2009-09-14_REVISION - C1980007 ‎(3)‎

• Permit No: C1980007
• IBM Index Class Name: REVISION
• Doc Date: 9/14/2009
• Doc Name: Preliminary Adequacy Review & Comments
• From: DRMS
• To: Mountain Coal Company
• Type & Sequence: TR119
• Email Name: TAK
• 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 C O L O R A D O

Phone: [phone] DIVISION OF
RECLAMATION
FAX: [phone] MINING

SAFETY
September 14, 2009
Bill Ritter, Jr.
Ms. Kathleen G. Welt Governor
Mountain Coal Company LLC Harris D. Sherman
Executive Director
P.O. Box 591
Ronald W. Cattany
Somerset, CO 81434 Division Director
Natural Resource Trustee
Re: West Elk Mine (Permit C-1980-007)
Technical Revision 119
Dear Ms. Welt:
The Division has conducted a preliminary adequacy review of the TR-119 application, and has
the following comments.
1. In accordance with Rule 2.05.3(4)(a)(ii)(B), please add a factor of safety analysis at an
appropriate location in the permit that demonstrates the embankment of Pond MB-5E will
have a minimum static safety factor of 1.3 for a normal pool with steady state seepage
saturation conditions (in compliance with Rule 4.05.9(8)(b)).
2. Rule 4.05.2(7) imposes the effluent limitations of 40 CFR Part 434 on discharges from
ponds MB-3 and MB-5E. The peak settleable concentrations in the 10-year storm
SEDCAD runs for those ponds exceed the 0.5 ml/1 limitation specified in 40 CFR, Part
434, Subpart F, section 434.63, paragraph (a)(2). Please explain how those calculated
peak settleable concentrations demonstrate the discharges will comply with the 0.5 ml/1
limitation. Is a storm exemption assumed?
3. The next to the last paragraph on page 2.05-33 refers to two inlet pipes, and then
discusses discharges from these pipes. Should these pipes be referred to as outlet pipes?
4. Please add to page 2.05-33 a description of how one cell of MB-5E is operated for
sediment control during a 10-year storm event. For example, describe detention prior to
discharge, when and from which pipes discharge occurs, and when gate valves for each
pipe will be opened or closed. Also, please explain why drawing CPP-L007.dwg shows
the elevation of the primary outfall as 6051.3, but the text on page 2.05-33 says the top
pipe in the 54-inch riser pipe (shown at elevation 6045.0 in the drawing) typically serves
as the primary discharge. Please explain when the top pipe would not serve as the
primary discharge.
5. In Table 42E, please either remove the asterisk next to MB-5E's 3-year sediment volume
or add a notation explaining its purpose.
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Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines