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is beginning to retrogress as aeeas above the main scarp begin to slide as <br />well, particularly noticeable at the F-Seam Portal Bench. <br />State of Activity: Reactivitated because the area was previously identified as a landslide <br />area in the original site plans and documents and had a previously known <br />history of movement prior to construction of the Facilities. <br />In summary the "main landslide" can be characterized as a reactivated, advmtcing, singular, very slow to <br />extremely slow, moist to wet, translational earthen slide. <br />For the "secondary landslide" areas above the rock bluff and F-Seam portal wall, the landslide can be <br />characterized as follows: <br />Overall Dimensions: Present Maximum Width of 400 feet. <br />Present Maximum Length of 340 feet. <br />Maximum Depth of 20 feet. <br />Surface Area of 3 acres. <br />Maximum Volume of 101,000 cubic yards. <br />Maximum Ratio of Depth to Length of 0.06 <br />Type ojMovement: Sliding with a downslope movement of soil occurring dominantly at the <br />interface between the bedrock and the colluvium. <br />Mode ojsliding: Translational sliding mode with a mass of relatively shallow depth <br />displacing along a planar surface, sliding out over the original ground <br />surface. <br />Material: Earthen with 80% of the material smaller than 2 mm. <br />water Content: Moist to Wet at the time of failure, but at present dry. Material contained <br />enough water to have liquid flowing from it or supporting significant <br />• Ban Engineering Company July at, 1999 <br />PCDOC51209220/CAK 6 Appendix H <br />1999 Addendum to <br />1997198 Landslide Corrective Measures Report <br />