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<br /> <br />R. J. Irish <br />Consulting Engineering <br />Geologist, Inc. <br />condition of high natural stability is evidenced commonly across the ridges of the quarry site by <br />tall cliffs faced by near-vertical joints. Those appear to have been stable for a very long time. <br />The risers of the cut-slopes should be dressed by barring-down of loose rock blocks and <br />slabs that otherwise, in time, could become detached and undermine the slope. The benches <br />should be sloped to their termini to promote rapid surface water drainage from the cut-slope. <br />This will minimize ponding and, in consequence, limit seepage into the jointed rock. Also, a <br />drainage ditch should be excavated immediately upslope from the upslope tip of the quarry to <br />capture surface water run-off and divert it around the quarry and quickly off the slopes of the <br />ridges. Surface water percolating into the rock mass could destabilize that mass by raising <br />water pressures along the joint and fracture surfaces; and by wetting, thus slickening the joint <br />and fracture planes, thus materially reducing friction factors. Prevention of that seepage can be <br />as important to cut-slope stability as the cut-slope angle and careful drilling and blasting. <br />We hope are observations, assessments, and conclusions will be of service to you. If you <br />would like to discuss any aspects of this report, however, please call. <br />Yours truly, <br />Robt. James Irish, P. G. <br />Consulting Engineering Geologist <br />4 <br />