2021-05-27_PERMIT FILE - C1981019 ‎(10)‎

• Permit No: C1981019
• IBM Index Class Name: Permit File
• Doc Date: 5/27/2021
• Doc Name: Geotechnical Stability Report For Highwall Mining At the Colowyo Coal Mine
• Section_Exhibit Name: Exhibit 23, Item 1
• Media Type: D
• Archive: No

March 21, 2014
Page 53
Design Depth
of Cover (ft)
Mining Height (ft)
4.0
4.25
4.5
4.75
5
5.25
5.5
5.75
6
6.25
6.5
6.75
7
100
77.4
76.5
75.3
74.4
73.7
72.5
71.8
70.7
70.0
69.3
68.3
67.6
66.6
120
75.4
75.0
74.2
73.7
73.0
72.2
71.5
70.4
69.7
69.0
68.0
67.3
66.3
140
73.5
73.1
72.3
71.9
71.2
70.4
70.0
69.7
69.0
68.6
67.6
67.0
66.0
160
72.1
71.3
70.6
69.8
69.4
68.7
68.0
67.7
67.0
66.7
66.0
65.7
65.1
180
70.3
69.6
68.9
68.2
67.8
67.1
66.5
65.81
65.4
64.8
64.2
63.9
63.3
200
69.0
68.3
67.6
66.9
66.2
65.6
64.9
64.3
63.7
63.1
62.8
62.2
61.6
220
67.4
66.7
66.1
65.4
64.7
64.1
63.5
62.9
62.3
61.7
61.1
60.5
60.0
240
66.2
65.5
64.9
63.9
63.3
62.7
62.1
61.5
60.9
60.3
59.8
59.2
58.7
260
65.0
64.4
63.4
62.8
62.2
61.3
60.7
60.2
59.6
59.1
58.3
57.8
57.3
280
63.6
63.0
62.3
61.7
60.9
60.3
59.5
58.9
58.4
57.6
57.1
56.6
56.1
300
62.3
61.6
61.0
60.4
59.8
59.0
58.5
57.7
57.2
56.4
55.9
55.4
54.8
320
61.0
60.4
59.8
58.9
58.4
57.8
57.3
56.8
56.0
55.5
54.8
54.3
53.7
340
59.7
59.1
58.3
57.8
57.2
56.71
55.91
55.41
54.9
54.4
53.8
53.1
52.6
Goal Strength (psi) btl
80
75
70
e
65
3
�a
60
55
671]
Mining Width (ft) 11.5U
50 100 150 200 250 300 350
DEPTH OF COVER (ft)
Figure 33c. Raw Recovery -West Pit, C Seam
Agapito Associates, Inc.
No. Web Pillars 19
Mining
Height
(ft)
-�- 4
4.25
mac- 4.5
4.75
5
5.25
5.5
5.75
6
--a-6.25
-6.5
6.75
7