2014-03-18_REPORT - C1981010 ‎(5)‎

• Permit No: C1981010
• IBM Index Class Name: Report
• Doc Date: 3/18/2014
• From: Trapper Mining, Inc
• To: DRMS
• Annual Report Year: 2013
• Permit Index Doc Type: Hydrology Report
• Email Name: JLE
• Email Name: SB1
• Media Type: D
• Archive: No

precipitation- and fairly steady water levels during- the 2012 low precipitation- year and the normal-
precipitation in 2013. These responses are- interpreted to be due to an increase in recharge followed
by a decrease in recharge. These -water levels -show -no response -to -the higher precipitation in 2005
while a good response in shown to the higher 2006 through 2011 precipitation. This data indicates
that a one year lag in the water level responses in well GP -5 to precipitation may occur. These
responses indicate that the mining from the QR seams, which is nearest in the F pit mining that began
in 1997, has not significantly affected water levels in well GP -5.
Figure A -11 presents the change in water -level elevation for alluvial- well -P=1, located -in
the Pyeatt drainage north of the PA. This data demonstrates classic seasonal responses, highs in
winter /spring, and lows in late summer /fall. Overall the water levels declined in well Pl in 2012 and
2013 due to less precipitation. Well P -3 is completed in the Lewis Shale outcrop, which is in contact
with the Pyeatt alluvium. It had demonstrated the same seasonal variations (Figure A -11) as -the
alluvial P -1 well but has been dry for a few years. Water -level elevations for the Johnson Gulch
alluvial well J -1 are also presented in Figure A -11. The J -1 water levels remained steady in 2012 and
2013, indicating that one year of below precipitation does not affect-these alluvial water levels.
2.2 GROUND WATER-LEVEL ELEVATION (PIEZOMETRIC MAP SUMMARY)
ITydro- Engineering developed three piezometric maps to show the water level flow
patterns for the QP, HI and 3rd White Sandstone aquifers at Trapper Mine. Water levels from the
fall of 2013 were used to develop these -maps. The structure maps for the coal seams-were used to
extend the piezometric contours in the proposed - permit extension area on the east side of Trapper
Mine. The dip of the beds change from mainly to the north to the northwest in the extension area.
This will cause the gradient in the ground water to gradually change from the north to the northwest.
Trapper Mining Company 2 -8
2013 Annual Report