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inspections, which includes providing a range of discontinuity spacing, persistence, and <br /> roughness for each scanline survey. These values correspond to a `Poor' to `Fair' rock mass <br /> based on this classification RMR system. <br /> All RMR Values <br /> is <br /> 100-81: Very good <br /> 16 80-61: Good <br /> 60-41: Fair <br /> 14 40-21: Poor <br /> 0-20: Very Poor <br /> 12 <br /> i; <br /> 10 <br /> c <br /> 8 <br /> 6 <br /> 4 <br /> 2 <br /> a <br /> [20,25) (25,301 (30,351 (35,401 f40,45] (45,501 (50,55] (55,601 (60,651 (65,701 <br /> Rack Mass Rabng <br /> Figure 5-2. Histogram showing distribution of low and high low RMR ranges measured in the <br /> active South Quarry as observed in the annual highwall inspections for the years between <br /> 2013 and 2019. <br /> 5.3 Q-system <br /> The Q-system is a rock mass classification system developed by the Norwegian Geotechnical <br /> Institute that was published in 1974 (Narton, et al., 1974). The Q-system was initially <br /> developed to assist in evaluating tunneling supports but has been used as a field mapping tool <br /> to characterize rock mass characteristics and evaluate above-ground excavations. <br /> The Q-system provides a rock mass classification based on six rock mass parameters and the <br /> following equation: <br /> _ RQD Ir Jw <br /> Q Jn x JQ X SRF <br /> Where: RQD = Rock Quality Designation <br /> in = Joint set number <br /> Jr= Joint roughness number <br /> Ja= Joint alteration number <br /> JW = Joint water reduction factor <br /> SRF = Stress Reduction Factor <br /> 21 <br /> Aggregate Industries—Morrison Quarry GEI Consultants, Inc. <br /> AM-07 Geotechnical Stability Exhibit November 2020 <br />