SITE INFORMATION AND CORRESPONDENCE

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/Monitoring Well Ilwallation Work Plan Our Job P89018 rhead Door Corporation May 15 , 1989 i, California Page 2 Drilling and sampling equipment would be thoroughly steam cleaned before drilling begins to prevent the introduction of off-site contamination. The boring would be logged under the supervision of a State of California Certified Engineering Geologist. Following completion of the boring, an open standpipe piezometer well would be installed within the boring. The monitoring well would be constructed by installing 2-inch diameter polyvinyl chloride ( PVC) flush-threaded casing and slotted pipe directly through the hollow stem auger. The slotted section of the PVC pipe installed through the saturated zone would have 0. 020-inch factory perforations. Materials used in the well construction would be thoroughly cleaned prior to introduction into the boring. The monitoring wells would be filter-packed with clean monterey silica sand throughout the screened interval. The filter-pack material would be installed in the angular spacing between the monitoring well pipe and the auger as the auger is removed and would extend a minimum of two feet above the top of the screened interval. To assure continuity and integrity of the filter material, and to prevent the bore hole from caving, no more than five feet of auger would be removed at a time. A two-foot thick layer of bentonite pellets would be emplaced above the filter material to provide an annular seal and the remainder of the boring would be filled with a cement slurry to within one foot of grade. The grouting would be performed with direct observation by a representative from the San Joaquin County Department of Hazardous Materials. The well casing would have a locking cap and would be enclosed inside a watertight aluminum traffic box installed in concrete flush with the surface. Figure 3 illustrates the construction of a typical monitoring well. The initial well development would be through the use of gas displacement pump or positive displacement bladder pump. The well would be developed until five to seven ( 5-7 ) well volumes have been purged from the well or until the water appears clear of sediment. Electrical conductivity, temperature, and pH of the ground water would be recorded throughout the development process. water samples for analytical testing would be obtained through the use of the gas displacement or bladder pump. Water samples would be preserved by acidification with nitric acid. Soil cuttings derived from the boring would be retained and stored on-site at the existing area currently designated for soil storage. All water generated by the well development and sampling would be contained on-site. Copy BSK