Laserfiche WebLink
6.2.4 South Walls <br />As with the north wall and west wall, the southern wall has also been subdivided <br />into separate slopes for analysis: two southwest walls and a southeast wall <br />orientation were selected based on the proposed Lafarge mine plan (Lafarge, <br />2003). This approach is the same as was used for the 2004 annual report, in <br />which the southern walls were measured based on configurations on the <br />proposed Lafarge mine plan. Figures 14 and 15 present the stereonets for each <br />wall. <br />Similar to the results of the 2004 investigation, the intersection of the planes for <br />discontinuity sets P-2 and P-4 lies just outside the 33° friction angle for all three <br />southern wall orientations, and therefore are not indicative of conditions <br />conducive to sliding along the intersection. <br />The wedge stability analysis for the southeast wall indicates one plunge of a line <br />of intersection that is just outside of the failure envelope. The intersection of the <br />planes for discontinuity sets P-3 and P-6 are therefore not anticipated to slide <br />unless the friction angle along the planes is lower than the average. This <br />condition has been noted in past reports, and the south walls should be <br />continued to be monitored as excavations continue. <br />As mentioned previously for the east wall, the individual benches along the south <br />walls with near vertical faces enable additional discontinuities to form potential <br />wedges that may slide during the temporary condition prior to reclamation. <br />Wedge failures limited to individual benches have been consistently observed in <br />the past along the south walls. <br />The newly identified discontinuity set, F-3, may facilitate some failures along the <br />south walls that would involve the formation of a wedge with discontinuities P-3 <br />and P-6 very close to the failure envelope. <br />_22_ <br />