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Subsurface Investigation Summary Report January 8,2007 <br /> Beneto,Inc.,Harlan Road,French Camp,CA Page 2 <br /> FIELD WORK <br /> L&P supervised the drilling and installation of three groundwater monitoring wells(MW 1-MW3)on <br /> September 5 and 6,2006. Spectrum Exploration (C57-512268) conducted the drilling utilizing a <br /> drilling rig equipped with hollow stem augers. John Lane, a California Registered Geologist, <br /> supervised the drilling and well installation. <br /> The pilot borings were drilled to a depth of approximately 32 feet using 8-inch diameter, hollow <br /> stem augers. Soil samples were collected at 5-foot intervals using a split spoon sampler for soil <br /> characterization and possible analyses. Soil samples selected for analysis were sealed with Teflon <br /> tape and plastic end caps, labeled,placed in a pre-cooled ice chest, and transported under chain of <br /> (L� custody to a State certified analytical laboratory. <br /> The wells were constructed of 2-inch diameter PVC piping, with slotted casing comprising the <br /> lowermost 15 feet of each well. The filter pack consisted of#3 Monterey Sand placed in the annulus <br /> from the bottom of the well to approximately 2 feet above the slotted casing. The annular seal <br /> consisted of approximately 3 feet of hydrated bentonite chips placed over the sandpack,then topped <br /> with neat cement grout to the ground surface. The wells were completed at the ground surface with <br /> locking well caps and traffic rated, grade level well boxes. Copies of the well logs and well <br /> construction details are attached. <br /> Deltech Geotechnical Support (Deltech) developed the wells on September 11, 2006 by purging <br /> groundwater from the wells using a dedicated Waterra Inertial Pump and tubing pursuant to Deltech's <br /> C standard operating procedures(Attachment 2). Deltech monitored,purged and sampled the wells on <br /> September 18,2006. At the request of SJ-EMD,Deltech collected confirmation samples on October <br /> r 27,2006 after purging the wells. In each case,groundwater samples were collected into appropriate <br /> 1 L containers, placed in a pre-cooled ice chest, and transported under chain of custody to a State <br /> certified analytical laboratory. Field logs prepared by Deltech are attached. <br /> RESULTS OF INVESTIGATION <br /> Soil encountered during drilling of wells MWl through MW3 consisted primarily of silt and clay <br /> with some sand. Soil encountered during drilling MW2 contained more sand than wells MW 1 and <br /> MW3. No petroleum hydrocarbon odors were noted during drilling. Groundwater was encountered <br /> at approximately 22 feet in all three bore holes. Soil samples collected from the capillary fringe and <br /> bottom of the bore hole in each well were submitted to Argon Laboratories(FLAP 2359)for analysis <br /> C of TPHd using EPA 8015M,benzene,toluene,ethylbenzene,xylenes(BTEX),and methyl tert-butyl <br /> ether (MTBE) using EPA 8021B. No constituents of concern were detected in any soil sample. <br /> Analytical results are summarized in Table 2. <br /> L Groundwater samples were analyzed for TPHd using EPA 8015M,BTEX using EPA 8021 B, and <br /> oxygenated gasoline additives including MTBE using EPA 8260B. No constituents of concern were <br /> itr <br /> L' <br />