2010-06-04_PERMIT FILE - C1982056A ‎(9)‎

• Permit No: C1982056A
• IBM Index Class Name: Permit File
• Doc Date: 6/4/2010
• Doc Name: Pages 2.05-1 to 2.05-64
• Section_Exhibit Name: 2.05 Operation and Reclamation Plans
• Media Type: D
• Archive: Yes

Rockdust Distribution
. A rockdust tank located north of the portal area, as shown on Map 24, Surface Facilities and Freshwater Systems,
supplies rockdust to the underground mine (see Figure 16, Rockdust Bin Operations Design). The tank pad and
associated truck access /unloading area is surfaced with pit -run gravel to control drainage and erosion. A borehole
measuring 12.25 inches in diameter drilled to the underground workings supplies rockdust, and power for the Tank
Feeder Drive and Top Blower. The pipes inserted in the borehole for these purposes include a 6 5/8 -inch O.D. pipe and
a 2 3/8 -inch O.D. pipe, respectively. The remaining open volume around the pipes is filled with grout. The pad for the
bin consists of a solid one -foot thick footer and four concrete pillars. The total concrete volume is approximately 11
cubic yards.
Surface Facilities
The Foidel Creek Mine portal area is located in a partially backfilled final cut. This excavation was filled to an
elevation of 6,860 feet and leveled. Before fill materials were placed in the pit, a low - permeability barrier was
established against the highwall to isolate the spoils aquifer from the underground mine workings. Approximately
20,000 bcy of surficial materials high in clay and silt were required to construct a barrier berm about 15 feet in
thickness. An average depth of 1.5 feet of soil materials was removed from an area north of the portal pit to construct
the barrier. The suitability of the materials selected for the barrier is illustrated by the following textural analysis of soil
samples collected from the designated salvage site:
DESCRIPTION
% CLAY
% SILT
% SAND
Loam -Clay Loam
27
47
26
Clay Loam- Silty /Clay Loam
37
43
20
Pit walls have been pre -split or trim - blasted to an angle of 65 degrees to the horizontal. Blasting was conducted in
• accordance with all regulations and procedures presented in the Minor Revision of Technical Revision to Permit
No. 79 -177, Area 1, Final Pit. The 68,000 bcy of blasted rock was utilized to partially backfill the old Area 2
dragline pit, presently serving as the portal area to the 6,860 foot elevation, as described above. Highwall
modification and partial backfilling were designed to provide greater safety and enhance stability for the entrances,
by initiating the rock tunnels used for permanent entries in competent sandstone.
Detailed cross - sections of the final -cut that is being utilized as the staging area for the Foidel Creek Underground
Mine are shown on Map 25, Surface Area Cross - Sections.
The spoils to the south of the portal area were dozed down to a 2H:1 V slope to comply with stability requirements.
Three slope stability monuments have been installed as shown on Map 24, Surface Facilities and Freshwater
Systems. Past monitoring results indicate the slopes to be stable. Monuments will continue to be monitored and
the results submitted to CMLRD annually.
•
MR09 -238 2.05 -53.1 06/26/09