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26 September 2000 <br /> AGE-NC Project No 96-0263 <br /> Page 9 of 10 <br /> After Installing the well casing, filter pack material consisting of pre-washed#2 Lonestar sand will <br /> be added from the bottom of the borehole to approximately two feet above the screened interval <br /> Following placement of the filter pack, the well will be surged to assist in settling the filter pack <br /> Additional sand will be added if settling occurs <br /> A nominal two-foot bentomte seal (bentomte chips)will be placed above the filter pack to minimize <br /> the potential for grout penetration into the screened section of the well The bentonite seal will be <br /> formed by pouring bentonite chips into the annulus and allowing them to settle on the filter pack <br /> Bentonite chips will be hydrated using approximately five gallons of tap water The bentonite chips <br /> will be allowed to hydrate for a minimum of one-half hour prior to grouting <br /> The remaining annular space will be filled to the ground surface with a cement grout The grout <br /> mixture will consist of Type LM portland neat cement and not more than 6 gallons of water per 94- <br /> pound sack of cement The grout will be placed by pumping through tremie pipe A grouting <br /> inspection will be scheduled with PHS-EHD personnel <br /> . 4 4 WELL DEVELOPMENT AND SURVEY <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 submersible pump to finish the removal of fine-grained sediment Developmental purging activities <br /> will be continued until field parameter(pH, electrical conductivity, and temperature) readings have <br /> stabilized and purged water is visually sediment-free The proposed wells will be surveyed relative <br /> to the closest City of Tracy benchmark by a licensed surveyor <br /> 4 5 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 All down-hole drilling and sampling equipment will be pressure <br /> washed prior to starting the boring <br /> 4 6 GROUND WATER MONITORING PROCEDURES <br /> Groundwater sample collection will be performed in accordance with PHS-EHD guidelines (San <br /> Joaquin County Public Health Services Environmental Health Division Well Standards) and <br /> CVRWQCB guidelines (Tri-Regional Water Quality Control Board Recommendations for <br /> Preliminary Investigations and Evaluation of Underground Storage Tanks) <br /> Advanced GcoEnvironmental,Inc <br />