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ARCADIS Amy S. Terrell <br /> November 14, 2012 <br /> Well Destruction by Casing Removal <br /> Fourteen wells were destroyed by removing the entire casing by either over-drilling or <br /> by using a winch on the drill rig mast after using an auger to break the sanitary seal. <br /> After the casings were removed, the borings were filled completely with neat cement <br /> grout pumped into the boring via a tremie pipe (for borings greater than 20 feet <br /> deep). For borings that were less than 20 feet deep, neat cement grout was poured <br /> directly into the open borings from the mixing buckets. <br /> Well Destruction by Pressure Grouting <br /> Well MW-16B was destroyed by pressure grouting in place. The concrete well box <br /> was removed and neat cement grout was pumped under pressure into the well <br /> casing via a tremie pipe placed near the bottom of the well. The tremie pipe was <br /> lifted as the grouting progressed. Following pressure grouting activities, a hole with a <br /> diameter larger than the well casing diameter was excavated to a depth of <br /> approximately three feet bgs. The well casing was cut approximately 6-inches above <br /> the bottom of the excavation and additional grout was added to the well casing to <br /> overflow into the excavation creating a "mushroom cap"of neat cement above the <br /> casing to seal the boring and create a protective cement cap above and around the <br /> top of the boring. Native soil was used to backfill the excavation to natural grade. The <br /> grout volume was calculated to ensure that it exceeded the casing volume. <br /> Waste Management Activities <br /> Investigation-derived waste (IDW)soil and decontamination water was placed into <br /> Department of Transportation-approved 55-gallon drums. The drums were stored <br /> on-site temporarily so they could be characterized. After the IDW soil and water were <br /> characterized, UPS transported the IDW off site for disposal. <br /> Closing <br /> Thank you for your continued support with this important project. Please let me know <br /> if you have any questions or comments. <br /> Sincerely, <br /> ARCADIS U.S., Inc. <br /> James Eisert, PG (No. 7000), CHG (No. 779) <br /> Principal Hydrogeologist <br /> Page: <br /> Tracy NMnt_Well Destruct Poll 1-14-12).cbc 3/4 <br />