2014-10-10_PERMIT FILE - C1996083A ‎(22)‎

• Permit No: C1996083A
• IBM Index Class Name: Permit File
• Doc Date: 10/10/2014
• Doc Name: Information on Environmental Resources
• Section_Exhibit Name: Volume I 2.04 Information on Environmental Resources
• Media Type: D
• Archive: Yes

2.04.7 Hydrology Description
The monitoring data for well 2010 -1 B suggests that the well was initially
contaminated during construction, but has since (by natural processes or by
intervention) reached an equilibrium state from which future changes may be
observed. Eliminating the first two monitoring events from the historic data
yields the following information. In well 2010 -1 B completed in the B -Seam
the average conductivity is 1,250 umhos /cm with a range of 1,220 to 1,270
umhos /cm, the average ph was 7.2 with a range of 7.0 to 7.3, average total
iron was 3.04 mg /I with a range of 2.43 to 3.82 mg /I and average manganese
was 0.09 mg /I with a range of 0.08 to 0.10 mg /I for the period September
2012 to October 2013.
The data for well 2010 -1 SS suggests that the well was poorly constructed
rendering the water quality data invalid. Eliminating the first two monitoring
events from the historic data yields more consistent information with the high
pH the most questionable data. In well 2010 -1 SS completed in a sandstone
water bearing zone located above the B -Seam the average conductivity is
2,900 umhos /cm with a range of 2,400 to 3,900 umhos /cm, the average ph
was 12.7 with a range of 12.5 to 12.9, average total iron was 0.32 mg /I with a
range of 0.18 to 0.63 mg /I and average manganese was 0.02 mg /I with a
range of <MDL to 0.02 mg /I for the period September 2012 to October 2013.
The PR -13 mine plan areas, west of Terror Creek, has up gradient and down
gradient monitoring wells. CWI -58 and CWI -DH -60 are up gradient
monitoring wells and 2010 -1 B and 2010 -1 SS are down gradient monitoring
wells. See Map 9 for well locations.
The down gradient monitoring wells will be mined through during 2015 based
on current mine plan timing. The Applicant intends to replace wells 2010 -1 B
and 2010 -1 SS with two down gradient points of compliance completed in the
same formations (above the B -Seam and in the B- Seam).
(b) The subsurface hydrologic regime may be divided into four discrete
subsystems: 1) the alluvium and terrace deposits associated with the North
Fork of the Gunnison River; 2) localized deposits of alluvium - colluvium within
the Hubbard Creek, and Terror Creek areas; 3) groundwater occurrences
within the Mesaverde Formation; 4) colluvial discharges associated with soil
PR -14 2.04-36- 06/14