2008-03-21_PERMIT FILE - C1980007A ‎(46)‎

• Permit No: C1980007A
• IBM Index Class Name: Permit File
• Doc Date: 3/21/2008
• Doc Name: pg 2.05-200 to 2.05-300
• Section_Exhibit Name: 2.05.6 Mitigation of Surface Coal Mining Operation Impacts Part 2
• Media Type: D
• Archive: Yes

West Elk Mine
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Table 51
NPDES Effluent Limits for Dischar a From Sedimentation Ponds at West Elk Mine
Effluent Characteristics Maximum Allowable (m /L) 30-Da Avers a (m L)
Total Sus ended Solids 70 35
Total Iron 7.0 3.5
Oil and Grease 10.0
H S.U. 6.5 to 9.0
WEM has implemented an extensive water quantity and quafity monitoring program for both the
surface water flows and groundwater dischazges in the Minnesota Creek drainage and the North
Fork of the Gunnison drainage azea potentially affected by mining operations. Surface and
groundwater discharge monitoring sites will provide WEM with accurate information regarding
changes in water quantity and quality discharges. This information allows the mine personnel or
its consultants to determine what, if any, impacts aze occurring to the mine azeas water resources
as a result of mining activity.
The mine's water monitoring stations (both surface and subsurface) and monitored pazameters
for sites in both drainages is provided in Section 2.04.7(1) & (2) of this document. Table 9 of
that section presents the name of the site, the type of analyses to be performed at the sites, and
the frequency of monitoring. The locations of the monitoring sites are provided on Map 34,
which is contained in Volume 5. Also Exhibit 71 defines the monitoring plan for SOD.
The results of the water monitoring WEM or its consultants perform each year aze analyzed on
an annual basis and the results of the analyses are reported to CDMG. If significant changes are
noted during the monitoring event, WEM is obligated to report the changes immediately to
CDMG.
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In addition to quantity and quality monitoring of surface and groundwater resources, WEM has
committed to performing extensive monitoring of subsidence effects in the azeas of the
Minnesota Creek drainage potentially impacted by mining acfivities. A program to monitor the
subsidence impacts through the installation of survey monuments on the Monument Dam, dam
abutments, and shoreline of Minnesota Reservoir and seismic event recording stations on the
dam is included in this permit document. This monitoring activity will allow WEM to track
mining related impacts, if any, to this important irrigation structure. Tlris monitoring program is
discussed in the section titled "Detailed Description of Predicted Subsidence Phenomena -
2.05.6 (6)(e)(i)(D)", subsection "Effects Of Subsidence And Mine-Induced Seismic Activity On
Man-Made Structures And Renewable Resources", subsection "Minnesota Reservoir".
A plan to monitor the flows within the sections of Dry Fork that aze anticipated to be impacted
by subsidence in the SOD is also presented in "Detailed Description of Predicted Subsidence
Phenomena - 2.05.6 (6)(e)(i)(D)", subsection "Effects Of Subsidence And Mine-Induced
Seismic Activity On Man-Made Structures And Renewable Resources", subsection "Streams and
Ditches". This monitoring plan describes a frequent stream flow measurement program that will
allow WEM to take quick action if flows appear to be diverted due to mining related subsidence.
2.05-229 Revised November 1004 PRIG; Rev. March 2006; Rev, May 2006 PR10