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31 August 2016 <br />AGE Project No. 96-0235 <br />Page 6 of 8 <br />groundwater sampling, boring abandonment, equipment decontamination and sample <br />handling, pilot soil boring advancement, well installation, well development, well survey <br />and well sampling are described below. <br />4.1. SOIL PROBE BORING ADVANCEMENT <br />Deep soil borings will be advanced to a depth of 85 feet bsg or until refusal is encountered <br />for collection of groundwater samples at approximately 50 and 85 feet bsg or at total depth <br />if refusal is encountered. Soil borings will be advanced utilizing a direct push probing unit <br />or a modified truck-mounted drill rig equipped with 1.5-inch diameter hollow-stem rods. <br />The direct push probing unit or drill rig will utilize a hydraulic hammer to advance the rods <br />to the desired depth. <br />4.1.1. Groundwater Sampling <br />At each probe boring location grab groundwater samples will be collected using a <br />Geoprobe (or similar) push-driven water sampling device that will be advanced four feet <br />into the specified zones (50 feet and 85 feet bsg), then withdrawn approximately three to <br />four feet to expose an inlet screen. Each groundwater sample will be extracted by <br />dedicated disposable polyethylene tubing through the hollow center of the push rods into <br />the screen section. Following sample collection, samples will be transferred into four <br />volatile organic analysis (VOAs) vials; all samples will be properly labeled and placed in <br />a chilled container to be transported under chain of custody to a CDPH-certified laboratory <br />for analysis of petroleum hydrocarbons and VOCs by 8015 and 8260B. <br />4.1.2. Boring Abandonment <br />All probe soil borings will be permanently sealed to prevent vertical migration of potential <br />contaminants. Soil borings shall be abandoned by backfilling with cement grout from the <br />total depth to surface grade. Borings advanced below the groundwater table will be <br />abandoned with grout utilizing tremie procedures. The top three to six inches of the boring <br />abandonments will be completed flush to surface grade with concrete. The SJCEHD will <br />be notified for grout inspection at least 48 hours prior to conducting grouting procedures. <br />4.2. PILOT SOIL BORING ADVANCEMENT AND SOIL SAMPLING <br />The pilot soil boring for installation of deeper monitoring well will be advanced to a depth <br />of approximately 85 feet bsg (deep HU3 well), utilizing a truck- or track-mounted drill rig <br />equipped with 8.25-inch diameter hollow-stem augers. The hollow-stem auger drilling <br />method is performed without the introduction of drilling fluids and allows for the <br />construction of wells with minimal introduction of disturbed soil. Soil cuttings and rinseate <br />Advanced GeoEnvironmental