2007-06-29_PERMIT FILE - C1981022A ‎(2)‎

• Permit No: C1981022A
• IBM Index Class Name: Permit File
• Doc Date: 6/29/2007
• Section_Exhibit Name: 2.05 Operation and Reclamation Plans
• Media Type: D
• Archive: Yes

Section - 2.05.3
Where: phi =Internal friction angle
• cohesion =Cohesion of material
gamma =Unit weight of material
The material characteristics from all three mines were used to calculate a safety factor for the East
Yard Coal Refuse Facility. The factor of safety against failure for final design conditions for the East
Coal Refuse Facility was determined utilizing acomputer-assisted limit equilibrium method of slices.
The program used to analyze the stability of the East Yard Coal Refuse Facility (GEOPRO) utilizes
the Bishop's method of analysis. The GEOPRO program was developed by Dr. N. F. Nash, under
the company name DataSurge. The most conservative factor of safety (lowest) was generated using
the material characteristics from the Blue Ribbon Mine site. These materials came from the neazby
West Elk Mine and aze physically similar to those generated by the Sanborn Creek Mine having come
from roof falls and mine development in the Sanborn Creek and Bear Mines. The stability analyses
indicated a minimum static safety factor for the East Yazd Coal Refuse Facility slopes of 1.6.
The East Yard Coal Refuse Facility area will be reclaimed by grading bench surfaces and outslopes to
astable configuration with rounded edges blending with the surrounding terrain. The regraded
surfaces will be capped with a minimum of 4 feet of suitable soil materials from the Elk Creek soil
stockpile and/or other sources and revegetated.
West Valley Coal Refuse Facility -The West Valley Coal Refuse site, located in the first ephemeral
drainage to the west of the existing Elk Creek surface facilities, was selected from several potential
sites evaluated because existing slopes aze flatter than several of the other prospective disposal azeas,
upslope drainage can be readily diverted, the azea provides sufficient disposal capacity £or currently
anticipated future mining operations, and the area is readily accessible from the existing mine facilities.
• The West Valley Refuse Facility will provide additional disposal capacity for approximately 120,000
cubic yards of refuse material. The facility will be accessed from the West Valley Haul Road.
The refuse materials to be placed in the West Valley Coal Refuse Facility will be essentially the same
as chose now going to the East Yazd Coal Refuse Facility since they will come from the same or
similar sources. The stability of the West Valley Coal Refuse Facility was analyzed using essentially
the same material characteristics as used in analyzing the East Yard Coal Refuse Facility and the
program PCSTABL (Version 6H, Purdue University, 1988) which utilizes the Modified Bishop
Method. The stability analyses indicated a minimum static safety factor for the West Valley Coal
Refuse Facility slopes of 2.1. The West Valley Coal Refuse Facility was designed and it's stability
evaluated by Westec as documented by the design report included in Exhibit 2.05-E4, Mine
Development Rock/Coal Refuse Facility Design. Designs were reviewed and modified as appropriate
to address DMG concerns by Balaz & Associates.
Soil materials from the West Valley Coal Refuse Facility have been stockpiled in the expanded Elk
Creek soil stockpile for future reclamation use. Surface drainage from the refuse pile, stripped areas,
and adjacent areas as well as any infilaadon intercepted by the underdrain will be routed to
Sedimentation Pond C to allow settlement of suspended solids prior to dischazge to the North Fork of
the Gunnison River. At any point in time, the area stripped for subsequent refuse placement and
related activities is not anticipated to exceed approximately one-third of the overall refuse pile
footprint. The progress and timing of refuse pile construction will be wholly dependent on the
amount of coal mine refuse generated by ongoing mining operations. This amount can vary
significantly dependent on mining conditions but is projected to range from approximately 3,000 to
6,D00 cubic yards annually. The West Valley Coal Refuse Facility area wiU be reclaimed in a manner
similar to that described for the East Yard Coal Refuse Facility.

TR-43 2.05-47a Revised August 2003