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Mountain Coal Company, LLC <br />Exhibit 67 <br />West Elk Mine Wind?Gap Process <br />General Discussion <br />The following information has been compiled using data that is consistent with a <br />maximum coal production rate of 8.2 million tons per year (TPY) from the West Elk <br />Mine (WEM). Although WEM has not yet reached the maximum coal production level, <br />the following calculations represent the water depletion to the North Fork of the <br />Gunnison River (North Fork) at this maximum production rate. <br />Reviews and updates to the depletion calculations have been considered with each <br />proposal to add or delete mine facilities and/or operations, such as the additional <br />sediment and mine water ponds in the Main Mine site and Sylvester Gulch Facilities <br />areas. MCC's water usage has also been reviewed and updated to account for varying <br />water usages and throughputs in the Water Treatment Plant and Waste Water Treatment <br />Plant (WWTP) due to various operations and construction projects. Even though <br />significant water inflows occurred within the WEM in 1996 and 1997 (2,500+ and <br />8,000+ gpm, respectively) and were pumped out into the North Fork, the contribution of <br />water to the river from these two significant inflow events was not used to influence or <br />update the calculations. Rather, WEM has used moderate percentages of the average <br />actual water volumes from recent and the highest coal production years for its <br />calculations, and as such, the following estimate continues to be very conservative. <br />Depletions from the North Fork by WEM can be attributed to mine uses of stream flow <br />diversions under WEM's existing water rights, as well as evaporative losses from water <br />storage ponds. Return flows to the North Fork from WEM can be attributed to treated <br />water from both the WWTP and water circulated through the mine and/or mine site. <br />Other return flow contributions include treated mine water discharged from non-alluvial <br />and/or non-tributary groundwater inflows from within the WEM. <br />Depletions <br />WEM pumps water from the North Fork for storage in its fresh water storage ponds. <br />Water may also be pumped from the North Fork directly to the water treatment plant, into <br />the mine, and/or into WEM's 1.2 million gallon raw water storage tank. WEM also <br />utilizes water storage rights contained in sedimentation ponds on the WEM site and rights <br />to water produced in the mine. At a production rate of 8,200,000 TPY, WEM's <br />maximum water requirement is estimated at approximately 150 acre-feet per year, and a <br />conservative maximum water requirement is approximately 300 acre-feet per year. <br />In-Mine Dust Suppression <br />Water use for underground dust suppression is estimated at 2% of production <br />tonnage. Based upon an annual coal production of 8,200,000 TPY, approximately <br />120.62 acre-feet of water per year is depleted as a result of dust suppression. This <br />number includes water leaving the mine as added moisture on coal and gob. <br />Exhibit 67-1 Revised 03105- PRI1; 01106- PRI1; 03106- PRI1; 09109- TR118; 09109- TR119