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

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Post-1981 movement of this point is due to reactivation
• of 7 North No. 1 mine (mined early 1972) -7 South No. 3
mine (late 1973) -6 South No. 3 mine (late 1975) subsid-
ence zones by longwall 202 (1 , 030 ft NE, mined mid-1983)
and longwall 203 , later combined with longwall 203 pri-
mary subsidence zone. See Figure 4 .
Point No. : TP-6
Type : control
Installed: 9/1984 Surveyed: 8/85
Location (mine coordinate system) : 11395.78N, 2830 . 90E
original Elevation (ft) : 11 ,750 . 17
Total Movement Since Installation (ft) : -0 .89
Estimated Coal Removed Within Subsidence Zone (ft) : 10 .00
Subsidence Ratio : 0. 09
Location Relative to Mine Workings : over longwall 102 , No. 1
mine; 1 ,330 ft WSW of 5 North, No. 2 mine.
Discussion: installed 9/84 , only survey 8/85. Within subsid-
ence zone of longwall 101 (325 ft NE) , area mined mid-1979,
unknown whether or not stable before 102 mined in this area,
early 1985 . See Figure 5 .
Point No. : MC-1
Type : monitoring
Installed : 1981 Surveyed: 1982 , 1983
Location (mine coordinate system) : 5677 .46N, 8268 .21E
original Elevation (ft) 11 ,454 .72
Total Movement Since Installation (ft) : +0. 01
Estimated Coal Removed Within Subsidence Zone (ft) : 8 . 00
Subsidence Ratio: --
Location Relative to Mine Workings: over 2nd Right, 3 South
No. 1 mine.
Discussion: both incremental movements measured- in 1982 and
183 within survey margin of error of +/-0 . 05 ft; therefore
assumed to be stable. This area was pillared in early 1970 ,
and it is not within the region of influence of any signif-
icantly-more-recent mining. See Figure 6 .
Point No. : MC-2
Type : monitoring
Installed: 1981 Surveyed: 1982 , 83 , 7/84 , 9/84 , 8/85
Location (mine coordinate system) : 9345 .20N, 4532 .33E
original Elevation (ft) : 11 ,696 .27
Total Movement Since Installation (ft) : -2 .03
Estimated Coal Removed Within Subsidence Zone (ft) : 8 .00
Subsidence Ratio: 0. 25
Location Relative to Mine Workings: over lw 102 near tailgate
startline, No. 1 mine; just north of Main Slopes below 5
North, No. 2 mine.
Discussion : in zone of influence of longwall 101 , No. 1 mine,
. area mined in late 1977 ; nearly stable by 7/84 . Movement
resumed with longwall 102 mining, which began late 1983 . The
highly-active lower Main Slopes of the No. 2 mine were devel-
oped from early 1979 to mid-1980. See Figure 7 .