ARCHIVED REPORTS_WELL DESTRUCTION REPORT

Home Browse Search

approximately 3 feet. The remaining 3 feet of boring was backfilled with either grout, concrete or native soil. The top approximate 6 inches of each boring was capped with either concrete dyed black (when ' necessary)or native soil in order to match the surrounding ground surface. Destruction by Overdrilling 1-Inch-Diameter PVC Wells ' A total of five wells were destroyed by overdrilling the casing and annulus to the total depth of each well using a combination of a sonic drilling rig and a HSA drilling rig equipped 10-inch-diameter augers. Each of these wells were pressure grouted prior to the advancement of any rods or augers. A sonic drilling rig then advanced 4-inch-diameter rods around the grouted well casing to the total depth of each well. Ten- inch-diameter augers were then advanced around the sonic drilling rods ensuring that the augers stay ' centered on the well. Upon reaching total depth, each well was backfilled with grout introduced through the augers via a tremie pipe to a depth of approximately 5 feet. The remaining 5 feet of boring was backfilled with either grout, concrete, or native soil. The top approximately 6 inches of each boring was ' backfilled with concrete or native soil in order to match the surrounding ground surface. Destruction by Drilling Out '/4-Inch-Diameter Nylon Tubing Wells ' Wells SV-2 and SV-3 were destroyed by drilling out the casing and annulus to the total depth of each well using a HSA drilling rig. Eight-inch-diameter augers were advanced to the total depth of the wells (6 feet). The augers were then removed and the borings were backfilled with grout to a depth of ' approximately 0.5 foot. The top approximately 6 inches of each boring was backfilled with concrete and dyed black(when necessary)to blend in with the surrounding ground surface. ' In the case of SV-1, the entire casing and well screen was extracted by hand. The well box and top foot of concrete was broken up and removed using a jackhammer. The resulting hole was backfilled to the surface with native soil. ' Destruction by Overdrilling '/4-Inch-Diameter Teflon Tubing Wells A total of ten remediation wells were destroyed by overdrilling the casing and annulus to the total depth of each well using a sonic drilling rig (Photo 7) with 4-inch-diameter drilling rods. The rods were three times larger than the 1.25-inch direct-push rods that were used to install these wells. Grout was ' introduced via tremie pipe from the bottom of each boring to a depth of approximately 5 feet. The remaining 5 feet of annulus was backfilled with grout and topped at the surface with approximately 6 inches of concrete dyed black(when necessary)to blend in with the surrounding asphalt. ' Waste Disposal The soil and debris generated during the well destruction activities was stockpiled within six plastic- lined, 20-cubic-yard bins, which were stored onsite pending waste profiling and disposal facility acceptance. When practical, large blocks of concrete and metal were removed from the bins and taken to the Sims Metal Management facility in Rancho Cordova, California, for recycling. The analytical results for the composite stockpile soil samples were submitted along with a waste profile form to the Potrero Hills Landfill near Suisun City in Solano County, California. The soil was approved for waste disposal on January 31, 2012. On February 2, 2012, five 20-cubic yard bins containing 57.46 tons of soil and one 20-cubic yard bin containing 10.14 tons of miscellaneous construction debris were loaded and transported under Uniform Non-Hazardous Waste Manifest Nos. ' 65740-01 through 65740-05 and 65740-CONSTRUCT by NRC Environmental Services to the Potrero ' Project No.59482-06-02 -4- March 30,2012