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8) The small surficiat slide located in the exposed highwall faces along the <br />west wall appears to have experienced a slight increase in size relative to <br />conditions photographed and documented in 2002. The slide does not <br />have any impact on the overall stability of the wall (Photo 8), as it is limited <br />to less than a single bench in height, and is considered a localized wedge <br />failure. <br />9} A section of the northeast wall of the main pit originally experienced planar <br />failure along the foliation planes in 1998. Following removal of the next <br />bench in 1999, a larger section that is approximately 350 feet wide by 250 <br />feet, experienced planar failure. The north wall pit slopes were modified in <br />response to these failures, and based on continued photo documentation <br />and visual monitoring since that time, no additional movement has been <br />detected (Photo 9). As described in previous annual reports, the failure is <br />believed to have occurred when a continuous foliation plane was <br />intersected by two or more existing discontinuities, and daylighted in the <br />exposed highwall. (See the Wedge Stability Analysis section of this report <br />for a complete description of this type of failure). <br />Based on the current topographic map (December, 2003) of the quarry, the <br />overall effective angle of the north pit walls has been modified over the last <br />' three benches to an angle of 35° per L&A recommendations in May 2003 <br />report. The failure surfaces (i.e. the surtaces along which movement has <br />' occurred) remain at a "residual strength" and therefore are less resistant to <br />additional loading. Although the slope configuration is currently stable, the <br />failure mechanism could be reactivated upon removal of subsequent <br />benches, resulting in movement of additional material. <br />10) The highwall adjacent to the lower asphalt plant facilities and the area <br />above the highwall were visually inspected as part of the field <br />reconaissance inspections performed on February 27, 2004. Unlike the <br />' highwalls for the areas currently being mined, the bedrock in the highwall of <br />' -t0- <br />