2010-09-03_REPORT - C1980007

• Permit No: C1980007
• IBM Index Class Name: REPORT
• Doc Date: 9/3/2010
• Doc Name: 2009 AHR Review Letter
• From: DRMS
• To: Mountain Coal Company, LLC
• Annual Report Year: 2009
• Permit Index Doc Type: Hydrology Report
• Email Name: TAK
• Media Type: D
• Archive: No

Require-

Requirement Requirement
citation ment
complied
Comment
with ?
(yes / no)
Q. Restoration of
ground water CDRMS Mining in the permit area cannot be expected to significantly decrease infiltration of snowmelt or
recharge to
i regulation
4
05
11
3 yes runoff into the subsurface. Monitoring data do not show an impact on recharge.
approx
mate .
.
(
)
remining rate
Data from the down-gradient B-seam monitoring well 1-11-1 indicate the West Elk Mine has not
caused adverse impacts to bedrock ground water outside the permit area. Water level fluctuated in
this well in 2009 due to gas flow from the well, preventing accurate water level measurements. Since
R. Prevention 2007, total iron in 1 -11 -1 has risen to more than 13 mg/l from historical levels below 1 mgl (dissolved
adverse impacts CDRMS iron remains negligible). The changes in iron content and water level coincided with the gas flow
systems ground outside water
s 4.05.11 regulation yes from the 1-11-1 well and the filling of B seam workings with water a short distance upgradient from
the permit area the well. The rise in total iron in well 1-11-1 could have been caused by water level rising in the
casing and dislodging iron from the inside of the casing. Alluvial (colluvial) monitoring wells that are
completed in North Fork River valley downgradient from the mine (GP-3 and GP-4) were too dry to
allow sampling in 2009, as in previous ears.
S. Prevention of
impacts to CDRMS
ground water regulations
that adversely 4.05.1(2) and yes
impact the 4.05.11
postmining
land use
Monitoring data indicate impacts to ground water and surface water have been the minimum that can
be expected for an underground coal mine. The most significant hydrologic impacts from mining at
T. Minimization of West Elk in 2009 was, as in previous years, mining in long-wall panels may have been the cause of
disturbance to CDRMS water level fluctuations in monitoring wells located within a few hundred feet of the workings.
the hydrologic regulation yes
balance within
and adjacent to 4.05.1(1) Water quality in the water of the North Fork of the Gunnison River showed no change in 2009 where
the permit area the stream flows past the mine, remaining near 100 mg/l above and below the mine in the sample
collected during irrigation season in August. As explained in item U below, monitoring data indicate
North Fork TDS remained well below a level of concern for irrigation water.
Page 5