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27 March 2000 AGF-NC Project No. 98-0450 Page 16 of 19 hourteen IAS injection wvells will be installed utilizing a truck-mounted drill rig equipped with fl- inch diameter hollow stem augers. The IAS injection wells will be advanced to depths of approximately 55 feet bsg. The lAS injection wells will be completed with 2-inch diameter, schedule 40 PVC casing emplaced through the hollow stem augers, utilizing five feet of slotted well casing (0.020-inch) from 50 to 55 feet bsg. A # 3 Lonestar lapis Luster Sand will be poured down the annulus between the well casing and the inner wall of the hollow stem auger, The filter pack will be placed adjacent to the screen from the bottom of the boring to a point approximately 1 foot above the top of the screen. A three-foot interval of coated bentonite pellets (poll plug) will be placed above the filter pack and will serve as an annular seal The bentonite seal will be formed by pouring bentonite chips into the annLllus and allowing them to settle on the filter pack. Bentonite chips will be hydrated using five. gallons ofwater. The remaining annular spaces will be filled to the ground surface with a cement grout. The grout mixture will consist of Type 1111 Portland neat cement and not more than 10 gallons of water per 94-pound sack of cement. The grout will be placed by pumping through augers. A traffic-rated well box will be installed over the wells. in accordance with County relyulations. A proposed IAS injection well diagram is included as fiaw-e 11. 5.3.2. hi-sins Air Spargin- Piping System A network of one-inch diameter, schedule 40 PVC piping: will be installed six inches below the surface of the site. The PVC piping will be routed from each valved IAS well head to an air compressor. A PVC ball valve will be installed at each IAS well ]lead so that air flow can be controlled independently. A plan ofthe proposed air sparging piping system is depicted in Figure 8. The proposed location of the air compressor is near the northwest corner at the site (l igure 8). The air compressor will be secured by a chain-linked- gated enclosure as previously described. 5.3.3. In-si11r Air Sparging Monitoring Activities Quarterly ground water monitoring and sampling will be conducted throughout the remediation period. I lowever. AGI: recommends monthly measurements of ground water depth and dissolved oxygen in growld water monitoring wells at the site to determine if 0round water Moundin-, is occurring as a result of the ]AS system operation. 5.4. MONITORING WELL INSTALLATION ,Advanced GCOEM irunmcnta1.1 INC.