2013-08-28_REVISION - M1990057

• Permit No: M1990057
• IBM Index Class Name: REVISION
• Doc Date: 8/28/2013
• Doc Name: TR-04 ADEQUACY REVIEW NO. 3
• From: DRMS
• To: OPERATOR
• Type & Sequence: TR4
• Email Name: MAC
• Media Type: D
• Archive: No

DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
STATE OF COLORADO
COLORADO
D I V I S I ON OF
RECLAMATION
MINING
SAFETY
August 28, 2013 John W. Hickenlooper
Governor
Nick Michael Mike King
Union Milling Company, LLC Executive Director
P.O. Box 620490
Loretta E. Pineda
Littleton, CO 80162 Director
Re: Leadville Mill; DRMS File No. M -1990 -057; Technical Revision No. 4 — Adequacy
Review No. 3
Dear Mr. Michael,
The Division has identified several other comments and questions that must be addressed prior to the
Division's decision due date. Please be advised that if you are unable to satisfactorily address any
concerns identified in this review before the decision date, it will be your responsibility to request
an extension of the review period. If there are outstanding issues that have not been adequately
addressed prior to the end of the review period, and no extension has been requested, the Division
will deny this application.
The Division met with Union Milling Company on August 23, 2013 to discuss the remaining
adequacy issues of Technical Revision No. 4. As we discussed during the meeting the Division has
concerns with the long term structural integrity of the geosynthetic clay liner (GCL) as it relates to the
seeps on the east side of the tailings storage facility (TSF). The Applicant has demonstrated to the
satisfaction of the Division that the GCL can be installed without premature hydration. However, the
Applicant must provide additional information which demonstrates that the GCL can withstand the
external hydrostatic pressure from the seeps. The Applicant may provide any available data from
laboratory or field testing from the manufacturer which demonstrates the capacity of the GCL to
withstand hydrostatic pressure.
As previously mentioned, if you are unable to provide satisfactory responses to any inadequacies prior to
August 31, 2013, it will be your responsibility to request an extension of time to allow for continued
review of this Technical Revision. If there are still unresolved issues when the decision date arrives and
no extension has been requested, the Technical Revision will be denied.
If you have any questions, please contact me at (303) 866 -3567 x8116.
Sincerely,
Lt C &----
Michael A. Cunningham
Environmental Protection Specialist
Office of Office of
Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines