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0 1627 Army Court <br />Stockton, California <br />January 31, 2017 <br />Project No. 100834002 <br />OBJECTIVE <br />The objective of the work described herein is to abandon two on-site monitoring wells installed <br />in 1988. <br />SCOPE OF WORK <br />The following scope of work will be completed to meet the objective. <br />Pre-Field Activities — Ardent will notify Underground Service Alert to identify the locations <br />of underground utilities in the drilling area. A Health and Safety Plan which will be used by <br />Ardent and its subcontractors during the subsurface investigation has been prepared and <br />provided in Attachment A. Ardent will retain a geophysical company to search for the well <br />that may have been covered with asphalt slurry. <br />Well Abandonment — The wells will be abandoned by a C-57 licensed drilling company <br />(Cascade Drilling, L.P., of Richmond, California). Prior to abandoning, the total depth of <br />each well will be measured. The approximate depth of the casing is expected to be <br />approximately 25 feet below ground surface (bgs). The well boxes will be removed and <br />disposed. A drill rig equipped with 8-inch hollow stem augers and a bulldog bit will be used <br />to over-drill and destroy the well casing. The 8-inch diameter borehole will successfully <br />remove all backfill materials used during the construction of the well. Following destruction <br />activities, the augers will be removed and the bulldog bit will be replaced with a hollow rock <br />bit. The augers will be advanced to the total depth, where a tremie pipe will be used to <br />pump neat cement grout (cement grout with approximately 6 percent bentonite by weight) to <br />the bottom of the hole. The augers and tremie pipe will be slowly raised to allow the cement <br />to be placed from the bottom of the hole up. The remaining borehole will be backfilled with <br />cement grout and topped with an approximate one-foot concrete plug. Wastes generated <br />during drill out activities will be containerized in 55-gallon drums and properly disposed at an <br />off-site facility. Well boxes will be disposed as construction debris. <br />Report — After completing the above tasks, a report will be prepared summarizing the well <br />abandonment activities. The report will be submitted to the San Joaquin County <br />Environmental Health Department for review. <br />rrARDENT <br />ENVIRONMENTAL GROUP, INC. <br />100834002 Work Plan 2