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17 July 2001 AGE-NC Project No. 97-0327 Page 5 of 7 3.2. SOIL SAMPLING Soil samples will be collected in P-Y, P-10 and MW-4 at five-foot intervals, beginning at a depth of 15 feet bsg, utilizing either a modified California split-spoon sampler or a Geoprohe soil sampling assembly loaded with brass sleeves. The sampler will be driven by dropping a 140-pound weight from a height of 30 inches (blow counts). The blow counts required to drive the sampler over each 6-inch interval will be recorded on the boring logs. Upon soil sample retrieval, the middle brass sleeve will be removed from the sampler. The ends of the brass sleeve will be immediately covered with Teflon tape, sealed with plastic end caps, secured with duct tape and immediately placed in a chilled container for transportation under chain of custody to a state-certified laboratory. Each sample sleeve will be labeled with the boring location, sample depth, sample time, sampling date and sampler's initials. Soil sample duplicates will be monitored for the presence of organic vapor using a photo-ionization detector(PTD: Thernlo Environmental 580A, 10.0 eV, calibrated to isobutylene) and will be visually described on boring logs using the Unified Soil Classification System (USCS). All sampling tools and brass sleeves used for sample collection will be thoroughly rinsed with clean water after washing with a solution of Alconox. All hollow stem augers will be steam-cleaned prior to advancement in each borehole. 3.3. WELL COMPLETION Soil boring MW-4 will be completed as a ground water monitoring well utilizing 2-inch diameter schedule 40 polyvinylchloride (PVC) 0.020-inch slotted well screen and blank well casing. Based on geologic/hydrogeologic conditions, a 20-foot length of well screen is anticipated for installation of ground water monitoring well MW-4; a proposed well construction diagram is depicted in Figure 5. After installing the well casing, filter pack material consisting of pre-washed 42112 Monterey sand 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 in settling the filter pack. Additional sand will be added if settling occurs. A nominal three-foot transition seal (bentonite pellets) will be placed above the filter pack to minimize the potential for grout penetration into the screened section of the well. The bentonite sea] will be formed by pouring bentonite pellets into the annulus and allowing them to settle on the filter pack. The bentonite chips will be allowed to hydrate a minimum of one-half hour prior to grouting. The remaining annular space will be filled to within I foot of the ground surface with a cement grout seal. The grout mixture will consist of Type I/II portland neat cement and not more than 6 gallons Advanced GeoEnvironmental,Inc.