REV02697

• Permit No: C1981071
• IBM Index Class Name: Revision
• Doc Date: 9/10/1987
• Doc Name: Little Middle Creek - Adequacy Letter
• From: MLRD
• To: COLO YAMPA COAL CO
• Type & Sequence: PR1
• Media Type: D
• Archive: No

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STRTE OF COLOIuwv
Roy Romer, Govei
DEPARTMENT OF NATURAL RESOURCES
MINED LAND RECLAMATION DIVISION
DAVID C. SHELTON, Dlreetor
September 10, 1987
Mr. Rick Mills
Colorado Yampa Coal Company
29588 Routt County Road 27
Oak Creek, Colorado 80467
Re: Little Middle Creek Permit Revision - File No. C-81-071 -
Permit Revision No. 1
Dear Mr. Mills:
We have preliminarily reviewed Colorado Yampa Coal Company's (CYCC) most
recent modifications to the subject revision application, and certain issues
which are of concern or require further clarification are addressed below. We
have not yet received permanent channel construction and stabilization plans
for the Wadge Mine area, and as a result, have not yet initiated detailed
geomorphic evaluation of the proposed post-mining topography of the entire
Little Middle Creek Mining area.
Geology
1. The Division has previously expressed concern with respect to potential
acid formation problems in reclaimed Wolf Creek spoils due to the
presence of strata exhibiting suspect Acid-Base Potential (ABP) levels.
The application concludes that this will not be a problem because adverse
effects would be mitigated with overburden mixing.
We question the above conclusion based on the data from Drill Cores
026-84-36C, 026-84-10, 026-84-9, 026-87-1 and 026-87-2. Suspect ABP
levels were present in, respectively, 7.1%, 33%, 48%, 22% and 34% by
volume of the overburden cores. Research by Dollhopf et al.; 1978,
suggests that when critical parameter percentages exceed 5 to 15% by
volume of the overburden core, overburden mixing during the course of
mining generally does not sufficiently dilute the problem material.
Based on the above, we reouest that CYCC develop an appropriate regraded
spoil monitoring plan, and mitigation procedures to be implemented in the
event that areas of suspect pH or ABP occur on the regraded spoils.
Topsoil
2. The application proposes that topsoil would not be salvaged from 148 of
the 244 acres to be disturbed in the Wadge Mine Plan Area. Forty-nine
(49) of the 148 non-salvage acres occur on slopes steeper than 200.
The remaining 101 acres are non-steep slope areas on which topsoil
salvage could be safely conducted. The rationale for the partial topsoil
salvage is that only 6"-10" of topsoil would be re-applied to
423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203-2273 Tel. [phone]