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1100318 R0T0 0811 JRW1 39 <br />result in higher rock strengths when compared to back calculated rock <br />strengths resulting from lower groundwater levels. The back calculated <br />strengths are consistent with the laboratory data for relevant bedrock strata <br />and conditions observed in the field (i.e., significant inhomogeneities, <br />fracturing and discontinuities of the lower limestone). <br /> A slope stability analysis was performed considering the effects of an over <br />excavation of the west wall of the quarry that occurred in the 1990’s.56 Circa <br />early 2002, the over excavation was backfilled with spill fill consisting of <br />decomposed granite pushed over the top of the quarried face. Photograph 1 <br />and Photograph 6 show the slope in an over excavated condition and a <br />backfilled condition. Photograph 21 shows the top of the spill fill in 2003. <br />The geometry of the maximum over excavation and maximum fill was <br />projected onto the nearby cross section D-D' and analyzed. The geometry of <br />the over excavation and fill are projected based on data contained in the 2000 <br />amendment and photographs of the slope with the fill contained in the <br />attached appendices. The results of the analysis are contained in <br />Appendix 47. The effect of the fill on the slope is minimal with an <br />approximately 4 percent reduction in the factor of safety when utilizing the <br />back calculated strength values and various groundwater conditions. This <br />characterization of the effect on the factor of safety is extremely conservative <br />because the narrow width of the over excavation is modeled to extend great <br />distances in the north and south direction in the slope stability analysis, <br />thereby exaggerating the effect of the narrow excavation on the stability of <br />the slope. Therefore, the effect of the local over excavation and fill on the <br />slope is insignificant on the slope stability particularly in light of the <br />relatively local nature of the fill and especially when compared to the <br />substantially greater effects of the clay bed on the slope stability. <br /> A slope stability analysis was performed considering the effect of the <br />inevitable surficial fracturing of un-mined rock from blasting (a.k.a. <br /> <br />56 State of Colorado, Colorado Geological Survey, Quarry Wall Rockslide at Pike View Mine – Summary Report, <br />January 7, 2009 (Appendix 48)