2009-06-22_GENERAL DOCUMENTS - C1981033 (2)

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B-Seam. This seam was mined at U.S. Steel's Elk Creek Mine (renamed the Sanborn Creek Mine), and the Bear Mines. Three coal seams have been identified in the Upper Coal (Bowie) member: the D-Seam (Oliver), E-Seam (Hawk's Nest), and the F-Seam. The D-Seam occurs directly above the massive sandstone of the Lower Coal Bearing member and contains three zones. This seam was mined at the Bowie No. 1 Mine and at the Bowie No. 2 Mine. The E-Seam occurs about 130 feet above the D-Seam and contains two coal zones. This seam was mined at the Hawk's Nest and Blue Ribbon Mines. The E-Seam is currently being mined at the West Elk Mine. The F-Seam contains two coal zones and is only mined at the West Elk Mine. Coal seams of the F horizon do not exist, in thicknesses sufficient for mining, to the north of the North Fork of the Gunnison River. The topography of the permit area is mountainous. The area has been dissected by streams resulting in local relief in excess of 6,000 feet. The elevation at the Bear No. 3 Mine facilities area is approximately 6,000 feet, and the elevation at the top of Mt. Gunnison is in excess of 12,000 feet. Numerous landslides are present on the permit area and throughout the North Fork of the Gunnison River drainage. The landslides are caused by surficial failure of colluvial material or rotational failure of incompetent bedrock on over steepened slopes. The geologic structure of the area lacks any prominent folding or faulting. The strata dip to the north-northeast at three to five degrees. Dips increase to the south as igneous intrusives influence the structure. A detailed geological description of the permit area is also given in the Probable Hydrologic Consequences section of this document and Cumulative Hydrologic Impact Study for the North Fork of the Gunnison River. Hydrologic Balance - Rules 2.04.5, 2.04.7, 2.05.3, 2.05.6(3) and 4.05 Groundwater - Groundwater resource information for the Bear No. 3 Mine is presented in Sections 2.04.7 and 4.05 of the Bear No. 3 Mine permit application. Additional groundwater information is presented on Map 10 (Mine Facilities Map) of the Bear No. 3 Mine permit application. Several potential aquifers exist in, and adjacent to, the permit area, including: (1) Alluvial and alluvial terrace deposits associated with the North Fork of the Gunnison River and Sylvester Gulch; (2) Colluvial deposits; (3) Lenticular, discontinuous sandstones and coals; and (4) The Rollins Sandstone. The most significant occurrence of groundwater in the general area is the alluvial aquifer adjacent to the North Fork of the Gunnison River. Several domestic wells are located along the river in the alluvial material. Local bedrock groundwater movement in the discontinuous lenticular sandstones above the Rollins Sandstone is controlled by stratigraphy, faults and fractures. Groundwater discharge occurs through numerous seeps and springs in the area. The spring flows are generally intermittent and emanate from localized, lenticular sandstones above the F-Seam of the Upper Coal Member. Small seasonal springs emanate from unconsolidated colluvial material. These springs flow in response to seasonal precipitation. No alluvial valley floors (AVFs), as defined in Rule 1.04(10), exist within the permit area. Alluvial deposits along the North Fork of the Gunnison River below the town of Somerset have been found to meet the geomorphic criteria and irrigation requirements of an alluvial valley floor. This area will not be affected by the operation. The facilities area at the Bear No. 3 Mine is located on alluvial material 6