2023-07-14_PERMIT FILE - C1981010 ‎(16)‎

• Permit No: C1981010
• IBM Index Class Name: Permit File
• Doc Date: 7/14/2023
• Doc Name: Summary of Geotechnical Design andf Operational Cnsiderations for Highwall Mining-I,J,N, and L Pits
• Section_Exhibit Name: Appendix X
• Media Type: D
• Archive: No

January 2, 2020 Page B-3
Agapito Associates, Inc.

Figure B-1b. J Pit, G2 Seam Barrier Pillar Design Chart
534-40 Trapper [534-40 Trapper_Design Charts18JUL2018.pptx]:dc/smvf (7-18-2018)
Design
Depth of Cover (ft) 3.6 3.8 4 4.2 4.4 4.6 4.8 5 5.2 5.4 5.6 5.8 6
50 3.8 3.9 4.0 4.0 4.1 4.2 4.2 4.3 4.3 4.4 4.5 4.7 4.9
65 6.0 5.9 5.9 5.8 5.9 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.6
80 7.9 8.1 8.3 8.5 8.6 8.7 8.6 8.6 8.6 8.5 8.6 8.7 8.8
95 9.6 9.9 10.1 10.3 10.6 10.8 11.0 11.2 11.4 11.6 11.8 11.8 11.8
110 11.3 11.6 11.9 12.2 12.5 12.7 13.0 13.3 13.5 13.8 14.0 14.2 14.5
125 12.9 13.3 13.6 14.0 14.3 14.6 15.0 15.3 15.6 15.9 16.2 16.5 16.7
140 14.6 15.0 15.4 15.8 16.2 16.5 16.9 17.3 17.6 18.0 18.3 18.6 19.0
155 15.3 16.1 16.8 17.5 18.0 18.4 18.8 19.2 19.6 20.0 20.4 20.8 21.1
170 15.6 16.4 17.1 17.9 18.7 19.4 20.2 20.9 21.6 22.0 22.5 22.9 23.3
185 17.0 17.5 18.0 18.4 19.0 19.8 20.6 21.3 22.1 22.8 23.6 24.3 25.1
200 18.4 19.0 19.5 20.0 20.5 21.0 21.5 22.0 22.5 23.2 24.0 24.8 25.6
215 19.9 20.4 21.0 21.6 22.1 22.6 23.2 23.7 24.2 24.7 25.2 25.7 26.1
230 21.3 21.9 22.5 23.1 23.7 24.3 24.8 25.4 25.9 26.5 27.0 27.5 28.1
Coal Strength (psi)568 Mining Width (ft)11.50 No. web pillars 19
Pillar widths in italics have width-to-height ratios of 0.8
Mining Height (ft)
0
5
10
15
20
25
30
50 70 90 110 130 150 170 190 210 230REQUIRED BARRIER PILLAR WIDTH (ft )DEPTH OF COVER (ft)
3.6
3.8
4.0
4.2
4.4
4.6
4.8
5.0
5.2
5.4
5.6
5.8
6.0
Mining
Height
(ft)