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ARCADIS Appendix B <br /> Appendix B Union Pacific Railroad <br /> Monitoring Well Installation Procedures Company <br /> Former Maintenance Facility <br /> Tracy,California <br /> Monitoring wells will be installed using hollow-stem auger drilling techniques. Soil <br /> samples will be lithologically classified in accordance with the Unified Soil Classification <br /> System (USCS)(American Society of Testing and Materials[ASTMI D2487).The wells <br /> will be constructed using 2-inch diameter Schedule 40 polyvinyl chloride(PVC)riser <br /> and 0.020-inch PVC slot screen. Monitoring wells will be screened in the A-Zzone from <br /> approximately 15 to 30 feet below ground surface(bgs). The specific depths of the <br /> wells will be based on CPT data and the lithology encountered during drilling of <br /> corresponding CPT/HydroPunch TM locations.A filter pack consisting of clean silica <br /> sand will be placed in the annulus from the bottom of the borehole to approximately 2 <br /> feet above the top of the screen.An approximate 2-foot thick bentonite seal will be <br /> placed above the filter pack and cement grout with 5 percent bentonite will be placed <br /> from the top of the bentonite seal to approximately 6 inches below ground surface. <br /> Downhole equipment will be properly decontaminated prior to and between each well <br /> boring. Boreholes will be backfilled from the bottom up with neat cement grout.The <br /> well will be completed with a stove pipe or flush-mounted traffic-rated Christy box. <br /> The new wells will be developed a minimum of 24 hours after construction using a <br /> surge block/bailer combination to remove entrained fines; approximately ten (10) <br /> casing volumes of groundwater will be purged from the well prior to groundwater <br /> monitoring. The wells will be considered developed when groundwater parameters <br /> vary less than±10%and the purged water is free of fines to the satisfaction of the <br /> ARCADIS field geologist. Purge water will be properly contained and labeled for later <br /> analysis and proper disposal. <br /> Prior to drilling activities, necessary drilling and encroachment permits and/or access <br /> agreements will be obtained. Locations will be cleared for underground utilities by a <br /> private utility locator and USA will be notified at least 72 hours before drilling is initiated. <br /> Additionally ARCADIS will contact the UPRR fiber-optics notification line at least 48 <br /> hours prior to initiating work. The first 5 feet of the boring will be hand-augured to <br /> confirm that utilities or obstructions are not present. <br /> 1/1 <br />