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<br />TABLE OF CONTENTS <br />DEFINITION OF SYMBOLS ........................................................................................................................lv <br />DEFIIVIITON OF TERMS ...............................................................................................................................v <br />1.0 INTRODUCTION <br />2.0 MINING METHOD ........................................................................................................................................1 <br />3.0 GEOLOGIC FACTORS INFLUENCING SUBSIDENCE ..........................................................................2 <br />4.0 FIELD RECOGNITION OF SUBSIDENCE AND NON-SUBSIDENCE FEATURES IN THE WEST <br />ELK MINING AREA ..................................................................................................................................................2 <br />4.1 $UESmENCE CRACKS Arm CDNFRESSIGN FEAT[mRS ............................................................................................3 <br />4.2 CONSTRUCTION CRACKS ........................................................................................................................................3 <br />4.3 DESICCATION CRACKS ............................................................................................................................................4 <br />4.4 PSEUDO SUE$mENCE FEATURES (GRAVITY-INDUCED TENSIGN CRACK$) .............................................................4 <br />• 5.0 SUBSIDENCE PREDICTION BASED ON LONGWALL MINING AT WEST ELK MIlVE .................5 <br />5.1 CAVED Z.ONE ....................................................................................................................... ...............................5 <br />5.2 FRACTURED ZGNE ............................................................................................................... ...............................5 <br />5.3 CONTTNUOUS DEFORMATION ZONE AND NEAR SURFACE ZONE .......................................... ...............................7 <br />5.3.1 YerKcal and Horizontal Displacement, Tilt, and Horizonta!Strain ............................ .............................. 7 <br />5.3.2 Maximum Projected Depths oj'Surjace Crackr ........................................................... ............................10 <br />5.4 ANGLE OF DRAW ................................................................................................................. .............................12 <br />5.5 BREAK ANGLE ..................................................................................................................... .............................12 <br />S.( ANGLE OF MAJOR INFLUENCE ............................................................................................. .............................13 <br />A7 RELATION BETWEEN DYNAMIC AND FINAL SUBSIOINCE DEFORMATIONS .......................... .............................13 <br />5.8 CRITICAL EJCIR.4CTTON WmTx of MIlVING PANELS .............................................................. ............................14 <br />5.9 RESULTS OF CONFUTER MODELING .................................................................................... .............................14 <br />6.0 RATE AND DURATION OF SUBSIDENCE .............................................................................................15 <br />C~ <br />7.0 EFFECTS OF TOPOGRAPHY AND STRUCTURE ON SUBSIDENCE PROCESSES .......................15 <br />7.1 EFFECTS OF TOFOGRAPIIlr ON SuBSIDExCE CRACRS ........................................................................................16 <br />7.2 EFFECTS OF RUGGED TOPOGRAPEIY ON SUBSIDENCE AND MINE STRESSES ......................................................16 <br />i <br />