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Work will commence on the site within 30 days of receiving <br /> workplan approval. We anticipate it will take one to two <br /> .' days for soil boring and well installation and one day for <br /> groundwater well development and sampling. Drilling will be <br /> scheduled upon approval of the workplan. The County of San <br /> Joaquin will be notified at least 48 hours in advance of <br /> site work. <br /> Three eight-inch soil rorings will be drilled and completed <br /> as two inch diameter groundwater monitoring wells. All <br /> procedures and protocol for groundwater monitoring well <br /> construction will conform the the standards recommended by <br /> San Joaquin County and the Regional Water Quality Control <br /> Board (RWQCB) . <br /> The wells will be completed to a depth of approximately 25 <br /> to 30 feet below grade. Well completion depth will be based <br /> on placement of the screened interval five feet above and <br /> fifteen feet below the static water table. However, if a <br /> stratum of five continuous feet of relatively impermeable <br /> material is encountered below the zone of saturation, the <br /> well will be terminated without penetrating the stratum. <br /> Drilling will be conducted under a C57 license asirg a <br /> hollow stem auger drill rig. <br /> The well will be constructed of 2 inch diameter F480 <br /> threaded PVC screen/casing. No glues or solvents will be <br /> used. Screen slot size will be 0.010 inch. Sand pack <br /> material will be No. 2/12 pre-washed silica sand. A minimum <br /> two foot bentonite seal will be placed prior to grouting <br /> with neat cement or a 1:1 cement-sand grout. Grout will be <br /> placed in the annulus using the tremmie method. Typical <br /> completion will be as shown on Figure 3. Actual completion <br /> depths will be determined in the field based on <br /> hydrogeologic conditions encountered. <br /> Drill cuttings will be logged continuously for <br /> characterization of contamination and soil type by an <br /> experienced staff geologist or civil engineer using the <br /> Unified Soil Classification System. Descriptions of soils <br /> encountered and monitoring well construction details will be <br /> recorded on boring/well logs and included within the <br /> assessment report. Soil samples will be collected from each <br /> boring at five foot intervals, beginning at a depth of five <br /> feet. <br /> Soils encountered will be monitored for organic vapors by <br /> placing a small amount of representative material in a <br /> sealed container, then measuring the concentra}ion of <br /> volatiles collected in the head space •.with a photoionization <br /> detector (PID) calibrated to the benzene molecule, as well <br /> as using olfactory detection. The values obtained at each <br /> measurement point will be recorded on the boring logs. <br /> 3 <br />