2014-06-06_REPORT - C1981044 ‎(7)‎

• Permit No: C1981044
• IBM Index Class Name: Report
• Doc Date: 6/6/2014
• Doc Name: Annual Hydrology Report
• From: Twentymile Coal Company
• To: DRMS
• Annual Report Year: 2013
• Permit Index Doc Type: Hydrology Report
• Email Name: JLE
• Email Name: SB1
• Media Type: D
• Archive: No

3.0 2013 HYDROLOGIC MONITORING PROGRAM
The WFM hydrologic monitoring program includes data collected specifically to meet requirements of the
DMG, as well as data collected to meet the requirements of the Colorado Wastewater Discharge Permit
System (CDPS). Note that "CDPS" parameters were formerly referred to as National Pollutant Discharge
Elimination System (NPDES) parameters in prior AHRs. Specific monitoring locations are illustrated on
Figure 2.
In June 2001, Technical Revision TRO1 -32 was approved, allowing suspension of many DMG hydrologic
monitoring requirements while the mine was in temporary cessation (TC). In 2005 BTU EC began to exam
options for future re- activation of the mine site. In view of this considerations, BTU EC revered back to the
active monitoring plan (pages 1 — 14 of Exhibit 29), during the second quarter of 2006. In the third quarter of
2013 the mine reverted back to temporary cessation monitoring, as it was decided that there were no short
term plans to reactivate mining. Permit documentation relating to monitoring requirements under TC is
provided as an attachment to the 2014 AHR.
WFM personnel will continue to be responsible for adhering to the monitoring requirements of its CDPS
permit. Thus, this AHR only addresses the data required under the TC monitoring plan:
• Bedrock well TR -7A,
• Alluvial well AVF -5,
• Surface water sites (Williams Fork) WF -1, WF -2,
• CDPS (Permit CO- 0034142) sites:
0 1) Mine discharge No. 5 Mine sump [CDPS Outfall 003, a.k.a. site 5D];
0 2) Mine discharge 7 North Angle Well Bore [CDPS Outfall 024, a.k.a. site 9P3], and
0 3) Spring - No. 1 StripPit [CDPS Outfall 022, a.k.a. site 1 SP].
Table 1 presents a summary of hydrologic monitoring requirements for these sites under TC (modified from
TRO1 -32, Appendix D of the TC monitoring plan). Field parameters are outlined in Table 2. Water quality
monitoring includes field parameters (Table 2), surface water quality parameters (Table 3), and CDPS
parameters (Table 4).
3.1 Groundwater Monitoring
3.1.1 Bedrock Wells
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