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Lease Tract and would be offered for Lease as part of that tract. The existing Deserado Mine would bypass this area. Approximately 2.1 million • tons of recoverable coal would be lost to further production. III. AFFECTED ENVIRONMENT Introduction The elevation of the lease application area ranges between 5,400 and 5,600 feet. Gently rolling to moderately sloping land forms cover a majority of the lease application area. Slopes range in steepness from 0 to 6 percent in the valleys and relatively level uplands to 50 percent or more along the sideslopes of major drainages. The area is characterized by mild summers and cold winters, and has a low average annual amount of precipitation. Seasonal temperatures can be extreme, ranging from 108°F in the summer to -33°F in the winter. Average summer temperatures range from 95°F in the daytime to 50•F at night. Average winter temperatures are 29°F. Precipitation averages from 8-1/2 to 9 inches annually, with the majority of it occurring in late summer and early fall. Average winter snow accumulation is usually less than 12 inches and generally does not remain on the ground very long. Southern exposures may remain free of snow for most of the year. The growing sea- son is short, usually Less than 100 days, and occurs from late May to mid-September. The Cretaceous Mesaverde Group in northwestern Colorado has been divided into two formations: the lower Iles Formation and the upper Williams Fork • Formation, which are separated by the Trout Creek Sandstone. The Williams Fork Formation is further divided into Upper and Lower members. The Lower Williams Fork Member contains coal seams A through J, of which the B and D seams are or will be recovered within the Deserado Mine LMU. The dip of the Mesaverde Group within the general area is controlled by the asymmetric Red Wash Syncline, which strikes northwest-southeast. Dips vary from 7 degrees to the northeast in the southern part of the LMU, to horizontal at the synclinal axis, to ae much as 70 degrees to the south- reat on the north flank of the syncline. The coal and sandstone beds out- crop along this steep northern flank. Minerals Coal The coal deposits of the Prairie Dog Lease Tract are located in the Lower White River coal field, within the late Cretaceous Mesaverde Group. Coal seams of interest occur within the main coal member of the Williams Fork Formation (seams A thru S). Only coal contained in the B and D seams is of adequate thickness to be considered minable. Exploration in the area indicated the pres- ence of splits and partings in both the B and D seams including a major parting in the D seam. The parting in the D seam reduces the minable seam thickness from 8 to 9 1/2 feet to 3 or 4 feet. The ~1 8