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28 July 2004 AGE-NC Project No 99-0657 Page 5 of 7 3 2 WELL COMPLETION Following advancement of each first ground water pilot boring to total depth, a 2-inch diameter Schedule 40 PVC 0 020-inch slotted well screen and casing will be installed A 20-foot section of well screen will be installed in each of the proposed shallow monitoring wells The bottom of the screen interval will be placed approximatly15 feet below the water table Following the advancement of each deep-zone pilot boring to total depth, a 2-inch diameter Schedule 40 PVC 0 020-inch slotted well screen and casing will be installed A i 0-foot section of well screen will be installed in each of the proposed deep-zone monitoring wells However, based on geologic/hydrogeologic conditions the screen length and placement may be modified with EHD approval The well casing,filter pack and sealing materials will be placed into the borehole through the interior of the augers After installing the well casing, filter pack material consisting of pre-washed silica 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 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 at least 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 LII portland neat cement and not more than 6 gallons of water per 94-pound sack of cement The grout will be placed by pumping or poring through a tremae 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 Monitoring well diagrams for each well type are illustrated on Figures 3 and 4 33 WELL DEVELOPMENT AND SURVEY Development will consist of a combination of bailing to remove the mayor 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 X and Y coordinates based on longitude and latitude measurements Advanced GeoEnvi ron mental,Inc