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TABLE 3 MAXIMUM SUBSIDENCE P FOR DRY FORK MINING AREA "' Parameter Panels E2 t = 9 ft Panels E3 - E6 t =10 ft W /d: (2) Max Min E2: 1080/1000 = 1.08 1080/1000 - 0.9 E3: 1080/800 = 1080/ 1200 = 1.35 0.90 Max Min E4: 1080/900 = 1080 / 1800 - 1.20 0.60 Max Min E5: 1080/1000 = 1080/1800 1.08 0.60 Max Min E6: 10BO / 1200 = 1080/1400 = 0.90 0.77 t =9ft t =10ft S a., -t a =S t) 0.90 to2.7ft (0.1 to 0.3 ) 1.0 to 3.0 ft (0.1 to 0.3) S a•t a = S 5.9 to6.1ft (0.6 to 0.8 ) 6.0 to 8.0 ft (0.6 to 0.8 S,dd i61 0.0059 to 0.0061 0.0033 to 0.010 M 2.2 to 2.3 Sm/d ifi) 0.013 to 0.0140 0.0073 to 0.023 E, (in terms of S,„ /d) r) 1.2 to 1.4Sdd 0.0071 to 0.0065 0.0040 to 0.014 -E (in terms of S /d) I'I -1.2 to -1.5 S /d - 0.0071 to - 0.0092 -0.0040 to 4015 Maximum Crack Depth (8) 1 2 5 -10ft 5 -10ft 10 -20ft 15 -25ft Break Angle (9) 0 - 5° 0 - 5° Angle of Draw (9) 14 - 19° 14 - 19° Maximum tilt and strain parameters apply only to ground surfaces with slopes less that 30 percent; values may be greater on slopes steeper than 30 percent. All panels are numbered according to planned panel identifications. Subsidence and subsidence factor above chain pillars. 14 � Subsidence (maximum vertical displacement) above longwall panel centers, based on planned coal extraction thickness listed. Ratio of the range of maximum vertical displacement to overburden depth range for the nine planned longwall panels. r Maximum range of tilt in terms of S, /d; values of 2.2 to 2.3 S,/d are obtained from the graph in Figure 5. Maximum range of horizontal strain in terms of 5,,,/d; values for tensile (positive) strain of 12 to 1.4 S,/d and compressive (negative) strain of -1.2 to -1.5 S Jd are obtained from the graph in Figure 5. Maximum crack depth (in feet) in bedrock predicted to locally occur on or near steep slopes and ledges in the Minnesota Creek and Lick Creek drainage areas and above barrier pillars and rigid chain (gate road) pillars. The first depth range (1) is for bedrock sloping less than, or equal to, 30 percent; the second depth range (2) is for slopes more than 30 percent. Add 5 to 15 feet where thick, brittle sandstones occur in ridges and near dills. No cracks are predicted to occur in alluvium. No cracks are predicted to occur at the surface of colluvium thicker than about 10 feet. �9i Angle measured from a vertical reference.