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5.0 Analysis of Structural Discontinuities <br />The stability of the rock mass that forms the highwalls of the quarry is mainly controlled by <br />the discontinuities. Discontinuities create the surfaces that sliding can occur upon and the <br />intersections of multiple discontinuities define the boundaries of wedges or blocks that <br />have the potential to slide. As observed throughout the quarry, the discontinuity sets all <br />' have a range of dip and dip direction, and therefore it is possible that discontinuity <br />orientations in a specific location of the quarry deviate from the general discontinuity <br />orientations assumed for the analyses presented in this report. <br />' 5.1 Evaluation of Discontinuity Measurements <br />As the database for discontinuity measurements has increased, various methods have <br />been utilized to efficiently analyze the new acquired geologic data. The analysis of the <br />' discontinuity data was conducted using Dips 5.1 (Rocscience, 2006), which is an <br />interactive program for the analysis of discontinuity orientations based on geological data <br />' inputs. For this study, the data were evaluated with stereographic plots using a <br />combination of contour analyses and cluster analyses to determine representative dip <br />' directions and dip angles for the predominant discontinuity sets. <br />' The contour analysis of the entire dataset (i.e., 3066 points) resulted in a plot of density <br />contours, which facilitated our determination of the general discontinuity orientations <br />across the entire facility (Figure 6). The cluster analysis has helped to further refine the <br />data by utilizing an iterative approach to group the data measurements into representative <br />1 clusters. The nucleus of each cluster represents the concentration center for a given data <br />set as is shown for the cumulative dataset (i.e. 3066 datapoints) in Figure 6. The <br />differences between each of the individual year's analyses can best be seen on a <br />stereographic presentation showing each of the concentration poles for the clusters for <br />each annual analysis, but due to the small sampling of datapoints for the current <br />investigation data for 2009 and 2010 have been combined (Figure 7). A combination of <br />the clusters from Figure 6 and the results of the contour and cluster analysis of the entire <br />dataset (Figure 7) were used to define the discontinuities and their orientations for use in <br />-11- <br />Lachel & Associates <br />A SCHHASr.l f.NGIKGM14G.ONGANY