2008-03-21_PERMIT FILE - C1980007A (46)

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West Elk Mine water may be used. Although the Minnesota Reservoir can store approximately 500 acrefeet, it is highly unlikely that all of this storage water would be prevented from reaching the reservoir due to the mitigation measures outlined in the permit. The combination of senior direct flow rights and nearly 100 AF of reservoir water should be adequate to prevent injury to downstream irrigators relying on Minnesota Reservoir releases. The Dry Fork basin has a very low yield. In fact, for water administration purposes, the water commissioner does not attribute any water exiting by Dry Fork as native flow produced by the basin. Rather the Dry Fork channel serves as an extension of the Deep Creek Ditch, which diverts water from Little Gunnison Creek and traverses Deep Creek prior to dumping into the headwaters of Dry Fork. The Deep Creek Ditch conveys irrigation water into Dry Fork for storage and release to downstream ranches along Minnesota Creek. The ditch typically diverts from May through July, with average annual diversions of 772 acre-feet based on SEO diversion records for 1970 to 2002. As discussed previously, there is little chance that mining will affect the Dry Fork channel. Consequently, it is unlikely that transbasin diversion from the Deep Creek Ditch will be disrupted by mining subsidence. However, MCC will monitor streamflows and channel conditions so that any potential impacts can be discovered quickly and mitigated as described in the Minnesota Creek Protection Plan. Mining in the Apache Rocks and the South of Divide permit revision area will not directly impact 40 Minnesota Reservoir because the reservoir will be outside the limits of mining influence. As discussed in Section 2.05.6 (3)(b)(iii & viii), Reservoirs and Stock Ponds, MCC will maintain a very conservative setback equivalent to an angle of draw of more than 25 degrees from the Minnesota Reservoir dam. Surface inflows to Minnesota Reservoir are unlikely to be significantly affected based on analysis in Exhibit 52. Springs that are within the Dry Fork basin may potentially be affected by mining to the extent that the flow is decreased, the flow moves, or the spring(s) dries up. It should be noted that flow from some springs never reaches a tributary stream because it is consumed by vegetation, evaporates or infiltrates. Reduced flow from these springs may not affect the flow of the basin's streams. However, for the many reasons discussed herein, these flow reductions will be modest and MCC's augmentation plan assures that no downstream water users will be injured. In addition, the only decreed spring (Deer Creek Domestic Springs Pipeline) within the South of Divide permit area is owned by MCC. A detailed discussion of measures taken to assess and ensure the protection of the Minnesota Creek water supply is contained in Exhibit 58, Protection of Minnesota Creek T+ater Supply. Furthermore, several of the key concepts discussed in the Protection Plan have been incorporated into the permit for the South of Divide (SOD) mining area. Among these are the subsidence monitoring plan, the hydrologic monitoring plan, and the impact mitigation plan. In the 25 years since the Protection Plan, subsidence phenomena at West Elk Merle have become well understood. Detailed subsidence monitoring was conducted over the initial longwall panels in the B Seam. In addition, Rich Dunrud has performed aiunual field studies over the past decade. Mining in the SOD permit area will occur in the E Seam, the overburden of which is a subset to that of the B Seam. Additional subsidence monitoring is proposed in the SOD permit area to 2.05-210 Revised Anne 1005 PRIO: Rev. March '006: Rev. April 2006 PRIO: Mai,2006 PR10: Sep. 2007 PR12; Feb 2008 PR12