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Job No 4780201 • • 5 <br /> ' 4.2 Monitoring Well Installation <br /> ' Monitoring well MW-1 was constructed by inserting two-inch diameter, flush- <br /> threaded, schedule 40 PVC well casing into the open borehole. After <br /> installation of the casing, the borehole annulus was backfilled with washed, <br /> kiln-dried sand to a point approximately 2.0-feet above the top of the casing <br /> slots. A 2-foot layer of bentonite pellets was placed on top of the sand, and <br /> concrete grout was placed on top of the bentonite and brought to the ground- <br /> surface (from approximately 31 feet to ground surface). Grouting of the well <br /> was observed by Ms. Mary Meays of the SJCEHD. The casing was capped <br /> using a locking, water-tight plug, and the well was covered with a bolted, <br /> tmanhole-type steel cover. Well details for MW-1 are shown on Figure 3. <br /> 4.3 Well Development <br /> ' Monitoring well MW-1 was developed using a Middleburg pump on August 6, <br /> 1997. The purpose of development is to stabilize the filter material surrounding <br /> ' the slotted interval of the well casing and remove turbid water caused by <br /> drilling operations. Approximately 22 gallons of water, or an amount in excess <br /> ' of ten well-casing volumes, were removed from the well during development. <br /> The purged-water exhibited a hydrocarbon odor (see Well Development Data <br /> tSheet presented in Appendix B). <br /> ' 4.4 Well Sampling <br /> ' Sampling of well MW-1 was conducted on August 6, 1997, using a disposable <br /> ' bailer. Prior to well purging and sampling, total depth and depth to <br /> groundwater measurements were obtained. An amount of groundwater in <br /> excess of three well casing volumes was then purged from the well. During <br /> purging, physical parameter readings (including turbidity, electrical conductivity, <br /> ttemperature, and pH) were taken to evaluate that the well had stabilized prior <br /> E2C, Inc. September 18, 1997 <br />