2012-10-01_REVISION - M1977305 (16)

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complete, evaporation, coupled with evapotranspiration losses associated with plant growth, will limit infiltration and fugitive dust. (7) Facilities Evaluation 7.1 Containment Measures A Drainage Design Plan has been developed for this site. The goal of this Drainage Design Plan is to route runon from offsite areas around the mining area and prohibit runoff from leaving the site during design storm events. See Appendix III - Drainage Design Plan for a full discussion of containment and diversion measures including maps. 7.2 Environmental Protection Evaluation 7.2.1 Radiometric Survey Cotter will conduct a site radiation survey prior to mining in order to establish a baseline of current conditions. The survey will be conducted on a maximum 50 foot by 50 foot grid. (8) Groundwater Information This section of the permit discusses the potential for environmental exposure of uranium - related constituents by the transport of groundwater. To evaluate this potential, the site geology, hydrology, geochemistry of the deposits, and possible groundwater migration pathways are discussed. 8.1 Area Geology The LP -21 mine site (see Figure U1) is located on the northeastern flank of the Paradox Valley anticline. Geologic units in the mine area steeply dip to the northeast at approximately 0.07 (ft/ft) toward the San Miguel River Valley. According to Cater et al. (1955), most of the geologic units of interest thin as they approach the flanks of the Paradox Valley anticline. Remnants of the Burro Canyon Formation form highlands to the north and directly adjacent to the site. Directly underlying the Burro Canyon Formation is the Brushy Basin Member of the Morrison - the location of the mine portal. This geologic unit is comprised of mostly bentonitic shale but contains some sandstone and conglomeritic lenses (Cater et al., 1955). This unit's stratigraphy plays an important role in understanding groundwater transport in this region. Bentonite is classified as a montmorillonite clay mineral formed by the weathering of volcanic ash deposited during the Jurassic Period and characterized by a three layer crystal lattice that exhibits significant swelling on wetting. These types of shales are not only extremely impermeable to water movement but also exhibit high cation exchange capacities that adsorb and prevent the migration of dissolved constituents related to uranium deposits. These same bentonitic shales are found in the Salt Wash Member and restrict the downward movement of dissolved minerals. O'Connor Design Group Inc. U - 8