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SUNDAY MINE COMPLEX-HYDROGEOLOGIC REPORT <br /> Underlying the D aquifer is the M aquifer which consists of the Morrison Formation, primarily the <br /> units of the Salt Wash Member. The M aquifer is confined above by the very low permeability of <br /> the Brushy Basin Member and below by the Summerville Formation (Avery, 1986). Regionally, <br /> the M aquifer is not commonly used for domestic water supplies, because of its relatively <br /> greater depth, lower yield, and poor water quality. Jobin (Fig. 32, 1962) indicates that <br /> sandstones of the Morrison Formation in the vicinity of the SMC have a permeability of 0.115 <br /> Darcy's (1.106 x 1e centimeters per second [cm/s] or 0.31 feet per day [ft/d]). <br /> The N aquifer underlies the M aquifer and consists of the Wingate Sandstone, the Kayenta <br /> Formation, the Navajo Sandstone, the Carmel Formation, and the Entrada Sandstone, all of <br /> Jurassic age. The N aquifer is confined above by the Summerville Formation and below by the <br /> Chinle and Moenkopi Formations (the Moenkopi Formation is not present in the area of the <br /> SMC). The N aquifer is exposed to the east and west of the SMC area, but is buried under <br /> approximately 1,000 feet of late Jurassic and Cretaceous sediments in the area under the mines <br /> and in Disappointment Valley. The N aquifer is commonly used as groundwater supply in the <br /> region when depth and water quality are suitable for development. <br /> Groundwater Data <br /> Specific data obtained from literature or acquired and evaluated for this study included: <br /> • Monitoring well groundwater elevation and water chemistry data acquired for a total of 9 <br /> sampling events, seven of which included contemporaneous sampling of all surface <br /> monitoring wells. <br /> • Vent shaft water level elevations for two events <br /> • Underground water chemistry sampling for two events <br /> • Underground water chemistry data from three subhorizontal wells (CDM and Denison, <br /> 2012) <br /> • Underground water level observations of flooded workings (CDM and Denison, 2012) <br /> • Groundwater information reported from a 2009 drill hole program (CDM and Denison, <br /> 2012) <br /> The study of groundwater at the SMC formally began in 2009 when Denison Mines (USA) Corp. <br /> (Denison) collected underground water samples and installed four subhorizontal monitoring <br /> wells inside the workings in the West Sunday Mine. These were installed to evaluate ambient <br /> Western Water& Land, Inc. ix <br />