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Gealogual Tecluikcs Inc Page 9 <br /> Additional Site Characterization Report <br /> M Project No 662 2 <br /> February 20,2004 <br /> Permeability Organics Density Porosity Cooper visual classification <br /> Sample <br /> ' (cm/sec) % (dry pcf) % <br /> EW-1 @ 28' 2 x 10E-7 09 1087 3642 Clayey SAND w/Sandy Clay <br /> EW-1 @ 32' 7 x 10E-7 1 4 945 4511 CLAY (silty) <br /> ' EW-1 @ 38' 1 3 x 10E-4 05 1 1054 1 3743 1 Silty SAND <br /> EW-1 @ 50' 1 4 x 10E-7 2 9 975 1 4458 SILTY CLAY w/gravel <br /> ' 3.4 Well Development <br /> Del Tech GeoTechnical Services developed well EW-I during the week of December 22, <br /> 2003 <br /> ' 4.0 DISCUSSION <br /> ' 4.1 Geology and Hydrogeology <br /> Geology <br /> The following section discusses the sub3ective interpretation of the Gregg Cone <br /> Penetrometer Test data in conjunction with the field observations and geology based on the <br /> interpretations of field geologists <br /> 4 ' In accordance with SJC/EHD directives, a continuously cored, single boring was installed <br /> I on May 30, 2002 in the location of the former UST excavation A discretely screened deep <br /> ' monitoring well, MW-104, was installed in the boring and it has contained MTBE for all six <br /> events in which it has been sampled The first CPT boring, CPT-4, was placed adjacent to <br /> MW-104 in order to define the lithology beyond the terminal depth of MW-104 The Gregg <br /> report of the CPT field work is included as Appendix F and the boring log for MW-104 is <br /> included in Appendix C <br /> ' Based on the MW-104 borehole data, the area beneath the former UST excavation is <br /> characterized by alternating layers of sands, silts and clays, with sands being predominant <br /> ' ❑ The sand units are typically brown at the surface and then change to a grey color at <br /> ten feet bgs The sands range from very fine to very coarse, and occasional silt <br /> ' lenses are encountered with variable iron oxide staining Sand layers at 42 —45, and <br /> 46 —49 feet bgs contain pebbles up to 15mm in diameter <br /> u The silt units are a maximum of 2 — 3 feet thick and occur at 17, 21, 26, 29, 31 and <br /> ' 32 feet bgs The silts are dark grey in color and occasionally contain root tubes, iron <br /> oxide staining and various percentages of sand grains/clay <br /> 1 <br /> 1 <br />