SITE INFORMATION AND CORRESPONDENCE

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San Joaquin County Environmental Health Department DIRECTOR Donna Heran, REHS 2' =i 600 East Main Street N '{ Stockton California 95202-3029 PROGRAM COORDINATORS ' Robert McClell on, REHS �. Jeff Carruesco, REHS, RDI ..p.•�i�P Website: www.sjgov.org/ehd Kasey Foley, REHS 4.!F R Linda Turkatte, REHS Phone: (209) 468-3420 Fax: (209) 464-0138 December 7, 2011 Paul Verma City of Tracy 325 Civic Center Drive Tracy, CA 95376 Subject: Boyd Service Center 560 Tracy Boulevard Tracy, CA 95376 The San Joaquin County Environmental Health Department (EHD) has received a No Further Action Required Concurrence letter from the Central Valley Regional Water Quality Control Board (CVRWQCB) dated December 2, 2011 for the above subject site. It is now necessary to plan the destruction of all wells installed as part of your site investigation and remedial action, as the EHD will not issue a Case Closure Letter for this site until the wells have been properly destroyed and all onsite waste material have been removed and properly disposed of. The wells are to be destroyed within 90 days of the date of this letter. Please submit a work plan that details the conditions and construction of the wells and the methods and materials to be used to destroy them. To be issued a well destruction permit the proposal must comply with the San Joaquin County Well Standards requirements, including: • Wells that have laboratory data from the last sampling event that demonstrate the presence of any contaminants of concern are to be destroyed by removing all the contents of the original borehole (conductor casing, well casing, screen, filter pack, grout sealant); the cleared borehole is then to be sealed with neat cement by grouting from the bottom up via tremmie pipe to a depth of three feet below grade. • All wells with unknown construction and/or located in an area of known contamination are to be destroyed by removing all the contents of the original borehole as described above; the cleared borehole is then to be sealed with neat cement by grouting from the bottom up to a depth of three feet below grade. • Wells that have laboratory data from the last sampling event that report non-detectable concentrations of contaminants of concern, with acceptable laboratory detection limits, may be destroyed by pressure grouting with neat cement, applied from the bottom up via tremmie pipe, while leaving the well casing in place. Following that, a hole at least one foot larger in diameter than the originally drilled borehole shall be excavated around the outside of the well casing to a depth of 3 feet below grade, and the well casing shall then be cut off 6 inches above the bottom of this excavation and removed. The grout used to seal the well shall then be topped off and allowed to spill over into the excavation and fill it for a thickness of one foot to form a `mushroom cap' over the top of the cut casing.