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3.0 Field and Laboratory Procedures This section provides a summary of the field and laboratory procedures used during the study conducted by Dames & Moore A detailed description of sampling procedures is included in the September 1998 Work Plan (Dames & Moore, 1998a) 3 1 Monitoring Well Installation Two two-inch diameter groundwater monitoring wells were installed in borings drilled at the locations shown on Figure 2 The wells were installed at the centers of two previously documented zones of soil contamination The well locations correspond with the former locations of two underground storage tanks (USTs) which were removed in 1988 The wells were installed on December 14 and 15, 1998 by Western Strata Exploration, under the supervision of a Dames & Moore geologist Well DMW-6 was completed to a final depth of 52 5 feet below ground surface (bgs), and well DMW-7 was completed to a final depth of 65 feet bgs The boreholes were drilled using an 8-inch diameter hollow stem auger The geology was logged at 5-foot intervals using a split spoon sampler Monitoring wells were completed with flush threaded, 2-inch inner diameter schedule 40 PVC casing and well screen Well DMW-6 has a 20 foot screened section, and well DMW- • 7 has a 35 foot screened section The screened intervals are filtered packed with pre- washed filter sand extending from total depth to two feet above the screened section Well screens consist of 0 020-inch slotted schedule 40 PVC A 2-foot thick bentonite seal was placed on top of the filter pack The remaining annulus was grouted with an approximately 3% bentonite/cement mixture Each of the wells was completed with a steel street cap The wells were developed on December 18, 1998, more than 48 hours after installation Well development proceeded using a combination of surging and bailing The well elevations and locations were surveyed by Morrow Surveying on December 18, 1998 Well construction diagrams and geologic logs are attached in Appendix C Additional well construction data for new and existing wells at the Site is presented in Table 1 Soil cuttings generated during drilling operations were placed in labeled drums A total of eight drums were filled and labeled Soil samples were sampled to assess appropriate disposal methods The soil will be disposed and documented in accordance with applicable regulations Decontamination rinsate and purge water generated during development and sampling of the monitoring wells was containerized and stored on-site in labeled steel drums A total of 3 IIDM_SAC1\SYS1013\AWREPORT\1 grpt doc