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URS Mr Harlin Knoll Page 2 San Joaquin County Environmental Health Department December 22, 2005 destruction activities described in the Well Destruction Workplan (URS, September 2005) were planned On November 29, 2005, and November 30, 2005, Woodward Drilling Company, Inc of Rio Vista, California, conducted well destruction activities The well locations built with 2-foot by 2-foot and 4-foot by 3-foot vaults were destroyed by pressure grouting with a neat cement grout containing less than 5% bentonite powder Pneumatic pressure was applied at the top of casing to ensure filter pack infiltration, and the well topped off with additional grout and pressurized again as necessary Any existing horizontal remediation piping located within the vaults was cut or broken to fill the void as the vault boxes were filled to at least half way with neat cement grout containing less than 5% bentonite powder The vault lids were closed to allow the grout to set in preparation for the amount of compactable material and concrete required to complete the surface completions Well Iocations ATR-2, ATR-5, ATR-6, and ATR-7 were pressure grouted by installing 1-inch diameter tremae pipe to near total depth and grouted with a neat cement grout containing less than 5% bentonite powder Pneumatic pressure was applied at the top of casing to ensure filter pack infiltration,topped off, and pressurized again as necessary The casings were cut down for ATR-2 and ATR-5 to near the vault floor, the vaults were filled to at least half way, and the grout allowed to set up in preparation for the concrete surface completions For ATR-6, ATR-7, and VES-7, the grout was allowed to set over night, the vault boxes were removed, sediment around the casings excavated to 1 5 feet and 3 feet bgs (both ATR-7 and VES-7), respectively, the casings cut down, topped off with additional neat cement grout to form a mushroom cap, and buried with sediment to match the surrounding surface During pressure grouting activities, ATR-1 was cleared for utilities by water-knife to a minimum of 24-inch diameter by 5 feet bgs around the entire casing ATR-1 was pressure grouted with a neat cement grout containing less than 5% bentonite powder Pneumatic pressure was applied at the top of casing to ensure filter pack infiltration, the well topped off with additional grout and pressurized again as necessary The casing was cut down to approximately 4 5 feet bgs and backfilled with additional grout to near ground surface A piece of 4-foot by 4-foot, 1-inch thick plywood was placed on top of the well location with delineators and caution tape for safety and to allow the grout to set up in preparation for the concrete surface completion ' Well locations ATR-8 and ATR-11 were dniled out to a total depth of 27 feet bgs with 8-inch diameter hollow-stem augers (HSAs) with a 9-inch bit (as discussed with the SJCEHD) The bonngs were then ' grouted through the augers with neat cement grout containing <5% bentonite powder, the augers were pulled, additional grout was added to near surface, and finished with concrete that was tinted to match the surrounding surface K 1WprocessV5 BP ARCO\020931Well Destr\2093 Well Destruction Report draft doc