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_~_ backfill material would consist of a mixture of on-site overburden soils of silt, sand and clay. The oversteepened temporary pit wall cut slope will have potential for failure but the extent of slope movement should be well within the property limits. The following parameters were assumed for the backfill and native gravel terrace soils: Compacted ~ = 30° Backl"ill Soils c = 100 psf ym = 115 pcf Gravel ~ = 40° Terrace Soils c= 0 ym = 140 pcf A limit-equilibrium stability analysis was performed with the computer program GEO-SLOPE/W using the Janbu method of slices. The design section was analyzed assuming ground water level is below the base of the pit excavation. The results aze presented in the stability printout shown on Fig. 7, and indicate a safety factor of about 1:6. The safety factor is the ratio of forces which resist slope movement to forces which produce movement in the model. A safety factor of at least l.4 is typically considered acceptable for a compacted earth embankment. Based on our findings, the design section for the final pit wall reclamation should have adequate stability against slope failure for the design conditions. The graded slopes should be protected against erosion by revegetation or other meaas. The topsoil on the property should be stripped and stocl.~il'ed separate from the underlying soils proposed for use as pit wall backfill. Groundwater seepage, if encountered in the pit wall cut, should be collected in trench drains that daylight to below the toe of the final pit wall slope. The Stremme and Gates Ditch will probably need to be piped through Phases 4, 5 and 6 to reduce leakage that could potentially affect long term slope stability. Pit wall backfill should be placed in lifts that aze compacted to at least 90% of standazd Proctor density and coasist of soils that meet the minimum strength parameters assumed in the stability analysis. We can assess the GEOTECH