APPCOR13392

• Permit No: C1981034
• IBM Index Class Name: Application Correspondence
• Doc Date: 5/8/1981
• Doc Name: GRAND MESA PERMIT APPLICATION FN C-034-81
• From: MLR
• To: GRAND MESA COAL CO
• Media Type: D
• Archive: No

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•Freliminary AdequacyReviow
Crand Mesa Coal Co. - Red Canyon Afine
May 8, 1981
2.05.3 (1) Operation Plan - Permit Arca
The applicant should submit any modification in the proposed mine plan
resulting From the poor roof conditions and information gained from the
recent drilling in the vicinity of Ward Creek. 7'Irc mine plan map, and
the appropriate geologic and hydrologic maps .should be amended to reflect
the changes in the mine plan and to indicate information obtained from
the drill holes.
Mine Facilities
1. The applicant should detail the measures that will ).~e taken to muffle
noise From the existing ventilation shaft fan, and any additional fans
that will be necessitated by mining tyre "D" seam and any future mine develop-
ment.
2. The applicant must submit specific plan drawing of all existing and
planned roads. Drawings should include typical cut and fill cross-sections
and centerline profiles. All drawings must be certified by a cegistered
professional engineer.
3. The applicant must define the use of a1I roads within the mine site, i.e.,
haul, Light duty or access, meet all requirements of the appropriate sections
of 4.03 pertaining to the designated road use, or apply in writing for a
variance from specific requirements of the zeyulations.
9. The roadway designated by GMCC as thr_ >czvicc Area road has a grade of
about 20o in some sections. The application shows the road grade as being
lOq. This may be accurate for overall grade, but extreme pitch grades also
need to be addressed.
2.05.3 (4) Ponds, Impoundments and Diversions
(1,~ With the completion of the proposed sediment control system, a number
~bf the existing ditches and culverts will apparently no longer be needed.
The applicant should indicate whether these structures, including ditches
8, 9, 12 and 19, the ditch between areas 9.and 12, and culverts I and K will
be removed or are to remain in place.
2. GMCC should explain the reason for several different calculations of
ditch peak flows. That is, what is the purpose of the calculations shown
in parenthesis?
From calculations l~erfoz'med in the office, it was found that none of the
designed ditches had the required 0.3 feet of freeboard at design flow.
Zn order to meet the requirements of 4.05.3(C)(b), all ditches must he
designed to provide 0.3 ft. of freeboard at design flow.
Estimated peak flows for ditches 9 and I2 in the affected area are in error.
Corrected estimates of peak flows must be presented, the ditches redesigned
to handle the revised peak and sufficient depth provided to meet the 0.3 ft.
of freeboard requirement.