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I ' 30 September 2005 • AGE-NC Project No 97-0333 ' Page 2 of 6 ' 28 September 2005 - Elevation, latitude and longitude survey of wells MW-13 through MW-15 ' 2.0. DRILLING PROCEDURES ' Between 05 July and 15 July 2005, multi-level ground water monitoring wells MW-13 through MW-15 were installed at the site Soil borings for MW-13 through MW-15 were advanced vertically to maximum depths of 150 feet bsg utilizing a RotaSomc, truck-mounted sonic drill ng equipped ' with 6-inch diameter hollow-stem rods (core barrel assembly), drilling services were provided by Resonant Sonic International Sonic drill techniques were utilized in bonng advancement by utilizing I a hydraulically powered drill head (oscillator) to vibrate the entire core barrel drill assembly at a frequency range between 50 and 150 cycles per second During sonic drill advancement,water was infected through the drill casings to the bottom of the core barrel assembly to(1) soften soil for dnlI I penetration and (2) displace sediment, thereafter, water and/or sediment was displaced upward between the borehole annular space and the outside of the drill casing to the surface, and containerized All displaced soil cuttings(approximately 5 cubic yards)generated during sonic drill ' activities were stockpiled in and covered in one, 20 yard soil bin located in the west section of the site, all displaced water was containerized in 1,000-gallon poly tanks located in the west section of the site ISoil boring/monitoring well locations are depicted in Figure 2 Ground water monitoring well installation procedures for the site were outlined in Work Plan Addendum-December 2004 (dated I 31 December 2004),and Revision to Work Plan Addendum(dated 16 March 2005)prepared by AGE and approved by San Joaquin County Environmental Health Department(SJCEHD) by letter dated 22 March 2005 (Appendix A) I 21 SAMPLING No soil sampling activities were perforined during drilling for wells MW-13 through MW-15, however, on 29 July 2005, a representative of AGE collected one soil sample from stockpiled soil containerized in the above referenced 20 yard soil bin utilizing a stainless steel slide hammer loaded with a brass sleeve The stockpiled soil sample was preserved by covering both ends of the brass I sleeve with Teflon sheets and plastic end caps and sealed with duct tape The preserved sample was labeled with a sample designation, time, date and sampler's initials ' The preserved sample was logged on a chain-of-custody form, placed in a chilled container and transported to a California Department of Health Services (DHS)-certified laboratory for analysis • for Advanced CeoEavnronmental,Inc I