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Potable tap water was available at the site for hydrating the bentonite chips, mixing grout <br /> and washing sampling tools Drilling tools were pre-cleaned using high-pressure steam <br /> by V & W Drilling Auger cuttings were placed in labeled 55-gallon drums and were <br /> stored at the site for disposition Drums of equipment decontamination nnsate and purge <br /> water were also stored at the site pending sample analysis Disposal of these wastes will <br /> be the responsibility of the owner, but Environeering, Inc will provide guidance and <br /> assistance with waste disposal arrangements <br /> 3.3 Well Construction and Development <br /> Monitoring wells MW-1 and MW-3 were constructed in two (2) of the soil borings The <br /> monitoring wells were cased with 2-mch diameter threaded, factory-slotted and blank <br /> Schedule 40 PVC casing pipe The perforated interval in the well (30 ft to 50 ft bgs ) <br /> consists of slotted casing with 0 020-inch wide by 1 5-inch long slots, with 42 slots per <br /> foot A threaded PVC cap was secured to the bottom of the casing, no solvents or <br /> i cements were used The well casing was purchased pre-cleaned, and arrived at the site <br /> still stored in its original plastic wrapping <br /> After setting the casing inside the hollow-stem auger, 93 filter sand was poured into the <br /> annular space between the well screen/casing pipe from the bottom of the bore hole (50 <br /> ft bgs ) to 2 feet above the top of the well screen (28 ft bgs ) The sand was placed <br /> slowly and the filling process was checked frequently with a weighted measuring tape to <br /> prevent bridging and creation of void spaces in the filter pack A 2-Foot thick bentonite <br /> plug, constructed of bentonite chips, hydrated in place, was set above this filter material <br /> to prevent cement grout from entering the filter pack A neat cement-grout mixture was <br /> placed into the annular space from the top of the bentonite plug within two feet of the <br /> surface A traffic-rated flush-mount well vault was installed around the wellhead, which <br /> was set with concrete <br /> After the sand pack was installed and prior to setting the bentonite seal, the well was <br /> thoroughly developed by surging for 10 minutes and purging 10 gallons to remove <br /> residual drilling material (grout cement) and native silt and clay from the filter pack <br /> 7 <br /> Following construction, the well was then allowed to settle and equilibrate for at least 72 <br /> Envkaneering,Inc- P"*d No.99-012A2 6 <br />