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s <br /> Filter pack will be installed through the annular space between the well <br /> casing and the augers as the augers are removed. The filter pack depth <br /> will be sounded continuously to ensure a solid pack with no bridging. <br /> approximately 2 feet above the tap of the <br /> The filter pack will extend <br /> screen. <br /> At least 1 foot of bentonite pellets will be placed into the borehole to <br /> form a seal above the sand pack. 1f there is water in the well annulus <br /> and bentonite is judged to be inappropriate, a fine sand, such as Lane <br /> Star No. 30 or its equivalent, may be tremmied in place oftsee bentonite <br /> pellets. <br /> Cement-bentonite grout containing approximately 5 percent bentonite <br /> will be installed from the top of the bentonite/sand seal to the ground <br /> surface. The grout will be pumped through a tremmie pipe from the <br /> ace. The <br /> bottom of to set efor •ataining annulus to the leastt 12 hours before well development. will be <br /> allowed <br /> Wells will be developed by surging, pumping, and/or bailing until the <br /> • pumped water is clear and free of sand and the pH, conductivity, and <br /> temperature are stabilized. Conductivity will be considered stabilized <br /> when two consecutive readings are within 10 percent and pH within <br /> 0.02 units. The well depths will be measured before development <br /> completion. Accumulated fine-sized mate mentstlwll be obtained while <br /> well. Water level and flow rate mea <br /> purging the wells. <br /> Wells will be completed at grade. A Christie box will be installed with a <br /> 2-to 3-foot-diameter cement pad,mounded to direct surface water runoff <br /> away from the monitoring well. <br /> The top elevation of the well casing will be surveyed to the nearest <br /> 0.01 foot. <br /> Development water, decontamination rinse water, ane cuttings will be <br /> collected for disposal. <br /> Figure 4-1 shows the typical construction details of a monitoring well. <br /> be taken and referenced <br /> Static water level <br /> the measurements The each <br /> method or the eletoring well lctric sounder method will <br /> to the top ofthe casing. Th <br /> be used to take the eforerand after use at each we f foot. <br /> cable <br /> Soil borings and well locations <br /> be decontaminated b <br /> will be surveyed. <br /> ...........---------- <br /> 4-5 <br /> ----- <br /> 4-5 <br /> " SF031605%WP%00—$1 <br /> E� <br />