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05 August 2021 <br />Project No. 02-0926 <br />Page 2 of 2 <br />Joaquin County Environmental Health Department (EHD); additionally, the EHD will be <br />notified a minimum of 48-hours prior to commencement of well destruction activities. <br /> <br />Prior to well destruction activities, all wells will be checked for total depth and well integrity <br />using a Solinst water level meter. Any obstructions found in the wells will be removed. <br /> <br />AGI proposes to destroy wells MW-3, MW-4, MW-7, MW-8, MW-9, and MW-10 by over <br />drilling. The wells will be drilled-out to total depths of 50 feet bsg (MW-3 and MW-4) and <br />55 feet bsg (MW-7 through MW-10) utilizing a hollow-stem auger drill rig equipped with <br />8-inch diameter augers. All original well construction materials will be removed (including <br />well casing, screen, filter pack, and annular seal) by the drill rig to ensure that no residual <br />contamination is sealed within the abandoned borehole and a vertical conduit does not <br />remain. The boring will be completely backfilled to surface grade with a cement grout <br />mixture (Portland type II) and finished at the surface with native soil or concrete to match <br />the existing surface. The grout mixture will consist of a ratio of not more than six gallons <br />of water for every 94-pound sack of Portland type II cement. The drill rig hollow stem <br />augers will be utilized as a tremie pipe during deployment of the grout mixture. Any <br />groundwater displaced by the grout mixture will be routed into properly labeled <br />Department of Transportation (DOT)-approved 55-gallon drums. All investigation derived <br />waste will be containerized in properly labeled DOT-approved 55-gallon drums and <br />disposed as a non-hazardous waste. <br /> <br /> <br />3.0. REPORTING <br /> <br />Upon completion of field work and disposal of waste, a well destruction report describing <br />the activities and procedures, including documentation of waste disposal, will be <br />prepared, and submitted to the SJCEHD. The report will be in a format acceptable to the <br />SJEHD and will be reviewed and signed by a California Professional Geologist. <br /> <br /> <br />Sincerely, <br /> <br />AdvancedGeo, Inc. <br /> <br /> <br /> <br />______________________________ ___________________________ <br />Evan J. Schmidt Daniel J. Villanueva <br />Staff Geologist Senior Geologist <br /> <br />