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orientations vary slightly from the values used in past reports and also include an <br />additional wall orientation along the west boundary of the quarry. The dip <br />direction and slope angle utilized to represent the final quarry walls are <br />presented in Table 1 below. <br />Table 1: Representative Quarry Wall Orientations <br />Quarry Wall Slope Direction of Wallr,r <br />East 242° <br />Northeast 175° <br />Northwest 151° <br />West 091 ° <br />West 120° <br />Southwest 036° <br />Southwest 016° <br />Southeast 335° <br />Slope Angle (degrees)tz~ <br />45° <br />35° " <br />35° <br />45° <br />45° <br />45° <br />45° <br />45° <br />Note: 1: Slope directions are shown as dip directions measured from true north (0°). <br />2: Dip angles are measured relative to the horizontal. <br />Based on lower slope angles as recommended from previous studies <br />In the previous L&A quarry evaluations (L&A, 1997-2002), a total representative <br />angle of friction (~ + >) = 40° was used for the wedge stability analysis, where "~" <br />was the basic friction angle and "i "was the surface roughness angle (Hoek and <br />Bray, 1977). The roughness angle is the angle between the basic plane of the <br />joint and the planes representing the surface of ripples or undulations of the joint <br />surface. This value was based on our research of the subject, including <br />published data from various sources, and was a "best guess" given that no <br />actual laboratory testing had been performed previously on rock from the quarry. <br />However, as a result of the 2003 geotechnical investigation, 20 rock samples <br />were selected for direct shear testing in order to better define the strength of the <br />rock (L&A, 2003). The test results produced only a basic friction angle, ~, and <br />indicated that the basic friction angle of the discontinuities ranged from 13.7° to <br />49.3° with an average value of 28°. These published results do not include the <br />two direct shear tests run on samples with clay along the foliation plane, which <br />produced an average friction angle of only 5°. For this study, a basic friction <br />angle of 28° plus a roughness angle of 5° (total of 33°) was used for all of the <br />-6- <br />