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f r <br /> 12 February 2002 <br /> • AGE-NC Project No 97-0312 <br /> I Page 13 of 18 <br /> s , <br /> A nominal three-foot thick bentonite seal will be placed above the filter pack to minimize the <br /> potential of grout penetration into the filter pack or screened section of the well The bentonite seals <br /> will be formed by pounng bentonite chips into the annulus and allowing them to settle on the filter <br /> I pack Bentonite chips will be hydrated using five gallons of water The bentonite chips will be <br /> allowed to hydrate for a minimum of one-half hour prior to grouting <br /> The remaining annular space will be filled to within one foot of the ground surface with a cement <br /> grout The grout mixture will consist of type LM portland neat cement and not more than 6 gallons <br /> of water per 94-pound sack of cement The grout will be placed by pumping through a tremmie pipe <br /> For inspection purposes, the EHD will be notified at least 48 hours prior to conducting grouting <br /> procedures A traffic-rated well box will be installed over each SVE well <br /> 444 Ozone Sparge Well-Installation <br /> Three pilot borings will be advanced for the installation of six sparge points The borings will be <br /> advanced with a truck-mounted drill ng equipped with 10-inch hollow stem augers Following <br /> advancment of the pilot boring,two manufacturer-assembled 2-inch by 30-inch macroporous sparge <br /> points and casings will be installed into a common boring The sparge points will be installed at <br /> depths of approximately 65 feet bsg and 90 feet bsg The well materials will be placed into the <br /> borehole through the interior of the hollow-stem augers After installing the sparge point and casing, <br /> filter pack material consisting of pre-washed#2/12 Lonestar sand will be added from the bottom of <br /> the borehole to approximately two feet above the lower sparge point A bentonite seal will be placed <br /> between the filter pack of the lower,sparge point and the bottom of the upper sparge point to prevent <br /> vertical migration of contaminants between the two zones The bentonite seal will be formed by <br /> pouring bentonite chips into the annulus and allowing them to settle on the filter pack of the lower <br /> zone Bentonite chips will be allowed to hydrate for a minimum of one-half hour prior to installing <br /> the upper sparge point `y <br /> F <br /> r r <br /> Following hydration of the bentonite chips, the upper sparge point will be installed utilizing filter <br /> pack and a nominal three-foot bentonite seal as described above to minimize the potential of grout <br /> penetration into the filter pack The remaining annular space wlll,be filled to within one foot of the <br /> ground surface with a cement grout The grout mixture will consist of type I/II portland neat cement <br /> and not more than 6 gallons of water per 94-pound sack of cement The grout will be placed by <br /> pumping through a tremmie pipe or the hollow stem augers For inspection purposes,the EHD will <br /> be notified at least 48 hours prior to conducting grouting procedures A traffic-rated well box will <br /> be installed over each sparge well <br /> Advanced GeoEnvlronmental,Inc <br />