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7. Stability Analyses Results <br /> This section presents the results from the analyses described in Section 5 and Section 6. The <br /> kinematic analyses are presented first, followed by the slope stability analyses. <br /> 7.1 Kinematic Analyses <br /> The results of the kinematic analyses provide an indication of the potential for localized <br /> block instability in the exposed benches and highwalls. The stereonet projections give an <br /> indication of potential instability by calculating the number of discontinuities (or <br /> combination of discontinuities) that could possibly result in a block failure for a given slope <br /> configuration. The number kinematically possible failure surfaces are divided by the number <br /> surfaces which would not likely result in slope failure, and the results are expressed as a <br /> percentage. The results give an indication of potential block failure modes based on different <br /> excavation orientations and are not intended to provide factor of safety for individual rock <br /> blocks. Results of the kinematic analyses are shown in stereonets contained in Appendix D <br /> and are summarized in the following sections. <br /> 7.1.1 South Quarry Kinematic Analyses <br /> Result of the South Quarry Kinematic Analyses are organized by local and global failure <br /> modes, where local failures modes for individual benches are represented with a slope angle <br /> of 850, and global failure modes for multiple benches are represented with a slope angle of <br /> 67' (40H:70V). The analyses included 655 discontinuity measurements and highlights <br /> which kinematic failure modes are most likely to occur in the different highwall orientations. <br /> Results of the analyses reflect changes and are summarized in Table 7-1, which indicates the <br /> most likely kinematic failure mode is wedge or planar sliding for the local benches, and <br /> wedge sliding or flexural toppling for the global condition. <br /> Annual reporting and field inspections indicate that the South Quarry highwall is generally <br /> stable, and although rockfall debris is commonly observed on benches the volumes are small <br /> and include rock wedge, boulder and cobble sized blocks that accumulate at the base of some <br /> vertical benches. The rockfalls are generally minor and likely a result of production blast <br /> induced rock fracturing and freeze-thaw in the rock face above the benches. Larger rockfalls <br /> are observed sitting on bench elevations at El. 7,000, 6,950, 6,900, and 6,840 feet on the <br /> northern side of the South Quarry, which are structurally controlled failures that have been <br /> observed and documented in annual reports. Several failures appear to have been controlled <br /> by discontinuities and are either planar sliding or wedge sliding failures. Photo 7-1 shows <br /> the South Quarry with localized rockfall areas, which are shown in more detail in Photo 7-2. <br /> 32 <br /> Aggregate Industries—Morrison Quarry GEI Consultants, Inc <br /> AM-07 Geotechnical Stability Exhibit November 2020 <br />