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,_ ,- <br />Reporting Period July 21, 1997 -July 27, 1997 <br />2 <br />Sylvester Gulch Main Road: Inclinometer I-12 was installed at the crest of the failed fill <br />slope on July 22, and monitored daily for the remainder of the week. The initial five days of <br />data indicates a slip plane at approximately 6' below surface, which places the slip plane within <br />the fill rather than in native ground; however, total movement in five days is less than 0.5 <br />inches. Monitoring will continue daily, and Golder Associates will continue evaluating these <br />results. Surface surveys do not indicate measurable (> 0.1') movement either above the cut <br />slope or below the fill area. <br />A draft of the sixth inclinometer survey at Borehole 97-4 (approximately Station 30+00) was <br />received. Movement continues, but velocities are reduced. Monitoring will continue and re- <br />evaluation of the current design slope at this location is in progress. The Main Road <br />alignment along the north slope of the shaft site area (Station 85+00 to end) remains dry and <br />stable. <br />Landing #2 Road: The light-use road to Landing #2 was inspected on July 25. Soil cut <br />slopes are dry and appear stable. Rock cuts appear solid and competent. No water was <br />observed in any cut slope. <br />Dewatering Borehole Road: The three sight lines (upper, middle, lower) between Stations <br />15+00 and 19+00 were observed on July 25 The sight lines and slope conditions remain as <br />previously reported. Minor seepage associated with sandstone strata along this road <br />continues, and construction of French drains in this area are planned. MCC will continue to <br />monitor these slopes. <br />Substation: Continued visual observation of the failed slope above the substation shows no <br />obvious additional movement in the slumped area and no advancement of the head scarp into <br />the Landing #2 road. Additional survey data were collected daily and are being evaluated by <br />Golder Associates. Some survey stakes were replaced due to being destroyed by boulder <br />blasting operations. Golder Associates evaluated tie-backs and pilings as potential remedial <br />stabilization methods for the head scarp; however, these were rejected by MCC for economic <br />and constructability reasons. Per MCC's slope stability action plan, MCC will continue to <br />look at alternative stabilization techniques, and will continue to monitor and evaluate this <br />slope. <br />Shaft Site #1 and #2: The top of the cut slopes was walked on July 25 and appeazs stable. <br />No cracking, slumping, or other instabilities were observed and no water was observed. Per <br />MCC's slope stability action plan, re-evaluation of the stability of the cut slope above the <br />intake shaft is in progress. French drains installed at the southwest corner of the site (start of <br />the Electric Borehole Road) are successfully dewatering the springs uncovered in this area. <br />