2011-05-31_REVISION - C1982057 ‎(2)‎

• Permit No: C1982057
• IBM Index Class Name: REVISION
• Doc Date: 5/31/2011
• Doc Name: 2nd Adequacy Review
• From: DRMS
• To: Seneca Coal Company
• Type & Sequence: TR73
• Email Name: SLB
• Email Name: SB1
• Email Name: MLT
• 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]
May 31, 2011
Roy Karo
Seneca Coal Company, LLC
P.O. Box 670
Hayden CO 81639
RE: Seneca II-W Mine (Permit No. C1982057)
Technical Revision No. 73
Pond 016 Slide Area Remediation Plan
Second Adequacy Review
Dear Mr. Karo:
COLORADO
D I V I S I ON OF
RECLAMATION
MINING
SAFETY
John W. Hickenlooper
Governor
Mike King
Executive Director
Loretta E. Pineda
Director
The Division has reviewed your responses to our preliminary adequacy review concerns for Technical
Revision No. 73 (TR-73) for the Seneca II-W Mine. We have the following comments on the
resolution of those items.
1. SCC's response provides additional details about the proposed construction sequence for the
backfilling of Pond 016A. This item has been satisfactorily addressed. The Division does
have one comment, however, regarding the final sentence of the response which reads,
"There will be no anticipated source of water for continued infiltration into the fill area."
While the reconfiguration of channels, as proposed with this revision, is intended to capture
and redirect the surface and subsurface flow entering the area of Pond 016, a more prudent
approach to design and construction would be to assume that water will inevitably find its
way into the fill.
2. SCC responds that NWCC will sample fill materials as they are being excavated from the slide
and placed in Pond 016A. Compaction testing during placement of the fill is a key part of the
process, but separate from the development of Standard Proctor curves. Moisture / Density
("Proctor") curves are developed in the laboratory prior to commencement of placement and
compaction. Curvos are developcd -for each separate typ^ of fill material for blend of
materials) likely to be used; each curve will have a specific maximum dry density and optimum
moisture content. During placement, accurate compaction results are dependent upon
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