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41 <br /> 10 Decembei 2001 <br /> AGE-NC Project No 00-0769 <br />' s Page 2 of 6 <br /> f y <br />' Hogentogler Co CPT computer program. The Hogentogler Co computer program utilized the CPT , r <br /> Soil Behavior Classification System (Robertson, P K , Campanella, R G, Gillespie,,D and Greig,J, <br /> 1986), to generate a general Iithology type and,display on{a CPT boring log (Se Appendix A) h <br />' Rinseate generated during drilling activities was contamenzed in properly labeled DOT-approved' ' <br /> 55-gallon drums, and stored on-site in an area lacking public access All soil borings were backfilled <br /> by inserting hollow rod_s to total depth of each boring and backfilling with a portland cement grout <br />� MIX <br />' 22 STRATIGRAPHY <br /> Based on the findings from CPT soil borings CPT-01 through CPT-06 and boring logs recorded <br /> during installation of groundwater monitoring wells MW-1 through MW-3, cross sections A-A', <br /> B-B' and C-C' were constructed and depict general hthology beneath the site (Figures 3, 4 and 5) <br /> Generally, sand to silty sand to sandy were encountered at depths between 112 and 125 feet bsg and <br /> 139 and 155 feet bsg Locally lithology varied from sand to silt at depths between 60 and 70 feet bsg <br /> and 85 to 103 feetfbsg Fine grained, silt, silty clay, clayey silt and clay were observed at all other <br /> depths CPT computer generated boring logs are included in Appendix A <br /> ° 2 3 IfYDROGEOLOGIC UNITS <br /> Based on cross sections A-A ', B--B'and C-C',AGE informally identified four hydrologic flow units <br /> between surface grade and 175 feet bsg (First Water Zone, Second Water Zone, Third Water Zone <br /> and Fourth Water Zone) as having significant intervals of apparently porous, coarser-graiined soil, <br /> separated by significant Intervals of finer-grained, less permeable soil The First Water Zone was <br /> subdivided into three sub-units (Upper, Middle and Lower Water Zones)_ that may not have , <br /> r 'significant barriers to vertical migration of contaminations Generally,First Water- Upper Zone was <br /> identified at depths between 25 feet (first encountered ground water) and 51 feet bsg, First Water- n ; <br /> Middle Zone was identified at depths between 48 feet and 75 feet bsg,First Water-Lower Zone was ' <br /> identified at depths between 60 feet and 90 feet bsg, Second Water Zone was identified at depths <br /> between 112 feet and 125 feet bsg, Third Water Zone was identified at depths between 140 feet and <br /> 160 feet bsg and Fourth Water Zone was identified at depths between 160 feet and 175 feet bsg <br /> 2 4 CPT DRILLING AND GROUND WATER COLLECTION PROCEDURES r <br /> 1 „ <br /> A 25-ton truck-mounted CPT drill rig equipped with 2-inch diameter hollow-stem rods fitted with <br /> a HydroPunch ground water sampling tool utilized a hydraulic ram to advance to specified depths <br /> • in each soil boring The HydroPunch sample tool was pushed into the selected depth zone,rthen <br /> Advanced Geo Environmental,inc <br /> i <br />