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1 ' was constructed using 6-inch-diameter Schedule 40 PVC flush- thread casing and screen. This well was constructed with 6-inch casing and screen so that if necessary it could be used as an extraction well for ground water remediation The remaining monitoring wells were constructed using 2-inch-diameter Schedule 40 PVC flush-thread casing and screen. All well screens have a slot ' size of 0 02 inches. The screened intervals in wells MW-1A, MW-3A, and MW-4A have a length of 10 feet. MW-2A has a screened interval with a length of 7 feet. The bottom of the screens are closed with a ' Schedule 40 PVC flush-threaded plug. The tops of the wells are capped with lockable, expandable plastic plugs and are covered with slip caps Prior to placement, all casing materials were cleaned and ' decontaminated by the use of steam. The annular space between the borehole wall and well screen was backfilled with clean Lone Star (or equivalent) 2/16 mesh sand. The sand was supplied to the fob site in sealed paper sacks. The sand pack extended from the bottom of the screened interval to ' approximately 2 feet above the top of the well screen Above the sand pack, a layer of bentonite pellets was a ced in MW-3A and MW-4A. The pellets were suPelted to the job site in ' sealed plastic pails The remainder of the borings were backfilled with grout. The grout consisted of Type I-II cement and was well mixed with bentonite powder and sufficient water to create a fluid. The grout was poured into place Grout was placed above the sand s he pack in wells MW-1A and MW-2A. The grouting procedure same as that discussed above. ' Each well was secured with a locking cap and was covered with a utility box which was set flush with the ground surface. Each box ' consists of a steel cover and was set in grout. Confined ground water conditions were encountered in MW-1A. Groundwaterassurfaially encountered at approximately 9 5 feet below ground ce in MW-1A. During subsequent drilling, the ground water level rose to an approximate depth of 5 feet bgs. Thus, a 10-foot screened interval ' was placed between 4.5 and 14 5 feet bgs. In MW-2A, a 7-foot screened interval extends between 3 5 and 10.5 fest bgs. The o } is boring was cpperched water ed with bentonite. This well construction ash sen becauseer was encountered in the gravel fill material Beneath these gravels at a depth of approximately 10 5 feet bgs, a 3-foot-thick silt layer was encountered. A split spoon ampderdriven dtenabeneath h this slit to obtain aplen o � potial cross - contamination the lower sand with perched water above the silt of ed layer, it was decided that the well screening should be set within the 5-6