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01 March 2002 iAGE-NC Project No 95-0130 Page 3 of 10 23 SAMPLE LOGGING Each five-foot macro-core soil sample section was sequentially placed on plastic sheeting and visually described on boring logs in accordance with the Unified Soil Classification System (USCS) Boring logs from MW-6 and MW-7 are included as Appendix B General lithology beneath the site 1s depicted in cross sectional views B-B' and C-C'on Figures 3 and 4, respectively 2 4 MONITORING WELL COMPLETION Soil borings MW-6 and MW-7 were advanced to depths of 150 feet bsg and completed as ground water monitoring wells utilizing 1 7-inch diameter mutt-level polyethylene well casing The inside of the multi-level well casing consisted of seven %2-mch diameter teflon chambers Based on review of the continuous macro-core lithologic data from soil borings MW-6 and MW-7, AGE utilized five of the seven multi-level chambers and installed screen intervals at depths between 35 and 45 feet bsg, 50 and 55 feet bsg, 70 and 75 feet bsg, 100 and 110 feet bsg and between 125 and 142 feet bsg (Figures 5 and 6) Each screen interval consisted of drilling 3/e-mch diameter holes at regular �• intervals, wrapping each 3/e-inch diameter hole with a stainless steel, 0 02-inch mesh screen and securing the mesh screen with stainless steel locking clamps After deploying the multi-level well casing in the hollow stem boring to total depth, filter pack material consisting of pre-washed #212 Lonestar sand was added through the hollow stem augers to approximately two feet above each screened interval A bentonite seal (coated bentonite pellets) was placed between each filter pack interval to minimize the potential for cross contamination into the screened section of the well Each bentonite seal was formed by pouring coated bentonite pellets into the annulus and allowing them to settle(hydrate)on the filter pack The remaining annular space above the uppermost screen interval and bentonite seal was filled to 1-foot bsg with a portland cement grout The grout mixture consisted of Type LU portland neat cement Water-tight, traffic- rated well boxes were then installed over the wells utilizing a neat cement Figures 5 and 6 depict the top-view of wells MW-6 and MW-7, respectively, for the screen interval locations relative to a reference mark located in "interval A", well construction diagrams for MW-6 and MW-7 are depicted in Figures 7 and S, respectively 25 WELL DEVELOPMENT ACTIVITIES On 09 and 10 October 2001, wells MW-6 and MW-7 were developed by lowering and raising (surging) a 3/8-inch outer diameter, length-discrete polyethylene hose equipped with a ball-valve water tip through each specific water-charged screened section A Watera-Hydro-Lift II pump • equipped with a mechanical arias was utilized to surge the polyethylene hose IAdvanced GeoEnvxronmental,Inc