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 3
MAXIMUM SUBSIDENCE PARAMETERS
BOX CANYON MINING AREA"'
Parameter Panels #1 and #2'=' Panel #3 Panels #4 through #6
W/d
Max.
Min.
Max.
Min.
#1: 11001750 = 1.47
1100/2200 = 0.50
#2: 1100/1000 = 1.10
1100/2200 = 0.50
#3: 110011000 = 1.10
1100/2200 = 0.50
#4: 110011000 = 1.10
1100/2300 = 0.48
#5-6: 1100/850 = 1.29
1100/2300 = 0.48
S~ a°;t 1.2 to3.6ft
(ate 0.1 to 0.3) 2.4 to4.8ft
(a° =0.2 to 0.4) 3.6 to7.2ft
(a° =0.3 to 0.6)
Sm=a•t 6.0 to9.6k
(a=0.5 to 0.8) 4.8 to8.4ft
(a=0.5 to 0.7) 3.6 to7.2k
(a=0.3 to 0.6)
Sm/d 0.0027 t0 0.0128 0.0027 t0 0.0084 0.0016 to 0.0085
Sm/d~ 0.00000124 to
0.00001707 0.00000124 t0
0.00000840 0.00000068 to
0.00000997
Mm (2.7 Sm/d) 0.007 to 0.035 0.007 to 0.023 0.004 to 0.023
Cm=(24 Sm/dZ)j5~ 0.000030 to 0.000410 0.000030 t0 0.000202 O.C00016 to 0.000239
-Cm=(-24 Sm/dZ)~5' -0.000030 to -0.000410 -0.000030 to -0.000202 -0.000016 to -0.000239
Em=(1.3~Sm/d) 0.004 to 0.017 0.004 to 0.011 O.J02 to 0.011
-Em=(-2.O~Sm/d) -0.005 t0 -0.026 -0.005 to -0.017 -0.003 t0 -0.017
Maximum Crack
Depth (feet)'6' 50 to 100; 75 to 200 50 to 100; 75 to 200 50 to 100; 75 to 200
Break Anglel'I 0 to 5° 0 to 5° 0 tc 5°
Angle of Draw"' 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 percent; values may he greater
on slopes steeper than 30 percent.
(Z) All panels numbered sequentially from north [o south.
(3) Subsidence above chain panels, based on 12-foot coal extraction thickness.
(4) Subsidence above panel centers based on 12 foot coal extraction thickness.
(5) Numerical curvature values are in radians per foot (rad/ft).
(6) Maximum crack depth is projected to locally occur on or near steep slopes and cliffs on the flanks of West Flatiron and
flanking ridges above chain pillars, haulageways, and barrier pillars. The firs[ crack depth range is for slopes less than 30
percent; crack depths may be much less than this range, particularly in shale and claystone.
• (7) Measured from vertical reference.
C.\831-032\IS lard\Exhibit 60.doc
831-032.181 Wright Water Engineers. Inc.