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ATTACHMENT 13-4D <br />Haul Road A/Pond 006 Landslide Remedla[Son Plan <br />• <br /> Thls attachment provides the remedial ac[Son plan for [he slope failure which 15 located <br /> below Haul Road A and in [he northeast corner of Pond 006. This slope origSnally failed <br /> in the summer of 1990 and a geotechnical investigation was conducted by Ground <br /> Engineering Con sultants, Inc. and a report prepared on October 10, 1990. Seneca, over <br /> the years, has addressed this slope several LSmes since then, but the area continues to <br /> slip. <br />After the Las[ slide occu rx ed, Seneca utilized a backhoe to excavate all [he saturated <br />slope materials to Let this area dry out. Du ri nq the excavation, we observed where water <br />was seeping out through the wall in several Locations. The excavation was continued <br />several feet below the elevation where water was seeping. A bench running from both ends <br />of [he failed slope and proceeding to the middle of the failure was constructed. A <br />trench was excavated from the middle down [o [he water level of the pond. A layer of <br />filter fabric such as Mira fi 140N will be placed on the bottom of the bench/trench. A <br />layer of approximately six inches of granular mate[tal will be placed on and wrapped in <br />the filter fabric [o act as an underd rain system. This uas one of the alternatives <br />considered in the original qeo techni cal investigation. The underd rain system and <br />reconstructed slope will then be backfilled with new, dry overburden materials and sloped <br />to a 3:1 or 9:1 slope from the toe of the slope. It is believed this will act as more of <br />a permanent fix than what has been attempted In Che past Eew years. <br />II 1 <br />l_J <br />• <br />13-4D-1 Revised 06/20/97 <br />