SITE INFORMATION AND CORRESPONDENCE_FILE 1

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kilned and bagged Monterey 2-16 silica sand placed around the well screen to a height of 2 feet above the top of the well screen. The sand size may require modification in the event a different screen size is required. A one foot thick bentonite seal will be placed above the sand pack and the well annulus will then be sealed to the surface with a 5% bentonite cement grout. As the wells are in an area experiencing a large volume of truck traffic, all of the wells will be completed at the surface in a reinforced, pavement level vault. Once installation is complete, the relative elevation of each well, as measured to the top of the 4 inch well casing, will be determined by hand leveling. The wells will be developed by a combination of swabbing, bail- ing, and pumpage using a 3 inch submersible pump; air development methods will not be employed. Development will continue until the well discharge water is sediment free, or until a total of 2 hours per well of development time has elapsed. The swab, bailer and pump will be thoroughly cleaned prior to first use and between each use with a high pressure, potable water spray rinse. Following development, the wells will remain idle for at least one week prior to sampling. 5.3 Soil Sampling During the drilling of the exploratory boreholes and the monitor well boreholes, soil samples will be collected from each location at 3 feet BGS and at 3 foot intervals thereafter down to ground- water. Sampling at the deep (40 foot) boring will continue into the saturated material at 5 foot intervals. Those unsaturated samples appearing visually stained, odorous or otherwise contami- nated, or producing a response on a field screening instrument (a HNu photoionizer) will be submitted fo�maximum Pmical analysis. If no samples a ear contaminated, aturated sample closest to groundwater will be submitted. A 3 soil samples per exploratory boring and 1 sample per monitor well boring will be submitted for chemical analysis. Those samples not initially selected for chemical analysis will be archived at the laboratory for possible future analysis. Prior to collection of these samples, the split -spoon will be decontaminated by scrubbing with a bristle brush in a solution of potable water and non -phosphate detergent (such as Alconox), followed by potable water rinse and completed with a final spray rinse of distilled water. The split -spoon will then be lined with laboratory cleaned brass tubes. Augers and drill bits will be steam cleaned with potable water between borings. Once the split -spoon has been driven into the ground and re- trieved, the spoon will be opened and two of the tubes will be removed. The ends of each tube will be covered with teflon sheeting and then capped with plastic end caps; these caps will be sealed to the tube by wrapping with an elastic tape such as - 12 -