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1 <br /> ' TreadweIERWND <br /> ' 3.4 Area 3 <br /> 3.4.1 Geophysical Survey <br /> On 18 August 1999,NORCAL conducted a geophysical survey at Area 3. The investigation <br /> area is shown in Figure 1 and 3 of the NORCAL report. The geophysical survey was performed <br /> using the VMG and TC methods. NORCAL measured points across the area in ten-foot spacing <br /> tand slowly covered the ground with the instrumentation. Results of the VMG survey indicated <br /> seven anomalies were present. <br /> 3.4.2 Soil and Grab Groundwater Sampling <br /> 1 On 15 September 1999, Precision used a backhoe to dig exploratory pits at the geophysical <br /> ' anomalies. Test pits 3TP-1 through 3TP-4 were excavated to ten feet. Soil samples were <br /> collected at the depths shown on the test pit logs in Appendix C and at the locations shown on <br /> Figure 6. <br /> ' On 17 September 1999, Precision used the SD-1 direct push rig to collect soil and groundwater <br /> samples. Soil borings 3B-1 and 3B-2 were pushed to a depth of 34 and 32 feet, respectively, and <br /> groundwater samples were collected. Soil samples were collected at the depths shown on the <br /> boring logs in Appendix C and at the locations shown on Figure 6. <br /> 3.4.3 Groundwater Monitoring Well Development and Sampling <br /> On 12 October 1999, THF installed a monitoring well under the direction of Treadwell & Rollo. <br /> Boring 3MW-1 was drilled to a depth of approximately 30 feet. Soil samples were collected at <br /> ' the depths shown on the boring log in Appendix C and the location is shown in Figure 6. <br /> tOn 12 October 1999, Blaine Tech developed monitoring well 3MW-1 by using a surge block and <br /> purging the groundwater with a submersible pump. Following the purging, groundwater samples <br /> ' were collected from the well using a disposable bailer. <br /> 11 <br /> 25970119.DGD 13 December 1999 <br />