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r <br /> Stantec <br /> February 4,2009 <br /> Mr. Robert Aragon <br /> Page 3 of 4 <br /> Re:Well Abandonment Work Plan <br /> TASK 2—WATER WELL INVESTIGATION <br /> The two wells will be investigated to attempt to determine the total depth of well casing. The investigation <br /> will be conducted using a rotary rig with rods equipped with a tri-cone tip. The rods will be advanced <br /> using water to displace bridged materials and clean casing walls. Based on the encountered resistance <br /> with the tri-cone tip and monitoring the cuttings, the base of the wells will be determined. The wells will <br /> be flushed and any accumulated water in the well be removed. Water in the wells will be allowed to settle <br /> overnight before video logging is conducted. <br /> Drilling operations will be conducted by Woodward Drilling (C-57 License No. 710079) under supervision <br /> by Stantec. <br /> TASK 3—VIDEO LOGGING <br /> Following well investigation activities and once the water wells have been allowed to sit for a minimum of <br /> one night, a subcontractor of Woodward Drilling under supervision by Stantec will use a downhole video <br /> camera to log the well construction to total depth. The water well investigation and video logging <br /> activities should provide sufficient information to determine the screen interval and total depth of the well <br /> casings. Based on the well construction, the wells will be abandoned in accordance with SJCEHD's Well <br /> Destruction Standards, Section 6. <br /> TASK 4—WATER WELL ABANDONMENT <br /> For the purposes of this work plan, the water wells are not expected to be deeper than 100 feet bgs, <br /> based on the depth of groundwater measured during remediation investigation activities in October 2008 <br /> to be approximately 60 feet bgs. In accordance with SJCEHD's Well Destruction Standards, Section 6 for <br /> wells that are 100 feet bgs or shallower, the wells will be sealed from total depth with grout, bentonite, or <br /> a minimum of 5-sack mix of concrete not greater than '/4-inch aggregate. If bentonite chips are selected <br /> they will be allowed to freefall if the space does not allow bridging. <br /> In addition, a hole at least one foot in diameter larger than the presumed originally drilled hole will be <br /> excavated around the outside of the well casing to a depth of three feet bgs. The well casing will be cut <br /> to 6 inches above the bottom of this excavation and removed. The approved bentonite that is used to <br /> seal the well will spill over the well casing into the excavation and fill the excavation for a thickness of <br /> 1 foot. With this procedure, 6 inches of grout will cover the casing. After the sealing operation and <br /> material have set, the excavation will be backfilled with native soil. <br /> All well abandonment activities will be performed under the supervision of Stantec. <br /> TASK 5—INVESTIGATION DERIVED WASTE DISPOSAL <br /> Wastes generated during the drilling investigation will be stored in 55-gallons drums. The drums will <br /> remain on-site until all well abandonment activities have been completed. Once completed, the drums <br /> will be transported by Woodward Drilling to the PG&E Service Center in Stockton, California. The drums <br /> will remain at the PG&E Service Center pending receipt of analytical data from the laboratory for profiling <br /> purposes. The analytical results will be used for waste profiling and disposal evaluation by PG&E. <br />