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appear more prevalent along the south wall. In many areas along the south <br />walls, the rock face has numerous overhangs exposing the underside of the <br />foliation joint surfaces. <br />8) Occasional shear zones were observed along the west wall and south <br />bench of the quarry (Photo 8). The shear zones varied in width from inches <br />to several feet across. <br />9) The small surficial slide located along the west wall appears to have <br />experienced little to no increase in size, relative to conditions photographed <br />in 1998, and still does not appear to have any impact on the overall stability <br />of the wall. <br />10) The northeast wall of the main pit has experienced some instabilities in the <br />form of planar failures along the foliation planes. However, no additional <br />movement has been detected since the slide occurred in November 1999 <br />(Photo 9). As described in previous annual reports, the failure is believed to <br />have occurred when a continuous foliation plane, intersected by two or <br />more existing discontinuities, daylighted in the exposed highwall. (See the <br />Wedge Stability Analysis section of this report for a complete description of <br />this type of failure). <br />Based on visual inspection, it appears that the effective angle of the slope <br />has been altered in the vicinity of the slide to approximately 34 degrees. <br />Discontinuity measurements obtained from exposed rock surfaces below <br />the slide zone in May 2001 indicate that the dip of the foliation ranged from <br />27 to 37 degrees, with an average dip angle of 31 degrees. This average <br />dip is less than the foliation joint dips measured elsewhere in the quarry. It <br />is important remember that the foliation undulates throughout the quarry, <br />2002 Spec-Agg Annual Report Page 10 <br />