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07 April 1999 AGE-NC Project No 98-0540 IPage 4 of 9 wells utilizing 2-inch diameter, schedule 40, blank polyvinyl chloride (PVC) casing and 2-inch diameter screened PVC casing (0 020-inch slot) Each well was completed by placing the PVC well casing assembly through the hollow stem of the augers to the total depth of the boring The augers were incrementally raised as#2112 Lonestar sand (filter pack)was slowly poured down the annulus between the well casing and the inner wall of the hollow stem auger The filter pack was placed adjacent to the screened casing from the bottom of the boring to a point approximately two feet above the top of the screen Following placement of the filter pack, a surge block was inserted into the PVC casing and was lowered then raised (surged) Irepeatedly for approximately 10 minutes Thereafter, the depth to the top of the filter pack was measured and bentonite chips were poured into the annulus and allowed to settle on the filter pack ' Five gallons of tap water was used to hydrate the bentonite chips for one-half hour prior to grouting The remaining annular space was sealed with portland type I/II neat cement mixed with no more than 6 gallons of water per 94-pound sack of cement The grout was placed by pumping through the center of the auger while sections of auger were incrementally raised I3 3 4 Equipment Decontamination Hollow stem augers used during drilling activities were steam cleaned prior to advancement in each I bore hole Sampling tools and brass sleeves used for sample collection were thoroughly washed in a solution of Alconox and rinsed with clean tap water prior to each sampling run Following drilling activities, rinseate generated from decontaminating the equipment was placed in properly labeled IDOT-approved Model 17H 55-gallon drums and was stored on-site in an area lacking public access I3 3 5 Monitoring Well Survey ' On 26 March 1999, a Califorrua- licensed survey engineer from Baumbach& Piazza, Inc surveyed a reference point on the top of each ground water monitoring well at the site to the nearest 0 01-foot relative to the San Joaquin County Bench Mark Datum# SR-07 J955, Elevation 61 18 The results Iof the monitoring well survey are contained in Table 2 I3 3 6 Well Development On I 1 March 1999, monitoring wells MW-1, MW-2, and MW-3 were developed utilizing a Grund IFos submersible pump and hand bailing techniques Ground water was purged from each well until . the water produced was essentially sediment free Approximately 8 to 20 gallons of ground water Advanced Geo£mironmenlal,Inc