REV97518

• Permit No: C1980007
• IBM Index Class Name: Revision
• Doc Date: 8/14/1997
• Doc Name: ADEQUACY REVIEW MR 220 WEST ELK MINE PN C-80-007
• From: DMG
• To: MOUNTAIN COAL CO
• Type & Sequence: MR220
• Media Type: D
• Archive: No

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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Depanmcnl of Natural Resources
111 J Sherman 51.. Room ? I S
Denver, Colorado SU30}
Phone: UO}) 866-7567
FA%: (}031 BS?-RIUG
August 14, 1997
Ms. Christine Johnston
Mountain Coal Company
P.O. Box 591
Somerset, CO 81434
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~, ~ ~.
Re: Adequacy Review; Minor Revision No. 220 West Elk Mine; Permit No. C-80-007
I~~~~
DEPAFZTME[~IT OF
NATURAL
RESOURCES
Roy Romer
Govemw
lames S. Lochhead
Evecuove Director
Michael B. Lons
Division Dirrcror
The Division has the following remaining comments concerning the adequacy of MCC's responses,
regazding Minor Revision No. 220.
2. The Division agrees with and will approve the additional information provided for ditch D2-
6C and culvert C2-3A. The design information provided for ditch DCW-2 and watershed 21,
however, appear to be in error. The SEDCAD tun provided is based on a watershed azea of
1.8 acres with a curve number of 72. The previous run in Exhibit 66 was based on an azea of
5.87 acres, which is consistent with what DMG gets digitizing the azea. The curve number
should be 79, since additional azea will be disturbed. The map transmitted to the Division on
July 11, 1997 (copy enclosed) shows a fill azea which is roughly half the acreage of
watershed 21. DMG digitized these azeas, and found the disturbed azea to be 2.8 acres, and
the undisturbed 3.1 acres. A weighted average curve number, using 88 for disturbed azeas
and 70 for undisturbed azeas, is 78.54, which rounds up to 79. Please revise the design for
ditch DCW-2 accordingly.
5. MCC needs to address the requirements of Sections 4.05, 4.06, 4.09, and 4.15. Specifically,
MCC needs to specify the final location of the excess 3,000 CY of excess spoil material, and
demonstrate [hat the material will be stable; the fill will minimize disturbance to the
prevailing hydrologic balance; topsoil in the proposed location will be salvaged, stored and
replaced as required; and disturbed azeas will be revegetated appropriately. In addition, MCC
needs to demonstrate that the designated fill azea can be returned to approximate original
contour with the addition of the excess spoil.
6. The topsoil stockpile locations and volumes are now clear to DMG. We did note, however,
that there remain appazent errors or shortcomings in the information provided.
a. Topsoil stockpile #4, listed on Table 36A, is not on the referenced Map 53B.
b. Topsoil stockpile #6, shown on Map 53B, is not listed on Table 36A.
c. A number of stockpiles, including the pile on the MSB, is not labeled on the