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' Prior to conducting subsurface work at the site, USA was contacted to delineate subsurface utilities near the site with surface markings In addition, a private utility locator service was contracted to clear each of the proposed drilling locations and the boring locations were ' hand-cleared to five feet bgs prior to beginning drilling activities 32 Soil Borings 1 CPT Advancement ' On June 2, 2004, SECOR supervised the drilling of one onsite groundwater monitoring well (MW-7), one oxygen infection test well (S-1), and one groundwater extraction test well (EX-1) (Figure 2 and Table 2) On July 26, 2004 SECOR supervised the drilling of two offsite groundwater monitoring wells (MW-8 and MW-9) (Figure 2, Table 2) The wells were drilled using a truck-mounted drilling rig equipped with 8-inch diameter hollow-stem augers (HSAs) for the infection and monitoring wells and 10-inch HSAs for the extraction well ' On August 2, 2004 SECOR supervised the advancement of two CPT borings (CPT-1 and CPT-2) (Figure 2, Table 2) to approximately 83 feet bgs A description of CPT installation ' procedures and sod logs showing interpreted soil types is included in Appendix C All soil and ansate water generated during the well installation and hole clearing activities ' were stored in Department of Transportation (DOT) approved 55-gallon drums pending disposal Waste disposal is discussed in Section 8 0 Field notes documenting the well installation activities are included in Appendix B 33 Soil Sampling Soil samples were collected continuously from 5 to 17 feet bgs in well MW-7, from 5 to 25 feet bgs in EX-1, from 10 to 17 feet bgs in MW-8, and from 10 to 20 feet bgs in MW-9 using a split spoon sampler lined with 2-inch diameter by 6-inch-long brass sample tubes Samples were not collected or analyzed from S-1 due to its close proximity i e , within 5 feet, of EX-1 ' Well construction details and soil boring logs are included in Appendix C Downhole drilling equipment was steam-cleaned before drilling each borehole and sampling ' equipment was cleaned between each sampling interval Each soil sample was screened for hydrocarbon vapors using a portable photoionization detector (PID) Soil samples retained for analysis were sealed with Teflon® sheets and plastic caps, labeled and placed on ice in ' an insulated container for delivery under chain of custody to Kiff Analytical LLC in Davis, California The soils encountered during drilling were logged using the Unified Soil Classification System by a SECOR field geologist, working under the supervision of a California registered geologist ' Lithology encountered in each of the borings generally consisted of silt and sandy silt with minor lenses of clay and sand SECOR constructed two Generalized Geologic Cross ' Sections (Figure 4) which depict the subsurface soil types along the approximate groundwater flow direction Boring logs are included as Appendix C and CPT logs are included in Appendix D 1 32262 Assessment&Feasibility Report&SCM doc 4 September 30,2004 ' 77EL 32262 04 0502