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soil samples collected from borings MW-19 and MW-20 No alcohols o r <br /> HVOCs were detected in any of the soil samples analyzed <br /> 7 . 0 MONITORING WELL INSTALLATION, DEVELOPMENT AND <br /> SAMPLING <br /> 7 . 1 ._ Monitoring Well Installation <br /> Groundwater monitoring wells MW-16 through MW-20 were constructed <br /> in borings MW-16 through MW-20, respectively Groundwater recovery <br /> wells RW-1 and RW-3 were constructed in borings RW-1 and RW-3, <br /> respectively Monitoring wells MW-16 through MW-18 were constructed <br /> with 2-inch diameter, 0020-inch factory slotted, flush-threaded, Schedule <br /> 80 PVC well screen and blank casing Monitoring wells MW-19 a n d <br /> MW-20, as well as recovery wells RW-1 and RW-3, were constructed with <br /> 2-inch diameter, 0020-inch factory slotted, flush-threaded, Schedule 40 <br /> PVC well screen and blank casing <br /> Monitoring well MW-16 is screened between 49-feet bgs and 64-feet b g s <br /> to monitor an intermediate water-bearing zone Monitoring well MW-17 <br /> is screened between 60-feet bgs and 70-feet bgs to monitor an <br /> intermediate water-bearing zone Monitoring well MW-18 is screened <br /> between 102-feet bgs and 112-feet bgs to monitor a deeper water-bearing <br /> zone Monitoring wells MW-19 and MW-20, as well as recovery wells <br /> RW-1 and RW-3, are screened between 9-feet bgs and 19-feet bgs, within <br /> the shallow water-bearing zone <br /> Lonestar #2112 Monterey sand occupies the annular space between t h e <br /> borehole and the casing from the bottom of each boring to approximately <br /> 1-foot above the screened interval A hydrated bentonite layer, at least 1 - <br /> foot thick, separates the sand from the overlying cement surface seal <br /> The cement surface seal in the wells less than 19-feet deep was placed by <br /> gravity free-fall The cement surface seal in the wells deeper than 19-feet <br /> bgs was placed by tremie pipe Since time-release (coated) bentonite <br /> pellets are no longer acceptable for seals due to the ethanol content in <br /> their coatings, a layer of #80 sand was placed over the sand pack in <br /> monitoring well MW-18 to assist in sealing this well from the bentonite <br /> slurry seal This bentonite slurry seal was placed in this deeper well <br /> instead of a bentonite pellet seal <br /> The wellheads of all of these wells are secured with locking wellplugs <br /> beneath at-grade traffic-rated vaults <br /> Franks One Stop Report — November 2000 <br /> -12- <br />