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V <br /> Work Plan For Groundwater Monitoring Well Destruction <br /> 7-Eleven Inc.,455 Grant Line Road,Tracy,CA September 7, 1996 <br /> Well Destruction <br /> The remaining nine site-related groundwater monitoring wells and two groundwater extraction wells <br /> will be destroyed in accordance with guidelines set forth in California Department of Water Resources <br /> Bulletins 74-81 and 74-90. The wells will be destroyed using a pressure-grouting technique and then <br /> drilled out to five feet BGS using a hollow stem auger drilling rig. Well construction details for existing <br /> and previously destroyed groundwater monitoring and groundwater extraction wells are included in <br /> Attachment 2, Table 1. <br /> Prior to pressure-grouting, each well casing and screen will be checked for obstructions and cleared <br /> as needed. A truck-mounted drill rig or a jack hammer will use to remove the monitoring well traffic <br /> boxes and extraction well vaults. Each well casing will be grouted with Portland cement from the <br /> bottom of each casing to grade via a one-inch-diameter tremie pipe. Displaced groundwater <br /> generated during the grouting of the wells will be captured and placed in 55-gallon DOT-approved <br /> drums and stored on site. Following placement of the grout, approximately 30 psi of pressure will be <br /> applied to the top of each casing using an air compressor to push the cement through the screened <br /> interval. The well casing will the be drilled out to five feet BGS using a drill rig with a hollow stem <br /> auger to match the diameter of the existing well borehole. The resultant borehole will be backfilled to <br /> grade with Portland cement and topped with hot patch asphalt to match the existing surface grade. <br /> Well locations in planters will be grouted to approximately 1 foot BGS and topped with clean top soil <br /> material. <br /> All well-related materials, including well casings, well boxes, vaults, and associate concrete, will be <br /> segregated from the well annulus material and transported to a local landfill. All well annulus material <br /> and rinse water/displaced groundwater will be placed in 55-gallon DOT-approved drums and stored on <br /> site pending characterization and disposal <br /> Report Preparation <br /> A letter report will be submitted upon completion of the field activities. The report will summarize the <br /> methods used for well destruction. <br /> 20304dwp,ltr <br />