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4 a t Revised Additional Vapor and Groundwater Monitoring Weft Work Plan Raymond Investment Corporation October 30,2009 Page 5 borings made for the installation of monitoring wells MW-7, MW-8, and MW-9 because sorbed phase _ soil contamination is considered to be improbable fat such a great distance from the source area. The monitoring well locations are approximately 130 feet down gradient of MW-4 and are positioned outside of the building due to structural considerations including interior walls and a basement with very limited )(_ access. The proposed borings and well locations are shown on Figure 3, Appendix A 4.0 BORING AND WELL INSTALLATION FIELD PROCEDURES 4.1 SITE PREPARATION Condor will prepare street and/or sidewalk closure, easement, and monitoring well installation permit applications for submittal to the SJCEHD and City of Stockton. Condor will receive the permits prior to initiating any fieldwork. The proposed monitoring well locations will be marked with white paint and Underground Service Alert (USA) will be notified atileast 48 hours in advance of the fieldwork to locate and identify underground utilities in and near the work area. However, because companies contacted by USA may not identify utilities past private property lines and into the Site, it is the responsibility of the property owner to identify any Site utilities. Prior to initiating fieldwork at the Site, all field personnel will familiarize themselves with the Site-Specific Health and Safety Plan (HASP). In addition, a tailgate safety meeting will be held prior to commencement hof fieldwork. The HASP pertains to field activities and includes 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 r S included in Appendix B. ,��/ j0411 `l `t[ � 4.2 MONITORING WELL INSTALLATION FIELD P OCEDURES " �` 4.2.1 Groundwater Monitoring Well Installation)Proce` dares Six 2-inch diameter monitoring wells will be installe'c. The monitoring well borings will be drilled using an 8-inch O.D. continuous-flight hollow-stem/al�iger. Drilling activities will be performed under the supervision of a Condor geologist in accordande with`he provisions of the SJCEHD and City of Stockton permits. The soil samples will be logged according to the Unified Soil Classification System (USCS). Portions of the soil samples will be placed I p lyethylene bags and checked with,a,.photoionization detector (PID) for the presence of volatile hydrocarbons. Geologic logs will be prepared containing field observations including soil type, PID measurements,hand the presence of staining or odor. Soil samples will be collected from the borings for laboratory analyses based_on„field .observations ,and PID y measurements,Soil samples will be collected from selected borings and intervals for.laboratory analyses. The soil cuttings will be placed in 55-gallon drums,i sealed, labeled, and 161 on Site to await disposal pending results of the laboratory analyses Soil samples will be collected from the drill cuttings 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. Disposal of hazardous materials, if any, will be the responsibility of the property owner. _ �p Monitoring well borings for MW-5 through MW-9 will be drilled to depths of approximately 45 feet bgs, f and the monitoring well boring for MW-4D and w`ll be drilled to approxi rn 4ely 70 feet bgs.It is anticipated that groundwater will be first encountered at approximately 31 feet bgs.—The shallow groundwater monitoring wells will include a screened interval between 25 and 5 feet, and the screened interval for the deep groundwater monitoring well (MW-4D) will extend- om 60 to 70 feet bgs. The L shallow monitoring wells will be constructed with 20 feet of 2-inch O.D., ScheduTe 0, flush-threaded, machine-slotted PVC screen (0.010-inch slot size). The screen will extend from a depth of approximately 1 I � « CONDOR