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05 June 2008 AGE-NC Project No. 95-0141 Page 6 of 8 boring location, sample depth, sample time, date, and sampler's initials. i During sampling activities, sample duplicates will be monitored for the presence of organic vapor using a photo-ionization detector (PID: Thermo Environmental 580, 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 of each borehole. 3.4. WELL COMPLETION The soil boring will be single-completed as a ground water monitoring well utilizing 2-inch diameter 5 Schedule 40 polyvinylchloride(PVC)0.020-inch slotted well screen and blank well casing. Based /� � on geologic/hydrogeologic conditions, a 5-foot length of well screen is anticipated for installation of the monitoring well;the bottom of the screen interval is proposed to be placed at 118 feet bsg.A proposed well construction diagram is depicted on Figure 3. After installing the well casing,filter pack material consisting of pre-washed#3 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. A four-foot bentonite seal (bentonite pellets) will be placed above the filter pack to minimize or reduce the potential for grout penetration into the screened section of the well. The bentonite seal will be formed by pouring bentonite pellets into the annulus and allowing them to settle on the filter pack, then hydrating them using approximately tap water and allowing them to swell and hydrate for a minimum of one-half hour prior to grouting. The remaining annular space will be filled to the ground surface with a cement grout. The grout mixture will consist of Type I/H portland neat cement and not more than 6 gallons of water per 94-pound sack of cement. The grout will be placed by pumping through a tremie pipe. A grout inspection will be scheduled with the EHD at least forty-eight hours prior to drilling. 3.5. WELL DEVELOPMENT AND SURVEY Development of the proposed wells will consist of a combination of bailing with a Waterra inertia pump to remove the major portion of fine-grained sediment from inside the well, surging to flush out or draw in sediment from the filter pack,and additional ground water evacuation(purging)with Advanced GeoEnviroumental,Inc.