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+ 1 Mr. Robert McClellon URSNovember 17, 2003 Page 2 review and approval how the gas monitoring probes will be engineered and implemented." URS contacted Mr.Tasiopoulos requesting clarification regarding whether the work plan was due to SJCEHD in November 2003, as specified in the inspection report, or 30 days after receipt of the letter. Mr. Tasiopoulos agreed that the November 2003 due date would meet their requirements. SCOPE OF WORK URS proposes to install a total of four gas-migration monitoring probes along the property boundary at one location midway between SJCEHD's borehole punch locations I and 2 and at SJCEHD's borehole punch locations 3,6, and 9 (Figure 1). The proposed locations of the probes were based on our understanding of SJCEHD's probe location preferences, which were specified during our discussions with you. Before installing the probes, URS will meet with an SJCEHD inspector to obtain approval of the proposed probe locations. Following approval of the probe locations, a utility survey will be completed. If utilities are located at or near any of the proposed probe locations,requiring probes to be relocated,the probes will be relocated to an area along the property boundary within 10 feet of the approved location without seeking SJCEHD approval. If any probe has to be relocated more than 10 feet from the approved location, URS will contact SJCEHD to obtain approval of that relocation. Based on our discussions with you, we understand that debris was placed from 15 feet to 5 feet below the ground surface (bgs). URS plans to use a truck-mounted drill rig equipped with hollow-stem augers to advance soil borings to a depth of 15 feet bgs at each of the four proposed probe locations. URS plans to install the probe at SJCEHD's borehole punch location 6 last. Soil samples will be collected from all borings using a clean California modified split-spoon sampler fitted with brass liners. Samples will be collected on a continuous basis for the first boring and at 5-foot intervals or at changes in lithology for the remaining three borings. The field geologist will log the soil from each boring using the Unified Soil Classification System. After each boring has been advanced to the desired depth, a gas-migration monitoring probe will be constructed within the boring. Each probe will be screened from 5 feet to 15 feet bgs. The probes will be �1 constructed using a 1-inch or 2-inch polyvinyl chloride(PVC)pipe. Sand will be placed between the annulus of the probe casing and the boring wall to 4 feet bgs. One foot of bentonite will be placed in the annulus from 5 feet to 4 feet bgs. The remainder of the annulus will be filled with neat cement. A christy box will be placed at the top of each probe. If groundwater is encountered during boring advancement, the probe will be constructed so that the bottom of the probe screen is placed 2 feet above the static water surface. The proposed probe completion details are shown on Figure 2. Soil cuttings will be placed on the ground surface of the site because it is not expected that contamination will be encountered. However, if discolored soil or odorous soil is encountered during the activities, URS will be prepared to place the soil in 55-gallon drums. Following the completion of the field activities, methane concentrations from each probe will be measured on a quarterly basis for four quarters using a hand-held portable landfill-gas monitor.These measurements will be recorded in a field log book. During each quarter, a report will be prepared K:\Wprocess\25532\Workp1an.doc