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"TWINING <br /> CONCRETE INSIGHT <br /> Morrison Quarry Phase II Rock Petrography Page 20 <br /> 5.0 CONCLUSIONS <br /> Results of petrographic testing indicate the samples consist of the following rock types: <br /> Rock Sample 1: Gneiss with Intermixed Sedimentary Material <br /> Rock Sample 3: Biotite-muscovite-kaolinite gneiss <br /> Rock Sample 1 represents a gneiss with intermixed sedimentary material and consists <br /> predominantly of feldspar and quartz intermixed with minor amounts of clay and carbonate <br /> material. The rock color on the polished surface is generally light to dark gray and reddish- <br /> brown. The rock sample exhibits a moderately well developed gneissose structure with <br /> alternating felsic (feldspar, quartz) and darker mineral layers (biotite). Gneissic layers measure <br /> up to —64 mm (2 '/2 in.) thick and are laterally continuous. Felspar and quartz are fine to medium <br /> grained and measure up to —1 mm (40 mil) in diameter. Mica grains exhibit a preferred <br /> orientation along quartz grain boundaries, indicating a moderately well foliated texture. The rock <br /> exhibits randomly oriented veins or fractures that consist of clay minerals (illite, smectite, <br /> kaolinite) and fine grained carbonate material (siderite, dolomite, calcite). No distinct <br /> laminations or bedding planes are observed. The rock sample is fairly hard and competent, and <br /> has a hardness of(Mohs 3.5-4+). A few clay-rich areas exhibit a Mohs hardness of<2. <br /> Rock Sample 3 represents a biotite-muscovite-kaolinite gneiss that consists of quartz, kaolinite, <br /> biotite, and muscovite with minor amounts of feldspar and sillimanite. The rock color on the <br /> polished surface is generally greenish-gray and pale yellow-green to reddish-brown. Rock <br /> sample 3 exhibits more distinct foliation relative to Sample 1, displaying a well developed <br /> gneissose structure with alternating compositional layers that measure up to —10 mm (% in.) <br /> thick and are laterally continuous. Compositional layers of quartz exhibit interlocking grains that <br /> measure up to —2 mm (80 mil) in diameter. Greenish-gray to pale yellow-brown banding <br /> throughout the rock sample is attributed to well foliated biotite and muscovite grains. Biotite and <br /> muscovite grains exhibit a Mohs hardness of 2-3. The rock sample exhibits several randomly <br /> oriented veins consisting of an off-white to pale yellow-green and reddish-brown mineral that is <br /> soft and friable (Mohs <2). This mineral exhibits physical and optical characteristics consistent <br /> with kaolinite and/or talc. Kaolinite is typically associated with weathering of feldspar and mica <br /> grains. Talc is associated low grade metamorphism. XRD analysis of the rock sample revealed <br /> that the mineralogical composition of the soft material is most consistent with kaolinite, which <br /> exhibits a Mohs hardness of 2-2.5. The rock sample is generally soft and friable but exhibits a <br /> Mohs hardness ranging between<2-4+. <br /> This concludes work performed on this project to date. <br /> r <br /> Conor O'Dowd Meredith Strow <br /> Petrographer Principal Petrographer <br /> Report No. 237923.d 20 February 2023 <br />