PERMFILE134368

• Permit No: C1981022
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: Water Communication Potential from Overlying Workings /Abel, 1992
• Section_Exhibit Name: Exhibit 2.04-E4 Part 6
• Media Type: D
• Archive: No

Sanborn Creek Project Paqe 11 August 21, 1992
Table 3. Probability of chimney collapse through overlying rock
(data from Gray et al, 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
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