2011-03-14_REPORT - C1982056 (3)

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Based upon TORT exceedances, TCC discontinued discharge in early 2009, and utilized a new piping system that • pumped water from TORT to the area # 1 Pit impoundment. To date, mine water that has overflowed from the Pit (through DRMS site 7) to Pond D has met CDPS permit limitations at Outfall 005A, as well as WET testing requirements. This is attributed to the significant resonance time for water passing through both impoundments, allowing for aeration and some mineral constituents to drop out. The emergency discharge permit was allowed to expire in September 2010. Despite the success of mine discharge through the two impoundments, TCC is still considering applying with CDPHE for a permanent CDPS discharge Outfall for TORT (east of the original discharge location). A proposal to create to baffled pond, leading into an enhanced wetlands before discharging to Foidel is being discussed. As of the first week in March 2010, there is approximately 48.5 feet of freeboard in the EMD. During the summer of 2009, a pilot study was conducted on water from the Area # 1 Pit using an electro- coagulation/Reverse osmosis hybrid system with nano-filtration. The results were quite promising. A copy of the pilot study report was attached as Appendix to the 2009 AHR. This system is currently under consideration by TCC for installation and treatment of Pit water. If installed, this system may supply treated water for our potable water system, the new wash plant, and possibly for underground use. Temporary Discharge Permit COG-073311 • A temporary CDPHE construction permit was applied for in March 2010, to allow a one foot diameter HDPE pipe line to cross under Fish Creek., This was a mine dewatering pipeline running from the 18 Left Fan pad area, and connecting with an existing pipeline which is used to dewater the old Western Mining District (also see TR09-70). Mine water from these areas is pumped through the piping to the Area # 1 Pit. Elevated values of total suspended solids were reported to CDPHE for months April through July 2010. These values were attributable to natural high flow erosion impacts along Fish Creek, and not from the pipeline construction back in April. Historical data on Fish Creek immediately upstream of the crossing indicated that elevated TSS values during high flows on this creek are typical. For example, a sample. collected upstream of the pipeline crossing yielded a TSS of 259 the last week of May versus the permit limit of 45 mg/L. The permit parameter limit constraints are simply not practical/realistic for that type of project. This permit was terminated by CDPHE as of November 1, 2010. CDPHE Discharge Permit COG-850054 The 18 Left Vent Fan Pad area drains into two sedimentation ponds which could discharge into a small unnamed tributary leading to Fish Creek. In February 2010, TCC submitted an application to CDPHE to make this a permanent CDPS site (also see TR09-70). A permit (COG-850054) was subsequently approved by CDPHE, effective April 15, 2010, expiring June 30, 2013. DRMS is copied on CDPHE DMRs for this site. There was no discharge from this site in 2010. 15