PERMFILE123352

• Permit No: C1980007
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: Exhibit 60 Subsidence Evaluation for Apache Rocks Mining Area & Box Canyon Lease Tract
• Media Type: D
• Archive: No

TABLE 2
• MAXIMUM SUBSIDENCE PARAMETERS FOR
APACHE ROCKS MINING AREAti1
•
Parameter Eastern Panels Western Panels
BSeam Mining ESeam Mining (11 feet)
Only BSeam Mining (12 feet)
W/d"' Panels 1 ,2. 3, 8 4 Panels 1, 2, 8 3 E-Seam Panels 1, 2, 8 3 B-Seam Panels 1, 2, 8 3
Max. 1SE. 950/1400 = 0.68 1:950/875 = 1.09 1: 950/1075 = 0.88 Sum of E 8 B
Min. 950/2200 = 0.42 950/1050 = 0.90 950/ = 0.76 Seam Parameters
Max. 2SE: 950/1000 = 0.95 2: 950/650 = 1 46 2: 950/850 = 1.12
Min. 950/1700 = 0.56 950/975 = 0.97 950/1175 = 0.81
Max. 3SE: 950/950 = 1.00 3:950/500 = 1.90 3: 950!700 = 1.36
Min. 950/1500 = 0.63 950/1000 = 0.95 950/ = 0.79
Max. 45E: 950/1125 = 0.84
Min. 950/1650 = 0.58
S~ amt 2.41o 6.Oft 0.6 to 3.6R 1.2 to 4.BR 4.6 to 13.88
(ate "t=S~/t) (0.2 to 0.5) (0.05 l0 0 3) (0.1 to 0.4) (0.2 to 0.6)
Sm=a4 4.8 to 9.6R 6.61o 8.Bft 72to 96R 13.8 to 18.4ft
(a=Sm/t"') (0.4 to 0 8) (0.6 to 0.8) (0.6 l0 0.8) (0.6 to 0 8)
S„Jd 0.00213 to 0.0101 0.00628 to 0.01760 0.00576 to 0.01371 -
S„ ~d' 0.00000095 to 0.0000106 0.0000060 to 0.0000352 0.00000461 to 0.0000196 -
M,~ (2.7•S„Jd) 0.006 to 0.027 0.017 to 0.048 0.016 l0 0.037 0.033 to 0.085
Cm (24~Sm/d')"' 0.0000228 to 0.000254 0.000144 to 0.000845 0.000111 to 0.000470 0.000255 to 0.00132
-Cm (-24~5„Jd')~`'~ -0.0000228 to -0.000254 -0.000144 to -0.000845 -0.000111 to A.000470 -0.000255 to -0.00132
Em (1.3~Sm/d) 0.003 to 0.013 0.008 to 0.023 0.008 to 0.018 0.016 to 0.041
-Em (-2.O~S,,,/d) -0.004 to -0.020 -0.013 to -0.035 -0.012 to -0.027 -0.025 to -0.062
Maximum Crack 50 to 100 50 to 100 50 to 100 75 to 150
Depth (R)'s' 75 to 150 75 to 150 75 to 150 100 to 200
Break Angle'n 0 to 5° 0 to 5° 0 to 5' 0 to 5°
Angle of Drawt^ 10 to 20° 10 to 20° 10 to 20° 10 to 20°
Notes:
(I) Maximum tilt, curvature and strain projections apply only to ground surface slopes less than 30%; values may be
greater on slopes steeper than 30°%.
(~) All panels numbered sequentially from north to south.
(3) Subsidence factor above chain pillars.
(4) Subsidence (actor above panel centers based on 12 foot coal extraction thickness.
(5) Numerical curvature values are in radians per foot (rad/R).
(6) tilaximum crack depth is projected to locally occur on or near steep slopes and cliffs on the Ranks of West Fla[iron
and flanking ridges above chain pillars, haulageways, and barrier pillars. The first crack depth range is for slopes less
than 30%: crack depths may be much less than this range, panicularly in shale and claystone.
(7) tvleasured from vertical reference.
C:\SJ I -032\ 181 and\Exhibit 60.doc
•
831-032.181
Wright Water Engineers, Inc.