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10 April 2006 <br /> AGE-NC Project No. 04-1239 <br /> Page 2 of 3 <br /> In order to ensure that the ground water monitoring well does not provide a vertical conduit for <br /> contaminants, AGE proposes to properly destroy MW-I 1 in accordance with San Joaquin County <br /> Environmental Health Department(EHD)Standards For Well Construction and Destruction. <br /> PROCEDURES <br /> As required by EHD permitting, a health and safety plan will be prepared in accordance with <br /> Occupational Safety and Health Guidance Manual for Hazardous Waste Site Activities (National <br /> Institute for Occupational Safety and Health Administration, U.S. Coast Guard and U.S. <br /> Environmental Protection Agency, 1985). Prior to drilling activities,the proposed drilling location <br /> will be clearly marked and a utility clearance obtained through Underground Service Alert. <br /> Based on the EHD Standards For Well Construction and Destruction,the well will be sounded for <br /> total depth and checked for integrity; any obstruction found in the well will be removed. The <br /> remaining 2-inch diameter well casing will then be completely backfilled with a Portland type II <br /> cement grout mixture. In accordance with Section 13.12.10., the cement grout mixture will be <br /> applied under pressure(25 psi for at least 10 minutes). The grout mixture will consist of a nominal <br /> ratio of 6 gallons of water per 94-pound sack of portland cement. <br /> In accordance with Section 13.12.12.and in preparation for well destruction,over-drilling ofthe well <br /> casing will be performed to a minimum depth of approximately 3 feet bsg utilizing 20-inch hollow <br /> stem augers or equivalent.A six inch riser of casing will be exposed for sealing purposes.Following <br /> backfilling procedures, the remaining void space (inside the annular space left by over-drilling <br /> activities)will be completely backfilled with a neat cement to surface grade. Soil cuttings generated <br /> during over-drilling activities and rinseate will be containerized in properly labeled,Department of <br /> Transportation(DOT)-approved 55-gallon drums and stored on-site in an area lacking public access. <br /> Since ground water samples collected from well MW-11 have been non-detect for petroleum <br /> hydrocarbon contaminants for four consecutive quarters,AGE believes that reinstallation ofMW-I 1 <br /> is unnecessary. <br /> Advanced GeoEnvironmentnl,Inc. <br />