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' 25 February 2005 <br /> ' AGE-NC Project No. 98-0500 <br /> Page 6 of 6 <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 one <br /> foot above and below each screened interval. A bentonite seal (pell plug-coated bentonite pellets) <br /> will be placed between filter pack intervals to minimize the potential for cross contamination <br /> between the screened sections of the well; the bentonite seal will be formed by pouring bentonite <br /> ' pellets into the annulus and allowing them to settle on the filter pack. The remaining annular space <br /> will be filled to the ground surface with a bentonite grout. The grout mixture will consist of a <br /> bentonite slurry at 30 by weight, and will be placed by pumping through tremmie pipe. A grouting <br /> inspection will be scheduled with EHD personnel.A proposed well construction diagram is depicted <br /> in Appendix A. <br /> 3.3. WELL DEVELOPMENT <br /> Development of the proposed wells will consist of a combination of bailing with a'/4-inch tubbing <br /> with a steel check-bailer to remove the major portion of fine-grained sediment from inside the well, <br /> surging to flush out or draw in sediment from the filter pack and additional ground water evacuation <br /> Ile (purging)with a3/8-inch outer diameter polyethylene hose equipped with a ball-valve water tip(lift <br /> bailer) to finish the removal of fine-grained sediment. Developmental purging activities will be <br /> continued until field parameter (pH, electrical conductivity, and temperature) readings have <br /> I <br /> stabilized and purged water is visually sediment-free. <br /> ' 3.4. 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 /> 3.5. GROUND WATER MONITORING PROCEDURES <br /> ' Groundwater sample collection will be performed in accordance with CVRWQCB guidelines(Tri- <br /> Regional Water Quality Control Board Recommendations for Preliminary Investigations and <br /> ' Evaluation of Underground Storage Tanks) sampling protocols. <br /> ' 3.5.1. Static Water Level Measurements <br /> Prior to all ground water purging and sampling, static water levels in each well will be measured <br /> Advanced GcoEnvironmental,Inc. <br />