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A Retrospective on LaModel or Dr. Heasley’s Wild Ride

A Retrospective on LaModel or Dr. Heasley’s Wild Ride. It doesn’t look so bad with my eyes closed. Dr. Keith A. Heasley Professor Department of Mining Engineering West Virginia University Keith.Heasley@mail.wvu.edu (304) 293-3842. A Retrospective on LaModel. Development Application

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A Retrospective on LaModel or Dr. Heasley’s Wild Ride

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  1. A Retrospective on LaModelorDr. Heasley’s Wild Ride It doesn’t look so bad with my eyes closed Dr. Keith A. Heasley Professor Department of Mining Engineering West Virginia University Keith.Heasley@mail.wvu.edu (304) 293-3842

  2. A Retrospective on LaModel • Development • Application • Enhancement

  3. MULSIM NIOSH Boundary Element Program for Displacement and Stress Analysis in Coal Mines

  4. Boundary-ElementDisplacement Discontinuity Method

  5. Ground Surface H z P Coal Seam Homogeneous Overburden

  6. 0.00 Homogeneous Elastic Overburden 0.10 C L L 0.20 M Convergence (m) 100 0 0.30 0.40 Laminated (t=15) Overburden 0.50 0 20 40 60 80 100 Distance from Center of Panel (m) Longwall Panel Convergence

  7. 0.0 Homogeneous Elastic Overburden -0.5 Surface Subsidence (m) H -1.0 Laminated (t=5.3) Overburden Empirical Subsidence Curve C -1.5 L L M -200 -100 0 100 200 Distance from Center of Panel (m) Surface Subsidence

  8. Ground Surface 0 H 1 z P j-1 j t E v j j j j+1 n-1 n Coal Seam n+1 Laminated Overburden

  9. 0.00 Homogeneous Elastic Overburden 0.10 C L L 0.20 M Convergence (m) 100 0 0.30 0.40 Laminated (t=15) Overburden 0.50 0 20 40 60 80 100 Distance from Center of Panel (m) Longwall Panel Convergence

  10. 0.0 Homogeneous Elastic Overburden -0.5 Surface Subsidence (m) H -1.0 Laminated (t=5.3) Overburden Empirical Subsidence Curve C -1.5 L L M -200 -100 0 100 200 Distance from Center of Panel (m) Surface Subsidence

  11. LaModel Laminated Boundary Element Program for Displacement and Stress Analysis in Coal Mines

  12. LaModel • Uses a Laminated Overburden Model • More Realistic Stresses and Displacements • Used to Model: • Multiple Seams • Variable Topography • Complex Mining Geometries • etc.

  13. Case Study

  14. Case Study • Upper Mine: • Room-and-Pillar • Overburden – 500 to 1300 ft (855 ft) • Seam Thickness – 5.0 ft • 7 Entry Rooms, Retreated • Lower Mine: • Room-and-Pillar • Interburden 45 ft • Seam Thickness - 5.0 ft • 7 Entries – 60 by 70 ft Pillars

  15. Overburden Stress

  16. Single Seam Stress

  17. Multiple Seam Stress

  18. Total Vertical Stress

  19. Stress Hazard Map

  20. Basic Features • Displacement and Stress Calculations • Multiple Seams • Multiple Mining Steps • 26 Different Seam Materials • 6 Non-Linear Seam Models

  21. 1 3 5 Strain-Hardening Linear Elastic Elastic Plastic 2 4 6 Linear Elastic Gob Bi-Linear Hardening Strain Softening Material Models

  22. LaModelEnhancements • Graphical Post-Processing (1996) • Graphical Grid Generation (1999) • Coal Wizard (2000) • Grid Size Increases • Pillar Safety Factors (2006) • Lam2D (2003) • Stability Mapping (2006)

  23. LamPlt

  24. Grid Editor

  25. Grid Size Keith; I need bigger grids, and more seams • Grid Size • 250 x 250 (1996) • 400 x 400 (2000) • 1000 x 1000 (2004) • 2000 X 2000 (2010)

  26. Grid Generator

  27. Grid Generator

  28. Pillar Safety Factor

  29. Energy Calculations

  30. Lam2D Keith: 2D is the way to go.

  31. Stability Mapping

  32. Crandall Canyon Mine Collapse

  33. Final Model

  34. Final Model

  35. LaModel Calibration • Developed a procedure that calibrated: • The Rock Mass Stiffness against the extent of the abutment zone • The Gob Stiffness against the expected gob loading (21° abutment angle) • The Coal Strength with empirically determined pillar strength (900 psi).

  36. Thickness Wizard

  37. Calibrated Database

  38. Calibration Results • Calibrated Safety Factor: • Keep the Safety Factor > 1.4 and • < 10% chance of failure

  39. Future Developments • Calibrate to “shallow cover” • Re-examine Abutment Extent • Local Mine Stiffness Calculation • ARMPS-LAM • Improve the speed of the Multiple-Seam calculation

  40. ARMPS-LAM Keith: You should build the laminated model into ARMPS • Incorporate a laminated overburden loading model into the ARMPS program

  41. Future Developments • Calibrate to “shallow cover” • Re-examine Abutment Extent • Local Mine Stiffness Calculation • ARMPS-LAM • Improve the speed of the Multiple-Seam calculation

  42. Dr. Heasley’s Wild RideWhere to next?

  43. Questions? Maybe, if I close my eyes, I won’t have to ask questions

  44. Boundary-ElementDisplacement Discontinuity Method

  45. Boundary-ElementDisplacement Discontinuity Method

  46. Boundary-ElementDisplacement Discontinuity Method

  47. Boundary-ElementDisplacement Discontinuity Method

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