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Surficial geology in the area consists largely of consolidated sedimentary rock of the upper Cretaceous Mesaverde Group. A veneer of colluvial/alluvial material is present in drainages, and becomes more significant along the major streams in the area. The Seneca II Mine extracts coal from the Middle Coal Group of the Williams Fork Formation, a member of the Mesaverde Group. The Williams Fork Formation, which conformably overlies the 1,550-foot thick Iles Formation, is a 1,100 to 2,000-foot-thick sequence of interbedded shales, sandstones, sandy shales and coal. The lower-most economically recoverable coal member of the Middle Coal Group is the Wolf Creek Coal, which averages 15 feet thick at the Seneca II Mine site. The underlying Trout Creek Sandstone, considered to be a regional aquifer, is separated from the Wolf Creek Coal by about 70 feet of carbonaceous shale, sandstone, siltstone, and clean shale. Overlying the Wolf Creek Coal is about 150 feet (stratigraphically) of lenticular sandstone, siltstone, shale and thin coal seams. This interburden is overlain by the Wadge Coal, a nine- to ten-foot thick coal seam. The Wadge overburden is a moderately thick sequence of sandstone, siltstone and shale. About 50 feet above the Wadge Coal is the 2.5- to 5.5-foot thick Lennox Coal. This poor quality coal was recovered in the southern portion of the permit area. Overlying the Lennox Coal is a thin sandstone cap which is overlain by a thick shale unit. Three coal seams in the Williams Fork Formation have been mined at the site. In ascending order, these seams are the Wolf Creek, Wadge and Lennox. The Lennox Coal is discontinuous and was recovered where economically feasible. Aquifers identified within and adjacent to the permit area include the Trout Creek Sandstone, Wolf Creek Coal, Wadge Coal and overburden, resaturated spoils and the alluvial bodies associated with local drainages. The current Wadge mining area lies in the Fish Creek drainage, while the Wolf Creek mining area lies within the Grassy Creek drainage. Both of these drainages are tributary to the upper Yampa River. Tributaries to Fish Creek have historically exhibited ephemeral characteristics, but mining-related flow may change these to perennial streams. Current and historic land use in the vicinity of the operation has been mining, grazing for livestock, and wildlife habitat. Irrigated cropland in the area is limited to portions of the Fish Creek alluvial body and to the Yampa River floodplain. Non-irrigated crops are grown on sloping upland areas, as well as on alluvial flats. No cropland will be disturbed by mining. The soils found within and adjacent to the mine plan area are typical of soils found in the cold, semi-arid regions of the western United States. The soils are moderately deep (20 to 40 inches) to shallow (10 to 20 inches). Soils were developed in weathered, interbedded fine sandstone, siltstone, and shale, and in local slopewash and colluvium. Vegetation in the vicinity of the operation is characterized by three vegetative types; mixed brush, sagebrush grassland, and aspen. Because of livestock grazing, shrubs have increased in density while fortis and grasses have decreased. 5