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Description of the Environment <br />Climate <br />The climate atthe•Edna Mine is typical of semi -arid' steppe regions with more than half ' <br />of the annual precipitation' (16 inches) falling as snow. The ternperatures'are cool, <br />61 F "average mean temperature in August to a cold 18 F average mean -in rFebrtiary `" <br />Regional winds are from the west. Local topography affects both precipitation and- wind <br />direction. <br />Geology <br />The Edna Mine is geographically situated between the drainages of Oak Creek`ori The east <br />and Trout Creek on the West. 'Topographically; the permit area`is dominated by a t: <br />north -south trending ridge line. A steep east - facing escarprner t extends'to Oak-Creek, <br />with a gentler west- facing_dip slope from the ridge line west to Trout Creek. Elevation of <br />the area varies from 7,000 to 7,600 feet. <br />Except for surficial deposits; only the coal bearing Cretaceous , Mesaverde Group outcrops <br />in the permit area. The Williams Fork Formation and the Iles Formation together <br />comprise the Mesaverde Group. The Williams Fork Formation is separated from the <br />lower Iles Formation by the massive Trout Creek Sandstone Member, the top of which <br />forms the upper` limit =of the Iles Formation. The coals'seams that were '`mined at the Edna <br />Mine are all situated within the Williams Fork Formation, approximately 150 -225 feet <br />above the Trout Creek Sandstone. The "Middle Coal Group" of the coal bearing <br />member includes, in ascending order, the Wolf Creek, Wadge, and Lennox coal seams. <br />The Lennox ` and ' Wadge seams Were mined in the West Ridge Area: The Wadge .seam <br />was Mined theMoffat Area: <br />The najor`:portion of the Edna'Miie'is`located'on eastern limb of the Twentymile' <br />Park Syiieline, the axis of which trends horthwest from the southernmo's't boundary of the <br />permit area through West Ridge: Two minor faults occur in the Moffat Area of the mine <br />site. <br />Landscape character-in and near the Edna Mine results mostly from moderate folding of <br />strata =followed by differential -- erosion of interbedded resistant-and non resist layers of <br />various'thicknesses. The southern portion'of the permit area ;'West Ridge, consists`of <br />large areas of previously 'strip -mined land characterized by spoil ridges `frohi dragline <br />operation conducted prior to enactment of the Surface Mining Control and Reclamation <br />Act (SMCRA). <br />C1980 - OOl Edna Mine Permit Renewal No. 6 <br />