2013-03-14_REPORT - C1982056 ‎(3)‎

• Permit No: C1982056
• IBM Index Class Name: REPORT
• Doc Date: 3/14/2013
• Doc Name: 2012 Annual Hydrology Report
• From: Twentymile Coal Company
• To: DRMS
• Annual Report Year: 2012
• Permit Index Doc Type: Hydrology Report
• Email Name: JDM
• Email Name: DIH
• Media Type: D
• Archive: No

representations of the 2012 flow rate and field conductivity data for Pond D at the Foidel Creek Mine and for
Pond E at the Fish Creek Tipple. Figure 114 depicts period of record total recoverable iron data for Pond E.
Note that ponds A (former Outfall 001A), and H (former Outfall 009A) were deactivated following Phase III
Bond release of the Eckman Park area, and were subsequently removed from the newly amended CDPS permit
on January 1, 2002. In late 2011 and early 2012, the Fish Creek Tipple area was reclaimed. This along with the
2012 drought appears to have resulted in decreased discharge at the site.
Construction Dewatering Permit COG - 850051
In July 2006, Twentymile Coal contacted CDPHE regarding the addition of this site (drainage for 6MN Pad area
and construction dewatering pond) and later submitted a Temporary Construction Dewatering — Wastewater
Discharge Application, which was subsequently approved ( Outfall 001A under CO- G072272). CDPHE requested
preliminary analyses of this water for alkalinity, COD, pH and TDS. A sample was collected and analyzed for
these parameters. A discharge channel was constructed in late July 2006, and weekly monitoring of discharge
from outfall 001A began in August 2006. Note that water was pumped from the sedimentation pond through
001A on an as needed/ sporadic basis. Pump flows were estimated. CDPHE Discharge Monitoring Reports are
copied to DRMS. TC subsequently applied for a CDPS permit to make 6MN a permanent Outfall. A permit
(COG- 850051) was subsequently approved in January 2010 by CDPHE, effective February 1, 2010, expiring
June 30, 2013.
Outfall 001A did not discharge in 2012, undoubtedly the result of low snow melt.
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 2012, TC 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
approximately six consecutive days of discharge from this site in 2012.
3.7 Mine Water Discharge Sites
Four mine water discharge sites associated with the TC operations are monitored. Site 109 requires quarterly
monitoring for flows, field parameters, and water quality samples (when flowing), and site 115 is monitored as a
CDPS discharge point in accordance with the requirements set forth under CDPS Permit 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 TORT #1, to the Area # l 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 did not discharge in 2012. Outfall 005A requires weekly, twice monthly,
monthly, and quarterly water quality sampling when flowing, under CDPS Permit CO- 0027154.
14