1992-12-16_GENERAL DOCUMENTS - C1980007

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All of the streams draining the West Elk Mine permit area are tributatires to the North Fork of the Gunnison River. Sylvester Gulch and Lone Pine Gulch are ephemeral streams draining the northern portion of the lease area. Minnesota Creek and its tributaries , Horse Creek, South Prong, Lick Creek, Dry Fork,- and East Fork, drain the southern portion of the coal lease area. Minnesota Creek enters the North Fork of the Gunnison River near Paonia. The overall drainage exhibits a dendritic drainage pattern with steep channels. Horse Creek and South Prong of the East Fork of Minnesota Creek are perennial streams , while Lick Creek, Upper Dry Fork, and Sylvester Gulch are ephemeral streams . Minnesota Reservoir controls much of the flow in the lower Dry Fork of Minnesota Creek, and Beaver Reservoir controls the flow in the East Fork of Minnesota Creek. Lone Pine Gulch has no evidence of recent flow; therefore, no gaging station has been constructed. Even when all of the six gaged watersheds were found to be flowing, Lone Pine Gulch showed no flow or evidence of flow. Geology - Rules 2.04.5 and 2.04.6 The applicant describes the geology of the permit and adjacent area in Section 2.04.5 of the permit application. Additional information is detailed on Map 9, which details the geology of the lease area, as well as the coal outcrop line and the strike and dip for the F seam. Stratigraphic cross-sections are shown on Maps 10, 11 , and 12. The permit area lies on the southeast margin of the Piceance Basin and just south of Grand Mesa. The general geology of this area consists of gently (three to five degrees) north-northeast dipping beds of sandstone, shale, and coal of upper Cretaceous and early Tertiary age. The geologic formations exposed in the North Fork Drainage Basin consist of Late Cretaceous to Early Tertiary Age sedimentary strata, Tertiary Age igneous intrusives, and Quaternary Age alluvial and colluvial deposits. The units are described below in ascending order. The Mancos Shale is the oldest strata exposed in the region, and is of Late Cretaceous Age. This unit is composed of over 4,000 feet of gray marine shales and minor interbedded buff sandstones. This unit is highly erodible and unstable. Erosion and oversteepening of slopes in this formation produce the numerous rock falls and landslides observed in the lower North Fork Drainage Basin (Junge, 1978) . The Mesaverde Formation is of Late Cretaceous Age and conformably overlies the Mancos Shale. This formation consists of approximately 2,300 feet of marine and terrestrial sedimentary rocks. The Mesaverde Formation is the coal-bearing formation in the region and is divided into four main members ; the Rollins Sandstone, the Lower Coal Bearing (Bowie) member, the Upper Coal Bearing (Paonia) member, and the Barren (Undifferentiated) member (Johnson, 1948) . The Rollins Sandstone is a white to buff-colored, well sorted, medium- to fine-grained sandstone, ranging from 150 feet to 300 feet thick. This sandstone is regionally extensive and resistant in outcrop and forms prominent Cliffs . -17-