2014-06-19_PERMIT FILE - C1981019A

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 6/19/2014
• Doc Name: Geotechnical Stability Report For Highwall Mining At the Colowyo Coal Mine
• Section_Exhibit Name: Exhibit 23, Item 1
• Media Type: D
• Archive: Yes

July 23, 2013
Page iii
Figure 30b.
Barrier Pillar Design Chart— South Taylor Pit, E and D2 /E Seams ........................43
Figure 30c.
Raw Recovery— South Taylor Pit, E and D2 /E Seams .............. .............................44
Figure 31a.
Web Pillar Design Chart—West Pits, F and E Seams ................. .............................45
Figure 31b.
Barrier Pillar Design Chart—West Pits, F and E Seams ............. .............................46
Figure 31c.
Raw Recovery—West Pits, F and E Seams ................................. .............................47
Figure 32a.
Web Pillar Design Chart—West Pit, D2 Seam ............................ .............................48
Figure 32b.
Barrier Pillar Design Chart—West Pit, D2 Seam ........................ .............................49
Figure 32c.
Raw Recovery—West Pit, D2 Seam ........................................... .............................50
Figure 33a.
Web Pillar Design Chart—West Pit, C Seam .............................. .............................51
Figure 33b.
Barrier Pillar Design Chart— West Pit, C Seam ......................... .............................52
Figure 33c.
Raw Recovery— West Pit, C Seam ............................................. .............................53
Figure 34.
Yield Condition in the E Seam for 684 psi In -Situ Strength ....... .............................56
Figure 35.
Vertical Stress in the F Seam for 684 psi E -Seam Strength ........ .............................57
Figure 36.
Yield Condition in the E Seam for 605 psi In -Situ Strength ...... .............................58
Figure 37.
Vertical Stress in the F Seam for 605 psi E -Seam Strength ....... .............................59
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