1997-07-28_GENERAL DOCUMENTS - M1973021 (9)

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and were used during development in combination with benches equal to or greater than 40-ft wide. The existing slope location is temporary and the highwalls and benches will change as the quarry is further developed. In addition, drainage diversion improvements were constructed in the southwest and ' southern parts of the Central Quarry in general accordance with approved drainage plans. These improvements consisted of 1) a contour diversion, 2) installation of three sedimentation drop structures, and 3) installation of a temporary 24-in. corrugated steel diversion culvert (with upstream settling pond)under a temporary haul road fill. ' 3.3 North Quarry Redevelopment and reconfiguration of the North Quarry per expansion approved in ' Amendment No. 4 was initiated during 1995. In general mining advanced from south and east to north and west, progressing up the ridge along the northeast and north boundaries of the North Quarry. This process continued at a larger scale during 1996 ' as mining activities for the year were concentrated in the North Quarry. North Quarry mining began primarily as a south to north operation, but was changed to primarily an east to west operation during 1996. This change was made by CAMAS ' to create more favorable interim mining slope orientations with respect to a dominant southerly dipping foliation jointing that exists in the North Quarry. ' Mining generally progressed in a sequence of 40-ft vertical highwalls with benches equal to or greater than 40-ft wide and, locally, 80-ft vertical highwalls with benches equal to or greater than 80-ft wide. Due to the geometry of the ridge and the mining ' sequence, none of the 1996 highwalls in this area were expected to be final quarry highwalls at the ultimate mine build-out. Hence, detailed geotechnical evaluations were not necessary and were not performed in the North Quarry during 1996, but ' routine observations were made. ' 4 G:\PROJECTS\20200\002\96ANNRPT.WPD