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S E C O R Mr. Mike Infurna July 9, 2003 Page 2 WELL ABANDONMENT— PROCEDURES AND METHODS On July 2, 2003, a SECOR geologist oversaw the abandonment of the five groundwater monitoring wells by over-drilling. The well abandonment's were performed by Gregg Drilling and Testing of Martinez, California (C-57 License#485165). The specific methods and procedures followed during .the work are detailed below. Preliminary Activities SECOR outlined the work areas in white paint and notified Underground Service Alert approximately 72 hours before beginning field activities. SECOR obtained a well destruction permit from the SJCEHD, and notified the agency of the intended work date and start time. A copy of the permit is attached. SECOR prepared a site-specific health and safety plan (HASP), and reviewed the HASP with the subcontractor immediately prior to beginning work. Groundwater Monitoring Well Abandonment The five groundwater monitoring wells were abandoned by over-drilling the wells with 8-inch- diameter hollow-stem augers. Each well was over-drilled to a depth of approximately one foot deeper than that of the completed well, thereby ensuring removal of all well construction materials including the polyvinyl chloride (PVC) well casing, the annular sand pack, the bentonite/grout sanitary seal, and the wellhead vault box. Prior to over-drilling, each well was sounded to confirm that the casing was free of obstructions to the total depth of the well. As the augers were removed, the borehole was backfilled with bentonite slurry to approximately 16 inches below grade. The slurry used was a blend of neat cement grout and bentonite formulated to minimize expansion of the grout and mitigate possible future upheaval of the column. Each well location, with the exception of well MW-2, was finished with concrete and colored to match the surrounding asphalt. The location of well MW-2, which is surrounded by grass, was finished with loose topsoil from an adjacent hillside. Waste Management Waste materials generated during over-drilling were placed in steel 55-gallon drums, labeled as to contents, and left on-site pending profiling and proper disposal. SECOR has contracted with Integrated Wastestream Management of Milpitas, California to remove and dispose of the materials. DOCUMENTATION In accordance with state regulations, SECOR has completed California Department of Water Resources well completion report numbers e005229 through e005233. Copies of the well completion reports are attached. I:\Tower Park\Well Destruction\Well Destruction Report.doc SECOR International Incorporated SECOR Job No.050T.02926.02 July 9,2003