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GROUND ZERO ANALYSIS, INC. 1714 Main Street V Escalon, California 95320-1927 Telephone: (209)838-9888 Facsimile: (209)838-9883 January 21, 2010 JAN 2 2 2010 Mr. Ross Atkinson ENVIRONMENT HEALTH CA Regional Water Quality Control Board, PERMIT/SERVICES Central Valley Region 11020 Sun Center Drive,#200 Rancho Cordova, CA 95670-6114 Subject: Workplan for Destruction of Groundwater Monitoring Wells M&L Commodities (Former Southwest Hide Company) Facility 11651 Palm Lane, Manteca, California Dear Mr.Atkinson: As requested in your letter of December 22, 2009, we are writing to provide you with a workplan for the destruction of the nine (9) groundwater monitoring wells remaining at the subject site. The location of the site is shown on Figure 1. A site plan with monitoring well locations is attached as Figure 2. Table 1 summarizes well construction details. PROPOSED SCOPE OF WORK A C-57 licensed drilling contractor will destroy monitoring wells MW4, MW5, MW7, MW8, MW 15, MW 16, MW 17, MW 19R, and MW21 by pressure grouting with neat cement. Prior to destruction, the total depth of each well will be measured to ensure no obstructions are present. Neat cement grout will then be pumped into each well through tremie equipment in one continuous operation until each well is completely full. Additional cement will then be added under pressure to force the grout through the well screen and into the filterpack, and subsequently checked for subsidence. If the grout level is observed to have dropped, additional cement will be added under pressure until stable. Upon stabilization, the well box and upper three feet of well casing will be removed from each well by overdrilling with a bit at least one foot in diameter larger than the originally drilled hole. At least one foot of grout will be placed in the hole followed by clean soil to grade. The surface will be restored to match the surrounding pavement. GAGROUNDZE\SWHIDE\REPORTS\Well Destruction 2010 WP.doc