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TECHNICAL APPROACH <br /> Based upon the information provided to this office by Chevron, and a review <br /> of the SJLHD Suggested Procedures for well destruction, the following proposed <br /> work plan has been developed for the destruction of groundwater monitoring wells <br /> at the subject property. <br /> Destruction will be performed utilizing a truck mounted drill rig equipped <br /> with a concrete pump and a backhoe. A Dames & Moore geologist or engineer will <br /> be present during destruction- to make observations of the site conditions. <br /> First, the interior of the well casing will be checked for any obstructions <br /> which might interfere with effective sealing procedures. Removal of the well <br /> casing and other well completion materials will be by means of "overdrilling" the <br /> existing wells. A sand-cemented slurry with 3% bentonite mix will then be <br /> tremmied into the well, forming a barrier to the vertical movement of water. <br /> For theP rotection of the seal and to facilitate the future use of the <br /> land, an approximately three foot square hole will be excavated around the <br /> outside of the well casing to a depth of three feet below the ground surface. <br /> During the sealing operation, the sand-cement slurry used to fill the well will <br /> be allowed to spill over into the excavation to form an approximate 2-foot <br /> diameter cap. After the sealing operation when sealing material has set, the <br /> excavation will be backfilled with soil and surface pavement repaired. <br /> PROPOSED PROJECT SCHEDULE <br /> Dames & Moore is prepared to begin this study upon receipt of approval of <br /> the proposed workplan from the local Health or Advisory agency,, or local OR <br /> State Water District (RWQCB) as required. It is estimated that the proposed <br /> scope of services will require approximately one week to complete. This schedule <br /> is dependent on the time .necessary for regulatory agency review; permitting and <br /> scheduling of drilling equipment destruction. We will arrange our visit to the <br /> site for the field portion of the destruction through your office. <br /> -000- <br /> I <br /> DAMES SL MOORE <br />