2006-03-28_REPORT - C1980007

• Permit No: C1980007
• IBM Index Class Name: Report
• Doc Date: 3/28/2006
• Doc Name: 2004 AHR Review Letter
• From: DMG
• To: Mountain Coal Company
• Annual Report Year: 2004
• Permit Index Doc Type: Hydrology Report
• Email Name: TAK
• Media Type: D
• Archive: No

Require-
Require- ment
Requirement ment compiled Comment
citation with ? (yes
i no
M. Content of CDMG
regulation
yes
pond reports 4.05.6(13)
Table 5 of
N. Sampling Sec.
frequency of 2.04.7 of
ground water CDMG yes
monitoring mining
wells permit C-
80-007
0. Para- Table 5 of
meters
Sec.
to be 2.04.7 of
analyze CDMG yes
d in
ground mining
permit C-
water 80-007
samples
CWQCC Regulation 41.5(C)(6)(b)(i) indicates ambient ground
water quality is the applicable standard and CWQCC Regulation
41.5(C)(6)(b)(ii) requires the use of water quality data
subsequent to January 31, 1994 for estimating ambient quality
because the West Elk Mine originated before that date.
Ground water points of compliance are not warranted for the
West Elk Mine because, as explained below, the mine does not
have the potential to cause what is considered a negative impact
to the quality of ground water under CWQCC Regulation
41.5(C)(6)(b)(i). The mine does not have the potential to
negatively impact the quality of ground water in bedrock units
because of the low permeability of those units (see following
discussion). The mine does not have the potential to negatively
P. Basic CWQCC impact the quality of ground water in alluvium because the
Standards regulation mine's discharge to the alluvium would be diluted by the
for Ground yes alluvial water (see following discussion).
Water 41.4 and
41.5
Rollins Sandstone -Although the Rollins Sandstone lies a short
distance, stratigraphically, beneath the mined sequence, high
head and low permeability in this Rollins precludes its invasion
by water from the mine workings; therefore, the mine does not
have the potential to degrade ground water in the Rollins
Sandstone. Flow from the Rollins into the mine workings is
more likely to occur than flow from the workings to the Rollins.
Sandstone and coal beds within the mined sequence - Holes
drilled to these units produce significant volumes of gas,
indicating the porosity is largely saturated with gas. The gas
saturation precludes the use of the water from these units.
Migration of gob leachate from the mine workings to these
sandstone or coal beds would not further impair the use of the
Page 3