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Abdelwahed Facility, Ultrar�Site No. 13792 %.1 May 5, 2012 Stockton, California Work Plan Well for DPE Well Installation and Soil Gas Investigation Task 2 Disconnect VES piping from the MW-1 well head; drill out well MW-1 well with a 8-inch diameter auger to a depth of 56 feet below surface grade (bsg); backfill boring with neat cement; and restore the surface. Task 3 Document the well destruction and update GeoTracker as necessary. Proposed Monitoring (DPE) Well Installation Proposed tasks for monitoring well installation will include drilling, installation, development and sampling. It is possible that analytical results for groundwater samples collected from the replacement monitoring well will reveal that formation water is not impacted to the extent indicated by current analytical data from well MW -1. In this case, it would be unnecessary to conduct DPE remediation. Tasks to complete a potential DPE remedial action, if deemed necessary, are included in this work plan. Some aspects of the proposed DPE remedial action may be amended in response to data collected subsequent to installation and sampling of the new well. The location of the proposed monitoring well is shown on Figure 4. Preliminary well construction details for the proposed monitoring/DPE well are shown on the attached Typical Well Construction Diagram. The actual screen interval of the DPE well will be evaluated on the basis of the depth of water encountered during drilling. The proposed drill out and well installation work shall consist of the following tasks: Task I Select and schedule a C-57 licensed drilling contractor to provide hollow - stem auger drilling and well installation services; obtain required well permit from the EHD; and prepare a Site Health and Safety Plan. Task 2 Drill new 10 -inch diameter boring to 60 feet bsg; construct a DPE well utilizing 4 -inch inside diameter casing screened from 30 to 60 feet bsg; actual screen interval may be adjusted depending on the water depth encountered during the field activities. Task 3 Develop and sample the well; survey the location and top -of. -casing (TOC) elevation of the new well to GeoTracker specifications. Task 4 Collect an additional groundwater sample from the DPE well 1 to 2 months after collection of the initial sample to confirm groundwater conditions; submit groundwater samples, with chain -of -custody documentation, to a state -certified analytical laboratory; analyze groundwater sample for total petroleum hydrocarbons as gasoline (TPHg), the volatile aromatics benzene, toluene, ethylbenzene and xylenes (BTEX); fuel oxygenate methyl -t -butyl ether (MTBE), lead scavenger 1,2-dichloroethane (DCA) by EPA Method 8260B. 1792 DPE Well WP Project No. 1792.26 3 HORIZON ENVIRONMENTAL INC.