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Al conducted a subsurface investigation and advanced four borings in the South Quarry of <br /> Morrison Quarry. GEI collected rock core samples obtained during drilling and submitted <br /> select samples to Advanced Terra Testing (ATT)for direct shear laboratory analysis (ASTM <br /> D-5607). The core samples were selected as representative samples of core obtained during <br /> drilling. GEI submitted a total of 17 core samples for direct shear testing to ATT. <br /> GEI added the information gathered during site visits to the current rock mass ratings (RMR, <br /> Bieniawski, 1976). The information includes joint orientation, foliation orientation, other <br /> structural features, and unusual rock features within the South Quarry. GEI has developed <br /> RMR values for the South Quarry during Annual Report mapping between 2014-2017. RMR <br /> data from Annual Reports is included in Appendix E. RMR data was also compared against <br /> the RMR data provided in the original Highwall Design Technical Revision(Tetra Tech, <br /> 2012) for the South Quarry. <br /> GEI used the current highwall configuration from elevation contour data collected onsite and <br /> laboratory testing data from core samples to conduct slope stability analyses on several <br /> typical sections within the South Quarry to provide a quantification of the local and global <br /> stability. Results of the stability analyses were used to evaluate the highwall stability with the <br /> proposed highwall configuration, including increased highwall height and the resultant <br /> overall highwall (pit) slope angle. The stability model included kinematic analyses to <br /> evaluate toppling, wedge, and planar failure and global pit slope stability evaluation. <br /> Kinematic analyses of the existing highwall configuration was necessary because the <br /> highwall orientation is different than was modeled in the Highwall Design Technical <br /> Revision(Tetra Tech, 2012). Global pit stability analyses are necessary to verify that overall <br /> pit configuration will be inherently stable (FOS > 1.2). <br /> GEI used RocScience's open pit mining evaluation software suite (DIPS, Swedge, <br /> RocTopple, and RocPlane) for the kinematic evaluation and Itasca Consulting Group's <br /> FLAC 7.0 Slope and GeoStudio's SLOPE/W software for the global pit slope stability <br /> analyses. <br /> Stability analyses focused on the new highwall configuration, including an increased <br /> maximum highwall height of 25H:70V. The typical sections are based on exposed and <br /> observed rock, borehole data, and GEI's experience within the quarry. Typical sections used <br /> for stability analyses included assumed conditions for the presence of lower strength <br /> sillimanitic gneiss at various locations within the highwall. <br /> The results of the field investigation and stability modeling are presented and summarized in <br /> this report, which will be submitted to the DRMS as a TR to the Morrison Quarry M-1973- <br /> 021 mining permit for Al. This TR presents the revised highwall configurations to the DRMS <br /> and demonstrates the highwall design and quarry development meet the minimum required <br /> factors of safety for rock stability (FOS > 1.2). <br /> Aggregate Industries Morrison Quarry GEI Consultants, Inc. <br /> South Quarry Highwall Design Technical Revision 3 August 2017 <br />