SITE INFORMATION AND CORRESPONDENCE

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f • • 1Weadwell&Rolb Jeffery Wong San Joaquin County Environmental Division 23 December 2003 Page 2 PROPOSED WELL DESTRUCTION A total of forty-four wells are planned for destruction. Ten wells are located in an area with groundwater impacts and shall be destroyed by drilling out the casings and pressure grouting the holes. Thirty-four other wells are in areas without significant groundwater impacts, and shall be destroyed by pressure grouting the well casings. The area of the site with impacted groundwater is in the proximity of the former Tank No. 7 location in the southern portion of the site (Figure 1). There are three monitoring wells, two groundwater extraction wells, three air sparging wells and two vapor extraction wells in this area (MW-3,MW-9,MW-22,EW-3,EW-4, SW-16, SW-19, SW-21, VW-4 and VW-5). These wells are in an area of confirmed or suspected groundwater impacts and the destruction method planned is to drill out the casings and pressure grout the holes. We request that destruction of these wells be approved by the SJCEHD because of the proposed site redevelopment. After site construction, wells in this area will be replaced as required by the SJCEHD. An additional workplan for this site pertaining to potential remediation of this area is also being prepared. Figure 1 shows the former Tank No. 7 area. Table 1 identifies the ten wells proposed for destruction by drilling out. The other thirty-four wells at the site are not located in areas of significant groundwater impacts and the destruction method planned for these wells is to pressure grout them in place. Table 1 identifies the wells proposed for destruction by pressure grouting(MW-6, MW-7,MW-10,MW- 16, MW-17, MW-23, MW-24, SW-1 through SW-15, 17, 18, 20, 22 and 23, VW-1 through VW- 3, A-1 through A-4,B-1 through B-4, C-1 through C-5 and D-1 through D-4). The same groundwater monitoring wells did not have any significant detections of petroleum hydrocarbons or volatile organic compounds (VOCs)in their most recent groundwater sampling and have generally had either no or low, sporadic detections of petroleum hydrocarbons or VOCs for several years. We request that destruction of these wells be approved by the SJCEHD because data from them has demonstrated that they are not in areas of significant groundwater impacts. Table 1 presents a summary of the existing wells at the site, their construction details and their proposed destruction method. All soil, groundwater and decontamination water generated during well destruction will be stored on site pending analytical results. All borings will be destroyed in accordance with California well destruction guidelines and SJCEHD requirements, and well destruction permits will be obtained for all wells. SCHEDULE Above ground demolition (down to building foundations)is scheduled to begin in the third or fourth week of January 2004. The subsurface demolition is planned for March 2004. The subsurface demolition will involve removing all building foundations, subsurface utilities, and Well destruction Area 16.doc