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Unocal Service Station No 0187 September 21, 1994 purged to remove accumulated sediments and improve hydraulic communication between the well and the surrounding aquifer. Development continued until the discharge water from each well ran clear and the groundwater parameters (temperature, pH, and conductivity) had stabilized Approximately 50 gallons of groundwater were removed from Well U-1, approximately 40 gallons from Well U-2, and approximately 34 gallons from Well U-3 Well development field data sheets are presented in Appendix C. Well Monitoring and Sam lin The newly installed wells will be monitored and sampled on a quarterly basis by MPDS Inc of Concord, California. Stockpile Sampling One sample of the drill cuttings was collected for disposal analysis. This sample (US-2) consisted of four discrete sample tubes, composted !n the laboratory prior to analysis Stockpile samples were handled as described in Appendix A Wellhead Survey Following completion of the wells, the well elevations were surveyed by Virgil Chavez Land Surveying of Vallejo, California (license #PLS-6323) Top of casing and vault box elevations were measured relative to Mean Sea Level These data have been forwarded to MPDS for inclusion in the Quarterly Monitoring Reports. A copy of the Surveyor's report is attached to Appendix D SOIL AND GROUNDWATER CONDITIONS Soil Conditions Based on subsurface work performed to date at the subject site, soil underlying the site is predominantly clay (CL) to approximately 40 feet bgs A clayey sand (SC) stratum, approximately two to six feet thick, was encountered in all borings except well boring U-2 at approximately 19 feet bgs Clayey sand units approximately three and five feet thick were encountered at approximately seven feet bgs in boring U-K and approximately 30 feet bgs in boring U-J, respectively These clayey sand strata do not appear to be laterally continuous across the site Report No 4827 703 5 4 GeoStrategies Inc. n i