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M 'h <br /> Installation of Two Air Sparse Wells and Three Vapor Wells <br /> This task includes mobilization to the site, advancing two soil borings and completing them as air <br /> sparge wells, and then advancing three soil borings and completing them as vapor wells. The <br /> proposed locations of the air sparge and vapor wells are shown on Figure 2. <br /> Two borings will be advanced to depths of 33 and 35 feet below ground surface (bgs) and <br /> completed as air sparge wells, and three borings will be advanced to depths of 30 feet bgs and <br /> completed as vapor wells. The borings will be advanced using 8-inch O.D. hollow stem augers. <br /> Drilling will be conducted by Spectrum Exploration, Inc., a State-licensed (C57) drilling <br /> company. A field geologist will be present to log all drill cuttings and soil samples. Descriptions <br /> of soil types encountered, sample collection intervals, and well construction details will be <br /> recorded on boring/well logs. Soil samples will be collected at five foot intervals and up to two <br /> samples from each boring will be sent using chain-of-custody record to a State-certified <br /> laboratory for analysis of total petroleum hydrocarbons as gasoline (TPHg) and benzene, toluene, <br /> ethylbenzene, and xylenes(BTEX). <br /> The wells will be constructed of 2-inch inside diameter PVC well screen and casing. The air <br /> sparge well located within the former tank pit will be constructed with a screened interval from <br /> approximately 32 to 35 feet bgs, and the air sparge well located east of the former tank pit will be <br /> constructed with a screened interval from 30 to 33 feet bgs. The vapor well located within the <br /> former tank pit will be constructed with a screened interval from approximately 20 to 30 feet bgs, <br /> and the two vapor wells located outside the former tank pit will be constructed with screened <br /> intervals from 10 to 30 feet bgs. To protect the integrity of the wells, locking, water-tight well <br /> plugs will be installed on each well, and water-tight, traffic rated, wellheads labeled "monitoring <br /> well' will be concreted over each well. All drill cuttings will be drummed and stored on-site <br /> pending laboratory results. <br /> Pilot Test <br /> The new wells will be used to conduct a pilot test to determine the efficiency of vapor extraction <br /> and air sparging as a remediation technique. The details concerning the pilot test will be discussed <br /> in a separate workplan. <br /> Report Preparation <br /> Following receipt of laboratory results, a report will be prepared summarizing the findings of the <br /> subsurface investigation for submittal to the client and PHS/EHD. The report will summarize <br /> field and laboratory procedures as well as all analytical data and contain recommendations for soil <br /> and groundwater remediation pilot tests. <br /> wA94373\repo`ts\wpO496a.doc 2 <br /> SMTH <br />