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SECTION 2.04.5 <br />GENERAL DESCRIPTION OF GEOLOGY AND HYDROLOGY <br />GENERAL GEOLOGY <br />Physiography. The New Horizon North Mine (NHN) area is located three miles <br />northwest of Nucla in Montrose County, Colorado. The mine is located within the <br />Colorado Plateau Physiographic Province, Canyon Land section in southwest Colorado. <br />The region is characterized by broad, fairly smooth surfaced plateaus and mesas with <br />gently dipping slopes dissected by deep canyons. Numerous large folds and rugged <br />laccolithic mountains attribute their topographic relief and steep slopes to geologic <br />structures; while local hills, drains, and canyons are erosional features produced by <br />surface drainage. Map 2.04.5 -1 General Geology and Hydrology Map, shows the <br />geology and drainage system in the general area of NHN permit area. <br />In relation to regional drainage systems, the permit area is located in the upper tributaries <br />of Tuttle Draw and Coal Canyon, both tributary to the San Miguel River. The San <br />Miguel River empties into the Dolores River northeast of Uravan, Colorado, which in <br />turn, leaves the state northwest of Gateway, Colorado and empties into the upper <br />Colorado River in Utah. <br />Approximately 4,870 feet of relief is present in the Nucla area, from a high elevation of <br />9,870 feet (MSL) at the crest of the Uncompahgre Plateau to the northeast, to below <br />5,000 feet (MSL) along the San Miguel River at Uravan. Steep slopes are common on <br />the flanks of the Uncompahgre Plateau; whereas more gentle slopes dominate in the <br />Nucla area. Vertical drops of several hundred feet are not uncommon along the San <br />Miguel and Dolores River canyons. <br />Surface elevations in the NHN permit area range from a high of 5,790 feet (MSL) in the <br />northeast corner of the permit, to a low of slightly less than 5,540 feet (MSL) at the <br />southernmost part where the permit area(equipment corridor) crosses Tuttle Draw (see <br />Map 2.04.5 -1). Total topographic relief for the permit area is 250 feet. The elevation on <br />the San Miguel River where Tuttle Draw joins it is about 5240 ft. <br />Topographic features on the permit include gentle southwest facing slopes, low rolling <br />hills, old spoil piles, regraded mined areas cut by open pits, and shallow drains <br />(ephemeral) which feed Tuttle Draw (intermittent). <br />Regional Geology. Southwest Colorado exhibits a wide and unusual variety of <br />physiography, mineral resources, soils, groundwater conditions, and surface water <br />conditions which are, to a great extent, influenced by the region's geology. In this part of <br />the San Juan Coal Region (Nucla - Naturita Coal Field), a series of major northwest <br />trending structural features and complex intraformational stratigraphic relationships <br />control the overall occurrence and quality of coal reserves. <br />Section 2.04.5 Page 1 April 2011 <br />