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 SystemCombines: 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 BowieBowie 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 BowieOverburden 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 WeightingsCritical 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 ResultsWeighting 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 CMRRThe 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?

28

29 Stress Mapping

30 Keith A. Heasley Biography B.S. Mining Engineering – Penn State – 1981Consolidation 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 AnalysisFour Major Methods: Finite-Element. Finite-Difference Discrete Element Boundary-Element

32 Finite-Element

33 Boundary Element MethodDiscretizes 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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