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Nov 29 05 12:48p Peter Weiler (925) 938-1610 p.7 <br /> 2.4.1 Monitor Well InstallatiOn <br /> Boreholes for the monitoring wells will be advanced using 8-inch hollow-stem auger drilling <br /> equipment. Soil samples will be collected at a minimum of every 5 feet to described the <br /> hydrogeologic structure and designing the well construction details. The soils encountered <br /> during drilling will be described and logged in accordance with the USCS. <br /> Boreholes for the monitor wells will be advanced using hollow-stern auger drilling equipment, <br /> and the wells constructed within the hollow-stem auger. The monitor wells will be constructed <br /> using 2-inch diameter schedule 40 PVC. The screen will be 0.020-inch factory-slotted and will <br /> be surrounded with a sand filter pack of Lonestar #2/16 sand, or similar. The sand pack will be <br /> "set" using a bailer to gently surge the water within the well screen. At least 2 feet of hydrated <br /> bentonite will be placed above the sand pack to provide a well seal. A cement-bentonite slurry <br /> will be placed above the bentonite seal to ground surface. The well casing will be placed <br /> within an above ground protective steel casing. Figure 11 shotes a schematic for a typical <br /> ground water monitor well. <br /> All equipment placed in the borehole will be cleaned between drilling and sampling Iocations. <br /> Because drilling will not be performed within the landfill cells, cuttings from the drilling will <br /> be placed on the ground. <br /> Survey Well Locations <br /> A licensed surveyor or civil engineer will vertically and horizontally locate the newly installed <br /> monitor wells. Vertical measurements will be made of the top of the well casing and the <br /> adjacent ground surface, and will be measured to within 0.01 feet relative to mean sea level <br /> (msl). The horizontal location will be determined by latitude and longitude using GPS, and <br /> will be referenced to the NAD 23 coordinate system as well. <br /> Monitoring Well Development <br /> The monitor swells will be developed by bailing or pumping. The development water will be <br /> monitored for electrical conductivity, pH, and turbidity. When these parameters have <br /> stabilized to within 10 percent of successive measurements, the well will be considered <br /> adequately developed. All development water will be contained in drums for proper disposal. <br /> Disposal options will be identified based on the analytical results of water samples to be <br /> collected from the monitor wells. <br /> November 2005 Page 4 <br /> Environmental Risk Services.Corporation <br />