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Geotechnical Stability Exhibit <br /> Engineering Evaluation of Highwall Design for the South Quarry of the Morrison Quarry <br /> y � <br /> LEGEND <br /> Colorado Geology Easemapps <br /> CO_geol_poly USGS Topographic Maps(Callopo) <br /> Igneous.intrUKW <br /> Metamorphic,gneiss <br /> Metamorphic,undifferentiated <br /> Sadlmantary clastic <br /> Sedimentary urr lifferentlaled <br /> Water <br /> CO_structure <br /> I formal fault,certain <br /> I+r <br /> PROJECT, AREA <br /> Figure 3: Geologic map of project area <br /> Morrison Quarry Geology <br /> Bedrock observed within the Morrison quarry consists of mostly fine to medium grained granitic <br /> gneiss or biotite gneiss. Occasional pegmatite intrusions are present throughout, as are shear <br /> zones visible in widths that range from several inches to approximately 20 feet. The rock is <br /> typically slightly to moderately weathered, with some highwall sections being more highly <br /> weathered. Locally, talc-gneiss or clay-rich gneiss is present, and is characterized by moderate <br /> to highly weathered conditions, soft to medium hard, and white to gray in color. <br /> Mining in the quarry primarily focuses on the Precambrian granitic and biotite gneiss units. <br /> Foliations dominate the structure of the South Quarry, and are present throughout the gneiss <br /> units, undulating locally, but generally striking in a northwest-southeast direction, and have a <br /> shallow dip to the northeast. Foliations are truncated by joints and shear zones, as well as <br /> mafic and pegmatite intrusions. Faulting has also been locally mapped throughout the south <br /> quarry and is indicated on the geologic mapping in the area. <br /> May 2023 1 7 <br />