SITE INFORMATION AND CORRESPONDENCE

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Scott Mansholt • - 2 - • 18 April 2006 Chevron Banta Road-UPRR Workplan The SAIC field activity report, dated 26 May 2004, summarizes the nature and extent of affected soils encountered during installation of the pipeline (within Banta Road) using a bore- and-jack method beginning approximately 75-feet north of the UPRR ROW. The top of the 30-inch irrigation line, at approximately ten feet, was hydraulically "pushed/augured" beneath Banta Road and the UPRR ROW. The 200-foot long pipeline was terminated within a "receiving" pit". Visible TPH-affected soil was encountered in the first 10-feet (horizontally) of the installation process and non-affected soil was present between 10 and 120-feet; petroleum-affected soil was observed between 120 and 175 feet. This 55-foot interval generally corresponds to the OVP alignment located within the southern portion of the UPRR ROW. Non-affected soil was noted in the final interval between 175 to 200 feet. Following the pipeline installation, 219 cubic yards of petroleum-impacted soil was transported to Forward Landfill for disposal. A soil sample was obtained from the soil stockpile and submitted for fuel fingerprint analysis by Chevron Energy Research and Technology Company to verity if the petroleum hydrocarbons encountered were crude oil/bunker fuel from the OVP. According to the 10 March 2004 lab report, the soil sample contained petroleum hydrocarbons described as ..."most likely a weathered crude oil or possibly a weathered bunker fuel. The sample contained prominent biomarkers typical of many San Joaquin Valley crudes and bunker fuels refined from San Joaquin Valley crude oil". WORKPLAN Based on the recent findings coupled with the Lyoth Loading Station investigative findings, SAIC proposes to advance up to five soil borings to obtain soil samples for analysis to define the extent of TPH in soil and groundwater. The borings will be advanced to approximately 30 feet using a direct push method. Soil and grab groundwater samples will be collected and submitted for analysis of TPH site constituents of concern. We concur with the 29 March 2006 workplan proposal. Depending on the results of the fieldwork, additional borings, monitoring wells and/or sampling may be required. By 20 July 2006, please submit your report of findings. Please notify Regional Board staff at least 48 hours prior to commencing the field activities. If ljou have any questions or comments, please contact Dean Hubbard at (559) 445-5179. SHELTON R. GRAY C. DEAN HUBBARD Senior Engineering Geologist Engineering Geologist PG No. 6357 cc: Michael J. Infurna, San Joaquin County EHD, Stockton Luis Mercado, SAIC, Sacramento