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August 6, 2014 Page 2 of 10 Reference: Well Destruction Work Plan ARCO No, 2130 Government Code 4216, Underground Service Alert ( USA) North and 811 will be notified at least two working days before drilling activities. Well destruction locations will be marked with white paint to indicate the area of drilling or pressure grouting . This will allow USA North members, including local utility companies, to identify and mark the horizontal path of their underground facilities located within the area of drilling. The area will be cleared if no underground facilities are found. In conjunction with USA North and 811 , a private utility locator will be utilized for clearing proposed well boring locations for underground utilities. l Well Destruction Activities A C-57-licensed drilling company will complete the well destruction activities following all relevant sections in the California Well Standards, Bulletin 74-90 and the Son Joaquin County Well Standards. Review of as-builts and a private utility survey was conducted in preparation of this Work Plan. Wells Scheduled for Over-drill Per the SJCEHD Letter dated August 23, 2013 wells containing detections of contaminants of concern (COCs) in groundwater during the last sampling event must be over-drilled and wells with non-detectable concentrations of contaminants of concern in groundwater can be pressure grouted (Attachment A) . Based on review of most recent groundwater data, the following monitoring and remediation wells will be ove - (AS- 1 , S- 1 AB, MS-2AB, MW-1 , 2, MW-3, MW-4, MW-11 , MW- 7, MW- 18, MW-22, MW-23, VW-1 , VW-2, VW-4 nd VW-5) . Each well borehole will be air-knifed to approximatelw6_faet 6 inches below ground surface (bgs) and 110% borehole diameter to confirm that no underground facilities exist within the area pk of drilling . The top t1jreefeelt will be cleared to at least one foot larger than the borehole �evD J � ft�� diameter, per SJCEHD Well Standards, dated February 2005 to allow for mushroom cap. ftp( Each well will be over-d(lled using a drill rig equipped with a hollow stem auger (auger to be eight or ten inch diameter depending on the borehole diameter) to remove material within the original borehole including the well casing, filter pack, and annular seal . The borehole will then be grouted with neat cement using a tremie pipe system forming a grout cap/surface seal from the bottom of the borehole to three feet bgs . A one foot mushroom one foot laraer than the / borehole diameter will be topped off with a mushroom grout cap. The borehole locations will then be backfilled and resurfaced with appropriate materials to match the existing grade. If J groundwater is expelled during the grouting process, it will be properly contained, { characterized and dlmLed . Wells Scheduled for Pressure Grout oyC 5 to ( y 11oe ( s kCY a Fl ALAI 17 Four wells W-7 MW- 14, MW- 19, and MW-21 ) will be pressure grouted since they do not M _ contain detectable levels of COCs, and are away from the source area, and in right-of-ways. � r marl Ivi)� 3 7V/ Ada Design with community in mind