1. Stability Mapping System

2. Geologic Hazard Map

3. Stress Hazard Map

4. Stability Maps
If the stability problems are primarily geologically determined – a geologic stability map can work quite well.
If the stability problems are primarily stress dependent – a stress stability map can work quite well.
However, mine stability is generally determined by the interaction of both the geologic and stress conditions.

5. Integrated Stability Mapping System
Combines:
AutoCAD as the basic drawing and mapping foundation.
SurvCADD as the geologic characterization and database model.
LaModel for the overburden and multi-seam stresses, subsidence-based strains and pillar safety factors.
CMRR for the structural analysis of geology
ARBS for the required support density

6. Stability Mapping Application

7. Stability Mapping Application

8. Grid Utilities

9. Stability Mapping at Bowie
Bowie Resources, LLC:
Paonia, Colorado, Somerset Coal Field, Piceance Basin, 4 Million tons per year
Bowie No. 2 – D Seam, 9.5 ft extraction
Bowie No. 3 – B Seam, 250 ft interburden

10. Southwest Mining District

11. Critical Parameters at Bowie
Overburden and Multiple-Seam Stress
Interburden to Rider Seam
Sandstone Channels
Faults, Slumps and Warps
Coal Mine Roof Rating

12. Southwest Mining District

13. Insitu Stress

14. Faults, Slumps & Warps

15. Faults, Slumps, Warps Index

16. Parameters Weightings
Critical Parameter
Final Weighting
Overburden Stress 20
Multiple-Seam Stress 15
CMRR
Sandstone Channels 10
Interburden Thickness
Faults
Slumps
Warps 5

17. Final Stability Map

18. Stability Mapping Results
Weighting Factors were optimized with results from mining in the first panel
In subsequent mining, the stability mapping successfully predicted problematic zones
With foreknowledge of the problem zones, the management was able to be pro-active in their ground support plan

19. Latest Additions
CMRR – Ability to Grid CMRR from Geologic and Geo-Mechanical input
ARBS – Ability to Grid ARBS from CMRR and Pseudo-Depth Grids

20. CMRR Worksheet

21. Define Number of Units

22. Unit Parameter Form

23. Analysis of Roof Bolt Systems (ARBS)
Statistical studies performed by NIOSH, roof bolt performances from 37 mines in U.S.
Guidelines for preliminary bolt parameters
Based on:
Roof Quality (CMRR)
Effect of stress (Depth)
Intersection Span

24. ARBS Calculation Form

25. Summary LaModel Stresses Geologic Features Structural Features CMRR
The Stability Mapping System can combine:
LaModel Stresses
Geologic Features
Structural Features
CMRR
For a Comprehensive analysis of Mine Stability and a recommendation for Support Density

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27. Questions?

29. Stress Mapping

30. Keith A. Heasley Biography B.S. Mining Engineering – Penn State – 1981
Consolidation Coal Co.
Project Engineer –
M.S. Mining Engineering – Penn State –
Thesis - Computer Modeling of Subsidence
U.S. Bureau of Mines/NIOSH –
Ph.D. Mining Engineering – CSM – 1998
Thesis – DDM Modeling – LaModel
West Virginia University – Present

31. Numerical Stress Analysis
Four Major Methods:
Finite-Element.
Finite-Difference
Discrete Element
Boundary-Element

32. Finite-Element

33. Boundary Element Method
Discretizes the Boundary of the Continuum
Computationally Efficient
Particularly Suited for Large Areas of Tabular Seams or a Few Large 3-D Openings
BSOLV, MULSIM, MINLAY, LAMODEL

34. Homogeneous Overburden

35. Total Vertical Stress

36. Discontinuity Form

37. Final CMRR Form

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