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Geotechnical Stability Exhibit <br /> Engineering Evaluation of Highwall Design for the South Quarry of the Morrison Quarry <br /> <br /> January 2024 | 16 <br />Table 7 – Summary of Aggregate Testing <br />Boring Depth <br />(ft.) Material Absorption <br />(%) <br />Specific <br />Gravity <br />Loss by <br />Abrasion <br />(%) <br />Sulfate <br />Soundness <br />Sieve Percent <br />Passing <br />HDR-002 245.0- <br />260.0 <br />Granitic <br />Gneiss 0.75 2.697 18 <br />3/8 3.9 <br />#4 8.1 <br />HDR-003 185.0- <br />195.0 <br />Granitic <br />Gneiss 0.41 2.69 21 <br />3/8 9.4 <br />#4 15.1 <br />HDR-004 121.0- <br />131.0 <br />Qtz <br />Pegmatite 0.38 2.675 30 <br />3/8 21.6 <br />#4 27.2 <br />HDR-005 61.0-71.0 Granitic <br />Gneiss 0.8 2.675 38 <br />3/8 67.4 <br />#4 67.5 <br />HDR-005 186.0- <br />196.0 Talc Gneiss 0.75 2.679 32 <br />3/8 41.2 <br />#4 48 <br />4.2.3 Petrographic Analysis <br />In order to better understand the existing rock materials at the Morrison Quarry, HDR selected <br />samples for petrographic testing. Testing included a review of mineral properties (including <br />frailty and hardness of mineral grains) by preparing a polished slab of the sample. Following <br />preparation of the slab, a thin section was prepared in order to view the samples under a <br />petrographic microscope equipped to provide magnification between 20-1000x. Upon <br />completion of the first round of petrographic analyses, a second round was performed which <br />included X-ray diffraction (XRD) analyses, to better estimate the clay mineral portion of the <br />sample. The results of the analyses are summarized below, and the full mineral assemblage <br />breakdown is included in Appendix A, Subsurface Exploration Findings. <br />