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3.0 SOIL BORINGS <br /> Five exploratory soil borings were drilled at the site between April 12 and 13, 1993. Four <br /> of the borings were drilled to a depth of 30 feet and were later converted to groundwater <br /> monitoring wells. A fifth boring was drilled down to a depth of approximately 16 feet <br /> ' and terminated just above the water table The location of the five borings is shown in <br /> Figure 3 A fifth monitoring well proposed in the February 24, 1993 Revised Workplan <br /> ' was eliminated due to the areal extent of contamination determined during this <br /> investigation, i e additional borings necessary to completely determine the lateral extent <br /> ' of groundwater contamination would need to be drilled on easements to the Langston <br /> property This procedure required special permits not available to Murray & Associates <br /> at the time of this investigation. <br /> Borehole drilling and sampling operations was accomplished using a truck mounted hollow <br /> stem auger drill rig operated by West Hazmat Drilling Corporation (C-57 License No <br /> 554979) All soil borings including the monitoring wells were drilled with 7.0 inch outside <br /> diameter, continuous flyte augers The four borings which were converted to monitoring <br /> wells were drilled to a depth of 30 feet, or approximately 15 feet below the water table, <br /> to evaluate the subsurface stratigraphy <br /> The entire length of each of the boreholes were continuously logged by a California <br /> registered geologist using the USCS for the purpose of describing the vertical variations <br /> in the soil profile encountered Soil samples were collected by split-spoon sampler at five <br /> (5) foot intervals Each sample collected was evaluated in the field using a 580B <br /> photojomzation detector (PID) calibrated dailyfor benzene nzene Only those soil samples which <br /> registered the highest readings on the PID were submitted for chemical analysis, however, <br /> a minimum of three soil samples for each boring were submitted for analysis In <br /> accordance with general Regional Water Quality Control Board (RWQCB) requirements, <br />' one sample from each borehole was collected from direct] above ave the groundwater <br /> interface This sample was collected from what was believed to be the cappilary fringe <br /> zone of the water table, at a depth of 18 feet below the surface Soil samples collected <br /> 7 <br /> 1 <br />