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 OF CONTENTS

DEFINITION OF SYMBOLS .........................................................................................................................iv
DEFINITION OF
1.0 INTRODUCTION
2.0 MWING METHOD ..........................................................................................................................................1
3.0 GEOLOGIC FACTORS INFLUENCING SUBSIDENCE ...........................................................................2
4.0 SUBSIDENCE PREDICTION BASED ON LONGWALL MINING AT THE WEST ELK MINE.........2
4.1 CAVED ZONE ............................................................................................................................... ...............3
4.2 FRACTURED ZONE ....................................................................................................................... ...............4
4.3 CONTMUOUS DEFORMATION ZONE AND NEAR SURFACE ZONE .................................................. ...............5
d. 3.1 Vertica! and Hari~onta! Displacement. Tilt. Curvature, and Hori=onto! Strain .............. .............. 6
4.3.1.1 Multiple Seam Mining .................................................................................... ...............6
4.3.1.2 Maximum Vertical Displacement ................................................................... ...............7
4.3.1.3. Maximum Tilt ................................................................................................. ...............9
4.3.1.4. Maximum Curvature ...................................................................................... ...............9
4.3.1.5. Maximum Horizontal Strain ........................................................................... .............10
4.3.2 Maximum Projected Depths ojSurjace Cracks ............................................................... ............12
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4.4 ANGLE OF DRAW ......................................................................................................................... .............13
4.5 BREAK ANGLE ............................................................................................................................. .............14
4.6 ANGLE OF MAIOR INFLUENCE ..................................................................................................... ............. 14
4.7 REPORTED RELATIONS BETWEEN DYNAMIC AND FRJAL SUBSIDENCE DEFORMATIONS .............. ............. I S
4.8 CRITICAL EXTRACTION WIDTH OF MfNING PANELS .................................................................... ............. l5
4.9 RESULTS OF COMPUTER MODELMG ............................................................................................ ............. I S
5.0 RATE AND DURATION OF SUBSIDENCE ...............................................................................................17
6.0 EFFECTS OF TOPOGRAPHY AND STRUCTURE ON SUBSH)ENCE PROCESSES .........................17
6.1 EFFECTS OF TOPOGRAPHY ON SUBSIDENCE CRACKS ....................................................................... .........17
6.2 BLOCK GLIDE .................................................................................................................................. .........18
6.1. l Block Glide Potentia! in the Oliver No. 1 Mine Area ......................................................... .........18
6.1.1 Block Glide Potentia! Due to Mining in the 8-Seam in the Oliver No. 1 Mine ,4rea ......... ......... /9
6.3 EFFECTS OF RUGGED TOPOGRAPHY ON SUBSIDENCE AND MINE STRESSES ..................................... ......... 19
7.0 FRACTURE-CONTROLLED DRAINAGES ..............................................................................................19
8.0 WATER AND METHANE ................................................................................................ .............................20
8.1 WATER AND METHANE IN THE OLI\'ER NO. 2 MME .................................................... .............................21
8.2 WATER AND METHANEDRAMAGEAFTEROLIVERN0.2MMECLOSURE .................. .............................21
8.3 METHANE CONCENTRATIONS M THE OLIVER NO. 2 PORTAL AREA ............................ .............................22
8.4 WATER AND METHANE POTENTIAL MTHE BSEAM-OLIVER NO. 2 MINE AREA ...... .............................23
8.J POTENTIAL IMPACT OF WATER ON SUBSIDENCE M WET MINING AREAS .................... .............................23
8.6 MODERN METHODS OF VENTILATION .......................................................................... .............................23
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