2022-01-27_PERMIT FILE - C1981019 ‎(7)‎

• Permit No: C1981019
• IBM Index Class Name: Permit File
• Doc Date: 1/27/2022
• Doc Name: Addendum Collom and South Taylor Highwall Mining Geotechnical Design
• Section_Exhibit Name: Volume 20 Exhibit 27 Item 7
• Media Type: D
• Archive: No

Mr. Lee Sampson
December 7, 2021
Page 6

Agapito Associates, Inc.

Design
Depth of Cover, ft 4 5 6 7 8 9 10 12 14 16 18 20 22
100 7.2 7.8 8.4 9.0 9.4 9.9 10.3 12.0 14.0 16.0 18.0 20.0 22.0
140 10.8 12.0 13.0 13.9 14.7 15.5 16.2 17.5 18.7 19.7 20.7 21.6 22.4
180 14.7 16.4 17.6 18.9 20.2 21.3 22.3 24.3 26.1 27.7 29.2 30.6 32.0
220 16.4 20.0 22.3 24.0 25.6 27.1 28.6 31.2 33.6 35.8 37.9 39.9 41.8
260 18.8 21.1 24.3 28.0 31.1 33.0 34.8 38.1 41.2 44.0 46.7 49.3 51.7
300 21.7 24.4 26.9 29.2 32.4 36.0 40.0 45.1 48.8 52.3 55.6 58.7 61.7
340 24.9 27.8 30.5 33.2 35.7 38.1 40.9 48.0 56.0 60.6 64.5 68.2 71.7
380 28.1 31.4 34.4 37.2 40.0 42.8 45.4 50.4 57.0 64.0 72.0 77.7 81.8
420 31.3 35.0 38.4 41.6 44.5 47.4 50.4 56.0 61.4 66.7 74.0 81.2 88.2
460 34.5 38.7 42.4 45.9 49.2 52.3 55.3 61.7 67.6 73.4 78.9 84.6 92.2
500 37.7 42.3 46.4 50.3 53.9 57.3 60.6 67.3 73.9 80.3 86.4 92.4 98.2
540 40.9 45.9 50.5 54.7 58.6 62.4 65.9 72.9 80.2 87.2 94.0 100.6 107.0
580 44.1 49.5 54.5 59.0 63.3 67.4 71.3 78.5 86.4 94.1 101.5 108.8 115.8
Coal strength, psi 900 Mining width, ft 11.50 No. web pillars 19
Pillar widths in italics have width-to-height ratios of 1.0
Mining Height, ft
7
11
15
19
23
27
31
35
39
43
47
51
55
59
63
67
71
75
79
83
87
91
95
99
103
107
111
115
100 140 180 220 260 300 340 380 420 460 500 540 580REQUIRED BARRIER PILLAR WIDTH, ft DEPTH OF COVER, ft
4
5
6
7
8
9
10
12
14
16
18
20
22
Mining
Height,
ft
Figure 2b. Barrier Pillar Design Chart—South Taylor G78 Seam