1 Application of Tensioned Cable Bolts for Supplemental Support Benjamin Mirabile Technical Sales and Service Engineer Jennmar Corporation of West Virginia J. Rodney Poland Regional Sales Manager Jennmar Corporation of West Virginia Alan Campoli, Ph.D. Vice President Jennmar Specialty, Inc

2 Outline Overview of Tensioned Cable Bolts Laboratory Tests Case Study 1 Case Study 2

3 Non Tensioned Cable

4 INSTáL Cable Bolts

5 Post-Tensioned Cable

6 Cable Tensioning Unit (CTU)

7 Laboratory Tests Illustrate Constant Stiffness of Cable Material Evaluate Effect of Pre-Load on Total Deflection at Failure Effect of Development of Bearing Plate Contact Seating Effects of Barrel and Wedge Assembly

8 Load-Deflection Tests

9 Trendlines in Elastic Range

10 Laboratory Test Conclusions Cable Material has Constant Stiffness in Elastic Range Pre-Load Decreases the Variability of the Load Response Curve in the Elastic Range

11 Laboratory Results/Practical Application Reduction of Total Deflection Enhances Roof Stability Use of Cable Tensioning Unit Allows Immediate Development of Full Bearing Plate Contact with Roof—Especially Important in Broken Ground or Strata with Many Discontinuities Consistent Load Response

12 Case Study 1 Longwall Head Gate in Eagle Seam Feet Depth Highly Laminated and Fractured Sandstone with Mica Streaks Primary Support—3/4” x 72” Torque Tension with 2 Eq. Ft Grout Supplemental Support--#8 Bar (1”) Rigid Bar Truss

13 Case Study 1 T5 Channel with 4 Bolt Slots Center Bolts—0.7” x 18’ Post-Tensioned Cable Outside Bolts—0.7” x 10’ Post Tensioned Cable Angled Over Ribs

14 Case Study 1 Installation and Site Conditions

15 Case Study 1

16 Case Study 1

17 Case Study 1

18 Case Study 1

19 Case Study 1

20 Case Study 1 Longwall Pass

21 Case Study 1

22 Case Study 1

23 Case Study 1

24 Case Study 1

25 Case Study 1

26 Case Study 2 Longwall Recovery Face in Alma Seam 700 Feet Depth Sandy Shale Longwall Face “Parked” for 60 Days Little or No Shield Leg Pressure Shields Extended to Maximum Height

27 Case Study 2

28 Case Study 2

29 Case Study 2

30 Case Study 2

31 Case Study 2

32 Case Study 2

33 Qualitative Effects of Pre-Tension Allows Designer to Select Starting Point on Load-Response Curve Allows Immediate Contact of Bearing Plate Against Mine Roof Empirical Data Suggests Superior Performance in Weak or Broken Ground as Compared to Non-Tensioned Cable Bolts

34 Further Research Additional Laboratory Testing to Investigate Seating Effects of Wedges and Bearing Plate Contact Investigate Effects of Resin Grout on System Stiffness Underground Instrumentation Comparing Performance of Non-Tensioned and Tensioned Cable Supports Determination of Optimum Pre-Load

35 Thank You Questions?