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ti passes through the former underground storage tank location, and adjacent, shallower wells (DMW-5 and DMW-6) show residual groundwater contamination. The wells will be overdrilled with 12-inch hollow-stem augers by Gregg Drilling and Testing of Martinez, California. The resulting boring will then be backfilled with a cement- used grout. The remaining monitoring eight wells (DMW-1, DMW-2, DMW-3, DMW-4, DMW-7, DMW-8, DMW-10, and DMW-13) will be destroyed by over-drilling with a hollow stem auger drill rig to a depth of approximately 5 feet bgs. The remaining casing will be sealed with a cement-based grout placed under pressure. The grout will be placed with a tremmie pipe from the bottom up. When the grout has filled the casing to the surface, a pressure-grouting adaptor will be installed and a pressure of 25 psi will be applied for ten minutes. The adaptor will then be removed and the grout topped off and allowed to spill into the excavation above the top of the remaining casing. The surface will then be capped to match the su 7 ounding surface. A well destruction permit will be obtained from the San Joaquin County Environmental Health Department, and a minimum 48-hour notice will be provided prior to commencing work. Daily health and safety briefings will be held in accordance with the existing Site Health and Safety Flan. Soil cuttings generated during the well destruction activities will be stored onsite in a rolloff bin or in 55-gallon drums prior to appropriate disposal pending analytical results. Approximately four weeks following completion of th work a report of well destruction will be prepared describing the procedures used, and pro iding analytical laboratory reports and manifests related to waste disposal. URS Corporation 2870 Gateway Oaks Drive,Suite 300 Sacramento,CA 95833 Tel:916.679.2200 Fax:916.679.2900 i