2023-10-31_REVISION - M1973021 (21)

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"TWINING CONCRETE INSIGHT Morrison Quarry Phase II Rock Petrography Page 12 4.2 Rock Sample 3: Biotite-Muscovite-Kaolinite Gneiss Received Condition The sample is a rock fragment that measures 230 x 180 x 110 mm (9 '/8 x 7 '/8 x 4 % in.) (Figure 4.2a). All exterior surfaces of the rock sample are rough and uneven. Freshly fractured surfaces display a sub-vitreous to pearly luster. The rock sample as a whole is friable and soft. Polished Slab The rock on the polished surface is greenish-gray and pale yellow-green to reddish-brown (Munsell Soil Color GLEY 1 3-5/5GY and 5YR 8-4/1 to 7.5R 5-6/6) and consists of quartz, kaolinite, biotite, and muscovite, with minor amounts of feldspar and sillimanite (Figure 4.2b, Figure 4.2c, Figure 4.2d). The rock sample exhibits a well developed gneissose structure with alternating compositional layers that measure up to —10 mm (% in.) thick and are laterally continuous. Compositional layers of quartz exhibit interlocking grains that measure up to —2 mm (80 mil) in diameter. Greenish-gray to pale yellow-brown banding throughout the rock sample is attributed to well foliated biotite and muscovite grains. Biotite and muscovite grains exhibit a Mohs hardness of 2-3. The rock sample exhibits several randomly oriented veins consisting of an off-white to pale yellow-green and reddish-brown mineral that is soft and friable (Mohs <2). This mineral exhibits characteristics consistent with kaolinite and/or talc. Kaolinite is typically associated with weathering of feldspar and mica grains. Talc is associated with low grade metamorphism. The rock sample is generally soft and friable but exhibits a Mohs hardness ranging between<2-4+. Thin Section The rock type is classified as a biotite-muscovite-kaolinite gneiss (Figure 4.2e, Figure 4.2f, Figure 4.2g). The sample consists of major amounts (>10%) of fine to medium grained quartz, kaolinite, biotite, and muscovite. Minor amounts (1-10%) of feldspar and sillimanite is observed, and trace amounts (<1%) of opaque minerals and clay minerals (illite, smectite, kaolinite) is also observed. Quartz occurs as segregated layers of interlocking subhedral grains measuring up to —2 mm (80 mil) in diameter. Mineral grains that display 1st order to high 2nd order birefringence colors exhibit mineral textures that are consistent with kaolinite and/or talc. Mica grains are elongated in shape and exhibit a preferred orientation. Sample 3: biotite- te-kaolinite gnei Major minerals o 0 0 (10-100%by volume of rock) Quartz( 60-70/o),kaolinite(�10-15/o),biotite and muscovite(�10-15/o) Minor minerals Feldspar 5 10% sillimanite 1 3% (1-10%by volume of rock) p (� )° (� ) Trace minerals Opaque minerals,clay minerals (<1/o by volume of rock) ARD Results X-ray diffraction (XRD) results indicate the rock consists of —65.1% quartz, —12.8% kaolinite, —10.6% mica, —9.5% feldspar, —1.1% sillimanite, and —0.9% illite/smectite (see attached report). Report No. 237923.d 20 February 2023