2012-10-01_REVISION - M1977305 (16)

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concentration) of the initial concentration in the pore water of the waste rock. The uranium plume is contained in the Salt Wash Member of the Morrison Formation. The plume does not enter the Entrada Sandstone. The Summerville Formation provides an additional buffer zone restricting potential contamination from entering the groundwater. The limited well data for the area suggests that the Entrada Sandstone is dry and the Wingate Sandstone is the upper most aquifer. With the low permeability values measured in the Peel Engineering study for the Kayenta Formation that overlies the Wingate Sandstone, there is even less likelihood of uranium mining impacting valuable local groundwater resources. The results of this analysis indicate that conditions are not conducive to the transport of uranium - related constituents to the environment. Geochemistry suggests that mobilization of these constituents is unlikely. There is no indication of a continuous groundwater system that could provide a pathway for these constituents to migrate from the mine into the environment. Transport modeling has shown that vertical migration from the upper Salt Wash sandstone to the upper -most aquifer in the area (Wingate Formation) is highly unlikely due to the lack of water, low permeability of the strata and the sorption of uranium related constituents. 8.7 Proposed Groundwater Monitoring Plan If water is encountered during mining, then the water will be sampled and a chemical analysis performed. If levels of uranium - related constituents are above established regulatory guidelines, then a well will be placed down gradient of the mining area that contains groundwater and monitored according to DRMS regulations. This approach will provide a better chance of encountering groundwater based upon the data gathered by Cotter. (9) Groundwater Quality Data There are no known groundwater wells located within two miles of the affected area. Considering the depth to water, especially to the Wingate Formation, and the low quantities of available water, it is unlikely that the groundwater resources in this area will be developed. Drill holes have shown indications of moisture but not sufficient for collection and analysis. (10) Surface Water There are no perennial streams, rivers, or drainages in the area surrounding the LP -21 mine. The nearest continuously flowing river to the site is the San Miguel River that is located approximately 3 miles from the mine. Surface runoff from the site would eventually flow west into Long Park before entering the drainage adjacent to Horsethief O'Connor Design Group Inc. U - 17