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AVA C <br /> February 12, 2020 <br /> Page 6 of 6 <br /> maintained at approximately 20 pounds per square inch for at least five minutes. The well vaults <br /> associated with MW8, MW11, MW12, and MW13 will be removed and an area at least 12 inches in <br /> diameter larger than the original borehole will be excavated around the well casing to a depth of three <br /> feet bgs. The well casing will be cut off six inches above the excavation and removed. The upper <br /> portion of the steel conductor casing associated with MW11 will also be cut off six inches above the <br /> excavation and removed. Cement grout will be added to the excavation and brought to grade at <br /> MW11, MW12, and MW13 to form a cap that has a diameter at least 12 inches larger than the <br /> diameter of the original borehole. Because MW8 is located in an agricultural field, soil will be placed <br /> above the top of the cement grout cap and brought up to the level of the existing grade. <br /> The remaining monitoring wells and the four vapor extraction wells will be destroyed by overdrilling <br /> with hollow stem augers and grouting the boreholes to the surface as the augers are removed from <br /> the subsurface. <br /> The two soil vapor wells will be destroyed by removing the well vaults and advancing a hand auger <br /> to a depth of five feet and then filling the borehole with cement grout to the existing grade. <br /> Report Preparation <br /> Upon completion of the well destruction activities, a summary report will be prepared that will include <br /> a description of well destruction field activities associated with the site, including records of waste <br /> disposal. Well Completion/Destruction Reports will be submitted to the Department of Water <br /> Resources by the drilling company. <br /> SCHEDULE <br /> Following approval of this workplan, ATC will submit well destruction permit applications and <br /> associated fees to the SJCEHD. ATC will notify the CRWQCB and the SJCEHD at least five days <br /> prior to commencement of field activities. <br /> If you have questions or comments regarding this project, please contact our office at (209) 579- <br /> 2221. <br /> Respectfully submitted, <br /> ATC Group Services LLC <br /> Todd Hafner, P.G. Jeanne Homsey, P.E. <br /> CA Professional Geologist No. 8090 CA Professional Engineer No. 47410 <br /> Q�ofESS/ON <br /> cc: Mr. Raymond Greer JEAN NE q�F <br /> Mr. Albert Veldstra �� H 9SEY <br /> Mr. Steve Sawyer <br /> 047410 m <br /> Attachments p J�� <br /> CIVIL <br /> TFOF CA►-�F�� <br />