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Martin Marietta Materials Spec-Agg 2017 Annual Report 6.3 Friction Angle A representative angle of friction (� + i) = 33' was used for our kinematic analysis, where"0" is the basic friction angle and '7 is the surface roughness angle (Hoek and Bray, 1977). The surface roughness angle is the angle between the basic plane of the joint and the planes representing the surface of undulations on the joint surface. This value was based on the results of the direct shear testing performed as part of the 2003 geotechnical investigation (Lachel, 2003). The test results produced only a basic friction angle, �,and results indicated that the basic friction angle of the discontinuities ranged from 13.70 to 49.30 with a mean value of 280. These results do not include the two direct shear tests conducted on samples with clay material along the foliation plane, which produced an average friction angle of 5°. A generally accepted and conservative value of 50 was selected for the surface roughness angle, 'T. 6.4 Kinematic Analysis We performed kinematic structural discontinuity analyses for each of the representative quarry wall orientations presented in Table 2. The analyses were performed to evaluate potential rock slope failure modes controlled by rock mass discontinuities based exclusively on the geometric relationships of the discontinuities measured. Potential rock slope failure modes include sliding of wedges formed in the slope by the intersection of two discontinuity planes, sliding of rock blocks along a single planar discontinuity, and toppling rock blocks. The computer program DIPS 6.017 (Rocscience, 2015)was used for the kinematic stability analysis. Inputs for the analyses include the following: 1) Representative discontinuity orientations (dip and dip direction)from data collected during the 2016 site visits (Table 1). 2) Mine Slope Orientations (dip and dip direction)as presented in Table 2 and shown in Figure 2. A total of 13 slope orientations were considered. 3) Estimated Rock Mass Discontinuity Interface Friction Angle. A typical interface friction angle of 33 degrees was considered in all cases for the kinematic analysis, as discussed in Section 6.3. The kinematic analysis stereonet plots are presented in Figures 8 through 15. Representative discontinuity orientations are shown as green lines. The slope orientation for the considered wall is shown as a blue line. The friction circle is shown as a black line. Each kinematic analysis plot is evaluated based on where discontinuities plot in relation to the"critical zone", which is shown as a light red shaded area on the stereonet plots. 6.4.1 Potential Failure Modes 6.4.1.1 Planar Failure Planar failure is indicated as a potential failure mode if the dip vector of a discontinuity falls between the dip direction of the slope face and the friction cone representing the assumed discontinuity interface friction angle. The following four conditions, defined by Hoek& Bray(1977), must be met in order for planar failure to occur: February 27,2017 Page 7 Lachel &Associates, Inc. Project 16C64003 00 ©2017 All Rights Reserved