Laserfiche WebLink
' 4. Procedures <br /> landscapes. Another advantage of utilizing the LAR was the 15 foot drill tower, which limited <br /> the requirement to remove substantial tree limbs from city and private residences trees and <br /> allowed the vehicle to work within safety limits of overhead utilities. <br /> Due to the locations of BC-2 and BC-7 near the eroding rim of the basin, none of the drilling <br /> ' platforms could safely set up over the well heads. An official from San Joaquin County permitted <br /> these wells to be destroyed by pressure-grouting. This procedure required the excavation and <br /> removal of the concrete apron and soil to 3 feet bgs. The remaining well casings were cut 6 <br /> ' inches above the bottom of the excavation. The well casings were repeatedly filled with grout <br /> and pressurized with air. This procedure continued until the well casings were full of grout and <br /> maintained approximately 25 pounds per square inch of air pressure for 5 minutes. The <br /> excavations were then completely backfilled with grout to surface grade. <br /> The remainder of the ground water monitoring wells that were not destroyed with the LAR or <br /> pressure-grouted were removed with a full-size Central Mining Equipment 85 auger drilling <br /> platform. <br /> ' The air sparging wells were installed with 3/4-inch Schedule 40 PVC within 7-5/8 inch borings. <br /> The previously mentioned method of installing drill pipe into the casing prior to destruction was <br /> not suitable due to the small inner diameter of the PVC. A sonic drilling platform was utilized <br /> with an 8-inch outer-diameter drill bit. The air sparging wells were constructed with <br /> approximately 55 feet of grout seal to surface grade. The grout seal was used as a guide for the <br /> interior of the sonic drill pipe. As the drill pipe descended, large amounts of water were used to <br /> wash out the made-made materials destroyed by the high frequency sonic drill platform. All <br /> man-made materials were removed as the drill pipe extended 1 foot beyond total depth of the <br /> boreholes. The well destruction debris was collected and stored in 20-yard roll-off bins. <br /> 1 <br /> ' Report on Well Destruction G-P Former Tracy Chemical Packaging Plant <br /> UA2011 Letters and Reports\16014.01\Reports\Well Destruction\Report.doc 75 W.Valpico Road,Tracy,California <br /> ©2011.Georgia-Pacific LLC.All rights reserved. <br /> ' 6 <br />