SITE INFORMATION AND CORRESPONDENCE

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Mr. James Taylor • - 2 - • 5 December 2007 The pilot study is proposed to be conducted for one year. If the pilot study provides the data necessary to prepare a Report of Waste Discharge for full-scale implementation before one year has been completed, the study may be terminated with Regional Water Board concurrence. The business cycle of the French Camp Grain Elevator includes a slow period in the spring when installation of wells and piping will cause minimal disruption to the site operations. Therefore, the pilot study components should be installed in the spring months, and the groundwater extraction and injection can begin when the pre-tests have been successfully completed. The extraction pump is fitted with transducers and switches that prevent the pump from operating if there is insufficient water in the extraction well or if there is a pressure loss in the system. During the start-up test procedures, ContiGroup will verify that the extraction pump shuts off when there is a loss of line pressure either upstream or downstream of the control panel. The Pilot Study Work Plan contains a narrative description of the proposed extraction well, injection well, and monitoring well design. The well installation portion of the Pilot Study Work Plan should also include a construction diagram and should be packaged such that it can be easily provided to San Joaquin County Environmental Health Department. The Monitoring Well Work Plan may be provided electronically. The conditions for conducting the recirculation pilot study stated in our 4 October 2007 letter are updated and repeated here for clarity. Since ContiGroup has satisfied the request to relocate MW-13B, this condition has been removed. A condition relating to pre-testing the pressure loss shut-off switches is added. Revised Conditional Concurrence with Recirculation Pilot Study Regional Water Board staff conditionally concur with the Groundwater Recirculation Pilot Study and Pilot Study Work Plan subject to the following conditions: • A Work Plan for installation of extraction wells, injection wells, and monitoring well MW-13B, including a schedule for implementation, shall be provided to Regional Water Board staff with a copy to San Joaquin County Environmental Health Department for approval before installation proceeds. The Work Plan may be submitted electronically. All wells shall be installed to the satisfaction of San Joaquin County Environmental Health Department. • Within one month prior to starting the extraction/injection system, groundwater samples shall be obtained from MW-36, MW-413, MW-513, MW-913, MW-10B, and 'MW-13B, and shall be analyzed for volatile organic constituents, dissolved iron, and chloride. • The pre-testing of the system will include verifying that the extraction pump will not operate. if there is a pressure loss in the system. • Install water level transducers in MW-3B, MW-46, and MW-913 in addition to MW-106, MW-13B, and EW-12B.