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- . -. f- r ar P :� c.:.: <br /> W-7-0.14-0 <br /> '. NYii .F <br /> w <br /> S <br /> Ground water monitoring wells will be installed using a six-inch minimum <br /> inside diameter, hollow-stem auger (HSA). The auger will be advanced using <br /> a truck-mounted drilling unit capable of< rotar V�•— torque of 6,000 <br /> foot-pounds. Auger flights (5 feet in length) will be added as needed <br /> during the drilling process until a total d29th of 2 <br /> Q ir— <br /> de th to water is 10 feet.) ? s achieved <br /> The four-inch»diameter, Schedule 40 PVC casing and 10 foot screen will be <br /> placed through the center portion of the augers. The casing and screen <br /> with a bottom cap will be suspended off the bottom of the hole during <br /> placement of the filter pack and annular seal. <br /> b- A filter pack of clear washed quartz sand will be placed adjacent to the <br /> entire screened section of the well. The size of the sand material will be <br /> determined by the size of formation materials. The dry filter pack will be <br /> placed by free-fall through the center of the HSA. The filter pack <br /> material will be introduced into the HSA so that at least two feet of <br /> borehole would be filled upon retraction of the auger. During placement of <br /> ^? the filter pack, the pack will be sounded with a two-pound weighted line to <br /> --� verify that bridging has not occurred. Theprocedure will <br /> r <br /> until the level of the filter pack is IS inches above "he top of the <br /> screen. <br /> Following placement of the filter pack, a three-foot thick bentonite seal <br /> "v will belaced �+_ <br /> P rectly on top of the filter pack. The 1/4-inch-diameter�l��j�p{ <br /> sodium bentanite pellets will be placed by the free-fall ma+hod.a A a e <br /> 4 two-pound weighted tape will be used to check for bridging and proper <br /> thickness of the seal. The HSA will be retracted so that the bentonite <br /> pellets lie just below the lead auger. The pellets will be hydrated with <br /> tap water and let stand for 30 minutes for hydration to occur before <br /> r placement of the grout seal. <br /> s _ <br /> -- --- �} - <br /> Acement-bentonite_graat_composed-of-the following-ration-(approximate):—10 <br /> gallons of potable.water, 2 pounds of American Petroleum Institute (API) <br /> x. € <br /> {. <br /> Can®fti-eEnvi rcnmenta l <br /> _ - <br />