WORK PLANS FILE 1 - Laserfiche WebLink

Home Browse Search

k • um Ms. Vickie McCartney,REHS Page 5 San Joaquin County Environmental Health Department February 13, 2004 Deep Monitoring Well Drilling and Sampling The total depth of the boring for the proposed deep monitoring well will be approximately 100 feet bgs. Groundwater at the site is expected at approximately 45 feet bgs. The boring will be drilled using an HSA-equipped drill rig with 8.25-inch outside-diameter(OD) augers to accommodate installation of a 2- inch-diameter well. During drilling of the proposed deep monitoring well, soil samples will be collected at 5-foot intervals to a depth of approximately 75 feet bgs. Soil samples will be collected continuously from approximately 75 feet bgs to total depth with a modified California split-spoon sampler to aid in hydrogeologic characterization of the previously unexplored subsurface below approximately 75 feet bgs. A URS geologist will log the soils according to the Unified Soil Classification System. Soil Vapor Extraction Well Drilling and Sampling The total depth of the boring for the proposed soil vapor extraction well will be approximately 40 feet bgs. The boring will be drilled using an HSA-equipped drill rig with 10.25-inch OD augers to accommodate installation of a 4-inch-diameter well. During drilling of the proposed soil vapor extraction well, soil samples will be collected at 5-foot intervals with a modified California split-spoon sampler. A URS geologist will log the soils according to the Unified Soil Classification System. Air Sparging Well Drilling and Sampling The total depth of the borings for the 10 proposed air sparging wells will be approximately 65 feet bgs. The borings will be drilled using an HSA-equipped drill rig with 8.25-inch OD augers to accommodate installation of 2-inch-diameter wells. During drilling of the proposed air sparging wells, soil samples will be collected at 5-foot intervals with a modified California split-spoon sampler. A URS geologist will log the soils according to the Unified Soil Classification System. WELL CONSTRUCTION Deep Monitoring Well The deep monitoring well will be constructed using 2-inch inside-diameter (ID), Schedule 40, flush- threaded polyvinyl chloride (PVC) well casing. The well will be screened in a water-bearing zone (saturated sand horizon) at approximately 100 feet bgs with 5 feet of 0.020-inch machine-slotted well screen. Exact screen interval will be determined in the field by the URS geologist. A Monterey No. 3 silica sand filter pack will be installed from the bottom of the baring to 3 feet above the well screen. A 3-foot bentonite transition seal will be placed above the sand pack and neat cement will be used to seal the remaining annular space to the surface. The surface completion will consist of an 8-inch flush- KAWprocessV5 BP ARCO\02186V196 WP 04.doc