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Former Beacon Station 494 - - — August 8, 1995 AD,��fllla*a Acapccmwnf 1?r PW total depth of the borings The sediments encountered in the borings were identified using the Unified Soil Classification System (USCS) A copy of the USCS is shown on the Bonng Log Symbol Key in Appendix C Soil cuttings generated during drilling operations were stockpiled on and covered with plastic and left on site for disposal by Ultramar at a later date Four soil samples were collected from the stockpile These four samples were composited at the laboratory and analyzed for gasoline hydrocarbons Vapor Well Installation Soil boring CB-2 was completed as a vapor extraction well (Figure 2) The vapor well was completed to a depth of approximately 47 feet bsg The lower portion of the well (37 to 47 feet bsg)was constructed of 2-inch ID schedule 40 polyvinyl chloride (PVC)well screen with 0 020- inch slots Blank PVC casing (2-inch ID) was extended to the surface The annular space opposite the well screen of each well was backfilled with#3 Monterey sand to 1 foot above the screen A seal of bentonite was then placed above the screen, and a mix of cement and sand was used to complete the seal to the surface The well was completed with a flush-grade well box at the surface The top of the well casing was secured with locking watertight expansion cap Well construction details are shown on the boring logs in Appendix C LABORATORY METHODS AND RESULTS Soil Samples Selected soil samples collected from borings CB-1 through CB4 and the stockpiled soil were submitted under chain of custody (COC) to West Analytical Laboratory (WEST) in Davis, California (Certification No 1346) Soil samples submitted for laboratory analysis were selected based on the field screening evaluation for the presence of petroleum hydrocarbons • 1494 11-RPT 4 HORIZON ENVIRONWNTAL INC