2017-05-08_REPORT - C1982056 (3)

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(COG -850051) was subsequently approved in January 2010 by CDPHE, effective February 1, 2010, expiring June 30, 2016. The penult is currently under Administrative Extension with CDPHE. li I � Outfall 001A did not discharge in 2016. CDPHE Discharge Pen -nit 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 2016, TC submitted an application to CDPHE to make this a pennanent CDPS site (also see TR09-70). A pen -nit (COG -850054) was subsequently approved by CDPHE, effective April 15, 2010, expiring June 30, 2016. The permit is currently under Administrative Extension with CDPHE. DRMS is copied on CDPHE DMRs for this site. The site did not discharge in 2016. 3.7 Mine Water Discharge Sites Four mine water discharge sites are currently associated with the TC operations are monitored. Site 109 (Twentymile Facility) requires quarterly monitoring for flows, field parameters, and water quality samples (when flowing). Note that this site has not discharged in about 20 years, and will not be discharging in the conceivable future. Site 115 (Fish Creek Borehole) is monitored as a CDPS discharge point in accordance with the requirements set forth under CDPS Pen -nit No. CO -0042161. Two other mine water discharge sites are discussed in greater detail under a subsection to Section 3.6 above. To dewater the old WMD and EMD, pumps and piping were installed to direct mine water from the Fish Creek Vent Shaft (FCVS) and IORT #1, to the Area # 1 Pit. Overflow from the Pit passes through site 7 to Pond D, and subsequently through CDPS Outfall 005A to Foidel Creek. Site 7 requires quarterly analyses when flowing per DRMS Permit No. C-82-056. Site 7 discharged during the second and third quarters of 2016. Outfall 005A requires weekly, twice monthly, monthly, and quarterly water quality sampling when flowing, under CDPS Permit CO -0027154. Note that mine water is pumped f -om underground to the urface (from the old WMD), and wa i historically (beginning in 2005) treated via an electro -coagulation process at the surface, where water enters he 3 former treatment ponds that can also be directed through discharge site 115, that can be directed to Fish Creek. This form of treatment ceased around 2014. This water was pumped directly back into the mine for underground dust suppression. Additional overflow piping was added so the treatments ponds cannot overflow. Overflow water is directed back into the mine via a fonner pump Ilwell. Site 115 had not discharged to Fish Creek since early 2005, but was reactivated in 2008 and 2009, both fora limited times (i.e. a prox. one to three months with low flows (25 — 500 gpm). Site 115 discharged for a couple of hours one day intarly 2015 due to a broken pipeline, which was subsequently repaired. Following approval in 2016 from CDPHE and DRMS to use a flocculant for mine water treatment, the site discharged during May through early July of 2016. 15