2008-05-02_REPORT - C1981044

• Permit No: C1981044
• IBM Index Class Name: REPORT
• Doc Date: 5/2/2008
• Doc Name: 2006 AHR Review Letter
• From: DRMS
• To: BTU Empire Corporation
• Annual Report Year: 2006
• Permit Index Doc Type: Hydrology Report
• Email Name: TAK
• Media Type: D
• Archive: No

Requirement Require-
ment Complied with?
Comment
citation (yes / no)
The disturbance to the hydrologic balance within
U. Minimization of and adjacent to the permit area caused by mining
disturbance to the CDRMS and reclamation at the Eagle Mines is the
hydrologic
regulation
yes minimum that can be expected from an
balance within
4.05.1(1) underground mining operation at this location.
and adjacent to Use of best management practices indicates
the permit area minimization of disturbance to the hydrologic
balance.
Mining and reclamation at the Eagle Mines have
not caused impacts to the hydrologic balance
outside the permit area. The probable hydrologic
consequences (PHC) section of the permit
application projects future impacts to be minor.
In 4~h quarter 2006 Eagle's mine water discharge
had TDS concentration of 900 mg/1, similar to
Prevention of
V past years. (An all-time high of 2,600 mg/1
.
material damage CDRMS occurred in 2005 when the pumps were reactivated
to the hydrologic regulation yes after being idle for a few months.) This mine
balance outside 4.05.1(1) water was discharged at a rate of 3.0 cfs to the
the permit area Williams Fork River when the receiving river
water probably had TDS of less than 300 mg/ with
flow of around 30 cfs. This discharge would have
caused TDS in the river to rise to 355 mg/l,
calculated as follows: [(30 cfs) X (300 mg/1) + (3.0
cfs) X (900 mg/1)] / [(30 cfs + 3.0 cfs)] = 355
mg/l. The calculated 355 mg/I is well below the
CDRMS material damage suspect level of
approximately 700 mg/1 for the Yampa River
Basin.
W. Requirement to The previously mentioned calculated TDS of 355
keep information mg/1 in the Williams Fork River is less than the
current maximum predicted in the Probable Hydrologic
Consequences (PHC) section of the permit
CDRMS application. Long-term (following cessation of
regulations mining) mine water pumping will cease at the
2.05.6(2) and yes Eagle Mines but there may be mine water seepage
2.03.3(1) of less than 1 cfs to the Williams Fork River
through the coal seam outcrops (see DRMS
Memorandum in SL-2 bond release file, dated
4/5/05). The PHC adequately accounts for this
ossible see a e.
X. Adequacy of CDRMS
ground water regulation yes
monitoring 4.05.13(1)
rogram
Y. Adequacy of CDRMS
surface water regulation yes
monitoring 4.05.13(2)
ro ram
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