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i 1 Mr Nuel Henderson . Page 4 of 9 ' Bentonite based drilling mud was maintained in an overbalanced condition (8 75-10 2 lbs/gal) to prevent formation water from the entering the borehole The lithology in boring MW15C was logged by the relative percentage of coarse grained material (sand and gravels) vs fine grained material (silt and clay) present in drilling mud ' returned to the surface C Zone Well Construction ' A 6 % inch diameter steel conductor casing fitted with centralizers, and a grout shoe was set in a clay bed at a depth of 90 feet bgs Neat cement grout was pumped through the grout shoe via ' tremm>!e pipe, and circulated to the surface in order to isolate the A and B Zone aquifers After waiting approximately 48 hours for the cement to thoroughly cure the grout shoe was drilled out The boring was advanced to a total depth of 121 feet bgs to allow for the settling of any drill cuttings or caving The well was completed to a depth of 120 feet bgs where 2-inch diameter Schedule 80 casing and 10 feet of 0 020 inch slot screen pre-packed with #3 sand fitted with centralizers was set The annular filter pack contained 18 feet of #3 silica sand The annular seal consisted of approximately 6 feet of bentonite overlain by neat cement/bentonite, grout to the ground surface 1 • Filter pack and sealing materials were tremmied in place The well was completed at the surface with a watertight traffic rated flush mount well box, and a locking well cap Construction details are shown on the boring log in Attachment A and are summarized in Table 1 tWell Development and Surveymg ' On January 28 and 29, 2003, V&W developed wells MW15A, MW15B, MW15C, MW16A and MW16B by surging and bailing until turbidity was minimized MW13B was developed by air mjection in order to remove the large amount of silt present in the well casing Depth to water was ' measured prior to well development in each new well Accurate depth to water well could not be determined in MW15C due to the drilling mud present in the casing Depth to water in A Zone wells MW15A and MW16A was approximately 42 8 feet bgs and 42 5 feet bgs, respectively ' Depth to water in the B Zone wells ranged from approximately 40 2 feet bgs in well MW13B to approximately 42 5 feet bgs in wells MW15B and MW16B Development notes are included in Attachment B Monitoring wells MW13B, MW15A, MW15B, MW15C,MW16A and MW16B were surveyed by ' a Registered Surveyor to a horizontal accuracy of less than one meter and a vertical accuracy of 0 01 feet On January 29, 2003, Morrow Surveying surveyed the latitude and longitude of the newly installed wells relative to the North American Datum (NAD83), and surveyed the ' wellhead elevations relative to North American Vertical Datum (NAVD88) A site map showing monitoring well locations, latitude and longitude coordinates and wellhead elevations is included . in Attachment B 1 11GZA_FSIVOL_11DATAIGROUNDZE%ROEKICLOSURE%ReportsLAdd_HSA_Mud wells doc