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At the same time, a second shallow vadose zone well will be installed, together with <br /> modifications to the existing vapor well, should enable a limited shallow vadose zone <br /> soil vapor extraction cleanup to begin at the depth interval of previously identified <br /> highest concentrations. This data should address the basic regulatory requirements, <br /> and help to begin a limited vadose zone shallow cleanup. However, please note that <br /> limited site assessment can affect the efficiency and duration of site cleanup and <br /> future work could be necessary pending ultimate site cleanup standards. <br /> Scope of Work <br /> Exploratory Borings <br /> Two exploratory borings will be drilled at the locations shown on Figure 1. Drilling <br /> and well installation permits will be secured prior to doing the field work. One <br /> borehole will be converted to a groundwater monitoring well and one will be <br /> converted to a shallow vapor extraction well. The boreholes will be drilled with <br /> truck mounted hollowstem auger drilling equipment. All drilling equipment and <br /> sampling tools will be cleaned prior to arriving, and before leaving the site. The <br /> augers will be advanced to the desired sampling depth interval, and a drive split <br /> spoon sampler will be driven ahead of the drill bit. The sampler will then be <br /> retrieved and dissembled, and the soil filled brass liner will be sealed with Teflon' <br /> paper and plastic endcaps, labeled, logged onto chain-of-custody forms and place in a <br /> chilled ice chest. <br /> The boreholes will be logged using the Unified Soil Classification System under the <br /> supervision of a registered geologist using the attached Wright Sampling Protocol. <br /> Additional lithologic information will be collected to describe the subsurface geology. <br /> The samples will be collected at five-foot intervals, at intervals of obvious <br /> contamination and at stratigraphic features of interest. <br /> Well Installation <br /> One groundwater monitoring well and one vapor well will be installed using the <br /> attached Protocol (see Figure 2). The wells will be cased with Sch. 40 PVC casing, <br /> threaded together; glues will not be used. The slotted interval will be a 0.020 inch slot <br /> and the annular space around the slots will be backfilled with a 2/12 size sand. <br /> Previous experience has shown this to be a reliable well design in fine grained and <br /> stratified aquifer depositional environments. The vapor well design will be similar <br /> to that of the groundwater well, except the sand pack will be slightly coarser to allow <br /> more vapor suction from the surrounding soil. <br /> Final well design will be modified to the site specific conditions encountered in the <br /> borehole during drilling. Once the aquifer strata has been defined, the casing will <br /> be lowered to the bottom of the borehole, leaving a slotted interval above the <br /> occurrence of groundwater to observe for floating product. The sand pack will be <br /> placed to a point about two feet above the slots. A bentonite sea] will be placed atop <br /> the sand pack, and a cement grout seal placed atop the bentonite using a tremie line, <br /> filling from the bottom to top of the borehole. A traffic rated well head access box <br /> and security device v4ll complete each well. <br /> Waterloo School Workplan Page 2 <br />