SITE INFORMATION AND CORRESPONDENCE

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Mr. Robert Vieira • •roject 0805-152.01 November 14, 1994 Page 2 during drilling. Every effort will be made to keep the work area clean and to restore the area to the original condition when the work is completed. We will contact you to coordinate drilling operations to determine which day of the week is most convenient. Our tentative schedule for the construction of the vapor extraction wells is December 1994. Upon receipt of your authorization, we will schedule a date for our work and we will inform you of that date. Depending on the findings of this phase of the investigation, we may have to connect the wells to a remediation system The vapor extraction wells would be used to remove hydrocarbons from soil by placing a vacuum on the well and drawing the hydrocarbon vapors through a pipeline to a remediation unit to be located on the ARCO site. To connect the wells to a remediation unit at the ARCO station will require EMCON and its contractors to lay horizontal pipeline from the wells to the station. A schematic of the piping design is shown on Figure 3. This work would take approximately 1 week to complete. If the wells are connected to a remediation unit, a technician from EMCON would periodically need to gain access to the wells for data acquisition and maintenance for approximately 1 year, or as required until remediation is completed. After the soil is remediated and the wells are no longer needed, the wells will be properly destroyed by drilling them out with a 10-to 12-inch-diameter auger and backfilling the borehole with neat cement. The ground surface will then be restored to resemble the surrounding ground material. A boring will be drilled adjacent to each well to collect soil samples to confirm that hydrocarbons have been removed from the soil; the borings will be backfilled with neat cement. We appreciate your cooperation in this matter. Please sign and return both copies to our office. We will forward both copies to ARCO. ARCO will then sign both copies and will return one copy to you for your files. Upon your authorization to access your property, we will arrange a time to perform the work and appraise you of the schedule. Please feel free to call Jay R. Johnson if you have any questions about the work. Sincerely, EMCON Associates Claud /aly . sonProject Geologist oject Supervisor Attachments: Figure 1 Area Site Plan Figure 2 Schematic Weil Design Figure 3 Cross-section of Vapor Extraction System Trench ARCO Products Company License Agreement(two copies) cc: Chuck Carmel, ARCO Products Company Margaret Lagorio, San Joaquin County Public Health Services SAC/P10N0805/08051520.1 BM-94/pas:1