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S ECOR Mr. Mike Infurna June 18, 2003 Page 2 WELL ABANDONMENT— PROCEDURES AND METHODS SECOR proposes abandoning the five 2-inch-diameter groundwater monitoring wells by overdrilling the borings with 8-inch hollow-stem augers. All well construction materials will be removed and the borings will be backfilled with bentonite slurry, topped with coarse aggregate, and finished to match existing grade. All waste generated will be disposed of appropriately. Specific methods and procedures are outlined in detail below. Preliminary Activities SECOR has submitted a completed Well Permit Application Form with the appropriate fee to the SJCEHD. Prior to initiating field activities, SECOR will prepare a site-specific health and safety plan to address potential hazards associated with well abandonment activities. A copy of the health and safety plan will be kept onsite during all field activities, and will be made available to all SECOR and subcontractor staff. SECOR will mark the work area in white paint, and notify Underground Service Alert at least 48 hours before well destruction activities. Groundwater Monitoring Well Abandonment The five groundwater monitoring wells will be abandoned by overdrilling the wells with 8-inch- diameter hollow-stem augers. Each well will be overdrilled to a depth of approximately one foot deeper than that of the completed well. The overdrilling method ensures that all well construction materials including the polyvinyl chloride well casing, the annular sandpack, the bendonite/grout sanitary seal and the wellhead vault box are removed. As the augers are removed, the borehole will be backfilled with bentonite slurry in accordance with state and local guidelines. The boreholes will be backfilled to approximately 2 feet below grade, and the bentonite will be allowed to expand and set up for the appropriate amount of time. The remaining space will be filled with approximately 20 inches of coarse aggregate or similar material, compacted, and finished to match the existing surface (asphalt or surrounding soil). This method of bentonite slurry, followed by compacted aggregate and final finishing material, is intended to minimize or eliminate future upheaval of the column of slurry. Waste Management Waste materials generated during overdrilling will be placed in steel 55-gallon drums, labeled as to contents, and left onsite pending profiling and proper disposal. SECOR estimates generating approximately five drums of soil cuttings during monitoring well abandonment. SECOR will contract with Integrated Wastestream Management of Milpitas, California to collect and dispose of the waste within ten business days of the end of field activities. Reporting Following well abandonment activities, SECOR will prepare a summary report for submission to the SJCEHD and the RWQCB. The report will contain a summary of field activities, a scaled site plan showing the locations of the former monitoring wells, a copy of the well destruction permit, and copies of pertinent correspondence between SECOR and SJCEHD and RWQCB staff. Well Destruction WP SECOP International Incorporated