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Well Over-Drilling Procedures A hollow stem auger rig with 10-inch inner diameter augers will be used to overdrill the borehole for the monitoring well.The existing KP-11S well borehole shall be cleaned out and cleared of well construction materials (well casing,screen,filter pack,and annular seal), soil,fly ash,or other debris to a minimum depth of 26 feet below ground surface. Well cuttings and construction materials shall be placed in 55-gallon drums. The well/borehole shall be sounded immediately before and after overdrilling to confirm obstructions that are present are removed prior to filling and sealing. IDW Management Soil cuttings,well construction materials,and PPE will be collected in 55-gallon drums during drilling.PPE and well casing materials will be placed in a separate drum from soil and fly ash removed from the borehole. Drums will be moved by the subcontractor to a location designated by Headwaters Resources that is onsite,but outside of the area of fly ash. Well Abandonment A well destruction permit will be obtained from San Joaquin County prior to drilling. A San Joaquin County grout inspector will be onsite to oversee overdrilling and abandonment.Well destruction and abandonment shall be performed in accordance with San Joaquin County Well Standards,Ordinance Code Section 9-1115.6 (hthi://www.sjgov.org/ehd/docs/pdf/Well%20Standz! is.pdf). The boring shall be destroyed by completely filling the cleared borehole with cement- bentonite grout.The grout shall consist of clean water mixed with Type I or II Portland cement(or equivalent) and bentonite(3 to 5 percent by weight)to help reduce shrinkage. The cement grout shall consist of not more than two (2)parts by weight of sand and one (1) part by weight of cement(per bag of cement)to 5 to 7 gallons of potable water. The well shall be filled by use of a tremie pipe or equivalent.The tremie pipe shall be placed within 5 feet of the bottom of the cleared borehole and removed as the grout is installed. Because soil in the surrounding area is contaminated with fly ash, the grout shall be brought to the existing ground surface,rather than backfilling the borehole with 2 feet of surrounding material. Overdrilling and sealing shall be completed in one day.Verification of the sealing shall be made by a representative of the San Joaquin County Environmental Health Department. Decontamination and Waste Management Al}personnel and equipment will be decontaminated before coming onsite and before leaving the site,as specified in the Site Health and Safety Plan. The subcontractor will be responsible for providing the appropriate decontamination tools,equipment,solutions, liquids,containers,and supplies.Prior to equipment and vehicles being removed from the site,all equipment and vehicles shall be rinsed using potable water,provided by the subcontractor,using a brush as needed to remove particulate matter and surface films. KCPPEL-KPI I SABANDONMENTSOW DOC 2 SOLICITATION NO.