2011-02-14_PERMIT FILE - C1980007A ‎(3)‎

• Permit No: C1980007A
• IBM Index Class Name: Permit File
• Doc Date: 2/14/2011
• 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

TABLE 3
MAXIMUM SUBSIDENCE PARAMETERS FOR
DRY FORK MINING AREA "'
Parameter
Panels E2 t = 9 ft
Panels E3 - E6 t =10 ft
W /d:(2)
Max
Min
E2: 1080 / 1000 = 1.08
1080/1000 = 0.9
E3:
1080/800 =
1080/1200 =
1.35
0.90
Max
Min
E4:
1080/900 =
1080/1800 =
1.20
0.60
Max
Min
E5:
1080/1000 =
1080/1800 =
1.08
0.60
Max
Min
E6:
1080/1200 =
1080/1400 =
0.90
0.77
t =9ft
t =10ft
S = app - t (3)
a. =S. t
0.90 to 2.7 ft
0.1 to 0.3
1.0 to 3.0 ft
0.1 to 0.3
S =a - t (4)
a = S /t
5.9 to 6.1 ft
0.6 to 0.8
6.0 to8.Oft
0.6 to 0.8
Sm/d (5)
0.0059 to 0.0061
0.0033 to 0.010
M 2.2 to 2.3 Sm/d
(5)
0.013 to 0.0140
0.0073 to 0.023
E (in terms of S /d) (7)
1.2 to 1.4 S
0.0071 to 0.0085
0.0040 to 0.014
-E (in terms of S (')
-1.2 to -1.5 S
- 0.0071 to - 0.0092
- 0.0040 to -0.015
Maximum Crack
Depth (e)
1
2
5- 10 ft
5- 10 ft
10 - 20 ft
15 - 25 ft
Break Angle (9)
0 - 5°
0-5
Angle of Draw (9)
14 - 19°
14 - 19°
Maximum tilt and strain parameters apply only to ground surfaces with slopes less that 30 percent;
values may be greater on slopes steeper than 30 percent.
All panels are numbered according to planned panel identifications.
Subsidence and subsidence factor above chain pillars.
� Subsidence (maximum vertical displacement) above longwall panel centers, based on planned coal
extraction thickness listed.
Ratio of the range of maximum vertical displacement to overburden depth range for the nine planned
longwall panels.
Maximum range of tilt in terms of S /d; values of 2.2 to 2.3 S,,/d are obtained from the graph in Figure
5.
Maximum range of horizontal strain in terms of S /d; values for tensile (positive) strain of 1.2 to 1.4 S,,,/d
and compressive (negative) strain of -1.2 to -1.5 S,,,/d are obtained from the graph in Figure 5.
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.
�y� Angle measured from a vertical reference.