Laserfiche WebLink
Mountain Coal Company Exhibit 67 <br />West Elk Mine Windy Gap Process <br />Contributions <br />As discussed in the 1994 Annual Hydrology Report, 8.7 acre-feet of water was measured <br />as mine water inflow. The natural mine water inflow is not proportional to the <br />production rate, but is affected by the areal extent mined and the geologic conditions. <br />Therefore, the 1994 data will be used for the entire term of permit. WEM believes that <br />this water is a valid contribution to the upper Colorado River basin because the water <br />would have remained isolated in perched confined aquifers if mining had not occurred. <br />MCC is currently experiencing net increases of water discharged to the N.F. of the <br />Gunnison River of +306 acre-feet (2003 WY). As more information and data have been <br />obtained (since TR-79, April 1997) regarding the mine water balance, Exhibit 67 is very <br />conservative because no depletions have been experienced since 1998. <br />No depletions have been experienced as a result of mining in the Box Canyon Federal <br />Lease COC-56447 (PR08). No depletions are anticipated as a result of mining in either <br />the South of the Divide Federal Lease C-1362 (PR10), the West Flatiron Federal Lease <br />COC-67011 (PR-11) or in the Dry Fork Lease COC-67232 (PR-12). <br />Net Depletion <br />Depletion for the North Fork <br />Return Flow to the North Fork <br />Contributions to the North Fork <br />170.2 acre-feet/year <br />77.3 acre-feet/year <br />8.7 acre-feet/year <br />NET DEPLETION <br />• <br />84.2 acre-feet/year <br />Exhibit 67-3 Revised March 2005 PR11; Rev. January 2006; Rev. March 2006