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Salvo Trucking Facility-Gl'4 P September 27, 1994 Page-5- --3.3 Monitor Well Construction _ - F. w.2: _ The monitor wells will be constructed with 4-inc diameter, Schedule 40, flush-thread, machine-slotted PVC screen. The screen size will be selected based on the results of the soil grain ; size analysis. The screened interval will extend from a depth of.approximately 10 feet to-a depth of x pVC'°bottom^capa ill-be-placed-at;the-bottom-of the screen. approximately 25 feet.- A flush=thread Blank PVC casing will be installed above the screen to the ground surface. The well casing will be delivered to the site in its original packaging and steam-cleaned on site prior to use. .No glue or solvents will be used in construction of the well. A sand pack of Monterey sand will be placed in °he annular space-to approximately one foot _ - i above the screen. The sand size will be calculated based on the results of the soil grain size analysis. s Approximately 3 feet of bentonite pellets will be placed Bove the sand'to form a protective seal. The. bentonite will be hydrated using potable water. A seal o neat cement will be poured in the annulus from the bentonite seal to the ground'surface and a locking, water-tight traffic box will be installed at Ythe ground surface. Condor will provide locks and keys or each well. A diagram of the proposed A T well construction is shown in Figure 3,--Appendix A. r 3.4 Monitor Well Development -- _ Approximately one week following construction, the monitor wells will.be developed by ' Ris ur ing the groundwater until the discharge water.is free of sediment,-clear to the unaided eye and theN P g electrical conductivity, pH, and temperature-of the water itive stabilized. All well-development e ui ment will be cleaned prior to use.b. y washing in.a s lution of.non-phosphate detergent and laboratory-grade,'hydrocarbon-free water, and double-rinsing with hydrocarbon-free water. The water purged from each well will be placed in 55-gallon drums and left on site. All field instruments will be calibrated to the manufacturer's recommended standar s. 3.5 Groundwater Sampling — Groundwater samples will be collected within 3 c ays after development of the wells. Prior to purging, the water level in each'well will:be,measured-to the nearest 0,01 foot with a battery-operated, flat-tape, water-level.meter. The weM will be purged of at least three-well-casing volumes of water. -A water sample will be collected after fhe electrical cond ictivity, pH, and temperature have stabilized - F, and the.depth to water has recovered to-at least 80%.of tie pre-purge water.level. The water purged from each well will be discharged to 55-gallon-drums and left on site. CONDOR