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{ Work Plan for Groundwater Extraction weft installation2 The Southland CoToration,455 Grant Line Road Tracy,CA April 12 19% TASK 2: SOIL BORING/SAMPLING Using a truck-mounted drill rig equipped with 12-inch-diameter hollow-stem augers, Groundwater Technology will install one soil boring to be converted to a groundwater extraction well in the former tank pit area at the location shown in Attachment 1, Figure 2. The boring will be drilled to approximately 20 feet below ground surface (BGS). It is anticipated that groundwater will be i encountered at approximately 3 to 4 feet BGS. Soil samples will be collected from the borehole at 5-foot intervals beginning at 5 feet BGS using a split-spoon sampler fined with 24nch-diameter by 64nch-long brass sample tubes. The hollow-stem augers will be steam cleaned before drilling, and sampling equipment will be cleaned between each sampling interval. Each soil sample will be screened for hydrocarbon vapors using a photoionization detector(PID). Soils encountered during drilling will be logged using the Unified Soil Classification System by a Groundwater Technology field geologist,working under the supervision of a California registered geologist. One sample tube from each sampling interval will be sealed with teflon sheets, capped,taped, labeled, and placed on ice in an insulated container. Based on field observations, selected soil samples from the borehole will be analyzed by a State-certified analytical laboratory for benzene,toluene, ethylbenzene and xylenes (BTEX), and total petroleum hydrocarbons-as-gasoline (TPH-G) by EPA methods 8020/8015 modified. An estimated two soil samples from the boring will be analyzed. All soil generated through drilling will be stockpiled on site and covered with plastic sheeting pending characterization and disposal. Water generated by steam cleaning will be contained and temporarily stored on site in Department of Transportation (DOT)-approved 55•-gallon drums pending treatment ! through the existing groundwater remediation system. i TASK 3: WELL CONSTRUCTION/DEVELOPMENTISAMPLING The groundwater extraction well will be constructed in the boring of 6-inch Schedule 40 polyvinyl- chloride (PVC) casing with flush threads and 0.020-4nch-slot well screen. The well screen will be installed from approximately 4 to 15 feet BGS. A 5-foot length of blank casing will be installed below the bottom of the screened interval from 15 to 20 feet BGS. The annular space will be filled with bentonite from 20 to 16 feet BGS, and sand from 16 feet BGS to 1 foot above the top of the well screen. The well will be sealed with 2 feet of bentonite,followed by a neat-cement grout to grade containing a mixture of 95 pounds of Portland Type I/ll cement to 5 gallons of clean water.The extraction well will be protected by a traffic rated 17_inch by 30 inch by 24 inch deep vault. r . I Following installation,the recovery well will be developed by using a surge block and bailing to remove fine-grained sediments from the well and filter pack. Water from the development process will be GRO ❑❑� LEI]❑❑ 1 TEEHNDOwa . r x �