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Description of the Environment The mine and loadout sites aze located in the lower Roaring Fork Drainage Basin. The loadout site is located about a mile below the confluence of the Roaring Fork and Crystal Rivers. The major drainages, divides and basins of the mine site are shown on Drawing D-4-7 of the Pernut Application Package (PAP). The permit azea of the mine site is located within the North and Middle Thompson Creek Drainage Basins. These two perennial streams combine to form Thompson Creek about two and one half miles below the mining facilities. Thompson Creek is a major tributary of the Crystal River, which is located about five miles downstream of the mining disturbance. The stream valleys of North and Middle Thompson Creeks have steep stream gradients and have steep valley walls. Elevations within the Thompson Creek drainage basin range from 10,927 feet at Twin Peaks, to 7,700 feet at the mine, down to 6,375 feet at the confluence with the Crystal River. Geoloev The mine site and the loadout site aze located along the Grand Hogback monocline. The Grand Hogback forms the steeply dipping eastern edge of the Piceance Basin. The Pennsylvanian through Tertiary Age sedimentary formations, which form the Grand Hogback, dip 15 to 45 degrees to the west. An unnamed syncline and the Wolf Creek anticline are located to the west of the mines. The Wolf Creek anticline plunges to the north-northwest. The sedimentary beds on the eastem limb of the unnamed syncline (in the azea of the mines) dip 25 to 34 degrees to the west. Most faults along the Grand Hogback aze perpendiculaz to the strike of the strata and trend east- west. The faults in the azea of the mines aze low displacement normal faults. The displacements of faults increase in faults located south of the mines. Sedimentary rock units within the permit and adjacent areas of the mines and loadout range in age from Pennsylvanian to Tertiary Formation. The formations, in ascending order, are the Mazoon Formation, Entrada Formation, Morrison Formation, Dakota Sandstone, Mancos Shale, Iles Formation, Williams Fork Formation, and Wasatch Formation. The most significant sandstones and coals in the permit and adjacent areas of the mines aze contained in the Iles and Williams Fork Formations. The mined resources included the A seam and the Anderson seam. Some mining had been previously accomplished in the B seam, and some later development was accomplished therein. These seams outcrop within the pemiit azea (bedrock, covered by colluvial or alluvial materials). The A seam is a seven- to ten-foot-thick coal that lies above the Rollins Sandstone of the Iles Formation. The B-seam, thee to five feet thick, lies forty to sixty feet above the A seam. The Anderson seam is approximately nine to ten feet thick and lies approximately eight-hundred feet above the A seam. Ground Water Hydrology There aze three major bedrock aquifers within the mine azea: the Upper Sandstone, the Middle Sandstone, and the Rollins Sandstone. These are regional aquifers and aze relatively thick and 5