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Geotogual Technics/a Well Abandonment Report Page 3 Project No 989 2 August 10,2005 and Appendix B Checklist Report discussing the work approved in the work plan and requesting site closure ' In a letter dated January 28, 2005, Margaret Lagorio, SJCEHD, stated that the site investigation and remedial action of contamination resulting from an unauthorized release from the underground storage tank(s) formerly and/or currently located at the VWDC site has ' been completed A Case Closure Summary was included with the letter On February 25, 2005, GTI prepared and submitted the Work Plan for Well Abandonment On March 1, 2005 Mr Brian Newman stated the site will be considered an open case until the wells have been properly abandoned The attached report discusses the proper abandonment of monitoring wells associated with the VWDC facility ' 2.0 WELL ABANDONMENT Nine (9) water table monitoring wells and one (1) deep monitoring well associated with the ' VWDC site were properly decommissioned between May 31 and June 1, 2005 These wells were abandoned in an effort to meet requirements leading to a "No Further Action Letter" All monitoring wells associated with the site were monitored regularly and were in good condition at the time of decommissioning No obstacles have been observed in any well prior to abandonment A summary of well construction is included as Table 1 in Appendix A and well locations are denoted in Figure 2 Gregg Drilling, a competent C-57 (#485165) well driller, was selected through a bidding process after the work plan was approved Gregg Drilling was employed to decommission ' the monitoring wells Permits were secured as necessary and the local regulatory agency was notified 48 hours prior to commencing work ' The wells were divided into two categories o Category 1 — Wells with contaminants detected more than one quarter during the previous eight quarters including MW-1, MW-4, MW-5, MW-6, MW-8 and MW-9 ' o Category 2 — Wells that have been non-detect for at least seven of the last eight quarters including MW-2, MW-3, MW-7 and MW-101 Category 1 wells were over drilled using 8-inch hollow stem augers guided down the center of the well casing via a guide rod attachment on the drill bit Grout, a cement-bentonite mixture, was used to seal the borehole To prevent bridging and ensure a good seal, the grout was kept under pressure by the use of a tremie pipe to feed grout into the borehole through the augers The tremie pipe was submerged several feet below the level of grout at all times The borehole was grouted to within three feet of the surface and the uppermost few feet was ' backfilled with clean material The surface was capped with the appropriate material (i c concrete or asphalt)to match the surrounding surface conditions I