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6 <br /> and prior to leaving the site to prevent cross-contamination Cuttings generated <br /> during drilling operations were placed in 55-gallon drums, which were labeled and <br /> stored on-site for future disposal <br /> All soil samples were collected from the borings at a minimum of every 5 feet using <br /> a split-barrel drive sampler, as described above Soil samples taken for chemical <br /> analyses were recovered with a sampler lined with clean brass tubes The brass tubes <br /> containing soils to be retained for chemical analyses were removed from the sampler <br /> and labeled as described in Section 4 3 Soil in the remaining tubes was used for <br /> lithological classification and field-screening with the photoionization detector (PID) <br /> 4 2 Well Construction Procedures <br /> Seven wells, four 4-inch-diameter wells ranging in depths from 15 5 to 30 5 feet, and <br /> three 2-inch-diameter wells ranging in depths from 29 0 to 30 0 feet were completed <br /> during this investigation Well construction details are presented in Appendix D <br /> All seven wells were constructed by lowering the appropriate diameter and lengths of <br /> Schedule 40 polyvinyl chloride (PVC) casing and screen through the augers A sand <br /> filter pack was then carefully poured between the annulus of the augers and the well <br /> casing from the extent of the well to 1 foot above the screened interval As the <br /> augers were withdrawn, the level of the filter pack was monitored with a weighted <br /> tape to ensure bridging of the filter pack did not occur A well screen slot of 0 020 <br /> inches was chosen based on lithology type and projected well use A No 3 <br /> Monterey-type Lonestar Sand was chosen for the filter pack material because sand <br /> is the predominant soil type and there is a relatively small amount of fines within the <br /> screened intervals <br /> ' A 1-foot-thick bentonite pellet seal was then placed above the filter pack sand Since <br /> the bentonite seal was located above the saturated zone, approximately five gallons <br /> of potable water was added to the borehole to hydrate the pellets A cement- <br /> PL1W 191 634IREPORTSISITE ASS4MANTECAWANTECA RPT IApr 26 931 CanoweEnvironmental <br />