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_ 20 October 2004 AGE-NC Project No. 04-1156 Page 3 of 6 3.1. ADVANCEMENT OF SOIL BORING On 21 and 22 June 2004, four soil borings (B-1 through B-4) were advanced to a total depth of 43 feet below surface grade (bsg) utilizing a CME-75HT truck mounted drill rig to advance 8.25-inch _ diameter hollow stem augers to the total depth of each boring.Two borings were advanced north and south of the fanner Tank 2 from the UST excavation; the third boring was advanced within the excavation at the location of the former Tank 3; the fourth boring was advanced north of the eastern _ dispenser island (Figure 2). The drill rig and two-man crew were supplied by Mitchell Drilling Environmental of Rancho Cordova, California. Auger returns generated by drilling were containerized in properly labeled Department of Transportation (DOT)-approved model 17H 55-gallon drums and was stored on-site. 3.2. SOIL SAMPLE COLLECTION Soil samples were collected ahead of the drill bit using a California modified split-spoon sampler loaded with three pre-cleaned 2-inch by 6-inch brass sleeves. The samples were collected from soil borings B-1, B-3 and B-4 at 5-foot intervals,beginning at 5 feet bsg using a 140-pound hammer to advance the sampler. The number of blows required to advance the sampler over each 6-inch increment of the 18-inch sampling interval was recorded on the boring logs. Soil was collected from boring B-2 continuously using a 5-foot split-spoon sampler beginning at 5 feet bsg. The sampler was driven every five feet with a hydraulic ram ahead of the drill bit, allowing for continuous soil recovery.The soil was removed from the sampler and then placed on plastic for further examination. This was conducted as per the END regulatory letter dated 27 April 2004,approving the Prehininary Site Assessment Work Plan, dated 31 March 2004. Soil samples were preserved by covering both ends of the second brass sleeve with Teflon sheets, capping and sealing with tape. Each preserved sample sleeve was labeled with soil boring location, depth, time, date and sampler's initials, then stored in a chilled container under ice. Soil samples retrieved from the borings were visually classified on a boring log by an AGE geologist in accordance with the Unified Soil Classification System(USCS);the soil boring logs are provided in Appendix A. Additionally, the soil samples were field-screened for the presence of volatile organic compounds using an organic vapor meter(OVM)equipped with a photo-ionization detector (PID: Thermo Environmental 580B, 10.0 eV, calibrated to isobutylene); the concentration readings were recorded on the boring logs. Advanced Geo Environmental,Inc.