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November 2010 Project No. 1001-0343 padmiff M020161 requested to identify all underground utilities in the vicinity of the Project Site that may be in conflict with the proposed drilling locations. Additionally, Padre will utilize a private utility locating company (Subtronic Corporation) in an attempt to locate potential underground lines and structures not identified through the USA notification. 3.4 DRILL HOLE ADVANCEMENT Padre proposes to advance two vertical drill holes (DH-1 and DH-2) near the UST to depths of approximately 15 to 20 feet below surface grade, or the depth at which groundwater is encountered, whichever occurs first. Additionally, one drill hole (DH-3) will be advanced near the underground fuel oil supply (FOS) line to an approximate depth of 5 to 7 feet. The FOS line is situated at an approximate depth of 12 to 18 inches. The proposed drill hole locations are shown on Plate 3 — Drill Hole Locations; however, the actual as-built locations will be determined based on the presence of underground utility lines. It is Padre's understanding that the area over and surrounding the UST contains numerous underground utility lines. Hand clearing of each drill hole location will be performed to approximate depths of 5 to 6 feet prior to advancing drilling rod. Soil samples will be collected at approximate depths of 5 and 10 feet, and a depth just above the first encountered groundwater. Based on available reports (Geotracker) of nearby LUST sites located west of the Project Site, groundwater is expected to be present at an approximate depths of 12 to 15 feet; however, actual groundwater depths will be determined during field assessment activities. The proposed drill holes will be completed by advancing 2-inch diameter direct push drill rod using Geoprobe drilling technology. Undisturbed soil samples will be collected at each drill hole location in 4 to 5-foot continuous core liners. In addition to soil samples collected for chemical analyses, soil from each sampled interval will be retained for field screening and lithologic logging purposes. Field screening will be completed using a hand-held photoionization detector (PID). Soil classification will be completed by a Padre geologist in accordance with the Unified Soil Classification System (USCS). The soil samples selected for chemical analyses will be sealed, labeled, and preserved on ice in the field. Grab groundwater samples will be collected from depths of approximately 10 to 15 feet using either teflon tubing fitted with a check-valve, or using a new, disposable bailer lowered through %-inch PVC piping fitted a five-foot screened section. The temporary wells will be purged of approximately 0.5 to 1 gallon of water prior to collecting a sample. The groundwater samples will be transferred to appropriate sample containers provided by the analytical laboratory and sealed, labeled, and preserved on ice in the field. Chain of custody forms will be used to document sample management procedures. All generated soil cuttings and rinse water will be stored in 55-gallon DOT approved drums pending laboratory analytical results. Upon completion, each drill hole will be abandoned in accordance with SJCEHD rules and regulations. I O.OUITWP HSP 9%&went - - -4 -