2023-10-31_REVISION - M1973021 (21)

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"TWINING CONCRETE INSIGHT Morrison Quarry Phase II Rock Petrography Page 3 4.0 FINDINGS/ROCK DESCRIPTIONS 4.1 Rock Sample 1: Gneiss with Intermixed Sedimentary Material Received Condition The sample consists of two rock fragments that measure 140 x 110 x 45 mm (5 '/2 x 4 % x 1 3/4 in.) and 130 x 80 x 65 mm (5 '/8 x 3 '/8 x 2 % in.) (Figure 4.1a). All exterior surfaces of the rock sample are rough and uneven. One rock fragment was selected to be cut to make a polished slab and thin section for petrographic examination. Polished Slab The rock on the polished surface is light to dark gray and reddish-brown (Munsell Soil Color GLEY 1 3-5/5GY and 5YR 8-4/1) and consists of feldspar and quartz intermixed with minor amounts of clay and carbonate material (Figure 4.1b, Figure 4.1c, Figure 4.1d). The rock sample exhibits a moderately well developed gneissose structure with alternating felsic (feldspar, quartz) and darker mineral layers (biotite). Gneissic layers measure up to —64 mm (2 '/2 in.) thick and are laterally continuous. Felspar and quartz are fine to medium grained and measure up to —1 mm (40 mil) in diameter. Mica grains exhibit a preferred orientation along quartz grain boundaries, indicating a moderately well foliated texture. The rock exhibits randomly oriented veins or fractures that consist of clay minerals and fine grained carbonate material. The rock sample is fairly hard and competent, and has a hardness of (Mohs 3.5-4+). A few clay-rich areas exhibit a Mohs hardness of<2. Thin Section The rock type is classified as a gneiss with intermixed sedimentary material (Figure 4.1e, Figure 4.1f, Figure 4.1g, Figure 4.1h). The sample consists of major amounts (>10%) of fine to medium grained felspar and quartz measuring up to —1 mm (40 mil) in diameter. Minor amounts (1-10%) of biotite, muscovite, clay minerals (illite, smectite, kaolinite), and carbonate material (siderite, dolomite, calcite) is observed, and a trace amounts (<1%) of opaque minerals is also observed. Quartz and feldspar grains are subhedral to anhedral in shape and occur as massive interlocking grains. Mica grains are elongated in shape and exhibit a moderately well developed preferred orientation. Clay minerals and carbonate material occur as anhedral grains within randomly oriented veins and/or fractures. Sample 1: Gneiss with Intermixed Sedimentary Mate Major minerals Feldspar (-50-60%),quartz(-30-40%) (10-100/by volume of rock) Minor minerals Biotite and muscovite (-5-10%), clay minerals (-5-101/o), carbonates (1-10%by volume of rock) —1-5% Trace minerals rite,opaque minerals <1%b volume of rock) p XRD Results X-ray diffraction (XRD) results indicate the rock consists of—54% feldspar, —33.8% quartz, —5.9% illite/smectite, —2.3% mica, —2.2% siderite, —1% dolomite, —0.3% calcite, —0.3% kaolinite, and—0.2%pyrite (see attached report). Report No. 237923.d 20 February 2023