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• i <br /> 28 January 2005 <br />• AGE-NC Project No 02-0964 <br /> Page 5 of 7 <br /> Figures 4 and 5 <br /> After installing the well casing in each pilot bonng, a filter pack material consisting of pre-washed <br /> #3 Lonestar sand will be added through the augers over the screen interval to approximately two feet <br /> above the screened interval Following placement of the filter pack,the well will be surged to assist <br /> in settling the filter pack Additional sand will be added if settling occurs <br /> A nominal two-foot bentonite seal (pell plug non-coded bentonite pellets)will be placed above the <br /> filter pack to minimize the potential for grout penetration into the screened section of the well The <br /> bentonite seal will be formed by pouring bentonite pellets into the annulus and allowing them to <br /> settle on the filter pack The bentonite pellets will be allowed to hydrate for a minimum of one-half <br /> hour prior to grouting <br /> The remaining annular space will be filled within one foot of the ground surface with a cement grout <br /> The grout mixture will consist of Type l/H portland neat cement and not more than 6 gallons of water <br /> per 94-pound sack of cement The grout will be placed by pumping through tremmie pipe A <br /> grouting inspection will be scheduled with EHD personnel <br />• Following completion of the monitoring wells, well elevations and locations will be surveyed by a <br /> California-licensed surveyor relative to a City of Stockton elevation benchmark <br /> 3 3 WELL DEVELOPMENT <br /> Development of the proposed wells will consist of a combination of bailing with a stainless steel <br /> bailer to remove the mayor 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 <br /> 3 4 GROUNDWATER SAMPLING PROCEDURES <br /> Ground water sample collection will be performed in accordance with the EHD's Recommended <br /> Groundwater Sampling Guidelines, dated 15 February 1995 <br />• <br /> Advanced GeoEnwronmental,Inc <br />