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Site investigation Work Plan-Second Revision Raymond investment Cotpoation Fanner Helena Chemical Facility Page 9 analytes requested for this assessment. QA/QC sample locations, depth of sampling, container type, labeling, preservation method, analytes, and analysis methods is included in the Helena Chemical- Sampling and Analysis Plan Summary Table,Appendix C. 7.0 PROPOSED MONITORING WELL LOCATIONS AND SAMPLE INTERVALS A total of three (3) groundwater monitoring wells are proposed. The primary purpose of the monitoring wells will be to verify the Site groundwater gradient. GeoTracker data for nearby sites indicate that the local groundwater gradient direction is to the east (Table B, Appendix B). The proposed locations of the monitoring wells are shown on Figure 2,Appendix A. Monitoring wells will be constructed with a screen interval of five to twenty-five feet from the surface. Soil samples will be collected from the soil borings made for the installation of each monitoring well at a depth of approximately 15 feet below the surface. The least disturbed, or most intact, of those soil samples will be tested to determine the permeability of Site soils and the other two will be disposed of in drums with other soil cuttings. 8.0 BORINGS AND WELL INSTALLATION FIELD PROCEDURES 8.1 MONITORING WELL INSTALLATION FIELD PROCEDURES Three two-inch diameter monitoring wells will be installed. The monitoring well borings will be drilled using an eight-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 SJCEHD permits.The soil samples will be logged according to the Unified Soil Classification System(USCS).Geologic logs will be prepared containing field observations including soil type and the presence of staining or odor. Soil samples will be collected from the borings for laboratory analyses based on field observations and planned collection depths for the permeability testing described in Section 7.0. 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 will be collected from the drill cuttings for the purpose of characterizing the cuttings for disposal. Characterization samples will be analyzed for BTEX, TPH-G, and LUFT 5 metals. All down-hole drilling equipment will be steam-cleaned prior to use at each location. 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. Monitoring well borings for MW-1 through MW-3 will be drilled to depths of approximately twenty-five feet bgs. It is anticipated that groundwater will be first encountered at approximately ten feet bgs. The groundwater monitoring wells will include a screened interval between five and twenty-five feet. The monitoring wells will be constructed with 20 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 fifteen feet below the water table to five feet above the water table. 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. A filter pack of#2/12 Monterey sand will be placed in the annular 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 two 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 poured from the surface 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 log, including +.1� CONDOR