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1 <br />0 <br />• The deep wells are anticipated to be 250 to 300 feet deep <br />and will be screened across an interval beginning a <br />minimum of 15 feet below first -encountered ground water of <br />the deep aquifer and extending to 5 feet above first -en- <br />countered water. <br />• If no shallow ground water is encountered in the explor- <br />atory boring for the first shallow well (MW -4), the well <br />will be screened over the upper contact of the Corcoran <br />Clay. If ground water is not encountered in Well MW -4, <br />Well MW -5 will not be installed. The shallow downgradient <br />borings and wells are anticipated to be approximately 30 <br />to 35 feet deep and will be screened from the bottom of <br />the hole to 5 feet above first -encountered ground water of <br />the shallow perched zone. <br />• Screen perforations of 0.020 inch will be used. <br />• Casing sections will be joined by threaded joints. No PVC <br />cement will be used for well construction. <br />• The filter -pack material will be Lonestar 2 x 12 washed <br />sand or equivalent. <br />A plug, approximately 2 to 5 feet thick, of bentonite <br />pellets will be placed above the filter pack. The depth <br />of the annular seal will be determined after drilling and <br />will be in compliance with applicable state and county <br />guidelines. The annular seal will be installed from the <br />bottom using a pressure grout technique (tremie method). <br />The annular seal will be a cement/bentonite mixture. <br />• The deep wells will be developed using a combination of <br />surging and bailing techniques. The shallow wells will be <br />developed using a combination of air lifting, surging, and <br />pumping. The wells will be developed until the water is <br />reasonably free of sand, silt, and clay. <br />All wells will be constructed in a manner that maintains the integrity <br />of the drill hole and minimizes communication of saturated zones. The <br />monitoring wells will be installed in compliance with Subchapter 15, <br />Sections 2555(c) and (d). After installation, casing and ground <br />elevations for all wells will be surveyed to the nearest 0.01 foot <br />relative to Mean Sea Level (U.S. Geological Survey datum). These <br />elevations will be used to determine ground -water elevations when the <br />wells are sounded during sampling events. <br />11 <br />EM(on Associates <br />