1987-12-01_PERMIT FILE - C1981017 ‎(284)‎

• Permit No: C1981017
• IBM Index Class Name: PERMIT FILE
• Doc Date: 12/1/1987
• Doc Name: Subsidence Study By Dr. Bruce Collins
• Section_Exhibit Name: Chapter IV Appendix IV-F-4
• Media Type: D
• Archive: No

- 17 -
• Table 1 summarizes monitoring data for the 22 points dis-
cussed above.
TABLE 1
SUBSIDENCE MONITORING POINTS SUMMARY
POINT 1981- 1982- 1983- 7/3/84- 9/17-20/84- TOTAL
NO. 1982 1983 7/3/84 9/17-20/84 8/9/85 SUBSIDENCE*
TP-1 ns ns ns -0.97** -0.97 -1.94
TP-2 ns ns ns nsd** . nsd nsd
TP-3 ns ns ns nsd** nsd nsd
TP-4 ns ns ns -0.13** -0.06 -0.19
TP-5 0.00 -0.38 ns -0.66**/nsd -0.25 -0.91
TP-6 - - - i -0.89 -0.89
MC-1 +0.07 -0.06 ns ns ns +0.01
MC-2 -0. 12 -0.91 -0.01 -0.61 -0.29 -2.03
MC-3 -0.02 -0.50 ns -0.18 -0.20 -0.90(d)
MC-4 -0.09 -0.09 -1.38 -0.54 nsd -2.10(d)
MC-5 -0.97 -0.30 -0.46 nsd nsd -1.73
MC-6 +0.03 -0.24 -0.27 nsd nsd -0.48
MC-7 +0.02 -0.01 ns ns ns +0.01
MC-8 ns +0.04 nsd ns nsd nsd
MC-9 ns +0.02 ns ns nsd nsd
MC-10 - - - i -0.32 -0.32
MC-11 - - - i -0.47 -0.47
• MC-12 - - - i -0.10 -0.10
MC-13 - - - i -0.17 -0.17
MC-14 - - - i nsd nsd
MC-15 - - - i nsd nsd
MC-16 - - - i nsd nsd
*To 8/9/85; net total where both positive and negative movements reported.
**Since 1981 baseline survey.
ns: not surveyed.
nsd: no subsidence detected.
is installed September 1984.
(d) : differs from MSE report, 9/8/85 (MC-3, -0.89; MC-4, -2.12) .
Table 2 summarizes total movement recorded at each control
and monitoring point from Table 1, an estimate of coal removed
in the area affecting that point, and the subsidence ratio cal-
culated by dividing the total movement by the coal thickness
removed. It should be emphasized that for the most part total
coal removed is based on isopach maps and recollection; in most
cases there is no exact record of average coal thicknesses
removed at or near point locations.
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