2012-09-06_REPORT - C1981010

• Permit No: C1981010
• IBM Index Class Name: Report
• Doc Date: 9/6/2012
• Doc Name: DRMS Review of 2011 AHR
• From: DRMS
• To: Trapper Mining Inc
• Annual Report Year: 2011
• Permit Index Doc Type: Hydrology Report
• Email Name: JLE
• Email Name: SB1
• Media Type: D
• Archive: No

Page 3
Require-
ment
Requirement
Regulation
complied
Comment
with?
(yes / no)
M. Filing frequency
CDRMS
of pond reports
regulation
yes
4.05.9(17)
N. Timely filing of
CDRMS
pond reports
regulation
yes
4.05. 9(17)
O. Content of pond
CDRMS
reports
regulation
yes
4.05. 9(17)
P. Sampling
Table 4.8 -13a
frequency of
of CDRMS
groundwater
mining permit
Yes
monitoring wells
C -81 -010
Q. Parameters to be
Table 4.8 -13
analvzed in
of CDRMS
groundwater
mining permit
yes
samples
C -81 -010
Based on previous analysis by DRMS staff, the Third White
Sandstone aquifer is the only bedrock stratigraphic unit having
significant permeability that is in the groundwater flow path of
any coal spoil leachate; therefore, the Third White Sandstone
is the only bedrock stratigraphic unit whose ground water
quality may be negatively impacted by mining at Trapper.
Well GP -9 monitors the Third White Sandstone immediately
downgradient from Trapper's pits at a location where a
leachate plume can be expected to form, as explained in the
PHC (Section 4.83 of the penult). Well GP -9 is Trapper's
ground water point of compliance for the Third White
Sandstone as explained on permit page 4 -242. In general, the
2011 data from well GP -9 does not exceed Basic Standards
for Ground Water for a Domestic Use classification. (This
CWQCC
classification is for the Third White Sandstone in a Specified
R. Basic Standards
regulations
Area that extends outward from Trapper's northern permit
for Ground Water
41.4 and 41.5
yes
boundary on the east half of the mine to the axis of the Big
Bottom Syncline, a distance ranging between 1/2 and 3/4 mile
from the boundary.) There are exceedances of drinking water
standards for Fe and Mn, however, Fe and Mn exceedances
also occurred in GP -9 prior to mining in the area upgradient of
this well. Furthermore, other hydrogeologic and water quality
factors (e.g., concentrations of TDS and sulfate) indicate that
coal spoil leachate has not reached GP -9.
Trapper is not expected to negatively impact water quality in
the Third White Sandstone aquifer outside Flume Gulch, as
documented previously by DRMS staff.
Flume Gulch alluvium could also be contaminated by coal
spoil leachate. The Coy well is the ground water point of
compliance for the Flume Gulch alluvium, as explained on
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