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Ms. Margaret Lagorio Page 3 ,E <br /> San Joaquin County EHD Clayton Project No. 70-05669.00 <br /> April 27, 2005 <br /> • One deep boring will be advanced to 30 feet below ground surface (bgs) or to <br /> groundwater, whichever occurs first in the location of a proposed structure. <br /> • Five shallow borings will be advanced along the run of a planned utility trench <br /> (220 feet in length) to approximately 4 feet bgs. <br /> • Two shallow soil borings will be advanced in the area of a proposed equipment <br /> shelter to a depth of approximately 4 feet bgs. <br /> The locations of the soil borings are shown on Figure 1.The borings will be advanced <br /> using truck-mounted drilling equipment. Drilling operations will be performed by a <br /> licensed, experienced drilling company under Clayton's supervision. <br /> Soil samples will be obtained with a coring system for the purposes of soil classification, <br /> headspace testing, and laboratory analyses. The coring system will contain acetate plastic <br /> liners used for collecting the soil samples. Up to three (3) soil samples will be obtained <br /> for laboratory analyses from the deep boring, approximately 5, 15, and 25 feet bgs. Soil <br /> samples will not be collected below groundwater. One(1) soil sample will be collected <br /> from each of the shallow borings from between 1.5-2 feet bgs. Up to ten (10) soil <br /> samples will be obtained during drilling activities and submitted to the laboratory. <br /> Recovered soil samples will be examined for soil classification and be described on <br /> detailed borings in general conformance with the Unified Soil Classification System. <br /> Additional lithologic descriptions and drilling information will be recorded on boring <br /> logs. <br /> Headspace tests will be performed with a PID to detect the potential presence of volatile <br /> organic compounds (VOCs) in the retained soil samples. To initiate the headspace <br /> testing procedure, soil samples will be removed from the plastic liners,placed into <br /> labeled plastic bags, and sealed for conducting the tests. After sufficient time elapses for <br /> vapor buildup inside the bags, they will be punctured with the probe tip of the PID to <br /> allow measurement of the headspace. Qualitative measurements of the headspace will be <br /> obtained in the parts per million(ppm)range for total VOCs. The results of the <br /> headspace tests will be recorded on the boring logs. If elevated levels of VOCs are <br /> detected during the field activities, additional soil samples may be collected. These <br /> samples will be submitted to the laboratory and placed on hold. <br /> If groundwater is encountered in any of the borings during drilling operations, then grab <br /> groundwater samples will be obtained for laboratory analyses. One-inch diameter <br /> temporary well casing with the lower five feet of the casing being slotted will be installed <br /> in each boring for collecting grab groundwater samples. Grab groundwater samples will <br /> be collected using clean disposable bailers. Upon collection, the samples will be poured <br /> into appropriate laboratory-supplied containers. The sample containers will be <br /> capped/sealed, labeled with identifying project information, as previously described, and <br /> S TS\PROMCTS\Vai .Wirck.\2W b56 9 Mik Phase Mw.r plan.d.c <br />