WORK PLANS - Laserfiche WebLink

Home Browse Search

monitoring Well Destruction Work Plan Raymond Investment Corporation November 20,2012 Page 3 work area. Prior to commencement of fieldwork, a tailgate safety meeting will be held and a site-specific Health and Safety Plan will be discussed with, and presented to, all field personnel for their signatures. 4.0 DESTRUCTION OF MONITORING WELLS A California C-57 licensed driller will perform the destruction of the monitoring wells in accordance with State of California Department of Water Resources (DWR) and SJCEHD requirements. The SJCEHD well destruction standards require complete over-drilling of wells of unknown construction and/or located in an area of known or suspected contamination. SJCEHD well destruction standards allow for pressure grouting of wells that have laboratory data from the last sampling event that report non-detectable concentrations of contaminants of concern. Condor will obtain a City of Stockton encroachment permit as required for well destruction activities for MW-7. Each monitoring well casing will be sounded for water level and total depth prior to destruction. A Condor Professional Geologist will observe the well destructions. Historic groundwater monitoring data and the Site specific health and safety plan are included in Appendix B. Table 1: Most Recent Groundwater Sample Analytical Results Sample I.D.1 Datd BI Tj El X1 TPH- TEPH-D MWA 11/29/10 <0.5 <0.5 <0.5 <1.0 <5 <5 MW- 11/29/10 <0.5 <0.5 <0.5 <1.0 <5 <50 MW-3 11/29/10 <0.5 <0.5 <0.5 <1.0 <5 <5 MW 5/18/11 32- 7.4 26- 33 - 2,20 - 2,10 MW-4D 5118111 <0.5 <0.5 <0.5 <1.0 <5 <5 MW-5 5/18/11 37 . 1.0 - 0.9- 2.0 51 - 900 MW6 5/18111 <0.5 <0.5 <0.5 <1.0 <5 <50 MW-7 8/1111 <0.5 <0.5 <0.5 <1.0 <5 <5 �. All laboratory analytical results are reported in micrograms per liter(µg/L)=parts per billion(ppb), 1 B,T,E,X=benzene,toluene,ethyl benzene,total xylenes. TPH-G=total petroleum hydrocarbons,quantified as gasoline(G). TEPH-D=total extractable petroleum hydrocarbons,quantified as diesel(D). Condor proposes that MW-4 and MW-5 be destroyed by over-drilling to remove all of the contents of the + well including the well casing, screen, cement, bentonite, and sand. The borehole will then be backfilled with neat cement by pressure grouting from the bottom upward to one foot below grade.with concrete k added to surface grade. The grout will be placed in one continuous operation if possible. Any (U " groundwater displaced to the ground surface will be collected and contained in approved DOT drums, t G � sealed, labeled, and characterized for disposal. Condor proposes that MW-1, MW-2, MW-3R, MW-4D, MW-6, and MW-7 be destroyed by pressure f ,� grouting with neat cement from the bottom upward, while leaving the well casing in place, based on the �! most recent laboratory reported concentration data. The top three feet of the well casing and cement will �y { ' be removed and an additional six inches of ceme twill be removed below the depth where the casing was hU� removed. Additional neat cement will be added ward to one foot below grade with concrete added to ' surface grade. 1 Condor proposes that soil vapor monitoring wells SV--37, SV-4, and SV-5%e destroyed by over-drilling with a 4-inch hand auger. The borehole will then be backfilled with neat cement poured from the surface to within one foot b we olof grade with concrete added to surface grade. i is CONDOR i