2010-12-17_REVISION - C1981019 ‎(108)‎

• Permit No: C1981019
• IBM Index Class Name: Revision
• Doc Date: 12/17/2010
• Doc Name: Rule 2.05 Operation and Reclamation Plans
• Type & Sequence: PR3
• Media Type: D
• Archive: No

RULE 2 PERMITS
As discussed during the permitting of the South Taylor Mining Area (PR -02), as long as the total
percentage does not exceed 15% of the total truck/shovel sequence for each drill hole, suitability should
not be an issue based upon the upper overburden seam quality and the expected dilution of lower
overburden materials (more likely to exhibit elevated parameter levels) through mixing as part of the
logical mining sequencing of overburden and coal removal in the Collom area.
In the following analysis, Colowyo demonstrates the likelihood spoil material placed near the surface of
reclamation final regraded overburden areas will exceed the suitability range for overburden criteria (as
described within Table 2.04.6 -5) is low. This demonstration was completed by showing the total
percentage of unsuitable material as it relates to the drill hole data shown in Volume 17, Exhibit 6 Item 9
for the sources of the majority of overburden to be generated in the area. A review of the analysis
spreadsheet for drill hole C -04 -04 shows that the source of all elevated SAR levels (> 15.0) originates
from the bottom 121 feet of overburden from the bore hole. Normal overburden haulage and sequencing
will ensure this material will not contribute to elevated SAR levels on the reclaimed surface post- mining
in the Collom expansion area.
Drill Hole C -04 -14
Unsuitability range in feet:
SAR > 15 = 27.6 feet
Se > 0.3 = 7.3 feet
B > 5.0 = 0 feet
Sat <25 or >80 = 45.35 feet
Mo> 1.0 =0feet
10 Total Drill Hole Depth = 354.3 feet
Total Percentage of unsuitable material:
SAR = 27.6 feet/354.3 feet = 7.7900084674%
Se = 7.3 feet /354.3 feet = 2.0606007903%
B = N/A
Sat = 45.35 feet /354.3 feet = 12.799887101%
Mo = N/A
Drill Hole C -04 -25
Unsuitability range in feet:
SAR > 15 = 69.6 feet
Se > 0.3 = 15.15 feet
B > 5.0 = 0 feet
Sat <25 or >80 = 83.8 feet
Mo> 1.0 =0feet
Total Drill Hole Depth = 639.7 feet
Total Percentage of unsuitable material:
SAR = 69.6 feet/639.7 feet = 10.880100047%
Se = 15.15 feet/639.7 feet = 2.3682976395%
B = N/A
Sat = 83.8 feet /639.7 feet = 13.099890574%
Mo = N/A
0 Drill Hole C -04 -04
Unsuitability range in feet:
Collom - Rule 2, Page 96 Revision Date: 1/23/09
Revision No.: PR -03