2012-07-27_REPORT - C1981028

• Permit No: C1981028
• IBM Index Class Name: Report
• Doc Date: 7/27/2012
• Doc Name: 2011 AHR Letter
• From: DRMS
• To: Coors Energy Company
• Annual Report Year: 2011
• Permit Index Doc Type: Hydrology Report
• Email Name: JLE
• Email Name: SB1
• Media Type: D
• Archive: No

Require-
ment
Requirement
Requirement complied Comment
citation
with?
(yes / no)
Each pit disrupts the potentiometric surface. After final
backfilling, the pits can be expected to show full recovery
S. Restoration of
of the potentiometric surface outside of the pits and water
ground water CDRMS
table (unconfined) conditions inside the pits. No
yes
recharge to regulation

significant formation of surface spoil springs is expected
approximate 4.05.11(3)
due to the flat topography; therefore, there will be no loss
premining rate
of ground water flows to surface waters.

The Probable Hydrologic Consequences section of the
permit application predicts no appreciable impacts to
T.Prevention of
ground water systems outside the permit area. Water
adverse impacts CDRMS
quality data from well DH-96 indicate there have been no
yes
to ground water regulation

adverse impacts to ground water in the Ennis alluvium and
systems outside 4.05.11
eolian sand outside the permit area, several thousand feet
the permit area

The approved post-mining land use of most of the permit
area is rangeland (a few acres are approved for
U. Prevention of
commercial/industrial gas well use). As previously
impacts to ground
CDRMS discussed, ground water in the Ennis alluvium and eolian
water that
regulations sand have not been adversely impacted by mining and
yes
adversely impact

4.05.1(2) and reclamation operations at the Keenesburg Mine. Ground
the postmining
4.05.11 water in the Laramie coal and sandstone is not likely to have
land use within
had adverse impacts as explained in the previous discussion
the permit area
of Basic Standards for Ground Water.

V. Minimization of
disturbance to the
CDRMS Changes to the hydrologic balance within and adjacent to the
hydrologic
yes
regulation permit area, if any, would be the minimum that can be

balance within
4.05.1(1) expected from a surface coal mining operation.
and adjacent to
the permit area
W. Prevention of
material damage CDRMS Previously discussed monitoring data and ground water
yes
to the hydrologic regulation quality predictions indicate material damage has been

balance outside 4.05.1(1) prevented.
the permit area
The Probable Hydrologic Consequences section of the
CDRMS
X. Agreement of permit application predicts no appreciable impacts to the
regulation
observed hydrologic balance. Monitoring data in the hydrology
2.05.6(2) and
hydrologic report confirms this prediction. No impacts to ground
requirement
impacts with water have been found in downgradient alluvial/eolian
to keep
yes
sand monitoring well, DH-96. Should degradation of

information
hydrologic ground water by leachate immediately adjacent to pits
current,
occur, it would be a minor impact. No adverse impacts to
CDRMS
(PHC) projected surface water quality have been found at the Keenesburg
regulation
in mining permit Mine.

2.03.3(1)

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