APPCOR10968

• Permit No: C1981038
• IBM Index Class Name: Application Correspondence
• Doc Date: 8/12/1980
• Doc Name: PERMIT APPLICATION FOR ORCHARD VLY MINE COLO WESTMORELAND INC
• From: MLR
• To: PETE EVANS
• Media Type: D
• Archive: No

STATE OF COLORADO Ril:nnRn U. I•A, rf,.v r~~o~
DEPARTMENT OF NATUgAL RESOURCES
H aryls D. Sherman. Executive Director
11IINED LAND RECI~,AMA'TION
423 Centennial Builtling, 1313 Sherman Street
Denver, Colorado 80203 Tel. [phone]
David C. Shelton
August 12, 1980 Director
T0: Pete livans ~
PROM: .Jim Pendleton ~~~~-
SUEJECT: Permit Application Po The Orchard Valley D1ine,
Colorado We_tmorcl Inc.
III IIIIII III IIII III
999
I have completed the review of the permit application and subsequent
submissions by Colorado Westmoreland, Inc. for the Orchard Valley
underground coal mine. I forward the following comments for your
consideration.
Problems lYhich Require ,amendment
(1) Request for variance from approximate original contour.
The application contains a technical presentation concerning the
relative slope stability of benches and portals backfilled to
approximate original contour versus benches and portals left in
their operational configuration. liowever, the application does not
address the question of the related slope stability of either
situation.
The permanent OSM and proposed Colorado regulations approach to
backfilling benches and portals to approximate original contour
does not address the relative stability of the backfilled versus
unbackEilled situation. Rather, those regulations allow variation
from backfilling to approximate original contour only if a minimum
static factor of safety of 1.3 cannot be achieved. The application
does not include a calculation of the static factor of safety for
either the backfilled or unbackEilled situation. The application
will have to be amended in order to include the calculation for
the backf.ill AOC situation. If the backfilled benches and portal
arc determined to be sub-standard in terms of slope stability, an
application for variance from AOC would then be appropriate.
(2) 1Vaste disposal pile stability.
The application contains no stability analysis or foundational
description for the proposed waste pile. The application 1ai11 have
to be amended to include the appropriate analysis. This analysis
should include treatment of topics such as; (1) a description of the
geology and hydrology of the proposed disposal area, (2) complete
physical and chemical analysis of the waste materials, (3) proposed
construction specificotions for the disposal bank, (4) descriptions
of any appropriate underdrain systems, (S) design configuration f.or