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N 09 April 2002 AGE-NC Project No . 97-0301 Page 10 of 14 �1 I� , polyvinylchloride (PVC) well casing with 30 feet of 0.030-inch slotted well screen; the SVE wells L will be completed utilizing single 2-inch diameter schedule 40 PVC well casing with 30 feet of 0.020-inch slotted well screen; the air sparge well boring will be completed utilizing single 2-inch ` diameter schedule 40 PVC well casing with 5 feet of 0. 020-inch slotted well screen. Proposed well construction diagrams are depicted in Figures 5, 6 and 7 respectively. ( { Soil borings MW-8, MW-9, MW- 10 and MW-11 will be completed as multi-level ground water monitoring wells utilizing 1 . 7-inch diameter polyethylene (outer) tubing. The inner tubing will consist ofmultiple %z-inch diameterteflon tubes partitioned into separate chambers. A stainless steel, 0.02-inch screen will be wrapped around each perforated area of the tubing. A proposed well construction diagram is depicted in Figure 9. Additional multi-level design information is contained in Appendix B . -I One soil boring (OSW- 1) will be advanced for the installation of an ozone sparge point. Following advancement of the soil boring to 42 feet bsg, a manufacturer-assembled 2-inch by 24-inch microporous sparge point and 2-inch diameter schedule 40 PVC well casing will be installed into I` the commonboring. Aproposed well construction diagram is depicted in Figure 8. Additional ozone sparging information is contained in Appendix C . After installing the well casing in each boring, a filter pack material will be slowly emplaced through the augers over the screen interval to approximately two feet above the screened intervals; filter pack Jmaterial in the ground water extraction well will consist of a 50/50 blend of pre-washed small- grained aquarium gravel and #3 Lonestar sand; filter pack material for the S VE wells, LAS well, IOS well and ground water monitoring wells will consist ofpre-washed #2/12 Lonestar sand. Following placement of the filter pack, the screened interval from each well will be surged for approximately 20 minutes utilizing a surge block to assist in settling the filter pack. Additional filter pack material will be added if settling occurs. A nominal three-foot bentonite seal (bentonite pellets) will be placed above the filter pack to jminimize the potential for grout penetration into the screened section of the well. The bentonite seal will be formed by pouring bentonite pellets into the annulus and allowing the pellets to settle on the _ filter pack. The bentonite pellets will be allowed to hydrate with tap water for a mimmum of one-half hour prior to grouting. ll The remaining annular space will be filled to the ground surface with a cement grout. The grout _I� mixture will consist of Type UII portland neat cement and not more than 6 gallons of water per 94-pound sack of cement. The grout will be placed by pumping through tremmie pipe. A grouting I nspection will be scheduled with SJCEHD personnel. I- - Advanced GeoEnvironmental, Inc. U