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6.0 Geolgica(Tecfwics Inc. Well Installation Report Page 4 City of Escalon Project No.750.2 60 January 31,2000 N-.01 460surface. The wells were cut off five feet below ground surface, capped, covered with steel plates and buried with dirt. This was done to allow the road, sidewalk and other improvements to be completed without damaging the wells. See Section 2.2.3 for a discussion of when and how the wells were brought to ground surface. 6.4 2.2.2 Vapor Extraction Wells In order to prepare for a vapor extraction pilot test and possible remediation by vapor 16.0extraction, four (4) soil borings were drilled (2 to a depth of 55 feet and 2 to a depth of 27 feet) and converted into vapor extraction wells. The borings, VEW-1 and VEW-2 were drilled at the eastern edge of the site, under the former sidewalk along the old Escalon/Bellota Road. The borings for VEW-3 and VEW-4 were drilled in the northern part of the +� excavation, adjacent to the northern dispenser island(Figure 2, Site Map). The monitoring wells were constructed using 4-inch diameter PVC casing with flush threads. The table below shows the construction details. The filter pack was surged during placement to insure maximum filter pack density. Well .No. Mad' creep slot i ter ac rans. rout ea Seal Pea grave - - - - �. ea grave . - a grave - e -37' _ - ea grave -27, 6- A surface seal was achieved by pumping a neat cement grout via a tremie tube (augmented with <4% bentonite) from the top of the Transition Seal to within 5 feet of the ground surface. The wells were cut off five feet below ground surface, capped, covered with steel plates and buried with dirt. This was done to allow the road, sidewalk and other improvements to be completed without damaging the wells. See Section 2.2.3 for a discussion of when and how the wells were brought to ground surface. '-' 2.2.3 Additional Site Work On June 27, 1999, the two vapor wells, that are now covered by Escalon/Bellota Road (VEW-1 &VEW-2), were dug up by GTI and Del Tech personnel using a backhoe. A trench �. was dug at approximately 4 feet below grade, heading to the west from the vapor wells. Conveyance piping was laid in the trench and VEW-1 & VEW-2 were hooked to it. The conveyance piping was stubbed off at approximately 3 feet below ground surface at the location of where MW-1, VEW-3 and VEW-4 were to be drilled. The trench was backfilled and compacted. On September 3, 1999, GTI and Del Tech personnel arrived on site to dig up and finish off La MW-3. Finishing of this well had been delayed waiting for the center median of Escalon/Bellota Road to be installed. The well was brought up to ground surface, a locking cap installed and a well box was placed over the top of the well. The construction contractor ,r installing the median was supposed to concrete the box in place and finish it flush to the grade of the median. In late November GTI was notified that the well box had not been installed and that the concrete median had been finished, leaving the well casing exposed. On December 16, 1999, Del Tech mobilized to the site and installed a well box over MW-3 in order to secure it. Lo