2021-05-06_REPORT - C1981044 ‎(3)‎

• Permit No: C1981044
• IBM Index Class Name: Report
• Doc Date: 5/6/2021
• Doc Name: Annual Hydrology Report Adequacy Review
• From: DRMS
• To: Twentymile Coal, LLC
• Annual Report Year: 2019
• Permit Index Doc Type: Hydrology Report
• Email Name: RAR
• Email Name: JLE
• Media Type: D
• Archive: No

21. Prevention of
Comparisons with the Basic Standards for ground water and the
adverse impacts
CDRMS
baseline water data is discusses in item R. above. MCM believes
to ground water
regulation
that no significant impacts from mining had occurred on the
systems outside
4.05.11
groundwater system as a result of mining.
the permit area
22. Impacts to
The postmining land uses comprise rangeland/wildlife and
ground water
CDRMS
pastureland. See items R. S. and T.
that adversely
regulations
impact the
4.05.1(2) and
poshnining land
4.05.11
use within the
permit area
23. Minimization of
MCM reports no significant, unpredicted, or adverse impacts were
disturbance to
CDRMS
noted during groundwater hydrologic monitoring for 2019.
the hydrologic
regulation
balance within
4.05.1(1)
and adjacent to
the permit area
24. Prevention of
MCM reports that no significant, unpredicted, or adverse impacts
material damage
CDRMS
were noted during ground water and surface water hydrologic
to the hydrologic
regulation
monitoring for 2019.
balance outside
4.05.1(1)
the permit area
Section 2.05.6 of the permit discusses the probable hydrologic
25. Agreement of
consequences of the mining operation at the Williams Fork Mines.
observed
CDRMS
This section is focused primarily at discussing monitoring results
hydrologic
regulation
and trends from the 80's and early 90's. The possible impacts
impacts with
2.05.6(3)
discussed are very general for the most part and predicts that mining
PHC projected
should have no significant impact on the hydrologic balance. MCM
in permit
reports that no significant, unpredicted, or adverse impacts were
noted during hydrologic monitoring for 2019.
The ground water monitoring program appears adequate at this time.
MCM is reminded that well 913F requires quarterly sampling if the
26. Adequacy of
No. 9 Mine waste rock backfill area has undergone final grading.
groundwater
CDRMS
Level monitoring is required on a quarterly basis.
monitoring
regulation
4.05.13(1)
The sampling frequency discrepancy of alluvial wells AVF-3, 5 and
program
6 should be researched and corrected as needed.
MCM needs to determine if the YAW alluvial wells require
sampling.
27. Adequacy of
CDRMS
The surface water monitoring program appears adequate at this time.
surface water
regulation
monitoring
4.05.13(2)
program
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