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SUNDAY MINE COMPLEX-HYDROGEOLOGIC REPORT <br /> of the N aquifer unit. These geologic units are not encountered in the mine workings and <br /> Formations are buried at depth under Disappointment Valley (see Table 7-1). <br /> Being on the northeast limb of the Disappointment syncline (or southwest limb of the Gypsum <br /> Valley anticline), the above referenced geologic units dip approximately 20° to the west- <br /> southwest at the SMC. Block faulting on the flanks of Big Gypsum Valley complicates <br /> stratigraphy and has resulted in abrupt changes in strike and dip of bedding. On the southwest <br /> flank of Big Gypsum Valley, near the SMC portals, the northeast side of the northwest-trending <br /> faults are downthrown resulting in local stratigraphic dip to the northeast or east on the <br /> downthrown sides of faults and southwest dip on the upthrown side of the faults. Generally, <br /> mine declines descend down dip to the southwest at various angles to access uranium and <br /> vanadium ores in the Salt Wash Member. Mine workings are approximately 600 ft below ground <br /> surface at the top of ridge that separates the valleys. CDM has indicated in the 2009 report that <br /> the mine declines intercept one to two faults (CDM, 2009); however, underground descriptions <br /> of these faults were not provided. Interpreted schematic hydrogeologic cross-sections prepared <br /> by Denison that illustrate each mine area are shown in Appendix D. Normal faults along the <br /> edge of the southwest limb of the Gypsum Valley anticline have downfaulted the Salt Wash <br /> Member on the northeast sides of the faults, in some cases juxtaposing Salt Wash with Brushy <br /> Basin or Navajo Sandstone. <br /> 8.2 Groundwater Occurrence at the SMC <br /> Information on groundwater occurrence at the SMC was compiled from information reported by <br /> CDM in 2009 and data obtained by EFR and PRM in subsequent investigations. Denison <br /> mapped the location of flooded workings in February 2009. These 2009 locations are shown in <br /> Figure 8-1 with a black dashed line and include the southern-most extent of the Topaz Mine and <br /> the lower portions of the West Sunday and Sunday Mine workings. These groundwater <br /> occurrences are in the mined workings within the "Top Rim Sandstone" (a.k.a. Upper Rim <br /> Sandstone) unit of the Salt Wash Member. As shown on Figure 8-1, more recent monitoring <br /> indicates that the water levels have risen and now encompass more of the southern-most <br /> underground workings. <br /> There are few sources of information that specify details on how water is entering the mine <br /> workings. It is assumed that groundwater seeps into the workings from saturated zones of the <br /> Top Rim Sandstone and other water-bearing zones of the Salt Wash Member. The following <br /> Western Water& Land, Inc. 22 <br />