2013-10-07_REVISION - C1981025 (8)

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therefore lost to NFTM. The changes made to the treatment pond ditches by NTFM require a technical revision. MINREC will submit a technical revision at a later date to that meets the standards of the NPDES permit and the needs of the landowners. Previous analyses of the North Thompson Creek mining and reclamation operations have included reviews of the original permit, mid-terms, permit renewals, minor revisions, technical revisions and inspection reports. The reader is directed to File C-1981-025 for specifics of these reviews. MINREC, Inc. was in good standing on the initial check of the Applicant Violator System (AVS) on January 23, 2013 for this permit renewal. A second AVS check is required upon the proposed decision for this permit renewal; however, the AVS is not available at this time due to the government shut down and it is not known when the system will be available. The Division will propose its decision to approve this renewal with the stipulation that a second AVS check will be performed when the system is back online. Stipulation No. 10. An Applicant Violator System (AVS) check will be conducted to confirm findings numbers 7, 8, and 16. The AVS check will be completed when the system is back on line. Description of the Environment The North Thompson Creek Mine is located in the lower Roaring Fork Drainage Basin. The major drainages, divides and basins of the mine area are shown on Drawing D-4-7 of the permit application. The permit area of the North Thompson Creek Mine 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 mine portals. 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 gradients and valley walls. Elevations of the Thompson Creek drainage basin are 10,927 feet at Twin Peaks, 7,700 feet at the mine and 6,375 feet at the confluence with the Crystal River. Geology- The North Thompson Creek Mine is 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. 3