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 50
Design Depth
Mining Height (ft)
of Cover (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
74.7
73.9
73.1
72.7
71.9
71.6
70.8
70.4
69.7
69.0
68.0
67.3
66.4
125
71.6
71.2
70.4
69.7
69.0
68.6
68.0
67.3
67.0
66.3
65.7
65.3
64.7
150
69.4
68.7
68.0
67.3
66.6
66.0
65.3
64.7
64.1
63.5
63.1
62.6
62.0
175
67.0
66.4
65.7
65.0
64.1
63.5
62.9
62.3
61.7
61.1
60.6
60.0
59.5
200
65.1
64.5
63.5
62.9
62.0
61.4
60.9
60.0
59.5
58.9
58.4
57.9
57.4
225
62.7
62.1
61.5
60.9
60.3
59.5
59.0
58.2
57.7
56.9
56.4
55.9
55.2
250
60.6
59.9
59.1
58.6
58.0
57.5
56.9
56.4
55.7
55.2
54.5
54.1
53.4
275
58.7
57.9
57.2
56.6
55.9
55.4
54.9
54.2
53.7
53.2
52.8
52.2
51.7
300
56.8
56.0
55.3
54.6
54.1
53.4
52.7
52.3
51.6
51.2
50.6
50.2
49.8
325
55.2
54.3
53.6
52.9
52.2
51.6
51.0
50.3
49.9
49.3
48.8
48.4
47.8
350
53.5
52.8
51.9
51.3
50.7
49.9
49.3
48.7
48.1
47.6
47.0
46.5
46.0
375
52.1
51.2
50.6
49.8
49.0
48.4
47.7
47.2
46.6
46.0
45.5
45.0
44.5
400
50.7
49.9
49.1
48.4
47.6
46.9
46.2
45.7
45.1
44.6
44.0
43.5
42.9
Coal Strength (psi) 651 Mining Width (tt) 11.5U
75
70
60
O
3 55
50
45
40 t
50
DEPTH OF COVER (ft)
Figure 32c. Raw Recovery -West Pit, D2 Seam
Agapito Associates, Inc.
No. Web Pillars 1y
Mining
Height
(ft)
0 4
425
- 4.5
4.75
5
5.25
5.5
5.75
6
6.25
-6.5
6.75
7