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2.0 GENERAL NATURE OF THE AREA • The study area is located within the Wyoming Basin Physiographic Province, in northem Colorado (Bass et al., 1955). It is within USDA Major Land Resource Area 48, Southern Rocky Mountains (USDA-SCS, 1978). Elevations within the study area range from about 6530 feet along the northern end of the proposed haul road to about 7,980 feet at summits of ridges within the study area. 2.1 Climate The study area is located in an "ustic-acidic" soil moisture regime and a "cryic-frigid" soil temperature regime. The climate is typically continental (intermountain footslopes) with cold winters, warm to hot summers, moderately low rainfall, and relatively short growing seasons. The mean annual precipitation ranges from about 16 inches along the north haul road corridor to a maximum of about 22 inches in the higher areas of the mine study area. Moisture is limiting within these soils, but the soil moisture is present during the growing season as a result of the quantity and distribution of precipitation. Periods of peak precipitation occur as snowfall during winter and as thundershowers during early summer months. • Mean annual air temperature ranges from 36 degrees F at higher elevations to 40 degress F along the north haul road corridor. The average frost-free period ranges from about 45 to 90 days. Elevation, slope position, and aspect are responsible for the wide ranges of mean annual precipitation, mean annual air temperature, and length of growing season in the study area. Additional climatological data is contained in Tabs 8 and 24 of this permit application package (PAP). 2.2 Geology A detailed discussion of the study area geology is presented in Tab 6 of this PAP. The following is a brief summary. The study area structurally lies between the Sage Creek and Fish Creek Anticlines, two parallel south-southeast trending geologic structures with steeply dipping flanks (Bass et al., 1955). The coal reserves occur in the Middle Coal Group between the Trout Creek sandstone member of the Cretaceous Iles formation and the Twentymile sandstone member of the Williams Fork formation. The Iles formation contains a thick sequence of ledge-forming sandstones interbedded with sandy shale, shale, and coal beds, with a prominent ledge-forming sandstone named the Trout Creek sandstone member. The Williams Fork formation is similar in characteristics and bedding attitude to the Iles formation with a persistent cliff-forming white • sandstone named the Twentymile sandstone member. The resistant sandstone beds consist 3