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Kathy Welt and Christine Johnston <br />March 7, 1997 (DRAFT) <br />Page l6 <br />100 gpm across approximately 9,000 lineaz feet, or approximately 0.01 gpm per foot of length. As <br />described previously, roughly three-quarters of the water stored in the existing or proposed sumps <br />will not enter into the North Fork; instead, it will pass beneath the river in a direction assumed to be <br />similar to its historic path (Figure 2). WWE has estimated [ha[ one-quarter of the groundwater <br />outflow (25 gpm) will reach the North Fork. During routine monitoring, MCC will note any new <br />springs and seeps along this potential flow path. <br />Because of the non-uniformity of fault systems, it is difficult to assess the source and ultimate <br />destination of this groundwater. The direction of flow in these faults is still unclear. The 80°F to <br />85°F temperature of the groundwater may indicate the water has either been at a depth of 3,000 feet <br />or more based on a natural geothermal gradient (1°F per 100 feet), or has been in contact with an area <br />having a more exaggerated geotherntal gradient that might be found near igneous intrusives such as <br />those associated with Mount Gunnison. This could also indicate that the water has a deeper source <br />such as 1~actures within the Mancos Shale. <br />Based on the information and observations described above, WWE has reached the following <br />conclusions regarding the groundwater quantity PHCs of the fault inflows: <br />1. The tritium isotope analysis and the oxygen and hydrogen isotope ratio analysis all indicate that <br />the water has been in the ground for an extended period of time (i.e., as long as 1,000 years or <br />more). This, combined with the 80°F to 85°F temperature of the water, indicates that the source <br />of this water is not local. <br />2. The hydrostatic pressure on the system, as evidenced by the observation of flows emanating <br />from the floor, is the result of a rechazge source that is higher in elevation than the floor of the B- <br />Seam at this location. Given the discussion above, this recharge source is believed to be more <br />regional than local. Therefore, the interception of the B East Mains fault groundwater within the <br />mine is considerably different than any previous experience with the water resources of the <br />Mesaverde Formation, including the underlying Rollins Sandstone. <br />3. The flow into the mine is fracture/fault controlled. The initial high inflow and subsequent <br />decrease in flow is typical offracture-controlled reservoirs as observed in the oil industry. <br />4. To date, MCC knows of no injury to existing water users or water resources. MCC knows of no <br />known regional reliance on wells which have produced groundwater of such temperature or <br />flows. In fact, as of the time of this memorandum, these fault inflows have been appropriated by <br />MCC. <br />5. These conclusions do not include a technical evaluation of the 1 SE Headgate fault; however, <br />based on the limited initial data collected on that fault, it appears that these conclusions will <br />remain valid. <br />6. The groundwater outflow rate from the sumps ot~ not more than 100 gpnr when they are tilled to <br />the seals is insignificant. <br />WWE has briefly evaluated the significance of the NW Panel sealed swnp in terms of the <br />downgradient Bear No. 3 Mine B-Seam workings. Calculations indicate that it would take almost 2.5 <br />