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l <br /> Y <br /> WELL INSTALLATION <br /> Spectrum will construct a groundwater monitoring well in each borehole. <br /> Well construction is illustrated in the attached Typical Groundwater <br /> Monitoring Well . Flush thread pointed, Schedule 40, polyvinyl chloride <br /> (PVC) casing of 4-inch diameter will be placed down the hollow stem of <br /> the augers to the base of the boring. The lower 15-foot section of the <br /> well (depth interval of 7 to 22 feet below ground surface) will be made <br /> of screened casing with 0.010-inch slots. The remaining well section <br /> will be made of solid casing. A threaded well plug well cap will be <br /> placed on to the bottom of the well casing and a locking cap will be <br /> placed at the top. <br /> The filling of the annular space between the well casing and borehole <br /> wall will be as follows. Monterey-type (No. 3) sand will be placed in <br /> the annular space between the base of the boring to approximately 2 <br /> feet above the screened well casing. A seal of bentonite pellets, <br /> approximately 1 foot thick, will be placed above the sand pack. The <br /> remaining annulus between the ground surface and a depth of 6 feet <br /> will be filled with a neat cement slurry. A traffic rated, utility box <br /> will be placed around the wellhead and set in the neat cement even with <br /> the ground surface. A special tool is required to open the utility box <br /> • and a key is needed to open the wellhead lock so that the risk of <br /> unauthorized access to the monitoring wells will be minimized. <br /> A few days after well installation, Spectrum will develop the wells by <br /> the surging and pumping method. Water from the wells will be stored on <br /> site in a 55-gallon capacity, liquid-waste type steel drums and labeled <br /> as to the contents. Wellhead elevations will also be surveyed to <br /> evaluate groundwater gradient and flow direction. <br /> WATER SAMPLING <br /> At least 72 hours after well development, EVAX will sample groundwater <br /> at the site. For each groundwater monitoring well , sampling activities <br /> include depth to water measurement, subjective evaluation, and purging <br /> and sampling groundwater for laboratory analysis. Depth to water will <br /> be measured to the nearest 0.01 foot with a Solinst electronic water- <br /> level indicator. Subjective evaluation will then be performed by <br /> gently lowering a clean Teflon bailer approximately half its length <br /> past the air-water interface. A water sample will be retrieved and <br /> examined for possible evidence of hydrocarbon products in the form of <br /> floating product, sheen, and odor. <br /> 4� <br />