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Well Installation and Site lnvesti anon Re ort ARCO Facility No.5469 Stockton,California Page 4 using the Unified Soil Classification System. Boring logs detailing soil lithologies are presented in Appendix B. Well locations are shown on Figure 2. The initial 5 feet of each boring were advanced with a hand auger and/or post hole digger to reduce the possibility of damaging underground utilities. Soil samples were collected during the advancement of the borings using a California-type, split-spoon sampler. Samples were collected for lithologic description only; samples were not retained for laboratory analysis. Well Installation Wells IW-1 through IW-5 were constructed to depths ranging between 53.5 and 63 feet bgs. The screened portion (sparge point) of each well consisted of 2-inch diameter by 30-inch long microporous tubing, installed near the base of each soil boring. Stratus attempted to situate the microporous tubing sparge point across the soil horizon most likely to provide the largest radius of influence around each ozone injection well. The sparge points were installed across the first sandy interval encountered in the boreholes between approximately 15 and 25 feet below the average static water levels measured in the site monitoring wells (approximately 38 feet bgs). Blank PVC casing (0.75-inch diameter) was connected to the sparge point and installed up to surface grade. The standard "O-rings" installed on the casing joints by the manufacturer (Boart Longyear) were replaced with VitonTM "O-rings", which are manufactured to resist degradation by ozone. A filter pack of LonestarT" #2/12 sand was placed around the sparge point from the base of the boring to approximately 2 feet above the top of the sparge point. Approximately 2 feet of bentonite was placed on top of the filter pack to provide a sanitary seal for the well. The boring was subsequently backfilled with neat cement up to j surface grade. A 12-inch diameter traffic rated vault box was placed over the top of each well. Well details and California Department of Water Resources (DWR) well completion forms for wells IW-1 through IW-5 are presented in Appendix B. Waste Mana ement Drill cuttings generated during the field activities were placed on, and covered with,plastic sheeting and stored on site. Wastewater was placed into 55-gallon steel drums and stored on site pending disposal. Dillard Trucking Company of Byron, California, transported the soil and wastewater to a licensed facility for disposal. C?T Testing and Direct ]Push Sampling A Stratus geologist was onsite to oversee Gregg In-Situ, Inc.(Gregg [C57 #656407]) complete the CPT testing and direct push soil sampling on November 18, 2002. The CPT method consists of advancing a cone-tipped cylindrical probe (1.7 inches in diameter) into the ground while simultaneously measuring the resistance to penetration. The CPT P:1Bp-Arco for URS154691Reports15469report20o3.doc