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Project No. 9688 WORK PLAN '` June 11, 1999 <br /> 2373 Mariposa Road Page 7 <br /> notified as soon as possible of the confirmed drilling date. WDE will arrange <br /> and schedule all drilling, and laboratory subcontractor services. <br /> Soil Boring <br /> One soil boring will be drilled at the approximate location shown on Figure 3, <br /> attached. <br /> The soil boring location, in the approximate center of the tank removal <br /> excavation, was selected to provide information to determine the vertical <br /> extent of contamination below the tanks, the depth to groundwater, and the <br /> actual condition of the groundwater directly below the tank removal <br /> excavation. The boring will be sampled at five foot intervals until <br /> groundwater is encountered. The boring will be extended to between 5 and 10 <br /> feet below the first encountered water to obtain a "grab" groundwater sample. <br /> After sampling is complete the boring will be backfilled and sealed before the <br /> drill rig leaves the site. In order to seal the boring, the drill hole will be <br /> backfilled with neat Portland Cement grout tremied or pumped from the <br /> bottom of the boring up until the boring is completely sealed. <br /> The anticipated depth of the boring is about 70 feet. <br /> All down-hole equipment will be steam cleaned before arriving on site and <br /> before leaving to prevent off-site contamination. <br /> Drilling will be by a California Licensed Water Well Drilling Contractor (C57), <br /> using eight inch diameter hollow stem augers. The boring will be logged <br /> under the supervision of John Carver, Registered Civil Engineer 23772. Soil <br /> encountered will be classified in accordance with the Uniform Soil <br /> Classification System (USCS) by observing the samples and cuttings. The soil <br /> cuttings from each boring will be containerized in DOT 17H drums, labeled <br /> and stored on-site pending analytical results. <br /> Soil Sampling During Drilling <br /> The boring will be sampled starting at about 7 feet and continually at five foot <br /> intervals until groundwater is encountered at between 50 and 60 feet. <br /> Undisturbed soil samples will be obtained by driving a California (2.5 inch <br /> diameter, split-barrel) Sampler containing 2 inch diameter, 6 inch long brass <br /> tubes into the "undisturbed" soil beyond the augers. Driving energy will be <br /> provided by a 140 pound hammer falling 30 inches in accordance with ASTM <br /> procedures. The number of blows required to drive the sampler three <br /> successive 6 inch intervals (N value) will be recorded and used to evaluate <br /> the consistency of the sampled soil. The California Sampler and brass tubes <br /> will be cleaned between samples using soap, TSP, and clear water to prevent <br /> cross or down-hole contamination. <br /> WILLIAM DUBOVSKY ENVIRONMENTAL <br />