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Lot B Underground Storage Tank—Monitorin94e11 and Additional Delineation Work Plan 216 N.California Street,Stockton,California February 2,2010 Page 4 information on potential hazards expected to be encountered at the Site, personal protective equipment, and directions to and telephone numbers for the nearest hospital. A copy of the HASP is included in L Appendix B. 4.2 MONITORING WELL INSTALLATION FIELD PROCEDURES ` The monitoring well borings will be drilled using an 8-inch O.D. continuous-flight hollow-stem auger. Drilling activities will be performed under the supervision of a Condor geologist in accordance with the provisions of the SJCE) D and City of Stockton permits. The soil samples and drill cuttings will be ` logged according to the Unified Soil Classification System(USCS). Portions of the soil samples will be placed in polyethylene bags and checked with a photo-ionization detector (PID) for the presence of volatile hydrocarbons. Geologic logs will be prepared containing field observations including soil type, ` PID measurements, and the presence of staining or odor. Soil samples will be collected from the borings for laboratory analyses based on field observations and PID measurements. The soil cuttings will be placed in 55-gallon drums, sealed, labeled, and left on Site to await disposal pending results of the laboratory analyses. Soil samples collected from the borings will be used for the purpose of characterizing the cuttings for disposal. All down-hole drilling equipment will be steam-cleaned prior to use. The drill cuttings and steam cleaning effluent will be placed in DOT-approved 55-gallon drums, sealed, labeled, and left on Site pending analytical results. Disposal of hazardous materials, if any, will be conducted by Condor upon acceptance by a permitted landfill or treatment facility. Monitoring well borings will be drilled to a depth of approximately 45 feet bgs. It is anticipated that 61 groundwater will be first encountered at approximately 33 feet bgs. The shallow groundwater monitoring wells will include a screened interval between 20 and 45 feet. The monitoring wells will be constructed with 25 feet of 2-inch O.D., Schedule 40, flush-threaded, machine-slotted PVC screen (0.010-inch slot 60 size). A flush-threaded PVC bottom cap will be placed at the bottom of the screen section in the well. Blank PVC casing will be installed above the screens to the ground surface. Centralizers will be placed at approximately 30 and 40 feet bgs. A filter pack of#2/12 Monterey sand will be placed in the annular b, space to approximately two feet above the screens while the augers are in place. The depth of the sand in the annulus of the well will be monitored with a weighted tape measure while the sand is being placed and the augers are being gradually retracted to avoid bridging. To form a protective seal, approximately `, five feet of bentonite chips will be installed above the sand in the well. The bentonite chips will be installed as the augers are retracted.The bentonite will be hydrated using potable water.A surface seal of neat cement will be tremmied into the annulus of the well and will extend from the bentonite to the ` ground surface. The monitoring wells will be completed with locking caps and traffic boxes installed flush with the ground surface. Details of the well construction will be noted on the geologic logs, including the depth intervals of the screen, sand pack, and seals. Soil sampling and well construction details are included in Table 1 on the next page. A generalized shallow monitoring well construction diagram is included as Figure 6,Appendix A. L L L 6. is CONDOR