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I <br /> s <br /> All soil samples were collected from each boring at a minimum of 5-foot intervals <br /> 1 using a split-barrel drive sampler, as described above However, samples were not <br /> collected from Well W-1 , since it was placed adjacent to Boring SB-2 Soil samples <br /> taken for chemical analyses were recovered with a sampler lined with clean brass <br /> tubes The brass tubes containing soils to be retained for chemical analyses were <br /> removed from the sampler and labeled as described in Section 4 3 Soil in the <br /> remaining tubes was used for lithological classification and field-screening with the <br /> t <br /> photoionization detector (PID) <br /> t <br /> ` 4 2 Well Construction Procedures <br /> I <br /> Six vapor extraction/Inlet wells, three 4-Inch-diameter wells to 40 5 feet and three 2- <br /> inch-diameter wells to 30 5 feet were completed during this investigation Since <br /> Wells W-5 and W-S were originally drilled with a 6-inch OD auger, these wells were <br /> overdrilled with 8-inch OD augers to accommodate the installation of 2-inch wells <br /> Well construction details are presented in Appendix D <br /> All wells were constructed by lowering the appropriate diameter and lengths of <br /> 4 <br /> Schedule 40 polyvinyl chloride (PVC) casing and screen through an 8-inch OD auger <br /> A sand filter pack was then carefully poured between the annulus of the augers and <br /> the well casing from the extent of the well to 1 foot above the screened Interval As <br /> the augers were withdrawn, the level of the filter pack was monitored with a <br /> weighted tape to ensure bridging of the filter pack did not occur A well screen slot <br /> size of 0 020 inches was chosen based on lithology type and projected well use A <br /> No 3 Monterey-type L.onestar Sand was chosen for the filter pack material because <br /> I sand is the predominant soil type at the site <br /> i A 1-foot thick bentonite pellet seal was then placed above the filter pack sand Since <br /> t the bentonite seal was located above the saturated zone, approximately 5 gallons of <br /> � I <br /> potable water was added to the borehole to hydrate the pellets A cement-bentonite <br /> grout was placed above the bentonite seal after the pellets had been allowed to <br /> 1 W N81 634,RkPORTSSSITE ASS\LDCKEFORD\LDCKEFORO RPT April 26 19931 Canonle 1 <br />