2008-12-19_REVISION - C1996083 (7)

Home Browse Search

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 permit area exhibits an attitude of N66'W, with a 3 to 5-degree dip to the northeast. There is one identified fault located in the southwest corner of the permit area. The fault trends approximately N55'W and it dips 70 to 80 degrees to the northeast. The throw of the fault ranges from 7 to 30 feet, with the downside located on the south side of the fault. 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 permit application document. A brief summary is provided below, and the summary is derived from the information presented in permit application Sections 2.04.5 and 2.04.7. The permit and adjacent areas are generally bounded by three (3) perennial streams. These streams are Terror Creek, Hubbard Creek and the North Fork of the Gunnison River, and the streams are located west, east and south of the permit area, respectively. Tributary to the perennial streams are the following intermittent and ephemeral streams: Freeman Gulch, Stephans Draw, A-Gulch, B-Gulch, C-Gulch, D-Gulch, Dove Gulch and Sheep Corral Gulch. The specific locations of these streams are depicted on permit application Map No. 9. 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/l. 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 Spring 1995, and may be considered an intermittent stream. Stephans Draw is also an intermittent stream, and Stockpond P-1 is located along Stephans Draw. 14