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Section 7 <br />Groundwater Information <br />The Topaz mine decline is also shown on the section. The decline extends toward the <br />south to access mining areas located south of the groundwater divide between <br />Disappointment Valley to the south and Big Gypsum Valley to the north. This <br />orientation is similar to that observed at other Sunday Mines Group where <br />groundwater flow from areas of underground mining is interpreted to be south into <br />Disappointment Valley. <br />7.3 Potentially Water - Bearing Fracture Zones <br />Potentially water - bearing fracture zones range in size from very small -scale features <br />that primarily influence only the permeability of the rock, to large -scale features that <br />extend for miles and could potentially influence groundwater -flow paths. This section <br />focuses on identifying large scale fracture zones associated with the faults mapped by <br />Cater (1955), because these features have a potential to influence groundwater flow at <br />a larger scale. <br />The effect of major fracture zones on groundwater flow is dependent on the <br />rheological characteristics of the displaced rock units. Fault zones within relatively <br />brittle rocks such as massive sandstone are more likely to include zones of closely <br />spaced and interconnected fractures forming a fracture zone. The fracture zones may <br />have a marked influence of hydrogeologic characteristics. Fault zones within shale <br />units such as the bentonite -rich Brushy Basin Member are less likely to influence <br />groundwater, because the shale deforms plastically reducing permeability of the fault <br />zone as compared to the more brittle units (Weir et al. 1983). <br />The interpretive hydrogeologic framework cross - sections presented previously <br />(Figures 7 -6 to 7 -9) provide information regarding the relative permeability of the <br />fault zones. A hatched pattern identifies portions of faults where two shale units are <br />juxtaposed on either side of the fault. These are areas where the fault is less likely to <br />have a major effect on groundwater flow. Fault zones that are not hatched identify <br />areas where significant fracture zones are more likely to be associated with the fault. <br />These are areas where the fault zone would be more likely to affect groundwater flow. <br />7.4 Direction and Rate of Groundwater Flow <br />7.4.1 Area of Underground Workings <br />Although the regional direction of groundwater flow is towards the Dolores River, <br />the direction and rate of groundwater flow in the area of the Sunday Mines Group is <br />perturbed by the presence of the underground mine workings and integral activities <br />associated with mining such as dewatering and ventilation. Available data regarding <br />the rate and direction of groundwater flow in the interconnected Sunday- Carnation- <br />St. Jude -West Sunday mine workings, the Topaz Mine underground workings <br />suggests the following: <br />• The direction of groundwater flow in the vicinity of the West Sunday Mine <br />underground workings is into the mine; <br />C \ Users \cwoodwardeesktop \Sundays \FINAL - Environmental Protection Plan Sunday Mines Revised January 2012 Soon <br />7 -5 <br />