2008-01-24_APPLICATION CORRESPONDENCE - C2008086

• Permit No: C2008086
• IBM Index Class Name: Application Correspondence
• Doc Date: 1/24/2008
• Doc Name: DRMS Comments on Subsidence Section of PDEIS
• From: DRMS
• To: BLM and URS
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
COLORADO
DIVISION O F
RECLAMATION
MINING
- &-
SAFETY
Bill Ritter, Jr.
Governor
DATE: Janua 24 2~~g
~ Harris D. Sherman
Executive Director
Ronald W. Cattany
TO: Glenn Wallace (BLM), Bill Killam (URS) Division Director
Natural Resource Trustee
FROM: Dan Mathews
RE: Colorado DRMS Comments on Subsidence Section of PDEIS
FILE: CAM Redcliff Project
The subsidence report included in the Preliminary Draft Environmental Impact Statement
(PDEIS) is appropriately detailed for a DEIS, and predictions are based on standard,
widely used methodology. We have no objections to the report. Our office will conduct
a detailed review for compliance with DRMS subsidence regulations upon submittal of a
permit application, and we may require additional documentation or site specific
modifications in the context of the mining and reclamation permit. For example, based
on site specific considerations, the recommended 200 foot minimum overburden
thickness beneath intermittent or perennial streams may not be considered "conservative"
for an 11 foot thick seam. Conversely, the potential threat to range livestock posed by 2"
wide subsidence cracks may be so remote, that the possible minimum overburden cover
limits suggested in the report may be overly restrictive.
One comment we have is that the report speaks to rockfall concerns, which are legitimate.
A concern related to rockfall that was not identified in the subsidence report would be
possible damage to cultural resources such as historic/prehistoric rock art or dwellings
associated with steep sandstone cliffs. Ute and Fremont culture rock art sites have been
identified in the adjacent Munger Canyon permit area, and it is possible that such artifacts
might be present in the Red Cliff study area. If cliff faces that are currently a rockfall
hazard to people or structures exist, or if historic/prehistoric rock art or dwellings are
present, a hazard analysis will need to be conducted to determine what the baseline
hazard is and how mining might exacerbate that hazard.
C: Mike Boulay, DRMS Grand Junction
Denver File
Office of Office of
Mined Land Reclamation Denver Grand Junction Durango Active and Inactive Mines