REP19890

• Permit No: C1981034
• IBM Index Class Name: Report
• Doc Date: 1/16/1995
• Doc Name: REVIEW OF ANNUAL HYDROLOGY REPORT RED CANYON MINE C-81-034
• From: DMG
• To: BARBARA PAVLIK
• Permit Index Doc Type: HYDROLOGY REPORT
• Media Type: D
• Archive: No

.. iii iiiiiiiiniu iii
STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Depanmem of Natural Resources
1313 Sherman SI., Room 215 li(I`~
Denver, Colorado 80203 III
Phone: [phone]
FAX: [phone]
DEPARTMENT OF
NATURAL
RESOURCES
To: D8n Mathews Roy Ramer
Governor
'~ Wmes 5. Lochhead
FrOID: Barbara Pavlik E~emiive Dueaor
Michael B. Long
Date: January 16, 1995 Division Director
Re: Review of Annual Hydrology Report
Red Canyon Mine (C-81-034)
I have reviewed both the surface and groundwater portions of the
above referenced AHR. Particular emphasis was placed on comparing
PHC predictions with current hydrologic data and assessing data
needs for the final bond release application in 1999.
1) The PHC predicted that there would be no postmining
discharge from the mine at the surface based on pre-
mining water levels in the E seam. Current conditions
appear to support this prediction. The low dip of the E
seam (3-4°) renders it unlikely that a discharge would
occur in the portal area. The operator predicts that the
mine would discharge to the alluvium rather than to the
surface.
2) The PHC predicts that a spoil aquifer with a peak
discharge of 30 gpm will develop in the underground waste
disposal area and backfilled areas of the reclaimed
topography. A spoil aquifer is not mentioned in the AHR.
This leads the Division to believe that there is no
evidence of a spoil aquifer (i.e., spoil springs) on
site. Please have the operator verify this.
3) The PHC's worst-case prediction for TDS concentrations in
the alluvial aquifer is 900 mg/1. Although the Division
recommended resumption of alluvial groundwater quality
monitoring in a letter dated December 13, 199A;; the
operator responded to that suggestion by stating that
alluvial groundwater quality monitoring was not
necessary, because there had been no evidence of
increasing TDS levels, according to previous monitoring.
This was apparently acceptable to the Division at the
time. However, it may be in the operator's best interest
to resume alluvial groundwater quality monitoring one or
two years prior to applying for final bond release in
order to demonstrate that its predictions of