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• • KEI-P89-1104 .QR3 October 31, 1991 Page 5 During field activities on April 23 , 1990, the old pump (5 feet long) and pump casing (60 feet long) were removed from the well. The total depth of the well was measured at 135 feet below grade with the static water level measured at 55 feet below grade. The length of the existing casing could not be determined with the equipment on-site. Approximately 135 gallons of water were bailed from the water well using a clean stainless steel bailer. A water sample was obtained for analyses, and it was noted that the water sample contained sediment and what appeared to be iron flakes. The water sample was analyzed at Sequoia Analytical Laboratory in Redwood City, California, on April 24 , 1990, for TPH as gasoline and BTX&E. The analytical results indicated non-detectable levels of TPH as gasoline and BTX&E, except for 0.79 ppb of toluene. Mr. Knoll was informed of the results on May 10, 1990, and indicated that the ground water should be treated as contaminated because of the detected toluene. West Hazmat only had 100 feet of the 12-inch O.D. augers available on-site on April 23 , 1990, and therefore the well (135 feet deep) could not be fully drilled out and the casing could not be removed from the ground. A phone call was placed from the field to Mrs. Diane Henson of the SJCPHS to determine if the work plan could be modified to allow the six-inch diameter well casing to remain in the ground and to allow grout being placed only on the inside of the casing for the full depth of the well. This modification to our work plan was verbally approved by Mrs. Henson. However, further evaluation of the surface area adjacent to the six-inch diameter well casing identified a second casing, approxi- mately 10 inches in diameter, around the six-inch diameter casing. The depth of the second casing could not be determined, and it was unclear if the annulus between the six and ten-inch diameter casings was backfilled or open. A second phone call was placed to Diane Henson on April 23, 1990, and it was determined that only grouting of the inside of the six-inch casing would not necessarily provide an adequate seal to protect the ground water. Therefore, KEI was instructed not to destroy the water well at that time. The water well was provided with a temporary surface seal on April 23 , 1990, by driving in a circular wood plug, pouring one sack of bentonite powder gel over the wood plug and vicinity, and placing cement over the bentonite gel. KEI contacted Purviance Drillers, Inc. of Linden, California, for a proposal to properly abandon the dual cased water well. It was initially proposed to jet out any materials within the annulus spacing between the two well casings, split the six-inch diameter casing with a down-the-hole perforator tool, and to place Baroid Aquagrout Benseal within the annulus and within the six-inch