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LM LEEDSHILL HERKENHOFF INC September 1990 A photoionization detector was used to field monitor the volatile petroleum hydrocarbon ' vapors emitted from each soil sample. The field instrumentation did not replace the analytical laboratory testing. All samples were obtained under the supervision of a professional engineer A detailed boring log was kept at all times noting soil types encountered, using the Unified Soil Classification System, and noting moisture conditions, location and depth for each sample. Copes of the boring logs are presented in Appendix A. All drill cuttings were containerized in 55-gallon drums with lids, and stored on site ' awaiting the results of the analytical testing. MONITORING WELL INSTALLATIONS Monitoring Well MW6 was installed by LH on August 8, 1990 by deepeningand reaming out S621. Hollow-stem auger techniques were used to install this 4-inch diameter well at the location shown on Figure 1. MW6 was constructed of nominal 4-inch diameter, flush joint, Schedule 40 PVC casing ' to a total depth of approximately 73 feet. The well was constructed with a fifteen foot length of well screen The well screen had a slot size of 0.020-inch and was placed such that it extended above and below the depth at which groundwater was first encountered during drilling operations A uniformly sized sand pack was placed from the bottom of the well to a point approximately 3.5 feet above the top of the highest screen perforation A 3.5 foot bentonite pellet seal was placed above the sand pack, and a cement-grout mixture was placed in the remaining annular space to the ground surface All drilling was conducted dry with no fluids added to the borehole or lubrication to the drilling equipment All drilling equipment was thoroughly cleaned with high-pressure, hot water prior to use, to prevent potential cross-contamination The PVC well casing was capped with a lockable, water-tight seal, within a flush-mounted, water tight cover The drill cuttings were containerized in 55-gallon drums with lids, appropriately labelled and stored on-site to await future disposal based on the result of the analytical testing Well ' construction details are presented in Figure 2. MW6 was developed using a surge block/swabbing technique. Surge block development involves pressurizing and depressurizing the well by moving a 4-inch rubber swab flange up and down within the well, forcing water in and out of the well screens The agitation created by this development method helps to remove fine-grained and/or suspended material from the well After swabbing, twenty-five well volumes of water were bailed from the well for further development. The bailed water was containerized in 55-gallon drums with lids, appropriately labelled, and stored on-site to await disposal based on the results of the analytical testing. I