2011-03-11_REPORT - C1981028

• Permit No: C1981028
• IBM Index Class Name: Report
• Doc Date: 3/11/2011
• Doc Name: 2010 AHR Letter
• From: DRMS
• To: Coors Energy Company
• Annual Report Year: 2010
• Permit Index Doc Type: Hydrology Report
• Email Name: RDZ
• Media Type: D
• Archive: No

Require-

Requirement Requirement
citation ment
complied
Comment
with?
(yes / no)
Each pit disrupts the potentiometric surface. After final
S. Restoration of backfilling, the pits can be expected to show full recovery
ground water CDRMS of the potentiometric surface outside of the pits and water
recharge to regulation yes table (unconfined) conditions inside the pits. No
approximate 4.05.11(3) significant formation of surface spoil springs is expected
premining rate due to the flat topography; therefore, there will be no loss
of ground water flows to surface waters.
The Probable Hydrologic Consequences section of the
T. Prevention of permit application predicts no appreciable impacts to
adverse impacts CDRMS ground water systems outside the permit area. Water
to ground water regulation yes quality data from well DH-96 indicate there have been no
systems outside 4.05.11 adverse impacts to ground water in the Ennis alluvium and
the permit area eolian sand outside the permit area, several thousand feet
downgradient from the mine's pits.
The approved post-mining land use of most of the permit
U. Prevention of area is rangeland (a few acres are approved for
impacts to ground commercial/industrial gas well use). As previously
water that CDRMS discussed, ground water in the Ennis alluvium and eolian
adversely impact regulations es
y sand have not been adversely impacted by mining and
the postmining 4.05.1(2) and reclamation operations at the Keenesburg Mine. Ground
land use within 4.05.11 water in the Laramie coal and sandstone is not likely to have
the permit area had adverse impacts as explained in the previous discussion
of Basic Standards for Ground Water.
V. Minimization of
disturbance to the
hydrologic
CDRMS
Changes to the hydrologic balance within and adjacent to the
balance within regulation yes permit area, if any, would be the minimum that can be
and adjacent to 4.05.1(1) expected from a surface coal mining operation.
the permit area
W. Prevention of
material damage CDRMS Previously discussed monitoring data and ground water
to the hydrologic regulation yes quality predictions indicate material damage has been
balance outside 4.05.1(1) prevented.
the permit area
CDRMS The Probable Hydrologic Consequences section of the
X. Agreement of regulation permit application predicts no appreciable impacts to the
observed
2.05.6(2) and hydrologic balance. Monitoring data in the hydrology
hydrologic requirement report confirms this prediction. No impacts to ground
impacts with
"
to keep water have been found in downgradient alluvial/eolian
probable information yes sand monitoring well, DH-96. Should degradation of
hydrologic
"
current, ground water by leachate immediately adjacent to pits
consequences
CDRMS occur, it would be a minor impact. No adverse impacts to
(PHC) projected
regulation surface water quality have been found at the Keenesburg
in mining permit
2.03.3(1) Mine.
Page 3