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11-W SIV) <br /> URS <br /> Ms. Vickie McCartney, REHS Page 6 <br /> San Joaquin County Environmental Health Department <br /> February 13, 2004 <br /> mounted well box. A locking, water tight well cap will be placed on the well. The actual well <br /> completion details will be based upon subsurface conditions encountered. <br /> Soil Vapor Extraction Well <br /> The proposed soil vapor extraction well will be constructed using 4-inch ID, schedule 40,flush-threaded <br /> PVC well casing. Fifteen feet of 0.020-inch machine-slotted well screen will be set-In the unsaturated <br /> zone from approximately 25 to 40 feet bgs. The exact screen interval will be deterrAined in the field by <br /> the URS geologist. A Monterey No. 3 silica sand filter pack will be installed from the bottom of the <br /> boring to 3 feet above the well screen. A 3-foot bentonite transition seal will be placed above the sand <br /> pack and neat cement will be used to seal the remaining annular space to the surface. The actual well <br /> completion details will be based upon subsurface conditions encountered. The surface completion for <br /> the well will consist of a traffic rated vault box. A locking, water-tight well cap will be placed on the <br /> well after drilling until the well can be plumbed to the proposed site remediation system. <br /> Air Sparging Wells <br /> The proposed air sparging wells will be constructed using 2-inch ID, schedule 40, flush-threaded PVC <br /> well casing. Fiye,_feet of 0.020-inch machine-slotted well screen will be set in the depth interval from <br /> approximately 60 to 65 feet bgs. The exact screen interval will be determined in the field by the URS <br /> geologist. A Monterey No. 3 silica sand filter pack will be installed from the bottom of the boring to <br /> 3 feet above the well screen. A 3-foot bentonite transition seal will be placed above the sand pack and <br /> neat cement will be used to seal the remaining annular space to the surface. The actual well completion <br /> details will be based upon subsurface conditions encountered. The surface completions for the wells <br /> will consist of traffic-rated vault boxes. A locking, water-tight well cap will be placed on each well <br /> after drilling until the wells can be plumbed to the proposed site remediation system. <br /> Well Development, Surveying, and Sampling <br /> A minimum of 72 hours after installation, the wells will be developed by rigorously surging over the <br /> length of their respective screen intervals and by purging a minimum of 10 casing volumes of water <br /> from each well. The wells will be surveyed to northing and easting coordinates and mean sea level by a <br /> Iicensed surveyor. <br /> A groundwater sample will be collected from the newly installed deep groundwater monitoring well a <br /> minimum of 48 hours after well development. Groundwater samples will be analyzed for TPHg,BTEX, <br /> fuel oxygenates (MtBE, TBA, TAME, DIPE, EtBE, and ethanol), and lead scavengers (1,2-DCA and <br /> EDB) by EPA Method 8260B. Attachment B presents detailed soil and groundwater sampling and <br /> analysis procedures. <br /> KAWProcessV5 BP ARCON0218012186 WP 04.doe <br />