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feet above the water table encountered during drilling The well casing and screen were suspended during placement of the artificial filter pack material, bentonite seal and ce- ment/bentonite grout Well construction details are presented in Table D-2 TABLE D-2 ' Well Construction Details ' MW-4 MW-5 MW-6 Total Depth 107 feet 107 feet 106 feet ' Screen Interval/Slot Size 85-105 feet/O 020 inch 84-104 feet/O 020 mch 84-104 feet/O 020 inch Sand Interval 83-107 feet 82-107 feet 82-106 feet ' Bentonite Seal Interval 81-83 feet 80-82 feet 80-82 feet Casing Type PVC Schedule 40 PVC Schedule 40 PVC Schedule 40 ' Diameter of Casing Two inch Two inch Two inch Sand Pack #1C Lonestar Sand #1C Lonestar Sand #1C Lonestar Sand ' Grout 3-5% bentonite and Portland 3-5% bentonite and Portland 3-5% bentonite and Portland I-I1 cement 1-11 cement I-11 cement End Caps Flush-threaded screw-on Flush-threaded screw-on Flush-threaded screw-on bottom/expandable locking bottom/expandable locking bottom/expandable locking top top top Completion Flush mount Chnsty Sox Flush mount Chnsty Box Flush mount Chnsty Box ' All measurements are in feet below ground surface(BGS) ' The sand pack (consisting of Lonestar #1C sand) was placed through the eight-inch hollow stem augers by alternately filling the augers with two to three feet of sand and withdrawing approximately one foot of auger This process was continued (always keeping sand inside the augers) until the height of the sand pack was approximately two feet above the top of the well screen. After placement of the sand pack was completed, a two-inch surge block was used to swab each well In order to settle the sand pack Additional sand was added to attain the sand pack height of two feet above the top of the well screen A water level probe was then used to assess whether water was present on top of the sand pack Water was not present at this depth ' during each well construction, therefore, a bentonite pellet seal was placed on top of the filter pack A two foot thickness of bentonite pellets was placed on top of the sand pack and hydrated with potable water obtained from the site ICement/bentonite grout was then placed in the remainder of the annular space via a tremie pipe set through the augers to approximately 20 feet above the bentonite seal The grout mixture consisted of approximately two pounds of powdered bentonite added to approximately 10 gallons of water (obtained from the ng) per 94 pounds (one stack) of cement The bentonite was added to the water and circulated with a mechanical mixer to hydrate the bentonite After the bentonite Iwas hydrated (approximately five minutes), the cement was added and thoroughly mixed The ISTMRPYS\AREG3grR WP D - 4 11/12/92