2009-05-12_GENERAL DOCUMENTS - C1981025

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deficiencies was required in order for the Division to make determinations of compliance with the Act. The Applicant responded to the comments on March 22, 2009, with the submittal of revised pages to the Application. The Division finds that the permit may be renewed. Previous analyses of the North Thompson Creek mining and reclamation operation have included the original permitting review, mid-term and permit renewal reviews, and minor and technical revision reviews, and reviews of inspections and reports. The reader is directed to File No. C-1981-025 for specifics of these reviews. Description of the Environment The mine and loadout sites are located in the lower Roaring Fork Drainage Basin. The loadout site is located about a mile below the confluence of the Roaring Fork and Crystal Rivers. The major drainages, divides and basins of the mine site are shown on Drawing D-4-7 of the Permit Application Package (PAP). The permit area of the mine site is located within the North and Middle Thompson Creek Drainage Basins. These two perennial streams combine to form Thompson Creek about two and one half miles below the mining facilities. Thompson Creek is a major tributary of the Crystal River, which is located about five miles downstream of the mining disturbance. The stream valleys of North and Middle Thompson Creeks have steep stream gradients and have steep valley walls. Elevations within the Thompson Creek drainage basin range from 10,927 feet at Twin Peaks, to 7,700 feet at the mine, down to 6,375 feet at the confluence with the Crystal River. Geolo The mine site and the loadout site are located along the Grand Hogback monocline. The Grand Hogback forms the steeply dipping eastern edge of the Piceance Basin. The Pennsylvanian through Tertiary Age sedimentary formations, which form the Grand Hogback, dip 15 to 45 degrees to the west. An unnamed syncline and the Wolf Creek anticline are located to the west of the mines. The Wolf Creek anticline plunges to the north-northwest. The sedimentary beds on the eastern limb of the unnamed syncline (in the area of the mines) dip 25 to 34 degrees to the west. Most faults along the Grand Hogback are perpendicular to the strike of the strata and trend east-west. The faults in the area of the mines are low displacement normal faults. The displacements of faults increase in faults located south of the mines. Sedimentary rock units within the permit and adjacent areas of the mines and loadout range in age from Pennsylvanian to Tertiary Formation. The formations, in ascending order, are the Maroon Formation, Entrada Formation, Morrison Formation, Dakota Sandstone, Mancos Shale, Iles Formation, Williams Fork Formation, and Wasatch Formation. The most significant sandstones and coals in the permit and adjacent areas of the mines are contained in the Iles and Williams Fork Formations. The mined resources included the A seam and the Anderson seam. Some mining had been previously accomplished in the B seam, and some later development was accomplished therein. North Thompson Creek C-1981-025 12 May 2009 Permit Renewal 05 5