ARCHIVED REPORTS_MONITORING WELL INSTALLATION REPORT - SITE ASSESSMENT WORK PLAN

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1 25 February 2005 • AGE-NC Project No. 98-0500/04-1127 ' Page 2 of 7 diameter drive drill stems were advanced to 100 feet below surface grade (bsg), and the 6.0-inch drive drill stems were utilized to advance to a total depth of 150 feet. Starting on 05 January 2005, the pilot boring for monitoring well MW-37 was advanced using the same drilling rig;with the 8.0- inch diameter drive drill stems advanced to approximately 110 feet bsg,and the 6.0-inch drive drill stems were utilized to advance to a total depth of 200 feet. On 06 January, after advancing the 6.0- inch drive drill stems to a depth of approximately 170 feet,the drill rig experience a malfunction of the rig motor and clutch assembly and drilling stopped.The 8.0-inch diameter drive drill stems were isecured at the top of the casing and weatherproofed. The drill rig returned to the site on 11 January and began to advance the 6.0-inch drive drill stems to a depth of approximately 200 feet.Extensive sand heave was documented,which delayed the installation of the deeper well casing.The 6.0-inch drive drill stems were advanced to the total well depth on 13 January 2004. The drill rig and three-man crew were supplied by Cascade Drilling Corporation.Drill-stem returns generated by drilling and coring were containerized on plastic on the western edge of the site pending landfill disposal or treatment. Waste water from washing was stored on-site in properly labeled Department of Transportation (DOT)-approved model 17H 55-gallon drums. Soil samples were collected ahead of the drill bit from the boring for well MW-37,using a 10-foot core barrel; the samples were collected continuously in 10-foot sections, beginning at 5 feet bsg. After retrieval,a representative soil sample from each section was hand packed into a six-inch brass sleeve, and both ends of the sleeve were covered with Teflon sheets, capped and sealed with tape. The samples were properly labeled and stored with ice for chemical analysis and transported under chain of custody to a State of California Department of Health Services (DHS)-certified analytical ' laboratory. The samples were analyzed for: • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA ' Method 8015 Modified; • Benzene,toluene, ethylbenzene and total xylenes(BTEX)in accordance with EPA Method 8020; and • The fuel additives di-isopropyl ether (DIPS), ethyl tertiary-butyl ether (ETBE), methyl tertiary-butyl ether (MTBE), tertiary-amyl methyl ether (TAME), tertiary butanol (TBA), ' 1,2-dichloroethane (1,2-DCA) and ethylene dibromide (EDB) in accordance with EPA Method 8260 Modified. 2.1.2. Logging • Soil was manually and visually described on the boring log in accordance with the Unified Soil Advanced GeoEnvironmental,Inc.