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Table 7-1. Summarized Results of Kinematic Evaluation of the South Quarry <br /> Orientations with Potential for Failure <br /> Analysis <br /> West Highwall South Highwall East Highwall <br /> Wedge Sliding 32% 32% 27% <br /> Local Planar Sliding 18% 12% 14% <br /> Flexural Toppling 17% 15% 21% <br /> Direct Toppling 14% 14% 19% <br /> Wedge Sliding 19% 20% 17% <br /> Global Planar Sliding 11% 6% 10% <br /> Flexural Toppling 12% 14% 19% <br /> Direct Toppling 10% 8% 12% <br /> The failures shown in Photo 7-2 likely occurred as a result of planar sliding failure or wedge <br /> sliding failure, depending on the number of surfaces involved in the block. Records from the <br /> annual inspection reports suggest the sliding surface for these failures was a foliation joint. <br /> Although the highlighted rock falls are adjacent to a weathered mafic intrusion that extends <br /> through several benches, it does not appear as though the mafic dike contributes strongly to <br /> the failure and may have functioned only as a detachment plane. <br /> These types of block failures, where a sliding surface forms on adversely oriented foliation or <br /> a steeply dipping fracture surface, has been documented at Morrison Quarry in previous <br /> inspection reports. Although this type of failure appears limited to the northern portion of the <br /> South Quarry, it demonstrates that minor changes in the orientation of discontinuities in the <br /> highwall (particularly foliation joints) can lead to block failure when the toe of the slope is <br /> undermined. The potential for future kinematic failures will be strongly influenced by the <br /> orientation of the foliation planes and highwall height. If a persistent, adversely oriented, <br /> steeply dipping foliation pattern is encountered during excavation it could lead to a kinematic <br /> failure that encompasses multiple benches. Currently the South Quarry bench widths are <br /> just adequate to collect highwall rockfalls. If highwall heights increase we suggest bench <br /> widths be widened to collect expected rock falls. <br /> 33 <br /> Aggregate Industries—Morrison Quarry GEI Consultants, Inc. <br /> AM-07 Geotechnical Stability Exhibit November 2020 <br />