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' 4. Procedures <br /> ' 4. PROCEDURES <br /> This section describes the methods used during well destruction activities. All well destruction <br /> activities were under the direct observation of San Joaquin County personnel and complied with <br /> ' San Joaquin County Well Standards(. <br /> 4.1 Well Box Removal <br /> Prior to initiating well destruction activities, an air knife/vacuum truck and crew removed all <br /> ground water monitoring monuments (stand pipes), conductor casings, concrete aprons, and well <br /> boxes. All well debris was segregated from soil and water derived wastes and placed into <br /> 20-yard roll-off bins for subsequent removal as construction debris. <br /> 4.2 Well Destruction <br /> Historically, wells had been destroyed when it was deemed appropriate. Ground water <br /> ' monitoring wells BC-1, BC-8, BC-11, BC-12, and recovery well RW-1 were destroyed between <br /> 1991 and 2002. Historical and recent well destructions records are included in Appendix L. <br /> Due to the locations and the methods utilized to install the ground water monitoring and air <br /> sparging wells, three different drilling platforms were used to destroy the wells. All wells were <br /> completely filled with neat cement from 0 to 2 feet of surface grade dependent upon the location <br /> ' of the well. <br /> The ground water monitoring wells were destroyed with auger drilling platforms. Drill pipe was <br /> lowered into the Schedule 40 polyvinyl chloride casing (PVC) well casings to the total depth of <br /> the well prior to auger drilling. This procedure was performed as a guide for the augers to remain <br /> on track with the borehole to completely remove all the man-made materials and extend 1 foot <br /> ' beyond the total depth of the borehole. The diameter of the PVC casing varied ranging from 2 <br /> inch to 8 inches in diameter. The diameter of the boreholes varied ranging from 6 to 12 inches in <br /> diameter. To properly destroy and remove all the man-made materials, auger and sonic drill bits <br /> ' were required to be as large as or larger than the diameter of the borehole. The inner diameter of <br /> the auger flights were required to be larger than the outer diameter of the PVC casing in order to <br /> properly remove all of the casing intact. As an example, to remove RW-2 which was a 12-inch- <br /> diameter borehole with an 8-inch diameter PVC casing, it required the utilization of 15-inch <br /> augers that had an inner diameter of 9 inches to completely remove the man-made materials. In <br /> addition, centralizers were utilized every 10 feet of drill pipe to total depth to center the drill pipe <br /> ' inside the PVC casing and to maintain the auger alignment upon the borehole. Photographs of <br /> field activities are in Appendix M. <br /> ' The ground water monitoring wells installed within the City landscaped areas, sidewalk, and the <br /> public utility easement corridors were destroyed utilizing a limited access rig (LAR). In addition, <br /> one well within CCC's planter-box area utilized the LAR. The LAR was a motorized rubber- <br /> tracked auger drilling platform that prevented damage to roads, sidewalks, curbs, and grass <br /> ' ' San Joaquin County.2005.San Joaquin County Well Standards,San Joaquin County Ordinance Code Section 9-115-6.February. <br /> Report on Well Destruction G-P Former Tracy Chemical Packaging Plant <br /> LIA2011 Letters and Reports\16014.01\Reports\Well Destruction\Report.doc 75 W.Valpico Road,Tracy,California <br /> (72011.Georgia-Pacific LLC.All rights reserved. <br /> 5 <br />