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f GROUND ZERO ANALYSIS, INC. 1714 Main,Street Escalon,California 95320-1927 Telephone:(209)838-9888 RECENEDD Facsimile:(209)838-9883 FEB 0 8 2010 February 5, 2010 ENVIRONMENT HEALTH Ms. Lori Duncan San Joaquin County Environmental Health Department 600 East Main Street Stockton, CA 95202 Subject: Monitoring Well Destruction Permit Applications M&L Commodities(Former Southwest Hide Company)Facility 11651 Palm Lane, Manteca, California Dear Ms. Duncan: Enclosed herewith are two sets of completed drilling permit applications and the associated fee for the destruction of eight (8) groundwater monitoring wells located at the subject site and one (1) groundwater monitoring well located off site (Figure 1). The offsite well (MW4) is located in County right-of-way on the corner of the East Highway 99 Frontage Road and Olive Avenue intersection in Manteca, CA. An Encroachment Permit has been issued by the San Joaquin County Department of Public Works for drilling in County right-of-way. A copy of the Encroachment Permit can be provided upon request. The work will be conducted in accordance with Ground Zero's January 21, 2010, Workplan for Destruction of Groundwater Monitoring Wells, which was approved by the California Regional Water Quality Control Board (RWQCB) in correspondence dated January 28,2010,both of which have been included in Attachment A. Well destruction activities will be conducted by V&W Drilling, Inc. (C57-720904) under the supervision of a Ground Zero geologist. Groundwater monitoring wells MW4, MWS, MW7, MW8, MW 15, MW 16, MW 17, MW 19R and MW21 will be destroyed by pressure grouting with neat cement grout. 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. Monitoring well construction details are summarized in Table 1. The locations of the monitoring wells are shown on the site plan provided as Figure 2. GAGROUNDZE\SWHIDE\Permits\Well Dest Permit Cvr.doc