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NOA Drywall Closure and Investigation work Plan Page 5 of 16 <br /> March 18, 2014 <br /> Revised March 20, 2014 <br /> 3.0 DRYWELL DESTRUCTION ACTIVITIES <br /> 3.1 Pre-Field Activities <br /> Drywell destruction requires a permit issued by EHD. This work plan, a Master File Record <br /> Information Form, and a Site Mitigation Fee must be completed and submitted to EHD for work <br /> plan review and approval. Once the work plan is reviewed and approved, a Well Destruction <br /> Permit along with an Inspection Activity Fee and Permit Fee will be submitted to EHD to obtain <br /> the appropriate permit prior to destruction activities. EHD will be notified seven (7) days prior to <br /> field activities to schedule well destruction and sampling activities. <br /> S3.2 Destruction Activities <br /> 1 NOA proposes to perform well destruction activities under the direct supervision and oversight <br /> of EHD. <br /> 3.2.1 Well Destruction Methodoloov <br /> ' The two (2) on-site drywells will be destructed by overdrilling. The drywells consist of five (5) <br /> inch diameter casing in an eight (8) inch diameter gravel pack. The wells will be over-drilled <br /> using a hollow stem auger that is eight (8) inches in diameter. Drywell casing extends to forty <br /> (40) feet bgs, the wells extend to approximately fifty (50) feet bgs. Overdrilling will be <br /> performed to at least fifty-five (55) feet bgs to ensure complete well removal. However, soil will <br /> first be sampled at fifty (50) feet bgs, as detailed in the following section. Drill cuttings will be <br /> stored appropriately until proper disposal is determined and executed. All material within the <br /> original borehole will be removed, including the well casing if practicable. The open borehole <br /> will then be grouted. The grout cement will be given sufficient time to settle and set. The <br /> remaining hole will then be sealed with cement. <br /> The contents from the drain will be removed. The drain pipe discharge line will be disconnected <br /> from the wells, pressure washed, filled with grout cement and permanently sealed. <br /> 3.2.2 Waste Disposal <br /> Drill cuttings, decontamination water, drain and well contents will be properly containerized and <br /> stored as necessary during site activities. Disposal methodologies will be contingent upon <br /> analytical results. Laboratory samples will be disposed of by the analytical laboratory in <br /> accordance with their established protocols. All waste will be disposed of in accordance with <br /> federal, state, and local regulations. <br /> 3.2.3 Reoortino <br /> ' Following completion of well destruction activities as described above, NOA will prepare a well <br /> destruction completion report. This report will include the EHD well destruction permits. <br /> 902 Industrial Way•Lodi,CA 95240-209.367.3701•Fax 209.369.4228 02014 Neil O.Anderson&Associates,Inc <br />