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J Additional Vapor and '.undwater Monitoring Well Work Plan �.i Raymond investment Corporation August 4,2009 Page 5 Underground Service Alert (USA) will be notified at least 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 of 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 included in Appendix B. 4.2 MONITORING WELL INSTALLATION FIELD PROCEDURES 4.2.1 Groundwater Monitoring Well Installation Procedures Seven 2-inch diameter monitoring wells will be installed. The monitoring well borings will be drilled using an 8_-iinch'O.D. contin ouus-flight hollow-stem auger. Drilling activities will be performed under the supervision of a Condor geologist in accordance with the 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 in polyethylene bags and checked with a photoionization detector (PID.) for the presence of volatile hydrocarbons. Geologic logs_ will be prepared containing field observations,inccluding_soil type, PID measurements, and the presence of sta r g.orodor. Soil samples will be collected from the borings for laboratory analyses based on field -observations_and.PID measurements. Soil samples will be collected from selected borings and intervals for laboratory analyses,N The soil cuttings will be`placed in 55-gallon drums, sealed, labeled, and left on Site'to'awaiffdisposal— 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,557. gallon drums, sealed, labeled, and left on Site. Disposal of hazardous materials, if any, will be the responsibility of the property owner. S, Monitoring well borings for MW-6 through MW-10 will be dri fled to depths of approximately 45 feet bgs, and monitoring well borings for MW-41�and MW-5;w"i'l1 be drilled to depths of approximately 75 wy feet bgs and 45"'feet bgs, respectively. It is anticipated that groundwater will be first encountered at � , approximately 31 feet bgs.Condor recommends a_screened interval from 30 to 45 eet ecause the depth f f to water (DTW) was 37 feet in November 2004 and the average DTW since 2004 is 36.6 feet bgs. The i��%-ed'hl k/,c i� monitoring wells will be constructed with 15 feet of 2-inch O.D., Schedule 40, flush-threaded, machine- slotted PVC screen (0.010-inch slot size). The screen will extend from a depth of approximately 14 feet. !, below the water table to 1 foot above the water table. Condor recommends.the ruse;of,three casing stabilizers on the angled:monitoring well.MW-5.�A flush-threaded PVC bottom.cap will be piaced at bottom of`the,screen,section in.the well. Blank PVC casing will be installed above the Greens to the~ ground.-surface. A filter pack of #2112 Monterey sand will be placed in the annular space to approximately two feet above the,screenV s 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, approximate ly.five_i 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 behydrated using potable water. A urfac eal of neat cement will be tremied into the annulus of the well and will extend from the bentonite to the ground surface. A generalized shallow monitoring well construction diagram is included as Figure 4, Appendix A. ,r il� CONDOR