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'i N 15 June 2005 AGE-NC Project No. 03 - 1070 Page 5 of 7 4. 1 , PILOT BORING AND SOIL SAMPLING The extraction well pilot boring will be advanced using a CME-7511T drill rig equipt with 10-inch diameter hollow-stem augers to advance boring EW l . Cuttings and rinseate generated during drilling activities will be containerized in properly labeled Department of Transportation (DOT)-approved 55-gallon drums and stored on-site in an area lacking public access. Disposal alternatives will be evaluated based on results of soil and water analysis. Soil encountered in the pilot boring will be collected at five-foot intervals using a California modified split-spoon sampler fitted with three 24nch diameter, 6-inch long brass sleeves. Following sample collection, the exposed ends of the leading or other selected sleeve will be labeled with the boring location, depth, time, date and sampler' s initials; the appropriately sealed and labeled samples will be placed under ice in a chilled container and will be transported under COC to a DHS-certified laboratory for analysis. The soil in the two remaining sleeves will be visually classified by an AGE geologist in accordance with the Unified Soil Classification System (USCS) and field-screenedfor the presence of volatile organic compounds using an organic vapor meter (OVM) equipped with a photo-ionization detector (PID: Thermo Environmental 580B, 10.OeV [or equivalent] , calibrated to isobutylene). 4.2. EXTRACTION WELL INSTALLATION Following completion of drilling of the extraction well pilot boring, a 4-inch diameter Schedule 40 PVC 0.0304nch slotted well screen and casing will be installed in the borehole. The well-screen section will be 20-feet in length, extending from approximately 35 feet to 55 feet bsg. The well casing, filter pack and sealing materials will be placed into the borehole through the interior of the augers. After installing the well casing, filter pack material consisting of #3 sand and or mix with gravel will be added from the bottom of the borehole to approximately two feet above the screened interval. Following placement of the filter pack, the well will be surged to assist settling the filter pack; additional sand will be added if settling occurs. A nominal two-foot thick bentonite seal will be placed above the filter pack to minimize the potential for grout penetration into the screened section of the well. The bentonite seal will be formed by pouring bentonite chips into the annular space between the hammer casing and the well casing and allowing them to settle on the filter pack. Bentonite chips will be hydrated using five gallons of water. The bentonite chips will be allowed to hydrate for a minimum of one-half hour prior to grouting. The remaining annular space above the bentonite seal will be filled to within one foot of the ground Advanced GeoEnviro=ental, rne.