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January 15, 2008 <br />Page I1 <br />All four of the RMR indices are hyperbolic fits to the indices values above given by the <br />relations in Equation 1. <br />RMRI =-2e-4 xUCS2 + 0. 105x UCS + 0. 9 <br />RMR2 =6e-4 x RQD 2 + 0.1134 x RQD + 2.79 <br />RMR3 = 0.012 x 2000 x (1- F125) - 2000 x (I - F125)2 x 2e-6 <br />RMR4 = -1. 0714 x (FC + 1)2 -1.0714(FC+1)+32 <br />where <br />F = [0.5 x (FF - 3)(5 - FF) + FF]x [0.5 x (FT - 3)(FT - 1) + FT1 <br />FC=I+P+R+FD <br />4 <br />(Eqn. 1) <br />The fracture frequency factor, F, is scaled by the fracture frequency index and the <br />fracture type index. The .fracture condition factor, FC, is the average of the four fracture <br />condition indices infilling, planarity, roughness, and fracture durability. <br />The rock characteristics from the logs are summarized in plots of lithologic layer versus <br />RQD and RMR. Figures 5 through 13 show examples of the rock mass characterization for <br />seven boreholes within the landslide (07-GI1-CCR through 07-GI7-CCR) and the two boreholes <br />in the K-Pit area (07-GX5-CCR and 07-GX6-CCR). The logs from boreholes drilled inside the <br />landslide block indicate the"following: <br />The shear zone has been identified in 8 of 9 boreholes at an average depth of 96 ft below <br />ground in the L-Roof mudstone layer. <br />There is extensive disturbance above the'slip plane along the perimeter of the landslide <br />block, especially on the east side adjacent to the G-Dip Pit box cut. This disturbance is <br />the result of material from the pit floor being buckled up into the pit floor and bulking the <br />material above it. <br />• Open fractures were observed in nearly all holes in upper sandstone units. The massive <br />block is likely more loosely packed than expected immediately after the landslide. <br />• Only one borehole shows disturbance below L-Seam, but the projection of the slide plane <br />is consistent with other holes. This is likely due to a roll in the bedding which the slide <br />plane sheared through. <br />Low RQD and low rock mass strengths above shear zone are primarily due to slope <br />related ground disturbance and the degree of disturbance is dependent on local fracturing <br />and fracture orientations. <br />• The rock mass disturbance is primarily due to opening of larger-scale, tightly-packed <br />fractures exacerbated by the landslide sliding downhill on undulating bedding surfaces. <br />Agapito Associates, Inc.