REV105130

• Permit No: C1980007
• IBM Index Class Name: Revision
• Doc Date: 5/15/1995
• Doc Name: MINOR REVISION 150 WEST ELK MINE PN C-80-007
• From: DMG
• To: MTN COAL CO
• Type & Sequence: MR150
• Media Type: D
• Archive: No

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999
STATE OF COLORADO
DIVISION Of MINERALS AND GEOLOGY
Deparlmem of Natural Resources
1 313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: f3031 8328106
May 15, 1995
Ms. Kathleen Welt
Mountain Coal Company
P.O. Box 591
Somerset, CO 81434
RE: Minor Revision No
Dear Ms. Welt;
Upon further review of
Lone Pine gulch area,
which must be resolved
II~~~
DEPARTMENT OF
NATURAL
RESOURCES
Roy Romer
Governor
dames 5. Lochhead
Execw rve Directrr
m¢hael B. Long
Division D~retlor
150; Aest Elk Mine; Permit No. C-80-007
the revised SEDCAD demonstration for the
the Division has some additional concerns
prior to approval of Minor Revision #150.
Greystone's response to the Division's question regarding the
location of a silt fence on the fan bench (#1) , states that no
credit to water quality is recognized by either small area
exemption demonstration for silt fencing and they believe that an
element that does not contribute to the SAE demonstration should
not be presented as an integral element of the demonstration. The
Division disagrees. A SEDCAD demonstration should not be relied on
entirely to demonstrate that a recently disturbed area will produce
sediment levels below the maximum allowable level. Because the
area will be disturbed, additional structures such as silt fences,
hay bales, etc. should be utilized instead of relying only on the
natural vegetation to control sediment. Rule 4,05.5 discusses that
additional contributions of sediment should be prevented and that
erosion should be minimized to protect topsoil, vegetation, fish
and wildlife, and the hydrologic balance. Some of the sediment
control methods listed in this rule include retaining sediment
within disturbed areas and using straw dikes, riprap, check dams,
mulches, vegetative sediment filters, dugout ponds, and other
measures to reduce overland flow velocity, reduce runoff volume, or
trap sediment. The current SAE demonstration in the permit states
that best management practices of ditch feather distribution and
silt fences or straw bales for energy dissipation, and silt fences
to arrest erosion, are part of the facility. This statement has
been omitted from the revised demonstration and should be included
in the demonstration.
Until vegetation has a chance to stabilize the recently disturbed
slopes, and while construction is being completed, the Division
recommends that other structures be relied on in the beginning to
control erosion by keeping sediment within the disturbed area; to