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i Work Plan For Well a ' '{ Destructions Chevron Site ID 309075 January 2, 2013 3.4.2 Over Drill and Conductor Casing Removal During installation, monitoring well MW-6D was double-cased with steel conductor casing using 15-inch OD HSA to a depth of approximately 78 feet below ground surface (bgs). Once the conductor casing was set and sealed, an 8-inch diameter borehole was advanced through the conductor casing to a total depth of 120 feet bgs. The boring log for MW-6D is included in Appendix A. Due to the presence of conductor casing, well MW-6D will be destroyed by removing the well box and over..drilling to the total completion depth with 8-inch OD HSA to remove all-material (e.g. casing, filter pack, annular seal, etc,) associated with the well. Following over drilling of well materials, the boring will be grouted from the bottom of the borehole to within 5 feet of ground surface using a tremie pipe and cement-bentonite grout. Prior to completing grouting to within 3 feet of ground surface, approximately 4-feet of conductor casing will be removed utilizing a down-hole cutting torch. The remainder of the boring will then be grouted to within 3 feet of ground surface using cement-bentonite grout. The upper 3 feet will be backfilled with native soil to the surface of the borehole and then completed at grade with material matching the existing surface (e.g. asphalt concrete, etc). f 3.4.3 Soil Cuttings and Rinsate Water Soil cuttings generated during drilling operations will be containerized in Department of Transportation (DOT) 55-gallon: drums or stockpiled and temporarily stored on the subject property pending characterization and disposal. Soil cuttings will be removed and transported by Chevron's disposal contractor to an appropriate disposal facility. Water displaced during tremie grouting or generated during steam cleaning, will be temporarily stored in DOT approved 55- gallon drums pending transport by. Chevron's disposal contractor to an appropriate disposal or treatment facility. 4.0 REPORTING A report will be prepared to document the results of well destruction activities. The report will include at a minimum the following: • A summary of site conditions and background information • A scaled site plan illustrating the destroyed well locations and other relevant site features • A description of activities G:\Aproject\ENV\CHEVRON\309075\6 Deliverables\Work Plan\Well Destruction\309075 Work Plan for Well Destructions ML_01022013.doc 3 `r i