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6.2.3 Completion of Soil Borings to SVE Extraction Wells The completion of the soil borings to SVE extraction wells will be different for the shallow and deep wells. Each proposed completion practice is described below: Shallow Wells (<25 feet bgs) (Above the"A" Clay) SVE well casing will consist of 2-inch diameter Schedule 40 PVC with a 0.020-inch slot size screen. The screen interval is planned to span a vertical distance of approximately 20 feet of the upper zone, immediately above the "A" Clay. A coarse-sand filter pack will be placed from the bottom of the screen up to approximately 2 feet above the top of screen interval. A bentonite seal approximately 2-feet thick will be placed on top of the sand pack, and cement-bentonite grout will seal the remaining annular space. At the surface, each well will be completed with a 12-inch diameter steel traffic-rated box to allow space to connect the required SVE piping. Typical well construction diagrams for the shallow SVE wells are presented as Figure 13. Locations of the wells are presented in Figure 11. Deep Wells (-60 feet bgs)(Below the "A" Clay) SVE well casings will consist of 2-inch diameter Schedule 40 PVC with a 0.020-inch slot size screen. The screen interval is designed to span a vertical distance of approximately 30 feet of the lower zone, immediately below the "A" Clay and into the underlying first groundwater bearing zone. This spanned distance will extend into the first water bearing zone approximately 10 feet (Figure 14). Locations of the wells are presented in Figure 11. A coarse-sand filter pack will be placed from the bottom of the screen up to approximately 2-feet above the top of screen interval. A bentonite seal approximately 2-feet thick will be placed on top of the sand pack, and cement-bentonite grout will seal the remaining annular space to seal off the upper zone above the "A" Clay. At the surface, each well will be completed with a 12-inch diameter steel traffic-rated box to allow space to connect the required SVE piping. Typical well M ain\D:AEnvironmentaI\LN CV\10152007.wpd 37