2008-02-22_APPLICATION CORRESPONDENCE - C2008086 ‎(43)‎

• Permit No: C2008086
• IBM Index Class Name: Application Correspondence
• Doc Date: 2/22/2008
• Doc Name: PDEIS Appendix C Subsidence
• Media Type: D
• Archive: No

Draft Environmental Impact Statement/Subsidence
TABLE OF CONTENTS
Page No.
1.0 INTRODUCTION ....................................................................................................C-1
2.0 DEFINITION OF TERMS AND SYMBOLS .......................................................... ..C-1
3.0 GENERAL MINING INFORMATION ................................................................... ..C-3
3.1 Panel Design ........................................................................................... ..C-3
3.2 Gateroad Pillar Configuration and Design ................................................ ..C-4
3.3 Previous Mining ........................................................................................ ..C-5
3.4 Multiple Seam Mining ............................................................................... ..C-8
3.5 Compression Arches and Load Transfer .................................................. ..C-8
4.0 GEOLOGIC FACTORS INFLUENCING SUBSIDENCE ..................................... C-11
4.1 Structure ................................................................................................... C-11
4.2 Lithologic Factors Affecting Subsidence ................................................... C-14
4.3 Lithology and Angle of Draw ..................................................................... C-16
5.0 TOPOGRAPHIC FACTORS AFFECTING SUBSIDENCE .................................. C-16
5.1 Rugged Terrain ......................................................................................... C-16
5.2 Variable Overburden Thickness ............................................................... C-19
6.0 SUBSIDENCE ESTIMATION OVER CAMEO SEAM LONGWALL PANELS,
RED CLIFF MINE, PROJECT AREA .................................................................. C-21
6.1 Subsidence Zones .................................................................................... C-22
6.1.1 Caved Zone ............................................................................... C-22
6.1.2 Fractured Zone .......................................................................... C-23
6.1.3 Continuous Deformation Zone ................................................... C-25
6.1.4 Near-Surface Zone .................................................................... C-25
7.0 PREDICTED SUBSIDENCE OVER THE RED CLIFF MINE PROJECT AREA.. C-27
7.1 Maximum Vertical Subsidence (Smax) ....................................................... C-27
7.2 Maximum Horizontal Strain ...................................................................... C-32
7.3 Maximum Tilt (G) ...................................................................................... C-34
7.4 Angle of Draw ........................................................................................... C-36
7.5 Break Angle .............................................................................................. C-36
7.6 Rate and Duration of Subsidence ............................................................. C-38
8.0 IMPACTS OF SUBSIDENCE ON STRUCTURALLY SENSITIVE AREAS......... C-39
8.1 Longwall Mining in Geologic Hazard Areas of Landslides, Rockfalls,
and Unstable Slopes ................................................................................ C-39
8.2 Mining Beneath Stream Courses .............................................................. C-40
9.0 SURFACE SUBSIDENCE MONITORING ........................................................... C-41
10.0 REFERENCES ..................................................................................................... C-42
11.0 FIGURES ............................................................................................................. C-44
APPENDIX A RECOMMENDED STRUCTURE LIMITS FOR SUBSIDENCE
INDUCED STRAIN AND TILT
DBMS 290