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2009-09-14_REVISION - C1980007 (3)
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2009-09-14_REVISION - C1980007 (3)
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Last modified
8/24/2016 3:55:25 PM
Creation date
9/15/2009 11:33:07 AM
Metadata
Fields
Template:
DRMS Permit Index
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
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STATE OF COLORADO <br />DIVISION OF RECLAMATION, MINING AND SAFETY <br />Department of Natural Resources <br />1313 Sherman St., Room 215 <br />Denver, Colorado 80203 C O L O R A D O <br /> <br />Phone: (303) 866-3567 DIVISION OF <br />RECLAMATION <br />FAX: (303) 832-8106 MINING <br /> <br /> SAFETY <br />September 14, 2009 <br /> Bill Ritter, Jr. <br />Ms. Kathleen G. Welt Governor <br />Mountain Coal Company LLC Harris D. Sherman <br /> Executive Director <br />P.O. Box 591 <br /> Ronald W. Cattany <br />Somerset, CO 81434 Division Director <br /> Natural Resource Trustee <br />Re: West Elk Mine (Permit C-1980-007) <br />Technical Revision 119 <br />Dear Ms. Welt: <br />The Division has conducted a preliminary adequacy review of the TR-119 application, and has <br />the following comments. <br />1. In accordance with Rule 2.05.3(4)(a)(ii)(B), please add a factor of safety analysis at an <br />appropriate location in the permit that demonstrates the embankment of Pond MB-5E will <br />have a minimum static safety factor of 1.3 for a normal pool with steady state seepage <br />saturation conditions (in compliance with Rule 4.05.9(8)(b)). <br />2. Rule 4.05.2(7) imposes the effluent limitations of 40 CFR Part 434 on discharges from <br />ponds MB-3 and MB-5E. The peak settleable concentrations in the 10-year storm <br />SEDCAD runs for those ponds exceed the 0.5 ml/1 limitation specified in 40 CFR, Part <br />434, Subpart F, section 434.63, paragraph (a)(2). Please explain how those calculated <br />peak settleable concentrations demonstrate the discharges will comply with the 0.5 ml/1 <br />limitation. Is a storm exemption assumed? <br />3. The next to the last paragraph on page 2.05-33 refers to two inlet pipes, and then <br />discusses discharges from these pipes. Should these pipes be referred to as outlet pipes? <br />4. Please add to page 2.05-33 a description of how one cell of MB-5E is operated for <br />sediment control during a 10-year storm event. For example, describe detention prior to <br />discharge, when and from which pipes discharge occurs, and when gate valves for each <br />pipe will be opened or closed. Also, please explain why drawing CPP-L007.dwg shows <br />the elevation of the primary outfall as 6051.3, but the text on page 2.05-33 says the top <br />pipe in the 54-inch riser pipe (shown at elevation 6045.0 in the drawing) typically serves <br />as the primary discharge. Please explain when the top pipe would not serve as the <br />primary discharge. <br />5. In Table 42E, please either remove the asterisk next to MB-5E's 3-year sediment volume <br />or add a notation explaining its purpose. <br />Office of Office of <br />Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines
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