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Monitoring Well Destruction The destruction of the well will be in accordance with State and County well destruction regulations. Groundwater monitoring well ATR-12 is constructed of 2-inch-diameter, flush- threaded schedule 40 polyvinyl chloride (PVC). The well is screened from 5 to 25 feet below ground surface with 0.020-inch slotted casing. The well will be over-drilled using a truck- mounted drilling rig equipped with 8-inch-outside-diameter hollow-stem augers to the bottom of the well. After the well casing, sand pack, transition seal, and grout have been drilled out, a cement-bentonite slurry will be tremied from the bottom of the borehole to the ground surface. Monitoring well ATR-12 is located in the sidewalk on the north side of Clover Road. Prior to well abandonment, the section of sidewalk where the well is located will be removed. Upon completion of the well destruction, the section of sidewalk will be replaced to City of Tracy specifications. If cuttings are generated, the soil will be temporarily stored (at the ARCO facility) on plastic sheeting and covered with plastic, separate from the well debris. Stockpile soil samples will be collected from any cuttings generated from the drilling and analyzed for the presence of benzene,ethylbenzene,toluene,and xylenes(BETX), total petroleum hydrocarbons as gasoline (TPH-G), using U.S. Environmental Protection Agency (EPA) Method 8020 and 8015 Modified, reactive sulfides and cyanides by EPA Method 9010, corrosivity (Ph) by EPA Method 9045, Ignitability (flash point) by EPA Method 1010, and Soluble Threshold Limit Concentration for lead by EPA Method 6010/7000 series. Upon receipt of the laboratory report, BC will forward the results to ARCO's contracted soil disposal trucking company. Exhibit A describes Brown and Caldwell field procedures for sampling from stockpiles and sample handling. PROJECT SCHEDULE The fieldwork will require approximately one day to complete. The starting date will depend on County approval of the work plan and on driller availability. A summary report in letter form will be completed within approximately 3 weeks after field work is complete. The report will include a description of field methods and conclusions. The report will be submitted to ARCO for review, and the final report will be provided to the County and RWQCB for review. Use or disclosure of data contained on this sheet is subject to the restriction specified at the beginning of this document. 26401REPORTS1264"1.W P