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:~ ., Geoloev The Noah Thompson Creek Mines and the loadout areas are 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 eastern limb of the unnamed syncline (in the area of the mines) dip 2~ to 34 degrees to the west. Most faults along the Grand Hogback are perpendicular to the strike of the strata and trend east-west. The faults in the area of the mines are 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 Maroon Formation, Entrada Fotmation, 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 are contained in the Iles and Williams Fork Formations. The mined resources included the A seam and the Anderson seam. The A seam is a seven- to ten-foot-thick coal that lies above the Rollins Sandstone of the Iles Formation and is approximately 3,300 to 3,500 feet below the ground surface. The Anderson seam is approximately nine to ten feet thick and lies approximately 2,400 feet below the ground surface. Ground Water Hydrology There are three major bedrock aquifers within the mine area: the Upper Sandstone, the Middle Sandstone, and the Rollins Sandstone. These are regional aquifers and are relatively thick and laterally extensive throughout the mine area. The Rollins Sandstone is below the lowest coal seam that was mined (A seam) and is within the Iles Formation. The A coal seam, the Middle Sandstone and the Upper Sandstone all lie within the Bowie member of the Williams Fork Formation. The Anderson coal seam lies within the Paonia member. The North Thompson Creek No. 1 Mine is in the A seam, while the No. 3 Mine is in the Anderson seam. In addition to the sandstone aquifers mentioned above, several other potential sandstone aquifers exist above and below the Anderson seam. However, these sandstones are thin and laterally discontinuous. A shallow and discontinuous alluvial aquifer exists on portions of the permit area adjacent to North Thompson Creek. The loadout site, located adjacent to the Roaring Fork River, is situated on an ancient valley floodplain. The alluvium adjacent to the river at this point is laterally extensive with thicknesses from 50 to 100 feet in many areas. The alluvial aquifer 3