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id <br /> Mr. Harlin Knoll, SJCEHD June 18,2007 <br /> Well Installation Work Plan <br /> A. Teichert and Sons Property, Stockton,CA <br /> Page 9 <br /> Task 2: Field Activities <br /> Task 2A: Soil Borin s <br /> A licensed well driller will advance soil borings MW-15 through MW-17 to approximately <br /> 75 feet bgs using a truck mounted drill rig equipped with 8-inch hollow stem augers. <br /> Borings MW-18 will be completed to approximately 95 feet bgs using a sonic coring drill <br /> rig equipped with 7-inch or 9-inch diameter threaded steel casing. Each boring will be <br /> completed as a groundwater monitoring well, as described below. The initial 5 feet of each <br /> boring will be advanced with a band auger and/or posthole digger to reduce the possibility <br /> of damaging underground utilities. Details regarding exploratory boring procedures are <br /> included in Appendix A. <br /> Prior to advancement of borehole MW-18 beyond the uppermost water bearing strata, the <br /> drilling contractor will remove residual groundwater situated inside of the steel drive <br /> casing. Based on information gathered during the advancement of boring CPT-12, we <br /> anticipate initially advancing the borehole to fine grained soils situated at approximately 80 <br /> feet bgs. Once residual groundwater situated above 80 feet bgs is evacuated from the <br /> borehole, the boring will be advanced to lower water bearing strata. <br /> Soil samples will be collected at 5-foot intervals from borings MW-15 through MW-17 <br /> using a California-type, split-spoon sampler. Additional soil samples may be collected <br /> within the saturated zone of borings MW-15 through MW-17 to provide additional <br /> information regarding lithologic conditions. Soil cores will be continuously recovered <br /> from borehole MW-18. Soil samples will be used for lithologic comparison and <br /> description only; no soil samples will be collected for chemical analysis purposes. <br /> Task 2B: Monitoring Well Installation <br /> Monitoring wells MW-15 through MW-18 will be installed using 2-inch diameter schedule <br /> 40 PVC well casing and 0.02-inch diameter factory slotted well screen. Wells MW-15, <br /> MW-16, and MW-17 will be screened from approximately 55 to 75 feet bgs, and well <br /> MW-18 will be screened from approximately 90 to 95 feet bgs. Centralizers will be <br /> utilized to situate the MW-18 well casing within the center of the borehole. A filter pack of <br /> #3 LonestarTim sand will be placed in the annular space around the well casing from the <br /> bottom of the well screen to approximately 2.5 feet above the top of the well screen. Prior <br /> to installing the well seal, each well will be surged with a surge block to "seat" the filter <br /> pack around the well screen. Approximately 4 feet of coated bentonite pellets will be <br /> placed on top of the filter pack to provide a transition seal for the well. Neat cement will be <br /> used to backfill the remaining annular space around the well casing. A watertight locking <br /> cap will be placed over the top of the well casing, and a traffic rated vault box will be <br /> installed around the top of the well. The actual well construction may be modified in the <br /> field based on conditions encountered at the time of the investigation. <br /> K:1Teichertl5tockton-1031Work PlansVeichert-well install work plan 06-2007.doc SIMMS <br />