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31 <br /> • APPENDIX C <br /> FIELD PROCEDURES <br /> The general procedures used in site assessments for drilling exploratory borings, collecting <br /> samples, and installing monitoring wells are described in this appendix These general <br /> procedures are used to provide consistent and reproducible results, however, conditions may <br /> exist where variations of these procedures are applicable The following procedures are <br /> supervised by a California state-registered geologist <br /> CPT PROFILES <br /> Cone penetrometer profiles will be conducted using a 17 inch diameter electronic penetrometer <br /> advanced at a rate of 2 centimeters per second The electronic sensors record strains along the <br /> penetrometer tip and trailing sleeve A continuous record of tip resistance, lateral resistance, <br /> friction ratio, pore pressure, and pore fluid resistivity with depth is measured and recorded in the <br /> on-board computer The data are evaluated using computer software and interpret the soil types <br /> encountered <br /> At the completion of the CPT profile, the rods and penetrometer are removed and steam cleaned <br /> during the removal process Rinsate is collected in a DOT rated 55 gallon drum A second set of <br /> rods is placed in the borehole and serve as tremie pipe for placement of bentonite from the base <br /> • of the borehole to ground surface A concrete surface seal will be placed at ground surface <br /> HYDROPUNCH SAMPLING <br /> Groundwater samples will be collected at the water table (approximately 35 to 40 feet bgs) and at <br /> 80 feet bgs using HydroPunch sampling equipment The sampler will be advanced to the target <br /> depth using CPT rods The sampler will be opened approximately 2 to 3 feet by pulling back the <br /> rods to expose the sample screen and bailer will be lowered through the centers of the rods to <br /> collect the groundwater samples <br /> In order to reduce potential cross contamination when collecting the deep water samples the <br /> borehole annulus located between the CPT rods and the native soils will be sealed with bentonite <br /> grout pumped as the sampler advances <br /> After samples are collected, the sampling equipment will be decontaminated and the boreholes <br /> will be sealed as described above <br /> CP IE 1ARC0121861REP0RTs12186P103 DOC 9811sg 1 ;n"M4& <br /> C`1 <br />