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Pre-Design Investigation Workplan Former Manufactured Gas Plant—Lodi, California Field quality control (QC) samples for soil samples will consist of trip blanks. Trip blanks will be laboratory supplied, 40 milliliter (mL) glass VOA vials filled by the laboratory with pure water. The trip blanks will be analyzed for TPH-p, BTEX and/or VOCs by EPA Method 8260B. One trip blank, placed within coolers with soil samples, will accompany each shipment of sample coolers to the laboratory. Following completion of each soil boring, each borehole will be abandoned by grouting from the base of the borehole to approximately 0.5 foot bgs with bentonite-cement grout. The boreholes will be restored at the surface to match the surrounding conditions. The drilled location of each soil boring will be marked with a marking flag,white paint, or similar and measured accurately to locate it on Site plans. 4.6 TRENCHING PROCEDURES Trenching will be conducted using a small excavator or backhoe. In areas where asphalt or concrete pavement is present or where concrete foundations are known to exist, the pavement or concrete will be cut in a manner to facilitate the removal of the pavement or concrete by the excavator and/or backhoe. The excavator or backhoe team will consist of an operator and a spotter. The spotter will direct the operator when excavating, and will identify any observed underground utilities or other unknown buried objects encountered that may not have been identified during the utility clearance activities (see Section 4.4). To the extent possible, care will be taken to avoid possible damage to any unidentified underground structures that are encountered. At each trench location, excavated soils will be temporarily placed on plastic sheeting adjacent to the trench. During trenching activities, air particulate and vapor sampling and monitoring will be conducted using hand-held instruments. Dust suppression and control procedures will primarily consist of applying water on the excavated soil surface using a water truck or other water supply. Other dust control practices may include (1) maintaining minimal equipment speeds on-site, (2) covering temporary soil piles with plastic sheeting, (3) maintaining a moist ground surface to minimize the passive dust emissions, (4) pausing trenching activities during high winds, and (5) minimizing the number of moving equipment and soil handling activities at any one time. Lithologic trench logs will be prepared for each trench based on visual observations of trench sidewalls and collected soil samples. Soil types will be described in accordance with the USCS. Soil samples will be collected as needed either by using the excavator or backhoe bucket or by using a hand auger. For soil samples to be submitted for analytical testing, soil from the excavation tool will be transferred into a clean laboratory-provided jar using clean tools and/or by hand with new nitrile gloves. The representative depth of the sample will be documented on the trench log and sample identification number. Other soil sampling protocols used for soil sampling during the drilling activities (see Section 4.5) will be followed, including the use of Terra CoreTM samplers, field screening for the presence of VOCs, field QC samples (trip blanks), and sample handling. Following sampling, observation, and documentation, the trenches will be backfilled with the same materials removed from the trenches. TERRA PACIFIC GROUP Page 13 April 4, 2012