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22 February 2010 AGE-NC Project No. 96-0235 Page 5 of 7 3.2. WELL COMPLETION AND WELL ELEVATION SURVEY The 8.25-inch diameter pilot borings will be single-completed as a ground water monitoring well utilizing 2-inch diameter schedule 40 polyvinylchloride(PVC)0.020-inch slotted well screen.Well Well MW-27 will be complete with a 20-foot screen from 40 feet to 60 feet bsg and blank well casing. Well MW-28 will be complete with a 10-foot screen from 65 feet to 75 feet bsg and blank well casing. Proposed monitoring well construction diagrams are depicted in Figures 4 and 5, respectively. p ratA 1��' fix After installing the well casing in the pilot boring,a filter pack material consisting of,pre-washed#3 sand will be added through the augers over the screen interval to approximately two feet above the s 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 three-foot 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 coated bentonite pellets into the annulus and allowing them to settle on the filter pack. The bentonite will be allowed to hydrate for a minimum of one-half hour prior to grouting. Remaining annular space will be filled within one foot of the ground surface with a cement grout. The grout mixture will consist of Type IJH 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.A grouting inspection will be scheduled with EHD personnel. Following completion of the monitoring well, well elevation and location will be surveyed by a California-licensed surveyor relative to an elevation benchmark and GPS location. 3.3. WELL DEVELOPMENT Development of the proposed wells will consist of a combination of bailing with a stainless steel bailer 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 a Waterra bailing pump to finish the removal of fine-grained sediment. Developmental purging activities will be continued until field parameter (pH, electrical conductivity, and temperature) readings have stabilized and purged water is visually sediment-free. 3.4. GROUNDWATER SAMPLING PROCEDURES Advanced GeoEnvironmental.Inc.