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Mr. Dustin Czapla <br />Page 4 of 8 <br />Tertiary age volcanic rocks to the west and south. The eastern Precambrian -Paleozoic <br />contact is a high -angle reverse fault called the Chester Fault. This fault formed during <br />the Mesozoic and was subsequently mineralized. The surrounding rocks were altered <br />by hydrothermal solutions, which emplaced uranium throughout the fault zone. Uranium <br />minerals (e.g., pitchblende and coffinite) and iron sulfides (e.g., pyrite and marcasite) fill <br />the matrix of ore -bearing sedimentary rocks along the Chester Fault and within the <br />Precambrian rocks to the east. <br />The hydrogeology of the Pitch Reclamation Project is characterized by two primary <br />aquifers, which include a thin alluvial aquifer and an underlying bedrock aquifer. <br />Generally, overlying alluvium and waste rock emplaced during mining activities is <br />unsaturated except in drainage channels where the aquifer receives recharge from both <br />meteoric water and locally from bedrock aquifer discharge. The underlying bedrock <br />aquifer is unconfined and bisected by the Chester Fault which tends to impede <br />groundwater movement across its boundary. Most groundwater recharge occurs in the <br />spring when the snowpack begins to melt. <br />The underground mine workings, constructed in the Chester Fault zone, are a primary <br />source of uranium to groundwater and surface water resulting from oxidative dissolution <br />of uranium and sulfide minerals in the wall rock. The Pitch Reclamation Project surface <br />water and groundwater is calcium carbonate4ype with neutral to alkaline pH (average <br />pH 7.0 to 8.2), which promotes formation of mobile aqueous phase calcium -uranyl <br />carbonate aqueous complexes. Addition of phosphate will result in precipitation and <br />settling of highly insoluble uranyl phosphate minerals and other phosphate phases such <br />as calcium phosphate. <br />The Pinnacle adit, plugged in 1995, resulted in partial re -saturation of the underground <br />mine workings. Based on the available data collected since 1997, the water level in the <br />workings has essentially reached steady state. Monitoring of the bedrock aquifer <br />potentiometric surface in and around the underground mine workings shows seasonal <br />fluctuations that average between 16 to 17 feet (ft) since 2004, with the highest water <br />levels in late May or early June corresponding with snowmelt (Figure 4). Since 2004, <br />the average depth to water in the underground mine workings since 2004 ranges from <br />209 to 225 ft below ground surface (ft bgs) in the P-4 piezometer, and 153 to 170 ft bgs <br />in P-5. <br />Groundwater discharges from the underground mine workings to the North Pit Lake <br />' through seeps and springs along Chester Fault that reside between the underground <br />workings and the North Pit Lake and exhibit chemistry similar to underground mine <br />workings groundwater. <br />460 west 50 North, suite 500, salt Lake City. Utah 84101 TEL(WI)9W-37,0 <br />