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slope face and steeper than the failure envelope (P6:P1). The intersection of F1:P6 is <br />located outside the daylight window, including the plotted variance of dip for the foliation <br />plane, therefore, failure along this is unlikely. The plunge line for the intersection of plane <br />P-6 with the steeper dip for F-1 analyzed is just within the failure envelope, and so, if the <br />foliation dips at 46° in this area, a potential for sliding does exist and should be monitored. <br />The second western wall analyzed in this study, has a dip direction of 120° (Figure 14). <br />The results for this analysis yielded fairly comparable results. There are three pairs of <br />intersecting planes with plunge lines that daylight the slope face, but only two whose <br />plunge lines are steeper than the angle of friction. The plunge of the intersection of <br />discontinuities P1:P2 is just within the failure envelope as is the intersection of P1:F2. <br />This combination of planes has not frequently been found to have potential for failure, but <br />should be continued to be monitored and evaluated in future studies. <br />5.2.4 South Walls <br />' As with the north wall and west wall, the southern wall has also been subdivided into <br />separate slopes for analysis: two southwest walls and a southeast wall orientation were <br />' selected based on the proposed Lafarge mine plan (Lafarge, 2003). This approach is the <br />same as was used for previous annual reports, in which the southern walls were <br />' measured based on configurations on the proposed Lafarge mine plan. Figures 15 and <br />16 present the stereonets for each wall. <br />In the southwest wall, the stereonet shows several pairs of intersecting planes that have <br />plunge lines inclined shallower than the inclination of the slope face, but all are inclined <br />less than the friction angle. Consequently, all pairs of planes are capable of forming <br />wedge blocks, but none of these wedges are likely to be unstable. The stereonet also <br />shows two pairs of intersecting planes that have plunge lines inclined steeper than the <br />friction angle, but just steeper than the inclination of the slope face. As such both these <br />wedges are considered kinematically stable. However, if isolated pairs of planes should <br />intersect with shallower plunge angles due to natural. variability, unstable blocks could <br />-17- <br />Lachel & Associates <br />A4 SCHNASP FMGIN[f RING CONVANY