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Iln''11rP41l ' I 1 <br /> Iqn ,dd 1 I <br /> I tl II <br /> Project No 58080-06-02 <br /> May 5, 1995 <br /> ' 25 Vapor Extraction Well Construction <br /> ' Onsite vapor extraction wells were constructed at the locations depicted on Figure 2 Vapor <br /> extraction wells VW-2 through VW-6 were constructed using 4-inch diameter polyvinyl chloride <br /> ' (AVC) casing The vapor wells were constructed using 40 linear feet of 0 040-inch slotted screen <br /> AVC casing installed within each 30° slanted borehole Accounting for borehole geometry, the <br />' screened portion of each vapor extraction well was placed between the depths of 22 and 55 feet <br /> measured vertically from surface grade The screened intervals for individual vapor extraction wells <br /> are summarized in Table I and are depicted on the Boring/Well Logs included in Appendix A A <br /> filter pack consisting of pea gravel was placed around the screen from the bottom of the screen <br /> interval to an elevation of two feet above the screen zone A two foot thick seal consisting of <br /> 1 hydrated bentonite chips was placed above the filter pack Above the seal a mixture of bentonite <br /> powder and cement was placed to within two feet of grade level Traffic-rated security wellhead <br /> covers were used to complete construction <br /> 26 Groundwater Well Development <br /> Monitoring wells MW-4 and MW-5 were developed using a surge block to densify the sand pack <br /> followed by pumping to remove sediment and groundwater Development pumping was <br />' 4ccomplished using a 2-inch diameter Grundfos electric submersible pump Extracted groundwater <br /> was pumped into DOT 17-H 55-gallon drums which were labelled and stored onsite pending receipt <br />' of laboratory analysis and subsequent disposal following regulatory protocols <br /> 2 7 Groundwater Sampling <br /> Prior to groundwater sampling, depth to groundwater measurements were obtained from wells MW- <br /> 1 through MW-5 and each monitoring well was checked for the presence of free product <br /> Groundwater depth measurements were obtained using a battery operated Solonist water level meter <br /> -12- <br />