2009-02-17_REPORT - M1974004 (2)

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11 similar clusters were found in the expansion area, with only a weak fingerprint for the F- 3 discontinuity set differentiating the two (Figure 10). ' The emergence of F-2 and F-3 as definitive discontinuity sets has only been identified over the past several years as a result of the 2003 geotechnical investigation and the 1 subsequent years investigations. The intersection of the foliation planes (F-1, F-2 and F-3) with each other will not be evaluated in the wedge stability analyses presented 1 herein. ' Overall, the discontinuity sets obtained by analysis of the entire dataset (i.e., 3053 points) are consistent with the cluster analysis from previous years' individual analyses (Figure 8). Both of the foliation discontinuity orientations, F-2 and F-3 are identifiable within the quarry, but have not been recorded in large enough quantities to create a strong signature in the analysis of the entire dataset. However, based on the prevalence of these discontinuities in the southern expansion area, both of these orientations have also been continued to be used in this analysis. To adequately understand the impacts of the new data on wall stability, the planes representing each discontinuity set and the plane representing the orientation of the respective quarry wall slope face were plotted. The stereographic analysis of each quarry wall is presented in Figures 11 - 16. 5.2 Wedge Stability Analysis I As presented in previous annual reports, the method of stereographic analysis developed by Markland (1972) was used for this study. Markland's test is designed to identify the possibility of a wedge failure in which sliding takes place along the line of intersection of two discontinuities (Hoek & Bray, 1977). According to Markland's test, sliding can occur when: 1) The plunge of the lines of intersection is less than the dip of the slope face. 2) The plunge of the lines of intersection exceeds the angle of friction. -13-