2018-11-05_PERMIT FILE - C1980007A

• Permit No: C1980007A
• IBM Index Class Name: Permit File
• Doc Date: 11/5/2018
• Doc Name: SUBSIDENCE EVALUATION
• Section_Exhibit Name: Exhibit 60E Subsidence Evaluation for the South of Divide and Dry Fork Mining Areas
• Media Type: D
• Archive: Yes

Subsidence Evaluation for the
Exhibit 60E Southern Panels, Apache Rocks West, & Sunset Trail Mining Areas Page 16
• Panels B26 to B29: Maximum tilt in this panel is predicted to range from 0.008 to 0.028
(0.8 and 2.8 percent) where 9 feet of coal is mined, and from 0.012 to 0.043 (1.2 to 4.3
percent) where 14 feet of coal is produced.
The E -seam panels E1 to E5 and B -seam panels B26 to B29 occur on top of one another, but are
not stacked based on the current panel layout. However, to be conservative, the maximum tilt
(Mm) of the two seams is assumed to be additive. The maximum tilt due to two -seam mining is
only expected to increase by roughly 20 percent over the maximum for the individual seams.
• Maximum tilt (Mm) for the B -seam and E -seam mining is projected to range from 0.010
to 0.050 (1.0 and 5.0 percent) where 9 feet of coal is mined, and from 0.016 to 0.077 (1.6
to 7.7 percent) where 14 feet of coal is produced. This estimate is only for the areas over
panels E1 to E5 and B26 to B29.
Apache Rocks West Mining Area:
Tilt above the longwall panels (panels E10 to E12) is projected to range between 2.2 and 2.3 Sm/d
for coal extraction thickness ranging between 10 and 14 feet. These values are based on subsidence
measurements at West Elk Mine (Table 1, Figure 5). The overburden depth above the longwall
panel centers ranges from 400 to 1,100 feet (Table 3).
• Panels E10 to E12: Maximum tilt in these panels is projected to range from 0.012 to
0.046 (1.2 to 4.6 percent) where 10 feet of coal is extracted, and from 0.017 to 0.064 (1.7
to 6.4 percent) where 14 feet of coal is mined.
Similarly, tilt above the longwall panels (panels B12 to B13 -A) are projected to range between 2.2
and 2.3 Sm/d for coal extraction thickness 12 feet. These values are based on subsidence
measurements at West Elk Mine (Table 1, Figure 5). The overburden depth above the longwall
panel centers ranges from 600 to 1,525 feet (Table 3).
• Panels B12 to B13 A: Maximum tilt in these panels is predicted to range from 0.012 to
0.029 (1.2 and 2.9 percent), where 12 feet of coal is mined.
The E -seam panels E10 to E12 and B -seam panels B12 to B13 -A occur on top of one another, but
are not stacked based on the current panel layout. The maximum tilt (Mm) of the two seams is
projected to be 20 percent more than the maximum tilt associated with single -seam mining.
• Maximum tilt (Mm) for the B -seam and E -seam mining is projected to range from 0.014
to 0.055 (1.4 and 5.5 percent) where 10 feet of E -seam coal is mined, and from 0.020 to
0.077 (2.0 to 7.7 percent) where 14 feet of E -seam coal is produced. This estimate is only
for the areas over panels E10 to E12 and B12to 13A.
Sunset Trail Mining Area: Maximum tilt above the four longwall panels (panels SS 1 to SS4) is
projected to range from 0.0057 to 0.0414 (0.6 to 4.1 percent) where 9 feet of coal is extracted, and
0.0108 to 0.0644 where extraction thickness is 14 feet.
831-032.816 Wright Water Engineers, Inc.
October 2018