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r <br /> EXHIBIT A <br /> Proposed Field Methods and Procedures <br /> This section documents the methods and procedures proposed <br /> for borehole drilling and soil sampling during the site <br /> investigation. <br /> Borehole Drilling . Five boreholes are proposed to be <br /> drilled at the Geweke Lodi site to identify the vertical and <br /> lateral extent of hydrocarbon contamination, if any . The <br /> locations of the proposed boreholes are shown on Figure 1 . <br /> Locations of the boreholes were selected on the basis of: <br /> ( 1 ) location of the former underground storage tanks and pump <br /> islands, (2) information gained from data review and preliminary <br /> stages of the field work. <br /> The boreholes will be drilled using a Mobile B-53 truck- <br /> mounted drilling rig equipped with 6-1/2-inch-outside-diameter, <br /> hollow-stem, continuous-flight augers. Use of the hollow-stem <br /> augers will preserve sample integrity. Undisturbed soil samples <br /> will be obtained from specific depths using a Porter-type <br /> drive sampler inserted within the hollow-stem augers. Before <br /> drilling each borehole, the augers and all sampling equipment <br /> will be cleaned to prevent possible cross-contamination between <br /> boreholes. <br /> Soil Sampling. Soil samples will be collected at various <br /> depths in each borehole. The presence of hydrocarbon odors <br /> and visible products, if any, in the samples will define the <br /> number of samples and the subsequent depth of sampling. Soil <br /> sampling will be accomplished by driving a 2-1/2-inch diameter <br /> by 18-inch-long brass tube-lined Porter sampler into the soil <br /> using a 130-pound down-hole hammer (mounted on the drilling <br /> rig) . The Porter sampler will be washed with laboratory grade <br /> detergent between each use to prevent cross-contamination. <br /> Upon removal from the borehole, the ends of the soil cores <br /> contained in the brass sampling tubes will be visually inspected <br /> for soil characteristics and odor . The tubes will then be <br /> sealed with aluminum foil and an air-tight plastic cap, and <br /> labeled with the project and borehole number, depth interval, <br /> and date. The samples will be stored in a chilled ice chest <br /> until recieved by Brown and Caldwell 's analytical laboratory in <br /> Emeryville, California. <br /> Summary of Results <br /> A final report will be prepared documenting the borehole <br /> logs and the results of soil samples. <br />