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V M 3 . 1 Extraction Well and Manometer Point Installation Location and configuration of the extraction well is based primarily on the assessed distribution of petroleum hydrocarbons in the subsurface . The source of subsurface data is Western Geologic Resources, Inc. (WGR) "Subsurface Investigation" reports dated November 1989 and August 1990. 3 . 1 . 1 Location and Depth of Extraction Well and Manometer Points One extraction well pair (VEW-1) consisting of one shallow and one deep well casing, was installed at the west end of the former tank location. Two manometer pairs (MP- 1 and MP-2) were installed approximately 15 feet east of VEW- 1 and 25 feet west of VEW-1, respectively. Figure 2 shows the approximate locations of the extraction well and manometer points. MP-3 was not installed as originally planned. The presence of overhead and subsurface obstructions and overhead high voltage power lines prevented safe accessibility by the drill rig in the vicinity of MP-3's proposed location. The two manometer pairs (MP- 1 and MP-2) were installed to collect vacuum- pressure data from around the extraction well. Measurements recorded at each manometer during vapor extraction were used to evaluate the expected radius-of-influence for the selected blower. An inclined U-tube manometer filled with water was used to measure vacuum pressures at each manometer point. 3 . 1 .2 Extraction Well and Manometer Point Construction Bore holes for VEW4 Shallow and Deep, MP4, and MP-2 were drilled to / depths of 34 and 66 feet, respectively, using a Mobile Drill equipped with an eight inch Hollow Stem Auger. No groundwater was encountered in the bore holes. The VEW- 1 well pair is constructed of two-inch diameter, open-ended, blank PVC casing set in a #3 sand backfill to depths of 30 and 63 feet, respectively. MP- 1 and MP-2 pairs are constructed of 3/4 inch PVC casing set in #3 sand backfill to depths of 33 and 63 feet, respectively. The construction details for the extraction well and manometer points are shown on the Well Logs (Plates 2,3 & 4) Appendix A. 3.2 Soil Sampling & Baseline Chemical Analyses Chemical analyses were used to confirm the site assessment data, obtained by WGR in 1989-90, and to establish a baseline for soil contaminant concentrations which would be used to evaluate the effectiveness of the forthcoming in-situ vapor extraction remediation project. ,z REM E DIATI OI SERVICES , INC