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20 April 2007 AGE-NC Project No. 95 -0167 Page 7 of 10 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 surface with a cement grout. The grout mixture will consist of Type 1/Il 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 tremie pipe. EHD will be notified for grout inspection at least 72 hours prior to conducting grouting procedures. A traffic-rated well box will then be installed over the well casing. An extraction well diagram is illustrated on Figure 5 . 4.3 . 1 . Well Development and Survey Development will consist of a combination of bailing 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 bailing to finish the removal of sediment. Development activities will be continued until field parameter (pH, electrical conductivity, and temperature) readings have stabilized. After development, the top of each well casing (well head) will be surveyed to determine its elevation relative to mean sea level and its longitude and latitude coordinates based on the global positioning system measurements . 4. 3 .2 . Ground Water Extraction (Aquifer Pumping) Test A draw-down pilot test will be performed to evaluate feasibility of ground water extraction and radius of ground water influence from a single well. A 3 . 5-inch diameter Grundfos Rediflow self-priming submersible pump will be used to extract water from extraction well EW- 1 to induce a decline in the static water level in EW- 1 . Solinst Leveloggers Model 3001 instruments will be deployed in observation wells MW- 1 , MW-2, MW-3 , MW-7, MW-8, and OBW4 to obtain draw-down measurements at 1 -minute intervals to measure the difference in ground water levels before and during well pumping. The Leveloggers utilize ceramic pressure transducers to record water level data, which can be downloaded to a computer via an RS232 Optical infra-red data reader/port connected to a computer. The Levelogger -Advanced GeoEnvironmental, Inc.