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Pre-Design Investigation Workplan Former Manufactured Gas Plant—Lodi, California 48 hours prior to the start of work activities, and all provisions of California Government Code 4216 will be observed prior to and during any intrusive activities. In addition, a private utility locating services company may be retained to assist in the identification of underground utility lines and clearance of sampling locations prior to subsurface intrusion. These underground utility clearance activities will be performed using electromagnetic and acoustic-sonic techniques, as necessary. 4.5 DRILLING AND SOIL SAMPLING PROCEDURES Concrete or asphalt coring will be conducted in advance at sampling locations where paving or concrete is present. Once the surface cover is removed, the first 5 feet of each boring will be drilled using an approximately 3-inch-diameter hand auger. Borings deeper than 5 or 6 feet will generally be drilled using a track- or truck-mounted direct-push rig equipped with hydraulic hammer or a track- or truck-mounted drill rig equipped with continuous-flight, 8-inch-diameter hollow-stem augers. At these drilling locations, continuous soil cores will be collected from each boring by advancing a 1.5-inch to 2.5-inch outside-diameter core barrel into the subsurface. Drilling will be conducted by a State of California licensed C-57 contractor. Soil samples collected from hand augers will be collected by transferring soil cuttings from the selected sample interval into a clean laboratory-provided jar. Where a direct-push rig is used, soil samples will be collected into PVC or acetate sample liners which are placed within the core barrel. Soil samples for analytical testing will be collected either by cutting the liners on both sides of the desired sample interval or by transferring the selected sample interval into a clean laboratory- provided glass jar. If a hollow-stem auger rig is used, continuous, undisturbed soil samples will be obtained by advancing a split-spoon sampler lined with a 2 or 2.5-inch-diameter, 6-inch-long stainless steel tube. Geotechnical samples will be collected in 1-inch-long brass tubes. Select tubes and/or acetate liners containing samples will be sealed at each end with 2 mil Teflon° film, and fitted with plastic end caps. In addition, soil samples selected for TPH-p, BTEX or VOC analysis will be collected using Terra Core*"" samplers or equivalent sampling devices, in accordance with EPA Method 5035. Using the Terra Core sampler, an aliquot of soil (approximately 5 grams) is collected using the sampling device and transferred directly into laboratory-prepared 40 milliliter (mL) volatile organic analysis (VOA) vials containing sodium bisulfate and methanol preservatives. Soil samples collected from the hand auger cuttings or drill rig core barrel samplers will be field screened for evidence of VOCs and/or other impacts using visual observations and by either a flame ionization detector (FID) or photo-ionization detector (PID) vapor monitoring instrument. In addition, the samples will be used to describe the subsurface lithology in accordance with the Unified Soil Classification System (USCS) as described in ASTM Standard D 2488-84. A continuous log of the soil encountered at each boring will be created. Soil sample containers will be appropriately labeled using a waterproof marker. All samples will be placed in Ziploc®-type bags (or equivalent), sealed, and stored in coolers on ice to maintain samples at approximately 4° Celsius prior to and during shipment to the analytical laboratory. Chain-of- Custody forms will be completed on-site and will accompany the samples to the laboratory. TERRA PACIFIC GROUP Page 12 April 4, 2012