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•d MONITORING WELL DESTRUCTION REPORT University Park 600 1252 North Stanislaus Street Stockton, CA 95202 Yd 1.0 INTRODUCTION This report was prepared by Condor Earth Technologies, Inc. (Condor) to describe the destruction of nine rr groundwater monitoring wells at the Stockton Developmental Center, University Park, 1252 North Stanislaus Street (site) in Stockton, California (Figures 1 and 2, Appendix A). The purpose of the work was to destroy the wells prior to final closure of the site. The work was conducted as described in the bw Well Destruction Work Plan dated September 17, 2013, which was subsequently approved by Harlin Knoll of the San Joaquin County Environmental Health Department (SJCEHD) in his letter dated September 26, 2013. All work conducted by Condor was under the supervision of a California hNi Professional Geologist. 2.0 SITE PREPARATION .r A well destruction permit was obtained from the SJCEHD, Appendix A. Prior to initiating the fieldwork, the well locations were marked with white paint and Underground Service Alert (USA) was notified at least 48 hours in advance of the fieldwork to locate and identify underground utilities in the vicinity of the r„ work area. Prior to commencement of fieldwork, a tailgate safety meeting was held and a site-specific Health and Safety Plan was discussed with, and presented to, all field personnel for their signatures. 3.0 DESTRUCTION OF MONITORING WELLS and On January 8, 9, and 10, 2014, V & W Drilling of Stockton, CA, a California C-57 driller, license number 720904, performed the destruction of the monitoring wells in accordance with State of California wo Department of Water Resources (DWR) and SJCEHD requirements. Each monitoring well casing was sounded for water level and total depth prior to destruction, see field notes, Appendix A. Monitoring wells MW-6 and MW-9 were destroyed by pressure grouting with neat cement while leaving the well rr casing in place. The neat cement was placed into the well casing using a truck-mounted pump, hose, and tremmie pipe to fill the casing from the bottom upward. PVC pipe fittings and pressurized air fittings were then attached to the well casing. Pressurized air from a truck mounted air pump was then applied to the neat cement in the well casing at 25 pounds per square inch (psi) for 5 minutes to drive additional `r cement into the sand pack of the well and surrounding soil formation. For MW-9, a two-foot diameter and three-foot deep section of soil was removed from around the top of the well casing. The top three feet of well casing was removed by overdrilling. Additional neat cement was placed in the well casing and allowed to spill over into the excavated area below where the casing had been cut off and additional cement was added to within one foot of the surface. After the neat cement had been allowed to set for several hours, the remaining hole was backfilled with soil to match existing surface conditions. Approximately seven gallons of groundwater were displaced during grouting activities. rr For MW-6, a two-foot diameter and three-foot deep section of soil was removed from around the top of the well casing. The top five feet of well casing was then unscrewed and removed. The grout seal and .r grout cap were pulled up and removed with the well casing. Neat cement was placed in the well casing and allowed to spill over into the excavated area around the casing, and additional cement was added to the surface. Approximately 1.5 gallons of groundwater were displaced during grouting activities. Clean groundwater from MW-9 and MW-6 were used to mix neat cement. N4� V IL s CONDOR