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3.0 DRILLING AND SAMPLING PROCEDURES 3.1 Drilling and Sampling of Vapor Extraction and In-situ Air Sparging Wells From January 3 to 5, 1995, a total of five soil borings were drilled at the site The borings ' (P-1 through P-4 and AS-1) were drilled using a truck-mounted CME-55 drill rig equipped with hollow-stem augers The drill rig and two-man crew were supplied by Soils Exploration Services, Inc (SES) of Benicia, California During drilling, auger returns were monitored for the presence of organic vapors using a photo-ionization detector (PID Thermo Environmental 580A, 10 0 eV, calibrated to isobutylene) Discrete soil samples were collected ahead of the drill bit using a split-tube sampler loaded with three pre-cleaned 2-inch by 6-inch brass sleeves The samples«ere collected at five-foot intervals, using a 140 pound hammer to advance the sampler 18 inches_ The number of ' blows required to advance the sampler in 6-inch increments was recorded on the boring logs To avoid cross contamination, the sampling equipment was washed in an Alconox solution and rinsed twice with water prior to each sampling run For each sample, both ends of the lead sleeve were covered N�ith aluminum sheets capped and sealed with tape The samples %%ere then stored on ice and transported wider chain-of- custody to McCanipbell Analytical, Inc (MAI) in Pacheco, California Borings P-1, P-2 and P-3 .vere dulled to depths of 27 feet Boring P-4 was dulled at an angle of approximately 300 from veitical to a total vertical depth of 20 feet Boling AS-1 was drilled to a depth of 38 feet ' 3.2 Logging Soil was extruded from the second brass sleeve, screened for the presence of organic vapors, using a PID, and the ieadingsweie recorded on the boring loos The soil was then described in accordance with the Unified Soil Classification System (see Boring Logs, Appendix A) ' 3.3 Well Completion ' Boring P-1 was dual-completed as a 4-inch diameter vapor extraction X%ell (VE-1) and a 2- inch diameter in-situ air Sparging (IAS) observation well (ASO-3) VE-1 was completed using 4-inch diameter 0 020-inch slotted PVC casing from 5 to 20 feet and 4-inch blank PVC ' casing from, ground surface to 5 feet Well ASO-3 was completed using 2-inch 0 020-inch slotted PVC casing from 17 to 27 feet and blank PVC casing from ground sui face to 17 feet The filter pack (#3 sand) was then installed from 3 to 27 feet and a bentonite plug was ' installed from 1 to 3 feet Cement was then used from the surface to a depth of 1 foot Boring P-2 was completed as IAS observation well ASO-1 The well was completed using tv2-inch diameter 0 020-inch slotted PVC casing fiom 17 to 27 feet, blank PVC casing was Oeobdxal PwLi S.rvrra.Inc C'"P"'FRPJ3 9515094 12 105602 4 1