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Monitoring Well Destruction and <br /> Soil and Groundwater Investigation Report <br /> US Can—Welty Road September 24,2009 <br /> • SAIC obtained soil boring and well destructionermits from San Joaquin oaqum County <br /> Environmental Health Department (SJCEHD)prior to commencing field activities (see <br /> Appendix A). <br /> • SAIC obtained encroachment permits from San Joaquin County Department of Public <br /> Works (SJCDPW) and the California Department of Transportation (Caltrans) for work <br /> performed in Welty Road (see Appendix A). <br /> • SAIC conducted a site visit to mark boring locations for Underground Service Alert <br /> I (USA), notified USA at least 48 hours in advance of field activities, and requested USA <br /> to mark underground facilities in the adjacent public ROW. <br /> • SAIC subcontracted the following industry professionals: <br /> o Cruz Brothers Locators, a private utility locator, to clear the site and proposed boring <br /> locations for any potential overhead and underground hazards and/or other potential <br /> obstacles. <br /> o RSI Drilling (a C57-licensed driller) to provide and operate Geoprobe°direct-push <br /> drilling equipment, dual-tube tooling for discrete subsurface sample collection, and <br /> hollow-stem auger drilling equipment for the destruction of monitoring wells; <br /> o Flash Safety Company to prepare a traffic-control plan (approved by Caltrans and <br /> SJCDPW), and provide traffic-control measures for the boring advanced in Welty <br /> Road. <br /> 3.2 FIELD INVESTIGATION ACTIVITIES <br /> 3.2.1 Well Destruction <br />' MW-4 and MW-5 well destruction activities were completed on August 7 and 8, 2008. All well <br /> destruction activities were managed by on-site SAIC field personnel under the supervision of an <br /> SAIC California Professional Geologist. RSI Drilling was subcontracted to perform the well <br />' destructions. A representative from SJCEHD, Mr. Harlan Knoll, was the inspector during the <br /> destruction process and approved the destruction methods. <br /> MW-5 was installed March 15, 2005, and constructed of 2-inch diameter, flush-threaded, <br /> tSchedule 40 polyvinyl chloride (PVC) well casing with 20 feet of 0.020-inch, machine-slotted <br /> well screen set at depths ranging between 25 to 45 feet bgs. The annular space was backfilled <br /> with Lonestar#3 sand from total depth to 2 feet above the top of the screened interval. The sand <br />' was overlain by a 2-foot bentonite seal, and the remainder of the annular space was filled with a <br /> bentonite and neat-cement mix to ground surface. Well construction details are not available for <br /> MW-4. <br />' The condition of each well was inspected prior to destruction and the total depth was measured. <br /> Each well location was cleared for utilities to 8 feet bgs by advancing three perimeter hand-auger <br />' borings. The well construction materials were over-drilled just beyond total depth with a drill rig <br /> equipped with 8.5inch-diameter, hollow-stem augers. A 1 inch-diameter tremie pipe was <br /> inserted into the borehole and cement slurry was continuously added into the open well bottom <br /> as the pipe was retracted to the ground surface. MW-4 was capped with black-dyed concrete to <br /> match the surrounding grade. MW-5 was grouted to the surface with neat cement. Information <br /> 4 ri_7_ <br /> 46r:is <br /> ANWFi-11%�@ <br /> From Science to solutions <br />