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21 March 2003 <br /> AGE-NC Project No. 95-0114 <br /> Page 9 of 11 <br /> After deploying the multi-level well casing in the hollow stem boring, a filter pack material <br /> consisting of pre-washed#3 Lonestar sand will be added through the augers to approximately two <br /> feet above each screened interval.A bentonite seal(pell plug-coated bentonite pellets)will be placed <br /> between filter pack intervals to minimize the potential for cross contamination between the screened <br /> sections of the well; the bentonite seal will be formed by pouring bentonite pellets into the annulus <br /> and allowing them to settle on the filter pack. The remaining annular space will be filled to the <br /> ground surface with a cement grout.The grout mixture will consist of Type UII portland neat cement <br /> and not more than 6 gallons of water per 94-pound sack of cement, and will be placed by pumping <br /> through tremmie pipe. A grouting inspection will be scheduled with EHD personnel. A proposed <br /> well construction diagram is depicted in Figure 4. <br /> 4.2. WELL DEVELOPMENT <br /> Development of the proposed wells will consist of a combination of bailing with a'/a-inch stainless <br /> steel bailer to remove the major portion of fine-grained sediment from inside the well, surging to <br /> flush out or draw in sediment from the filter pack and additional ground water evacuation(purging) <br /> with a peristaltic pump consisting of polyethylene tubing and a ball check valve to finish the removal <br /> of fine-grained sediment. Developmental purging activities will be continued until field parameter <br /> (pH,electrical conductivity,and temperature)readings have stabilized and purged water is visually <br /> sediment-free. <br /> 4.3. EQUIPMENT DECONTAMINATION <br /> All sampling tools used for sample collection will be thoroughly rinsed with clean water after being <br /> washed with a solution of Alconox.Prior to each use all down-hole drilling and sampling equipment <br /> will be pressure washed prior to starting each boring. <br /> 4.4. GROUND WATER MONITORING PROCEDURES <br /> Groundwater sample collection will be performed in accordance with EHD guidelines(San Joaquin <br /> County Public Health Services Environmental Health Division Well Standards)and the CVRWQCB <br /> guidelines (Tri-Regional Water Quality Control Board Recommendations for Preliminary <br /> Investigations and Evaluation of Underground Storage Tanks) sampling protocols. <br /> Advanced GeoEnvironmental,Inc. <br />