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�VA � t—fir/�I7 Working to Restore Nature Vaipar Extraction Well onstruction Vapor extraction wells were constructed of thread jointed, 4-inch-diameter schedule PVC casing No chemical cements, glues, or solvents were used in well construction The screened portion of the wells consisted of factory-perforated casing with 0 020-inch-wide slots No. 3 sand was placed in the annular space opposite the screen to approximately 1 foot above the top of the slotted casing A 2-foot bentonite plug was placed above the sand pack, and a cement-bentonite slurry was used to fill the remaining annulus to the surface A traffic-rated cast-aluminum utility box with a PVC apron was placed over each wellhead and set in concrete flush with the surrounding concrete pad This box has a watertight seal to protect against surface water infiltration and is opened with a special wrench The design of the box discourages vandalism and reduces the possibility of accidental disturbance of the well. Monitoring Well Construction The monitoring well was constructed in the boring with thread-pointed, 2-inch-inner- diameter, Schedule 40 PVC casing No chemical cements, glues, or solvents were used in well construction The screened portion of the well consisted of factory-perforated casing with 0 020-inch-wide slots The well screen extends from the total depth of the well to approximately 5 to 10 feet above the groundwater surface This screened interval allows sampling at the air-water interface during seasonal fluctuations of the groundwater level The annular space in the well was packed with number 3 sand to approximately 1 to 2 feet above the slotted interval. A 3-foot thick bentonite plug was added above the sand pack to prevent the cement from entering the well pack The remaining annulus was backfilled to grade with a bentonite cement slurry The well was protected with a traffic-rated, cast-aluminum utility box equipped with a PVC skirt The box has a watertight seal to protect against surface-water infiltration and must be opened with a special wrench The design of this box discourages vandalism and reduces the possibility of accidental disturbance of the well Well Development We waited a minimum of 24 hours after well installation before developing the groundwater monitoring well to allow the grout to seal Before developing the monitoring well, a water sample was collected for subjective analysis from near the water surface in the well with a Teflon bailer cleaned with a laboratory-grade detergent and deionized water Floating product was not encountered The well was developed with a surge block and pump Well development continued until the discharge water was clear of silt and sand Clay-size sediments derived from the screened portion of the formation cannot be entirely eliminated by well development 11121ese/38009-4