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29 September 2003 <br /> AGE-NC Project No. 01-0865 <br /> Page 8 of 10 <br /> 5.5. WELL COMPLETION <br /> Soil borings will be single-completed as ground water monitoring wells utilizing 2-inch diameter <br /> schedule 40 polyvinylchloride(PVC)0.020-inch slotted well screen and blank well casing.A 10-foot <br /> length of well screen is anticipated for installation of monitoring wells; however, based on <br /> geologic/hydrogeologic conditions the screen length and placement may be modified with EHD <br /> approval. In the shallow, water table wells, the bottom of the screen interval will be placed 7 feet <br /> below the water table. The proposed well construction diagrams are depicted in Figures 3 and 4. <br /> After installing the well casing, filter pack material consisting of pre-washed#3 Lonestar sand will <br /> be added from the bottom of the borehole to approximately two feet above the screened interval. <br /> Following placement of the filter pack, the well will be surged to assist in settling the filter pack. <br /> Additional sand will be added if settling occurs. <br /> A nominal two-foot bentonite seal(bentonite chips)will be placed above the filter pack to minimize <br /> the potential for grout penetration into the screened section of the well. The bentonite seal will be <br /> formed by pouring bentonite chips into the annulus and allowing them to settle on the filter pack. <br /> Bentonite chips will be hydrated using approximately five gallons of tap water.The bentonite chips <br /> will be allowed to hydrate for a minimum of one-half hour prior to grouting. <br /> The remaining annular space will be filled to the ground surface with a cement grout. The grout <br /> mixture will consist of Type I/H portland neat cement and not more than 6 gallons of water per <br /> 94-pound sack of cement. The grout will be placed by pumping through tremie pipe. A grouting <br /> inspection will be scheduled with EHD personnel. <br /> 5.6. WELL DEVELOPMENT AND SURVEY <br /> Development of the proposed wells will consist of a combination of bailing with a stainless steel <br /> bailer to remove the major portion of fine-grained sediment from inside the well, surging to flush <br /> out or draw in sediment from the filter pack and additional ground water evacuation(purging)with <br /> a Waterra bailing pump to finish the removal of fine-grained sediment. Developmental purging <br /> activities will be continued until field parameter (pH, electrical conductivity, and temperature) <br /> readings have stabilized and purged water is visually sediment-free. The proposed wells will be <br /> surveyed relative to the closest benchmark by a licensed surveyor. <br /> Advanced GeoEnvironmenlal,Inc <br />