SITE INFORMATION AND CORRESPONDENCE

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Kennedy/Jenks/Chilton Attachment A to Kennedy/Jenks/Chilton's letter to Mr. Ron Valinoti dated 13 October 1989 Kennedy/Jenks/Chilton's Laboratory Division in San Francisco or to another state certified laboratory for analysis. Soil from a second brass liner at each drive interval will be placed in a self-sealing plastic container. After placing the container in a warm area for 5 to 10 minutes to promote volatilization, organic vapors in the container will be measured using an organic vapor analyzer. These measurements will be recorded and used to select samples for laboratory analysis. For budgetary purposes, the contents of three brass liners are proposed to be analyzed for BXTE and TPH. On the basis of the results of the previous investigation, it is anticipated that soils from the 15, 20, and 25 foot intervals will be analyzed. The drilling and sampling equipment will be steam cleaned prior to arrival on-site. The soil sampling equipment will also be cleaned between samples using a steam cleaner or TSP wash to reduce the likelihood of cross-contamination between samples. After drilling and sampling is completed, a monitoring well will be constructed using 2-inch Schedule 40 PVC well casing material . The lower portion of the monitoring well will consist of a factory machine slotted (0.020-inch slots) 2-inch Schedule 40 PVC casing, the screened interval of which will extend to approximately 10 feet below and 5 feet above the groundwater table observed at the time of well installation. This arrangement will accommodate seasonal water level fluctuations. The upper portion of the casing will consist of blank (non-slotted) 2-inch diameter Schedule 40 PVC casing. Casing joints will consist of threaded connections; PVC cement or lubricant will not be used on any part of the casing. Since the well will be located outside the fenced area, the completion will be flush with the ground surface using a water-tight traffic-rated vault. The annular space between the screened section and the wall of the boring will be filled with a Monterey No. 1C sand to provide an artificial filter pack. The artificial filter pack will extend approximately 2 feet above the top of the slotted casing. A 1-foot thick bentonite pellet seal will be placed on top of the artificial filter pack, followed by a cement/bentonite grout. The grout will be composed of approximately 2 pounds of granular bentonite, 90 pounds (1 sack) of cement, and approximately 7 gallons of water. The bentonite will be allowed to hydrate in the water before the cement is added. The bentonite/cement will be pumped through a tremie pipe or emplaced by freefall through the augers using the augers to stabilize the boring walls. Excess soils generated during the drilling and installation of the monitoring well will be placed in D.O.T. drums approved for the storage and transport of WPNMLI:STOCKTON.WP2 A - 5