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Mr.Brendan Kenney, CVRWQCB April 26,2013 Groundwater Monitoring Well Destruction Plan—Diamond Pet&Ripon Cogen Page 3 of 3 WELL ABANDONMENT METHOD Per section 6.3.7 of the San Joaquin County Well Standards: "a hole at least one foot larger in diameter than the originally drilled hole shall be excavated around the outside of the well casing to a depth not less than three feet below the ground surface. The well casing shall then be cut off six inches above the bottom of this excavation and removed. During the sealing operation,the grout used to fill the well shall be allowed to spill over into the excavation and fill for a thickness of one foot and form a cap which has a diameter of at least one foot greater than the diameter of the originally drilled hole. This procedure should result in the exposed edge of the casing being covered with six inches of grout. After the sealing operation and the sealing material have set,the excavation will be backfilled with clean native soil." L&A proposes using the pressure grouting method to abandoned monitoring wells. The pressure-grouting method consists of pumping a thin, cement-bentonite slurry into a well at a pressure of 100 pounds per square inch(psi). The slurry fills the well casing and then is forced out through the well's slotted screen interval, filling the void spaces in the sand filter pack around the casing, and out into the native formation. This effectively eliminates a well as a potential migration pathway for contaminants to reach groundwater. REPORTING L&A will prepare a well destruction report that describes the methods used to abandon each well and includes copies of the well abandonment permits issued by San Joaquin County. The report will be signed and stamped by a licensed geologist or engineer licensed n the State of California. The report will be submitted on or before it's December 30, 2013,deadline. Please do not hesitate to contact me at (530) 275-4800 or dkirk(a_),lwrnc.com if you have any questions regarding this work plan. Sincerely, ONAL GEO` Y �iT quo DAVID L. a G� KIRK David L. Kirk P 11 130//3 Principal Geologist, P.G. 6673, CHG 857 �+� NO. 6673 9�F OF CAL�FO�� cc: Mr.Mark Schell,Diamond Pet Mr.Mike Owens,Diamond Pet Mr.Jim Hinrichs,Ripon Cogen Mr.Kevin Warner,P.E.,City of Ripon Ms.Margaret Lagorio, San Joaquin County Public Health Services,Environmental Health Division Mr.Binayak Acharya,Environmental Cost Management 010107.05 Lawrence&Associates w:(clients kliamond pet foodslmonitoring well abandonment 20134work planlgroundwater monitoring well destruction plan.docx