2023-01-12_GENERAL DOCUMENTS - C1996083

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ranges from about 6,000 feet above sea level to over 8,000 feet above sea level. The general area is situated along the southern flank of the Piceance Creek structural and sedimentary basin. The area is bounded by Larimide structural and physiographic features on the following sides: West Elk and Elk Mountains on the east; the Gunnison Uplift on the south;the Uncompahgre Uplift on the west-southwest; and the Grand Mesa-Piceance Basin on the north. The geologic structure of the eastern permit area exhibits an attitude of N70°W and dips 3 to 5 degrees to the northeast. The western permit area exhibits an attitude of N88°W to N76°W and dips 4 to 7 degrees to the northeast. The structural dip direction changes near Terror Creek due to faulting. There are numerous faults located within and adjacent to the permit area. The faults in the central portion of the permit area are high angle normal faults. These faults trend N40°W and dip 70 to 80 degrees to the northeast. The faults have a strike-slip component. The throw of the faults ranges from 7 to 30 feet. The coal in the area is situated within Mesaverde formation which contains interbedded sandstones, mudstones, shales, siltstones and coal beds. The Mesaverde formation lies upon the Rollins Sandstone Member of the Iles formation and below the Wasatch formation. The coal bearing member of the Mesaverde formation locally contains up to nine (9)coal seams. These seams are located within a stratigraphic interval of approximately 500 to 600 feet above the Rollins Sandstone. These coal seams are,in ascending order,the A-Seam,the B-I Seam,the B-2 Seam,the C-Seam,the D-1 Seam,the D-2 Seam,the E-I Seam,the E-2 Seam and the F-Seam. The B-2 and D-2 Seams are mineable within the permit area. The D-2 Seam overlies the Rollins Sandstone by 350 to 450 feet,and it ranges in thickness from about 8 to 16 feet. The B-2 coal seam lies between the Rollins Sandstone and the D-2 coal seam and varies in thickness from 9 to 22 feet. Once longwall mining in the D-2 coal seam was finished, and with the approval of Permit Revision No. 8, longwall mining began in the B-2 coal seam. Hydrology Detailed information regarding the surface and groundwater hydrology in and adjacent to the Bowie No. 2 Mine permit area is provided within Sections 2.04.5 and 2.04.7 of the PAP. A brief summary is provided below, and the summary is derived from the information presented in Sections 2.04.5 and 2.04.7 of the PAP. The permit and adjacent areas are generally bounded by two perennial streams, Terror Creek to the west and Hubbard Creek to the east, and the North Fork of the Gunnison River to the south. Tributary to the perennial streams are the following intermittent and ephemeral streams: Freeman Gulch, Stevens Draw, A-Gulch,B-Gulch,C-Gulch,D-Gulch,Dove Gulch and Sheep Corral Gulch. The specific locations of these streams are depicted on Map No. 9 of the PAP. The North Fork of the Gunnison River drains an area of approximately 526 square miles. The average annual yield of the North Fork of the Gunnison River from October 1993 to September 1994 was approximately 330,500 acre-feet. The quantity and quality of this river is influenced significantly by agricultural and municipal uses. Near Somerset,Colorado,the water in the North Fork of the Gunnison River is a calcium-bicarbonate type,and total dissolved solids concentrations range from approximately 100 milligrams per liter(mg/1)to approximately 400 mg/1. Terror Creek is a perennial stream which drains approximately 29 square miles, and Hubbard Creek is a perennial stream which drains approximately 35 square miles. Freeman Gulch is a significant drainage which is tributary to Hubbard Creek. Freeman Gulch exhibited flow during the snowmelt period of 6