONS <br />At the time of the 2008 failure, the top of the highwall (elevation 7700 feet) <br />was about 610 feet above the excavated bottom of the pit (elevation 7110). The <br />estimated overall slope ratio from the top of the highwall to the toe was 1.23:1 <br />(horizontal to vertical). The dip of the limestone beds towards the cut slope varied <br />from about 45 degrees (1:1 ratio) near the top of the slope to about 25 (2.1:1 ratio) <br />near the toe, with an average of about 35 degrees (1.4:1 ratio). The highwall was <br />benched at an approximately 30-foot vertical and 30-foot horizontal configuration. <br />Where the benches had been reclaimed, a wedge of soil with a maximum thickness <br />of about 15 feet had been placed on the horizontal portions of the benches, with a <br />few feet of topsoil. The benches were vegetated. <br />• <br />The pre-failure slope topographies (ground surfaces) are based on estimated <br />quarry slopes, which are based on the existing slopes to the north and south of the <br />failure and the reported bottom elevation and dimensions (Fig. 3). <br />SLOPE STABILITY <br />We selected two cross-sections for slope stability analysis. Section F was <br />taken from the previous Banks and Gesso cross-sections to allow comparison with <br />their plan (Fig. 7) and has an east-west orientation. Section M was selected near the <br />maximum failed section, near perpendicular to the pre-failure slope (Fig. 8). The <br />subsurface conditions are based on interpretations of the information in the 2001 <br />Reclamation Plan Amendment and conditions observed within the quarry after the <br />failure. <br />We utilized the SlopeW Computer program to perform stability analysis of <br />. the selected cross-sections. The material properties we utilized are based on back <br />TRANSIT MIX AGGREGATES 17 <br />PIKEVIEW QUARRY SLOPE <br />CTLIT PROJECT NO. CS17341-125 <br />S:1CS17000-174991CS17341.000112512. ReportslCS17341-125-R1-Final.doc