Laserfiche WebLink
West Elk Mine <br />One of the locations for possible alluvial deposits within the mine permit azea is immediately <br />above the Minnesota Reservoir. The valley floor widens at this location and there is a definite <br />break in slope from the steep sides confining the valley floor. Numerous beaver ponds and <br />willow thickets occupy the valley floor in this location, and grazing is limited to isolated <br />locations along the margins of the valley. <br />Table 65 Surface Areas of Alluvial Deposits Near the West Elk Mine <br />Stream Total Area (mi) Alluvial Fan Area (mi ) <br />North Fork Gunnison River 1.40 0.29 <br />Sylvester Gulch 0.04 <br />Minnesota Creek 0.68 <br />D Fork Minnesota Creek 0.14 <br />East Fork Minnesota Creek 0.29 <br />South Fork Mimmesota Creek 0.07 <br /> <br />The soils in this location aze primarily deep clays. The Haplaquoll soil predominates. It is <br />associated with beaver activity and commonly exhibits mottled conditions in subsurface horizons. <br />The alluvial origin of this material is plausible because of the beaver activity and downstream <br />channel blockage from a landslide and from Minnesota Reservoir dam which was placed at the <br />blockage point. Normally the soil is saturated with water at or near the surface. Because of absence <br />of good aeration, organic matter content is high. <br />The valley floor in this reach of the Dry Fork would be incapable of supporting agricultural <br />activities without proper drainage. Approximately 20 percent of the total alluvial fill deposits above <br />Minnesota Reservoir has an artificially high water table as a result of backwater conditions from the <br />reservoir pool. This azea could not be drained adequately without removing the reservoir. Even with <br />adequate drainage on the remaining azea, the agricultural development would be restricted to <br />grasses and pasture because of the high elevations and short growing season. Furthermore, the <br />beaver ponds and willow thickets are an important factor in the general ecological picture, since <br />they help regulate stream flow, provide water for domestic animals and wildlife, and provide <br />wildlife cover. <br />The Hydrology and Mining Methods Sections detail the mining activities currently scheduled to <br />take place under Dry Fork and the safeguazds that will be taken to preserve the hydrologic integrity <br />of Dry Fork. MCC, with guidance from OSM and OMLR, has developed a subsidence monitoring <br />program for the SOD azea including both the Dry Fork of Minnesota Creek and Minnesota <br />Reservoir. The information obtained will be used to refine the subsidence control plan for the <br />mining azea under Dry Fork, if necessary, to protect the hydrologic balance. The hydrologic and <br />subsidence-monitoring and mitigation plans for SOD, including the Dry Fork azea, are summarized <br />in Table A-1 of this permit. Specific text regazding the mining and subsidence control plan and the <br />measures to be implemented to preserve the hydrologic balance of those portions of the Minnesota <br />Creek drainage to be undermined can be found in the subsections of Section 2.05.6(3)(a)(i) - <br />2.06-4 Revised June 2005 PR70; Rev. March 2006 <br />