GENERAL30336 - Laserfiche WebLink

Home Browse Search

• 3. Affected Environment The minesite is located at an elevation of approximately 5800 feet. Land use within the permit and adjacent areas is rangeland and wildlife habitat. Rangeland is generally confined to the lower lying canyon bottom lands. The upland area consists of steep slopes and rugged topography and is primarily used by wildlife. Some irrigated agriculture exists in the East Salt Creek Valley, which is adjacent to the permit area. McClane Canyon is located in the Roan Cliffs area just north of Grand Valley. This area is northwest of the Garmesa Anticline and on the southern flank of the Piceance Basin approximately 30 miles west and north of Grand Junction. Local strata dip to the northeast into the Piceance Basin at approximately 2 degrees. The coal to be mined is within a graben which is bounded by two high-angle faults. The upper Cretaceous, Mesa Verde Group, Mount Garfield Formation is the coal bearing formation in the Book Cliffs Coal Field. This formation consists of fine grained and medium grained sandstones and gray shales. The Sego Sandstone underlies the Mount Garfield Formation with the Hunter Formation overlying the Mount Garfield Formation. The Mount Garfield Formation contains four coal zones; the Loma, Carbonera, Cameo, and Palisade zones. The Cameo seam will be mined at the McClane Canyon mine. No major bedrock aquifers of regional extent have been identified in the permit and adjacent areas by the applicant, which is to be expected; since the bulk of the Cameo seam being mined is above water table. Short ~, term inflows along portions of the east fault saturate the lower portion of the Cameo seam. During active mining the total mine inflow is about 5.0 gpm. Upon drainage of the Cameo seam, flow into the mine stabilizes at about 1.6 gpm. This inflow varies with recharge of the east fault and is probably connected to McClane Creek. In-mine storage totals 1.5 million gallons and pumping capacity exceeds'220,000 gallons per month allowing discharge to be adjusted seasonally, as needed. About 4 million gallons were discharged between January 1982 and January 1985, an average rate of 2.5 gpm. Some local lenticular strata of limited extent have been identified above the Cameo seam, which contain perched ground water. Alluvial ground water exists within the East Salt Creek alluvium. The East Salt Creek Valley contains an intermittent stream channel. The climate in the region is arid. Prevailing winds at or near the ground level at the mine are dictated by the orientation of the deeply incised McClane Canyon. The annual average precipitation recorded at Fruita (22 miles southeast of McClane Canyon) is 8.8 inches. The soils mapped in the permit area are well to excessively drained and have formed in alluvial or colluvial sediments. Soils are deepest in the valley bottoms and become shallower along the canyon sideslopes where they intersperse with bare rock. All of the soils are rated good to fair • as sources of topsoil for reclamation. Limitations exist for subsoils in the alluvium, which are strongly alkaline. -3-