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B '1 depths. BTEX's are above detection limits in the 25 and 30 foot samples, but below detection limits in the 40 foot depth sample, see Table 1 and Appendix B. All samples were preserved, labeled, and chain of custody hand delivered to Chemtech Laboratories for analysis using EPA methods 8015 and 8020 with 5030 extraction. The excavated native soil produced by the borings was covered with polyethylene liners, but laboratory results show that this soil has very low contamination levels and can be aerated and used for back filling of depressions in the lot. - WELL CONSTRUCTION Using? Hogate Drilling Co's Mobile D-40L drilling rig, 10 and 8 inch hollow stem augers were used to drill through the excavation back fill and into the native soil to the `40" foot depth.. A WEGE geologist' screened the cuttings and samples using a HNU PID and selected samples for preservation and delivery for analysis to Chemtech Laboratories. Samples were obtained from areas that drill cuttings indicated likely soil contamination existed in the native soil drilled. Once the baring was completed the inner rod assembly was removed from the augers and "steam cleaned" 2 inch PVC casing was §- � installed through the augers. The casing is SCH 40 F480 PVC pipe, with machine slotted 0.020 inch screen in 10 foot threaded joints. The interval from.the base of the boring (40' depth) to the 30 foot contains the screen, the remaining casing to the surface is blank. After placing the casing through the augers to the base of the excavation, #2/12 monterey sand was used for the sand pack of the annular space of the boring. The sand was slowly poured through the augers, as the augers were removed five feet at a time; this helped to insure a proper sand pack fill. The sand pack was brought up to the 10-12 foot depth and the remaining augers were then removed. . A neat cement with 5% bentonite was then poured into the annular space of the boring to provide the sanitary seal for the well.. The. cement.was...brought up to the surface and .then allowed to cur.e, 'prior .to .any activity concerning the well (grout inspection by Dsin.a`Hinson-SJCHD) - MANIFOLDING THE VAPOR WELLS TO THE TREATMENT AREA Once the cement seal cured in the vapor extraction wells, the wells were manifolded to the treatment area using SCH 40 PVC pipe. The well heads were €itted-with--a 2-inch--PVC--T-that-will.—have---a.- - --------- -- water-vapor tight cap. A sample port and a ball. valve were placed off of. the T prior to the 2 inch manifold pipe for obtaining vacuum and vapor readings, adjusting the influence for that well and obtaining samples from the well, see Figures 3 and 9B. page 5 . ,. .•, . . wee _ ,.