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31 January 2000 <br /> AGE NC Project No. 97-0290 <br /> Page 7of10 <br /> 4.2.1. Soil Vapor Extraction Well Installation <br /> 5:i>e <br /> Installation of-€r-te additional SVE wells is proposed utilizing a truck-mounted drill rig equipped <br /> with 8-inch diameter hollow stem augers. Hollow stem augers will be cleaned prior to advancement <br /> in each borehole. Three borings will be installed near the southern property line at angles from 10° <br /> to 25° from vertical, directed toward the south; the three northern borings will be advanced <br /> vertically. The SVE wells will be advanced to depths of approximately 50 vertical feet bsg and will <br /> be completed with 2-inch diameter, schedule 40 PVC well casing installed through the hollow stem <br /> augers. <br /> Soil samples will be collected at 5-foot intervals as described in the SVE/IAS Pilot Test Work Plan, <br /> dated 18 March 1999 and prepared by AGE. A limited number samples will be transported to a <br /> DHS-certified laboratory and analyzed for TPH-g, TPH-d, BTEX and MTBE in accordance with <br /> EPA methods 8015m and 8020. <br /> Each SVE well will utilize approximately 34 feet of slotted well casing (0.020-inch screen size). <br /> Three-foot sections of blank casing will be installed at approximately 25 feet bsg and 40 feet bsg. <br /> Well materials (casing, No. 3 Lonestar sand and bentonite pellets) will be installed through the <br /> hollow stem augers. A two-foot bentonite plug will be installed adjacent to each of the three-foot <br /> sections of blank casing. The filter pack will be placed in the remainder of the borehole adjacent to <br /> the screen from the bottom of the boring to a point approximately 2 feet above the top of the <br /> uppermost screened section. The blank sections of casing and bentonite plugs will allow for future <br /> isolation of sections of the well to direct remediation to specific soil zones, if necessary. If impacted <br /> soil is not encountered in the upper interval of the borehole, based upon field indications, blank <br /> casing may b,-substituted through the area of non-impacted soil during installation of the wells. A <br /> two foot interval of bentonite pellets(annular seal)will be placed above the filter pack and hydrated. <br /> Portland cement will be utilized to grout from the annular seal to near surface grade. An SVE well <br /> construction diagram is depicted in Figure 4. <br /> 4.2.2. Soil Vapor Extraction Piping System <br /> A network of two-inch diameter, schedule 40 PVC piping will be installed above-ground at the site. <br /> The PVC piping will be routed from each SVE well head to a vapor dropout drum;the vapor dropout <br /> drum will be directly connected to the VES.A PVC ball valve will be installed in each SVE well line <br /> so that vapors can be drawn from each well independently. The two proposed VES unit locations are <br /> depicted in Figure 3. Proposals for future construction activities at the site will determine the actual <br /> VES unit location. <br /> Advanced GeoEnvironmental,Inc. <br />