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1 <br /> Well completion forms are provided in Appendix F MW-2A, located <br /> in the center of the former UST, was constructed using 6-inch- <br /> diameter, Schedule 40 PVC flush-thread casing and screen This <br /> ' well was constructed with 6-inch casing and screen so that if <br /> necessary it could be used as an extraction well for groundwater <br /> extraction remediation The remaining monitoring wells were <br /> constructed using 2-inch-diameter, Schedule 40 PVC flush-thread <br /> casing and screen All well screens have a slot size of 0 02 inches. <br /> The screened intervals in wells MW-1A, MW-3A and MW-4A have a <br /> length of 10 feet MW-2A has a screened interval with a length of 7 <br /> feet The bottom of the screens are closed with a Schedule 40 PVC <br /> flush-threaded plug The tops of the wells are capped with lockable, <br /> ' expandable plastic plugs and covered with slip caps Prior to <br /> placement, all casing materials were cleaned and decontaminated by <br /> the use of steam <br /> The annular space between the borehole wall and well screen was <br /> backfilled with clean Lone Star (or equivalent) 2/16 mesh sand The <br /> sand was supplied to the ,fob site in sealed paper sacks The sand <br />' pack extended from the bottom of the screened interval to <br /> approximately 2 feet above the top of the well screen <br /> Above the sand pack, a layer of bentonite pellets was emplaced in <br /> MW-3A and MW-4A The pellets were supplied to the ,fob site in <br /> sealed plastic pails The remainder of the borings were backfilled <br /> with grout The grout consisted of Type I-II cement and was well <br /> mixed with bentonite powder and sufficient water to create a fluid <br /> The grout was poured into place <br />' Grout was placed above the sand pack in wells MW-1A and MW-2A <br /> The grouting procedure was the same as that discussed above <br /> rEach well was secured with a locking cap and was covered with a <br /> utility box which was set flush with the ground surface Each box <br /> has a steel cover and was set in grout to secure it <br /> Selection of S mend In ry % <br /> Confined groundwater conditions were encountered in MW-1A <br /> Groundwater was initially encountered at approximately 95 feet <br />' below the ground surface in MW-1A During subsequent drilling, <br /> the groundwater level rose to an approximate depth of 5 feet below the <br /> ground surface Thus, a 10-foot screened interval was placed <br />' between 4 5 and 14 5 feet below the ground surface <br /> In MW-2A, a 7-foot screened interval extends between 3 5 and <br /> 10 5 feet below the ground surface The bottom 3 feet of this boring <br /> 3-4 <br />