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 47
Design Depth
Mining Height (ft)
of Cover (ft)
4.0
4.5
5
5.5
6
6.5
7
8
9
10
11
12
13
100
77.4
75.3
73.7
71.8
70.0
68.3
66.7
63.9
61.1
58.8
56.5
54.3
52.5
130
74.9
73.6
72.4
71.3
69.5
67.9
66.3
63.5
60.7
58.4
56.1
53.9
52.1
160
72.5
70.9
69.8
68.7
67.7
66.7
65.7
63.0
60.3
58.0
55.7
53.6
51.8
190
69.9
68.8
67.4
66.0
65.0
63.8
62.9
61.1
59.5
57.5
55.2
53.1
51.3
220
68.1
66.4
65.1
63.8
62.9
61.7
60.6
58.7
56.9
55.5
53.9
52.6
50.9
250
66.1
64.5
63.2
62.0
60.6
59.5
58.4
56.6
54.7
53.2
51.7
50.3
49.0
280
64.3
62.9
61.4
60.0
58.9
57.6
56.6
54.5
52.7
51.0
49.5
48.2
46.9
310
62.2
61.0
59.8
58.4
57.1
55.9
54.7
52.7
51.0
49.3
47.8
46.3
45.0
340
60.3
59.1
57.7
56.7
55.4
54.2
53.1
51.0
49.2
47.6
46.1
44.6
43.3
370
58.7
57.1
56.0
54.8
53.8
52.7
51.6
49.6
47.7
46.0
44.5
43.1
41.7
400
57.0
55.5
54.2
53.1
51.9
50.9
50.0
48.1
46.3
44.6
43.1
41.7
40.4
430
55.4
53.9
52.6
51.4
50.2
49.2
48.2
46.5
44.91
43.2
41.8
40.3
39.0
460
54.1
52.51
51.1
49.9
48.7
47.6
46.7
44.9
43.41
41.9
40.4
39.1
37.8
Coal Strength (psi) 900 Mining Width (ft) 11.50 No. Web Pillars 19
80
75
70
65
60
g
O
55
50
45
40
35
50
100 150 200 250 300 350 400 450 500
DEPTH OF COVER (ft)
Figure 31c. Raw Recovery -West Pit, F and E Seams
Agapito Associates, Inc.
Mining
Height
(ft)
�4
4.5
- -x - 5
5.5
6
6.5
7
8
9
-+- 10
11
12
13
�
I
r
I
I.�
I
I
1
�
I
100 150 200 250 300 350 400 450 500
DEPTH OF COVER (ft)
Figure 31c. Raw Recovery -West Pit, F and E Seams
Agapito Associates, Inc.
Mining
Height
(ft)
�4
4.5
- -x - 5
5.5
6
6.5
7
8
9
-+- 10
11
12
13