1. Daniel W.H. Su, Sr. geomechanical engineer Greg J. Hasenfus, Sr. geomechanical engineer Luke Stull, geologist Jun Lu, geomechanical engineer Mark Van Dyke, geologist Stephen Morgan, geologist Paul Kelley, mine engineer Don Teter, project engineer

2. Outline Introduction Objective Geology/Geologic Reconnaissance Hydro Frac Hole Locations and Frac Process Flac3D Models Longwall Visual Analysis (LVA) Monitoring Face Monitoring and Evaluation Conclusions

3. Introduction

4. Sandstone Intrusion Encountered During Development

5. Introduction Sandstone Intrusion Encountered During Development Base of Sandstone Channel

6. Introduction F20 Longwall Panel Problems Delayed caving behind shield supports Massive sandstone pot-outs in front of shields Increased risk to personnel Delayed Production Longwall production footage per week 344 24106306371 338 230

7. Objective To evaluate the effectiveness of the hydraulic fracturing program and the validity of Longwall Visual Analysis (LVA) software to mitigate the impact of a 1, 000-foot (305-meter) wide massive sandstone channel on a 1,500-ft-wide (457-meter-wide) longwall face.

8. Geologic Reconnaissance  In-Mine Core Drilling  Stratascope Observations  In-Mine Mapping  Primary Stress Orientation  Rock Lab Testing Average Axial Compressive Strength 8283 psi

9. Geologic Reconnaissance Trough of Sandstone Channel at Wall # 29 Base of Sandstone INBY OUTBY WALL #33 WALL #27 Drawslate Pittsburgh Seam 5 Feet Vertical Scale

10. Frac Hole Locations and Frac Stage Horizons

11. Frac Process Perforations were shot into the casing at the targeted horizons to pre- fracture the sandstone. The estimated shot penetration into the borehole surface was about 26 to 30 inches (0.66 to 0.76 meter).

12. Frac Process Water fracing was employed

13. Frac Process Fracing result Initial break Shut-in

14. Outline Introduction Objective Geology/Geologic Reconnaissance Hydro Frac Hole Locations and Frac Process Flac3D Models Longwall Visual Analysis (LVA) Monitoring Face Monitoring and Evaluation Conclusions

15. Flac3D Model Without Frac Massive Sandstone Clayey Shale Longwall face Massive Sandstone Clayey Shale Longwall face Shear stress, psi With Frac Frac horizon 15 ft

16. Longwall Visual Analysis (LVA) LVA was installed to track the face pressure and cavity formation index. Cavity Risk Index (CRI)

17. Face Monitoring and Evaluation To evaluate the effectiveness of the hydraulic fracturing program and the validity of LVA software, daily face monitoring over a 4-week period was conducted. Based on the collected information, the correlations among the observed face conditions, the hydro frac hole locations and the LVA cavity formation prediction were analyzed. Underground Observation Hydraulic Fracturing Longwall Visual Analysis

18. Ming Direction

19. Dec. 20, 2011

20. Face Monitoring and Evaluation

23. Longwall production footage per week 240 124232 142 115 194 323 F21—SS fraced 344 24 106306 338 230 F20—SS not fraced

24. Conclusions  Successful application of hydraulic fracturing technique.  Successful application of LVA software.  Improve safety and increase productivity.

25. Thanks! Questions?