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N la ko . Site The material will be sampled to determine the proper means of disposal All handling and disposal will be performed in accordance with the applicable DER and California Department of Water Resources regulations B.3 SPLIT-SPOON SAMPLING Split-spoon samples will be collected at 5-foot centers during the installation of the new morutonng well The samples will be used to determine a lithologic description of the subsurface, and for field screening (to determine the appropriate interval to submit for laboratory analyses) The split-spoon samplers will be 18-inches long, split-barrel, steel tubes with a threaded hollow point Split-spoons will be used in combination with the 4 25-inch (inner diameter) HSAs When the HSAs are drilled to a required sample depth, the split-spoons and drill rods will be lowered through the HSAs to the bottom of the boring, and the split spoons will be driven into the undisturbed sediments ahead of the bit using a 140-1b slide hammer The split-spoon sampler will contain three thin-walled brass tubes, each 6-inches in length, which will collect three discreet soil samples When the split spoon is extracted from the borehole, one of the three brass tubes will be removed and screened for organic vapors using a photoionization detector (PID) Another of the brass tubes will be covered with aluminum foil and plastic caps, covered with duct tape to provide an air-tight seal, labeled, and placed in a plastic bag The plastic bag containing the brass tube will be placed in an ice chest for delivery to a California accredited laboratory (if the field screening sample . indicates sufficient contamination) The third brass tube will be opened and the cuttings examined for lithologic analyses The split-spoon samplers will be decontaminated between samples using an Alconox-solution wash and a tap water rmse B.4 SHALLOW MONITORING WELL INSTALLATION The shallow monitoring well will be constructed to collect water samples from the water table The bonngs will be advanced to a depth of approximately 27 feet bgs using HSAs A 15-foot length of flush-threaded, Schedule 40, PVC well screen (0 020-inch slot size) with an attached PVC bottom cap will be installed inside the HSAs with an attached length of PVC nser casing sufficient to extend the top of the well to ground level PVC well materials will be decontaminated before installation with high-pressure, steam-cleaning r equipment A silica sand filter pack will be installed around the well screen inside the HSAs The HSAs will be withdrawn from the hole during the filter pack installation to allow the sand to fill the annular space between the well and the borehole The shallow monitoring wells will be constructed with a 2-inch-thick filter pack The filter pack will be installed to about 2 feet above the top slot of the well screen A 3 foot thick bentonite seal will be installed on top of the filter pack, and the annular space above the seal will be filled with cement grout The annualar seal will be allowed to set a minimum of 48 hours prior to development of the well j I l Illi Bpm_i 7 JAX/96-L94IMY4i1 i i I Ii I I I I I I I t i I I I I II II l I I I