2008-03-21_PERMIT FILE - C1980007A ‎(8)‎

• Permit No: C1980007A
• IBM Index Class Name: Permit File
• Doc Date: 3/21/2008
• Section_Exhibit Name: Exhibit 60E Subsidence Evaluation for the South of Divide & Dry Fork Mining Areas
• Media Type: D
• Archive: Yes

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TABLE 2
MAXIMUM SUBSIDENCE PARAMETERS FOR
snIITH nF DIVIDE MINING AREA (1)
Parameter Panels E1 - E4 (t = 8 to 14 Panels E5 - E8 (t =12 to Panel E9 (t =12 to 14 ft)
ft) 14 ft)
W/d:(2) Max E1: 1080 / 625 = 1.73 E5:1080 / 500 = 2.16 E9:1080 / 500 = 2.16
Min 1080 / 1425 = 0.76 1080 / 1100 = 0.98 1080 / 550 = 1.96
Max E2: 1080 / 400 = 2.70 E6: 1080 / 500 =2.16
Min 1080 / 1100 = 0.98 1080 / 1200 = 0.90
Max E3: 1080 / 500 = 2.16 ET 1080 / 550 = 1.96
Min 1080 / 1100 = 0.98 1080 / 1250 = 0.86
Max E4: 1080 / 400 = 2.70 E8: 1080 / 675 = 1.60
Min 1080 / 1025 = 1.05 1080 / 825 = 1.31
t=8ft t=14ft t=12ft t=14ft t=12ft t=14ft
SAP=acp•t(3) 0.80 to2.4ft 1.4 to4.2ft 1.2 to3.6ft 1.4 to4.2ft 1.2 ft 1.4 ft
(a?P=S.P/t) (0.1 to 0.3) (0.1 to 0.3) (0.1 to 0.3) (0.1 to 0.3) (0.1) (0.1)
Sm=a•t(4) 4.8 to6.4ft 8.4 to11.2ft 7.2 to 9.6 8.4 to11.2ft 8.4 to9.6ft 9.8 to11.2ft
(a = Sm/t) (0.6 to 0.8) (0.6 to 0.8) (0.6 to 0.8) (0.6 to 0.8) (0.7 to 0.8) (0.7 to 0.8)
Sm/d (5) 0.00377 to 0.00590 to 0.00576 to 0.00672 to 0.01527 TO 0.01782 To
0.0160 0.0280 0.0192 0.0224 0.0192 0.0224
Mm (2.2 to 2.3 Sm/d) 0.007 to 0.013 to 0.013 to 0.015 to 0.034 to 0.039 to
(6) 0.037 0.064 0.044 0.052 0.044 0.052
Em (in terms of Sm/d) 0.004 to 0.007 to 0.007 to 0.008 to 0.018 to 0.021 to
(7) (1.2 to 1.4 Sm/d) 0.022 0.039 0.027 0.031 0.027 0.031
-Em (in terms of -0.004 to - -0.007 to - -0.007 to - -0.008 to - -0.018 to - -0.021 to -
Sm/d) (7) (-1.2 to -1.5 0.024 0.042 0.029 0.034 0.029 0.034
Sm/d
Maximum Crack 1 5-10ft 5-15ft 5-10ft 5-15ft 5-10ft 5-15ft
Depth
2 10-20ft 15-35ft 15-25ft 15-35ft 15-25ft 15-35ft
Break Angle (s) 0-51 0 - 5° 0 - 5° 0 - 5° 0 - 5° 0-5*
Angle of Draw (s) 10 - 20° 10 - 20° 10 - 20° 10 - 20° 10 - 20° 10 - 20°
(i) Maximum tilt and strain parameters apply only to ground surfaces with slopes less inat OU peicant, vd1uc5 iiiay uc
greater on slopes
steeper than 30 percent.
(2) All panels are numbered according to planned panel identifications.
(3) Subsidence and subsidence factor above chain pillars.
(4) Subsidence (maximum vertical displacement) above longwall panel centers, based on planned coal extraction thickness
listed.
(s) Ratio of the range of maximum vertical displacement to overburden depth range for the nine planned longwall panels.
(6) Maximum range of tilt in terms of Sm/d; values of 2.2 to 2.3 Sm/d are obtained from the graph in Figure 5.
(7) Maximum range of horizontal strain in terms of Sm/d; values for tensile (positive) strain of 1.2 to 1.4 Sm/d and
compressive (negative) strain of -1.2 to -1.5 Sm/d are obtained from the graph in Figure 5.
(s) Maximum crack depth (in feet) in bedrock predicted to locally occur on or near steep slopes and ledges in the Minnesota
Creek and Lick Creek drainage areas and above barrier pillars and rigid chain (gate road) pillars. The first depth range (1)
is for bedrock sloping less than, or equal to, 30 percent; the second depth range (2) is for slopes more than 30 percent.
Add 5 to 15 feet where thick, brittle sandstones occur in ridges and near cliffs. No cracks are predicted to occur in alluvium.
No cracks are predicted to occur at the surface of colluvium thicker than about 10 feet.
(9) Angle measured from a vertical reference.
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