REV102136

• Permit No: C1981034
• IBM Index Class Name: Revision
• Doc Date: 2/5/1999
• Doc Name: PHASE II AND III BOND RELEASE EVALUATION RED CANYON MINE PN C-81-034
• From: DMG
• To: MINREC INC
• Type & Sequence: SL2
• Media Type: D
• Archive: No

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III IIIIIIIIIIIII III
DIVISION OF MINERALS AND GEOLOGY
Depanmenl of Natural Resources
1313 Sherman SI., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
February 5, 1999
Jim Stover
MINREC, INC.
2768 Compass Drive, Suite 101
Grand Junction, CO 81506
STATE OF COLORADO
RE: Phase II and III Bond Release Evaluation
Red Canyon Mine (Permit C-81-034)
Dear Mr. Stover.
This letter addresses issues pertaining to hydrologic impacts and subsidence effects which were
not resolved during the bond release inspection of December 1, 1998, nor in the inspection
report issued pursuant to that inspection, on December 17, 1998.
Hydroloaic Impacts
In the review of the 1997 Annual Hydrology Report, DMG identified a potential concern with
respect to rising water levels in monitoring well E-1, and questioned whether the water level rise
was associated with mine inflows. Based on E-1 water quality, the operator has speculated that
well E-1 may contain a mixture of water from the E-seam and the overlying alluvium, which
might explain the higher than expelled water level in the well. This assertion regaring the
source of increasing head in well E-1 has not been adequately documented. The mixing of
alluvial water and coal seam water could occur if the well was improperty constructed or has
perforated casing installed across both the alluvial aquifer and the wal seam. Information in the
permit application package (PAP) regarding well E-1 completion is incomplete and somewhat
contradictory. Accurate well completion information is important for understanding potential
sources of inflow to the well casing/borehole. Given the available information, potential sources
for the rising water inGude recharge from the glaciaUalluvial aquifer, inflow from the E-Seam
workings, and possibly infiltration from an irrigation ditch located adjacent to well E-1. Infiltration
from the irigation ditch is unlikely unless there is no surface casing or the surface casing is
damaged.
The Division is concerned that if the rising water level in well E-1 is associated with mine inflow,
there is the potential that the sealed and backfilled E-seam portals may discharge to the surface
in the future. surtace discharge from the portals was not projected in the permit application, and
as such the permit did not inGude provisions for safely handling and treating (if necessary) mine
discharge. Likewise, the probable hydrologic consequences evaluation (PHC) did not address
the potential impacts of surtace discharge from the portals. The PHC was based on the
projection that postmining discharge would be to the glaciaUalluvial aquifer, and eventually to
Ward Creek via the alluvial aquifer.
The operator will need to provide information to demonstrate that ultimate water level in the
abandoned workings will not result in discharge from the portals. Installation of a well into the
workings may be required. If it cannot be verified that surtace discharge will not occur, the
following measures will need to be taken:
~~
DEPARTMENT OF
NATURAL
RESOURCES
Roy Romer
Governor
lames 5. Lochhead
Ezecuiive Director
Michael B. Long
Division Dueaor