2014-10-10_PERMIT FILE - C1996083 ‎(8)‎

• Permit No: C1996083
• IBM Index Class Name: Permit File
• Doc Date: 10/10/2014
• Section_Exhibit Name: Volume IIIA Exhibit 15 Subsidence Prediction
• Media Type: D
• Archive: No

TABLE 15 -4
Probability of Chimney Collapse Through Overlying Rock
(data from Gray etal. 1977)
127 cases of chimney collapse to surface over Pittsburgh Seam, documented in the field.
Height Number of Cumulative Cumulative
Class Documented Number of Percent of
Interval Chimney Chimney Chimney
(feet) Collapses Collapses Collapses
200-210
1
1
0.8
190-200
0
1
0.8
180-190
0
1
0.8
170-180
0
1
0.8
160-170
0
1
0.8
150-160
1
2
1.6
140-150
3
5
3.9
130-140
1
6
4.7
120-130
0
6
4.7
110 -120
0
6
4.7
100 -110
2
8
6.3
90-100
2
10
7.9
80- 90
3
13
10.2
70- 80
5
18
14.2
60- 70
2
20
15.7
50- 60
8
28
22.0
40- 50
15
43
33.9
30- 40
21
64
50.4
20- 30
29
93
73.2
10- 20
29
122
96.1
0- 10
5
127
100.0
PR -14 -17- 03/14