ARCHIVED REPORTS XR0012673 - Laserfiche WebLink

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a� All drill cuttings will be stored temporarily on site on top of and covered by plastic sheeting pending laboratory analysis of the boring samples. Additional sampling and testing of the stockpiled soil may be required in order to meet landfill disposal criteria. Following receipt of the laboratory results, the drill cuttings will be trensported from the site by a state-licensed hauler to an appropriate disposal facility. Upon completion of drilling, any bore holes not utilized for monito0n.0 well construction will be backfilled with a 9-sack slurry. The slurry will not free tall more than ten (10)feet. The slurry will be placed by tremie to depths greater than ten feet. GROUNDWATER MONITORING WELL CONSTiRIICTION For:hs proposed groundwater monitoring wells MW-4 and MW-5, approximately 20-feet of 4-inch diameter PVC screen with 0.020-inch slots will be installed from the bottom of the boring to approximately 5 feet above the observed water table. For the proposed groundwater monitoring well/vapor extraction well MW-113, approximarnly 20 feet of 6-inch diameter PVC screen with 0.020-inch slots will be installed from the bottom of the boring to approximately 5 feet above the observed water table. Figure 4 shows a typical monitoring well construction detail. Solid-walled, 4- or 6-inch diameter PVC will be installed from the top of the screened interval to the surface. The filter will consist of No.3 Lone Star sand, and will be placed to an elevation approximately z-;set above the top of the screen. The approximate volume of sand necessary to construct the filter will be calculated in order to identify and prevent bridging during filter placement. Bentonite pellets will be placed on top of the filter pack for an approximate 24eet interval. A sand-cement grout will be placed from the top of the Bentonite pellets to the surface. The monitoring wells will be developed, purged and sempled in accordance with Aegis' SOP. Groundwater samples will be sent to a state-certified Iauoratory fcr analysis. The groundwater monitoring wells will then be surveyed and water levels W] be measured. The water samples will be analyzed for concentrations of: a) total purgeabie petroleum hydrocarbons, as gasoline (TPPH); b) benzene, toluene, xylenes, and ethylbenzene (BTX&E) and c) ethylene dibromide and 1-2 dichloroethane (EDB & EDC), by CAL DHS DRAFT TPH (modified) and EPA Method 8240 (GC/MS). ANALYTICAL LABORATORY AND PRACTICAL QUANTITATION LIMITS The laboratory to be used for the analyses discussed above is tentatively identified as Coast-to-Coast Arafytical services of Napa, California, a state-certified analytical laboratory. Selected soil and groundwater samples will be collected and submitted to the laboratory in accordance with Aegis' SOP. 90a9BA.WPy .4' E