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Dc:,cri lr ti o++ oC the En vi r. onmenL The 1,360 acre Bear No. 1 and Bear No. 2 permit area and the 287 acre Ue: u- No. 3 revision area (which wi 11 be mined during Che permit term) lie within the drainage of the North Fork of the Gunnison River which is tributary Co thr Colorado River System. 'lhe area is mountainous, with elevations ranging fzom 6,000 feet at Somerset to 12, 719 feet at the summit of Mt. Gunnison, tc the south of the permit area. The North Fork has cut a deep canyon througi~ tlr~a area which separates high tablelands south of the river from the slopes of the Grand Mesa to the north. The canyon is narrow and steep-sided in the vici;rity of the Bear mine, widening out into a broad alluvial valley in the vicinity of Paonia. The tableland to the south of the North Fork is deeply dissec(ed by tributary streams, and is bounded on the south and east by the West E11: f•:ountain Range. The climate of the region is typical of the Rocky Mountain area. The valley in which Paonia and Somerset are situated is semi-arid with annual precipitation averaging about 15 inches per year. Mean annual precipitation increases ioi th elevation, reaching approximately 40 inches per year on the summit of Dlt. Gunnison. The May-September precipitation is 5 inches for the lowlands and 13 inches for the mountain peaks. This indicates that snowfall patterns play an important part in determining the hydrology of the area. Temperature extremes at Paonia have ranged from -28o Fin January to 100o F during July and it ugus t. The average annual temperature is approximately 49o F. Snowfall averages 58 inches per year. The North Fork of the Gunnison is the major drainage for the mine site. to!+r ephemeral streams drain the permit area, and join the North Fork in tl+c= vicinity of Somerset. The water in the North Fork is characterized as a ralcium bicarbonate type with moderate levels of sulfate. No alluvial valley floors (AVF's) exist within the permit area. Alluvial deposits along the North Fork below the town of Somerset have been found to meet tl;e geomorphic criteria and irrigation requirements of an AVF. The coal to be mined is located in the Paonia Coal Field. The rocks exposed in the Paonia Coal Field consist of the Mancos Shale and the coal-bearing Mesa Verde Formation of Upper Cretaceous Age, the Ohio Creek Conglomerate, the Wasatch Formation of Early Tertiary Age, and the Quartz monzonite porphyry of Tertiary Age. Coal is to be produced from the Mesa Verde Formation, a 2,570 foot thick sequence of sedimentary strata overlain by the Ohio Creek Conglomerate and underlain by the Mancos Shale. Beds exposed in the mine area dip 3-5 degrees north-northeast. The Bear mine will extract coal from the "C" seam, ot" the Lower Coal Member of the Mesa Verde Formation. The Lower Coal Member averages 270 feet thick in the permit area and bears three minable coal scams. '1'1,_~ member consists of interbedded sandstonc~, silts tones and coals, and is unnor- Iain by the Rollins Sandstone. A massive sandstone .25 to 225 feet thick ovcc- lies the "C" seam and marks the top of the Lower Coal Member. The "C" seam overburden ranges from Zess than 100 feet near the north edge of the per:ni.t area to over 1,400 feet in central and sou Ch ern pot tions of the permit area. Three categories of potential aquifers exist in the general area: A12uvi.il ru+d terrace deposits associated with the North Fork of the Gunnison River and Sylvester Gulch to the east; lenticular, discontinuous sandstones and co.i.1~:: and the Rollins Sandstone. Local bedrock ground water movement above t1+.^