2008-01-15_PERMIT FILE - M2007044 (2)

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7) Ground water monitoring: To monitor potential ground water impacts due to leachate from waste rock piles, it may be necessary to install one or more down gradient monitoring wells. The depth to ground water might be extreme, and if so, the applicant should provide a rationale for why monitoring wells are not needed. The applicant proposes only one down gradient ground water monitoring location (PR SpringJ, and page G-23 states that the PR Spring is not hydraulically connected to the mine workings. If true, then the spring will not be representative of impacts to down gradient ground water due to mining activities. The waste rock piles and other surface facilities will sit on top of clayey subsoils and over 150 feet of low-permeable Brushy Basin mudstone. The closest water-bearing strata to the surface facilities is the sandstone lens intercepted by the decline approximately 2200 feet southwest of the portal at an elevation of about 6,950 feet. The Whirlwind Portal elevation is approximately 7,080 feet. Allowing for a northeast dip of 1.6 degrees, the elevation of the sandstone lens can be projected to be at an elevation of about 6,890 feet at the portal, or 190 feet below the surface (see Figure 3 of Attachment A). Because of the discontinuous nature of the channel sandstones, this water-bearing strata may not even be present below the mine facilities. Energy Fuels believes that the potential for contaminating the underlying water- bearing zone is virtually nil because of the low-permeability and extensive thickness of the intervening mudstones. Mudstones typically have a vertical permeability between 1 x 10"' and 1 x 10"" centimeters per second (cm/s) (Freeze and Cherry, 1979), which is within the permeability range used for many liner systems. It is also worth noting that the water quality of the lower Brushy Basin sandstone lenses is relatively poor. Samples collected in the Whirlwind Decline in May 2007 (refer to Table E-2 in Appendix E of the 112d Application) contained combined radium-226 and 2281evels of 7.4 picoCuries per liter (pCi/L) and uranium concentrations of about 0.1 mg/L. These sampling results are also corroborated by the sampling done at boring BM00-1 by Umetco in the fall of 2000 (see Appendix C of the 112d Application). Although there is no apparent potential for ground water contamination, Energy Fuels will install a monitoring well (Well W-1) at or near the location shown on revised Map C-2 (see Attachment C). This monitoring well is located downgradient of the Whirlwind surface facilities and the bulkhead seal in the decline. The monitoring well will consist of threaded 2-inch polyvinylchloride (PVC) pipe screened in the lower water-bearing zone of the Brushy Basin (approximately 150 feet below ground surface). If the well produces water, it will be sampled for four quarters to establish baseline conditions and annually thereafter. Water level monitoring will be conducted quarterly. Sampling parameters will be the same as proposed for stormwater (see Item 16 below). If the well does not produce sufficient water to sample or is dry, water levels will be recorded for four quarters and quarterly thereafter. If the lower Brushy Basin sandstones are not present, the boring will be abandoned in accordance with state requirements. E:a~er.~~: I,~uc~ls lies«ut•ces C;or~oratit~s~ =14 l,!nic~~~ f3oule~~~t•d, quite fi0t) 7 l_,~al:~~~~o«~i. C:'(:} $0124 Phc~E~c: 3Q3-~7~-2~1~0