Laserfiche WebLink
undisturbed conditions. <br />Minor revision 29 was received on December 21, 2016, deemed complete on December 22, 2016, <br />and approved on December 22, 2016. The revision incorporated the recently issued NPDES <br />discharge permit associated with the final reclamation of the sediment pond. <br />Stipulations to the Permit <br />There are no current stipulations on the permit. <br />Description of the Environment <br />The surface facilities of the mine were located on north -sloping fan terraces at the foot of a <br />spectacular, steep hillside formed by steeply -dipping bedrock (the Grand Hogback). The lower <br />terraces of the site, at elevation approximately 5,800 feet, are approximately 150 feet above the <br />Colorado River, and are used as cropland (grass and alfalfa) and for grazing. The base of the steep <br />slopes is used for grazing (sagebrush areas). <br />Geology <br />Rock strata dip ranges from 30 to 70 degrees to the west-southwest. Minor folds trending north -south <br />to northwest -southeast occur throughout the region. However, there is little evidence of faulting along <br />the Grand Hogback. <br />The exposed rock sequence in the permit area is Jurassic through Tertiary in age and includes <br />(proceeding from the base to the top, oldest to youngest) the Morrison Formation, Dakota Sandstone, <br />Mancos Shale, the coal -bearing Mesaverde Group, and the Wasatch and Ohio Creek formations. <br />The stratigraphy of the Mesaverde Group includes interbedded and lenticular sandstones, shale, <br />siltstone, and coal beds. In ascending order (oldest to youngest), the Group contains (1) the Corcoran <br />Sandstone, a marine shale sequence, and the Rollins Sandstone; (2) the Bowie (coal -bearing) member; <br />(3) the Paonia (coal -bearing) member; and (4) the Upper (non -coal bearing) member. The Corcoran <br />and Rollins Sandstones are the bottom and top, respectively, of the Iles Formation, and the upper three <br />members belong to the Williams Fork Formation [see Figure 3.3-3 in the Permit Application Package <br />(PAP)]. <br />The Wheeler coal seam, which was planned to be mined at the Coal Ridge No. 1 Mine, is in the <br />Williams Fork Formation within the Bowie member. Coal seams in the Bowie member are the most <br />continuous of any of the Mesaverde coals. Their cumulative thickness is 33 to 54 feet. <br />The Wasatch and Ohio Creek formations unconformably overlie the Mesaverde Group. These <br />formations consist of red and buff shale, red sandstone, and red to gray conglomerate and form the <br />ridge bluffs of the Grand Hogback. <br />Quaternary unconsolidated sediments in the mine area, as represented by surface features, fall into <br />three geomorphic categories: <br />Coal Ridge Mine <br />Permit Renewal No. 7 5 December 5, 2016 <br />