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Reporting Period August 18, 1997 -August 29, 1997 Page 4 Substation: Visual observation of the slope above the substation on 8/20, 8/25, and 8/28 indicates the reappearance of the former scarp lines is continuing at a slow and gradual pace, and no advancement of the head scarp further upslope and into the Landing #2 road was observed. Survey stakes placed across the head scarp were observed on 8/25 and indicate approximately I/4 to 1/2 inch of additional dowgslope movement since 8/19. Survey data taken on 8/22 also indicates approximately 0.3 feet of additional movement at station SL-3 (just below the head scarp) in the previous week. On 8/26, MCC began implementing the slope stabilization measures for this slope described in the report of August 20th. (e.g., filling the midslope ditch with rock and gravel to re- establish astable slope configuration) A test trench was also excavated across the eastern scarp line to investigate scarp depth, as recommended by CDMG. Although the soil material became moister with depth, no saturated zones or obvious slip planes were observed. Monitoring of this slope will continue. Shaft Site #1 and #2: The compacted soil buttress installed to stabilize the shallow slope failure on the steep cut slope south of Shaft #1 was observed on 8/20, 8/25, and 8/28. No new movement was visually detected. Slopes to either side of the buttressed area were also observed and appeazed stable. Data from the survey prisms and hubs placed on and above this slope confirm no movement is occurring. Visual monitoring and collection of surface survey data will continue. Electric Borehole Road No additional springs have been encountered. Road cuts and fills (under construction) aze dry and stable. Shaft Site #3 Cleazing/topsoil removal operations at the Shaft #3 site were completed on 8/21 and cut slopes benches at Shaft #3 were begun on 8/22. As of 8/28, approximately 7 benches have been completed using top down construction methods. All benches except the top two have been excavated into hazd sandstone rock. Slopes are dry and stable. Golder Associates completed stability analyses of the cut slope which indicated acceptable safety factors (FS=1.26) for cuts through colluvium, however, the significant amount of rock being encounterd indicates the strengths (and safety factors) will be significantly higher than calculated. As discussed with CDMG staff on 8/19 and 8/20, the site layout for the Shafr #3 bench and cutslopes has been field modified to address MCC (and CDMG) concerns pertaining to hydrology and slope stability. Field modifications consist of reorienting the pad such that potentially unstable cut slopes on the southern hillside aze eliminated. This reorientation also allows the use of open channels for stotmwater control, reducing total culvert length, and reduces total earthwork from approximately 150,000 CY to 40,000 CY. As agreed to with CDMG staff', a letter detailing these field modifications will be submitted to the Division.