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CDPHE Discharge Permit COG -850054 <br />The 18 Left Vent Fan Pad area drains into two sedimentation ponds which could discharge into a small unnamed <br />tributary leading to Fish Creek. In February 2015, TC submitted an application to CDPHE to make this a <br />permanent CDPS site (also see TR09-70). A permit (COG -850054) was subsequently approved by CDPHE, <br />effective April 15, 2010, expiring June 30, 2015. The permit is currently under Administrative Extension with <br />CDPHE, DRMS is copied on CDPHE DMRs for this site. The site did not discharge in 2015. <br />3.7 Mine Water Discharge Sites <br />Four mine water discharge sites are currently associated with the TC operations are monitored. Site 109 <br />(Twentymile Facility) requires quarterly monitoring for flows, field parameters, and water quality samples (when <br />flowing). Note that this site has not discharged in about 20 years, and will not be discharging in the conceivable <br />future. Site 115 (Fish Creek Borehole) is monitored as a CDPS discharge point in accordance with the <br />requirements set forth under CDPS Permit No. CO -0042161. <br />Two other mine water discharge sites are discussed in greater detail under a subsection to Section 3.6 above. To <br />dewater the old WMD and EMD, pumps and piping were installed to direct mine water from the Fish Creek Vent <br />Shaft (FCVS) and TORT #1, to the Area # 1 Pit. Overflow from the Pit passes through site 7 to Pond D, and <br />subsequently through CDPS Outfall 005A to Foidel Creek. Site 7 requires quarterly analyses when flowing per <br />DRMS Permit No. C-82-056. Site 7 discharged during the second and third quarters of 2015. Outfall 005A <br />requires weekly, twice monthly, monthly, and quarterly water quality sampling when flowing, under CDPS <br />Permit CO -0027154. <br />Site 115 had not discharged to Fish Creek since early 2005, but was reactivated in 2008 and 2009, both for a <br />limited times (i.e. approx. one to three months) with low flows (25 — 500 gpm). Site 115 discharged for a couple <br />of hours one day in early 2015 due to a broken pipeline, which was subsequently repaired. <br />Note that mine water is pumped from underground to the surface (from the old WMD), and was treated via an <br />electro -coagulation process at the surface, where water enters the 3 former treatment ponds that can be directed <br />through site 115. Treatment was not conducted in 2015. This water is pumped directly back into the mine for <br />underground dust suppression. Additional overflow piping was added so the treatments ponds cannot overflow. <br />Overflow water is directed back into the mine via a former pump well. <br />Historically, when pumping mine water from the Fish Creek Borehole (mine discharge site 115) the flow <br />becomes a contributor to sulfate levels in Fish Creek. Fish Creek in turn contributes to the sulfate levels in Trout <br />Creek. Trout Creek currently had a secondary drinking water standard limiting sulfate concentrations above 250 <br />mg/l. Table 53a provides historical water quality data. <br />15 <br />