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SECTIONTHREE Welllnstallation 1 One extraction well and two monitoring wells were installed along the northeast side of the north access road in the vicinity of the Ute Pazk pump station (Figure 1). The extraction well (HMEX-01) was installed within the deepest part of the alluvial channel, which occurs near the eastern boundazy of the channel. The monitoring wells were installed at distances of 50 feet (HMMW-02) and 100 feet (HMMW-03) from the extraction well along the northeast side of the road. The wells were installed using the SONIC drilling method. The boreholes were advanced to the ' contact between the alluvium and the Troublesome Formation, which was identifieii by transition to afiner-grained matrix. Once the Troublesome Formation was encountered, the inner core barrel was extracted and the well was constructed. Boring logs and well completion diagrams for the three wells aze attached with this memorandum. ' 3.1 SITE HYDROGEOLOGY The Site hydrogeology generally consists of alluvium underlain by the Troublesome Formation, which is underlain by bedrock (Figure 2). The alluvial sediments range in thickness: between 12 ' and 37 feet across the Site, and consist of very dense sands and gravels ranging fronn gravely to very gravely, sandy to very sandy, and clean to silty. The alluvium becomes more lgavely with depth and large cobbles and some boulders were encountered near the base of the alluvial ' channel. The alluvium is typically brown in color. The underlying Troublesome Formation consists of very dense sands and gravels ranging from gravely to very gravely, sandy to very sandy, slightly silty to very silty, and with occasional cobbles. Zones of clean fine stands and ' uniform silts occur within this unit. The material from the Troublesome Formation is typically iron stained and brown to orange in color. The underlying bedrock consists primarily of red siltstone. ' 3.2 EXTRACTION WELL ' The contact between the alluvium and Troublesome Formation was estimated to occur between 40 and 45 feet below ground surface (bgs) at the extraction well site. Therefore, the borehole was terminated at 45 feet. Groundwater was encountered at 12 feet bgs during drilling and rose ' to 11.45 feet bgs within 24 hours after well completion. The extraction well was conswcted of 5-inch diameter SCH 40 PVC casing, and screened from approximately 10 to 39 feet bgs. The screen consisted of 0.060-inch machine slotted casing. This screen slot size was chosen to provide greater open area, which increases well Efficiency and decreases potential for screen plugging due to precipitation of iron oxide. The annular space ' between the screened section and the formation was filled with #6-#9 silica sand filt:r pack Oglebay Norton Industrial Sands. The remainder of the annular space was sealed wrath bentonite chips and cement-bentonite grout. 3.3 MONITORING WELLS t The contact between the alluvium and the Troublesome Formation was estimated to occur between 30 and 35 feet at both monitoring well sites. Therefore, each borehole was terminated at 35 fweet. During drilling, groundwater was encountered at 10 feet bgs at both monitoring well ' ~~` \~5061N1FREIU]MPHD.IECIL~6lKW_HEWEXSON_NLt-FFA1W6_WI.O_PHW_DElINAENSEDTEGII NELP111 DJL11/YM 3.18 PY 3-1 1 Y-vI