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284 SURFACE SUBSIDENCE <br /> Table 9.2.2 Subsidence Factor and patio of Maximum Horizontal Displacement to <br /> Maximum Possible Subsidencd" <br /> Subsidence <br /> Coal Field and Method of Packing Factor RutiLO <br /> British coul fields (8) <br /> Solid stowing 0.45 0.16 <br /> Caving or strip-packing 0.90 0.16 <br /> Ruhr coal field, Germany <br /> Pneumatic stowing 0.45 0.35-0.45 <br /> Other solid stowing 0.50 0.35-0.45 <br /> Caving 0.90 0.35-0.45 <br /> North and Pas de Calais coal field, <br /> France <br /> Hydraulic stowing 0.25-0.35 0.40 <br /> Pneumatic stowing 0.45-0.55 0.40 <br /> Caving 0.85-0.90 0.40 <br /> Upper Silesia, Poland <br /> Hydraulic Mowing 0.12 — <br /> Caving 0.70 _ <br /> U.S.S.R. <br /> Donbass district 0.8 0.3 <br /> Lvov-Volyn district 0.8-0.9 0.34 <br /> Kizelov district 0.4-0.8 0.3 <br /> Donets. Kuznetsk, and Karaganda <br /> districts 0.75-0.85 0.3 <br /> SubMoscow and Cheliabinski districts 0.85-0.90 0.35 <br /> Pechora 0.65-0.90 0.3-0.5 <br /> U.S.A. <br /> Eastern (room and pillar) (9) 0.10-0.60 <br /> Central (longwall) (Ill) 0.50-0.60 <br /> t Central (room and pillar) (10) 0.10-0.40 <br /> Western (5, 6) 0.33-0.65 <br /> I •Unless otherwise stated, all values are from Brauner (13, 20). <br /> •Ratio - maximum horizontal displucement/maximum possible subsidence. <br /> r <br /> coal seam, the larger is the surface subsidence, because a larger void is <br /> left to be filled. The maximum possible surface subsidence is <br /> S. - ma <br /> where m is seam thickness and u is a subsidence factor that ranges from <br /> 0.10 to 0.9. Table 9.2.2 lists the subsidence factors used in various coun- <br /> tries with different gob support methods. In the table, stowing refers to <br />