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Work Plan for Preliminary Subsurface Investigation January 31, 1992 <br /> City of Stockton, former Western Pacific Railroad Property, Stockton, CA W0601.1B <br /> borings will be drilled to a depth of approximately 40 feet below grade and completed as <br /> groundwater monitoring wells. One soil boring will be advanced in the inferred upgradient <br /> groundwater flow direction and two soil borings will be advanced in the inferred downgradient <br /> direction, near the northern and eastern boundaries of the property. Figure 2 shows the <br /> proposed locations of the three wells. <br /> Drilling will be conducted by a state licensed (C57) drilling company, using a hollow-stem auger <br /> drill rig. A field geologist will be present to log all drill cuttings and soil samples utilizing the <br /> Unified Soil Classification System. Descriptions of soil types encountered, sample collection <br /> intervals, and well construction details will be recorded on the boring/well log and included in <br /> the summary report. Cored soil samples from the 40 feet deep borings will be collected above <br /> the water table at 5-foot intervals, and below the water table at select intervals in accordance <br /> with the site Soil Sampling Protocol (Appendix A). The soil sample collected at five feet below <br /> grade in each boring will be submitted for laboratory analysis. Analysis will be conducted for <br /> California Title 22 Metals, Volatile Organics (EPA method 8240), and Semi-Volatile Organics <br /> (EPA method 8270). The samples will be analyzed by RESNA Environmental Laboratory in <br /> Fremont, California. Soil sample protocol including sample containers, holding times, means <br /> of preservation, and chain-of-custody documentation is provided in Appendix A. <br /> All drill cuttings will be placed on plastic sheeting, covered with same, and stored on-site, <br /> pending laboratory results. The shallow soil borings will be backfilled with native soil at the <br /> site. To avoid cross-contamination, drilling augers will be steam-cleaned before drilling each <br /> borehole. Water used to clean the augers after drilling each boring will be collected and stored <br /> in 55-gallon drums approved for hazardous liquid storage, pending laboratory analysis. <br /> The monitoring wells will be constructed of 4-inch diameter F480 PVC well screen/casing and <br /> completed as shown on Figure 4. A well screen slot size of 0.010-inch and a Lone Star 2/12 <br /> sand or equivalent will be used as the filter pack. A neat cement will be used to seal the well, <br /> WP013192.SAY 4 <br />