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a i 20 August 2009 AGE-NC Project No . 064457 Page 5 of 7 i advancement of each borehole. 3 .2. WELL COMPLETION Soil borings will be single-completed as ground water monitoring wells utilizing 2-inch diameter Schedule 40 polyvinylchloride (PVC) 0.020-inch slotted well screen and blank well casing. Based on geologic/hydrogeologic conditions, and currently drowned existing site monitoring wells MW- 1 through MW4, a 20-foot length of well screen is anticipated for installation of the water table monitoring wells; the bottom of the screen interval will be placed at 40 feet bsg. Based upon CPT data, intermediate ground water monitoring wells are anticipated to have a 5 -foot length of well screen with the bottom of the screen interval to be placed at 80 feet bsg. Based upon CPT data, the deep screened ground water monitoring well is anticipated to have a 10-foot length of well screen with the bottom of the screen interval to be placed at 105 feet bsg. After installing well casings, filter pack material consisting ofpre-washed #2/12 Lonestar 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 two-foot bentonite seal (bentonite chips for the water table wells and bentonite pellets for the intermediate and deep wells) 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/pellets into the annulus and allowing them to settle on the filter pack, then hydrating themusing approximately five gallons oftap water and allowing them to swell and hydrate for a minimum of one-half hour prior to grouting. Remaining annular space will be filled to the ground surface with a cement grout. The grout mixture will consist of Type IM portland neat cement and not more than 6 gallons of water per 94-pound sack of cement. The grout will be placed bypumping through a tremie pipe. A grout inspection will be scheduled with the EHD personnel at least forty-eight hours prior to drilling. Proposed water table, intermediate, and deep well construction diagrams are depicted on Figures 3, 4 and 5, respectively. 3 . 3 . 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 Advanced GeoEnvironmental, Inc.