2020-03-19_REPORT - C1981010 ‎(7)‎

• Permit No: C1981010
• IBM Index Class Name: Report
• Doc Date: 3/19/2020
• Doc Name Note: 2019 Annual Hydrology Report
• Doc Name: Annual Hydrology Report
• From: Trapper Mining, Inc.
• To: DRMS
• Annual Report Year: 2019
• Email Name: RAR
• Email Name: JLE
• Media Type: D
• Archive: No

Mine is presented on the attached CD in Appendix D. The wells are grouped on the water-level
plots according to aquifer where possible but, in most cases, are grouped by similar water-level
elevations. Table A-1 in Appendix A presents a tabulation of the water-level elevations for each of
the monitoring wells. Figure 2-1 presents the total annual precipitation at the Trapper Mine from
1978 through 2019. Precipitation declined from a high in 1983 to a low in 1988 and had increased
again to a peak in 1993 with a below average value in 1994. The years 1995 through 1997 had
above average precipitation relative to the Trapper Mine record, while 1998 through 2004 were
below. The precipitation in 2005 through 2011 was above or near normal while precipitation in
2012 was slightly below the 1988, 1994 and 2002 low precipitation years and 2013 precipitation was
equal to the Trapper Mine average while 2014 and 2015 were slightly above, 2016 slightly below
normal, 2017 above normal, 2018 below normal and 2019 above normal. Water levels in many of
the wells reflect the natural variations in recharge. These changes may lag the actual precipitation
events due to the time it takes the head change to move through the aquifer to the monitoring well.
Figure A-1 presents water levels versus time for wells GF-5 and P-5. The wells are
completed in the HI backfill and 2nd White Sandstone aquifers, respectively. Water levels in well
GF-5 slightly rose in 2007 and 2008 and have been fairly steady through 2019. Well P-5 went from
being dry in early 2010 to recovering four feet in late 2010 and 2011 but then was dry except for one
or two quarters in each of the last eight years.
The GC wells (GC-1, GC-2, GC-3, see Figure A-2) are located near the northeast corner
of the permit area (PA) slightly more than 1100 feet from mining activity. These wells are
completed in the HI, 3rd White and alluvial aquifers, respectively. The water-level changes in these
wells may not still be good indicators of natural recharge impacts on these aquifers due to the
upgradient mining. Water levels in well GC-1 have been overall steady from 2003 to 2009. In 2010
and 2011 the water level rose while a decline was observed in 2012 through 2019. Water levels in
Trapper Mining Company 2-4
2019 Annual Report