2008-11-05_REVISION - C1981022

• Permit No: C1981022
• IBM Index Class Name: REVISION
• Doc Date: 11/5/2008
• Doc Name: Adequacy Review
• From: Joe Dudash
• To: Marcia Talvitie
• Type & Sequence: TR60
• Email Name: JJD
• 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]
DATE: November 5, 2008
TO: Marcia Talvitie
COLORADO
D IV IS I ON OF
RECLAMATION
MINING
SAFETY
Bill Ritter, Jr.
Governor
Harris D. Sherman
Executive Director
FROM: Joe Dudash Ronald W. Cattany
Division Director
RE: Elk Creek M ermit No. C-1981-022, Oxbow Mining LLC Natural Resource Trustee
Technical Revision No. 60, Bear Creek Fan Site, Adequacy Review
I have finished my review of the hydrology aspects for Technical Revision No. 60 for the Elk
Creek Mine. The following are my comments and questions:
1. Please describe the fan shaft construction measures that Oxbow will employ to prevent or
minimize ground water flow seeping into the fan shaft.
2. Rule 2.05.6(3) requires that ground water quantity be protected from proposed mining
operations. Please propose a hydrologic monitoring program to determine the occurrence
and quantity of water that seeps into the fan shaft from the Bear Creek alluvium.
3. The text at the beginning of Section 9 of the TR-60 submittal states that the entire Bear
Creek fan site is a small area exemption (SAE). However, the hydrology designs
presented in TR-60 designate only three portions of the disturbed area as SAEs. Other
disturbed areas, such as the cut slopes and pad area, are not designated as an SAE on Map
2.05-El-BCA2, nor are there any Sedcad designs for them. Please revise Map 2.05-E1-
BCA2 to indicate that the entire disturbed area is designated as an SAE and provide
appropriate Sedcad designs for the remaining disturbed areas.
4. Please explain why there is no small area exemption area at the south or outlet end of the
Bear Creek fan site culvert, as was done at the north or inlet end of the culvert.
5. There are no hydrology and sedimentology Sedcad designs for the proposed check dams
in drainage channel BCCD-1 to show that the check dams can handle the flow and meet
the settable solids limit of 0.5 ml/l. Please provide these Sedcad designs.
6. There are no Sedcad designs for the check dams that show the construction requirements
for the check dams. Since the check dams are part of a designed sediment control
structure, please revise the Sedcad designs to show their construction requirements.
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Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines