Coal Mine Primary Support Selection: Tension Versus Non Tensioned Roof Bolt Systems

Unrug, Kot
Organization: International Conference on Ground Control in Mining
Pages: 6
Publication Date: Jan 1, 2004
The selection of tensioned versus non-tensioned roof bolts, for primary coal mine roof support, has been debated for well over 25 years. The wide spread use of fully grouted rebar marked the beginning of the discussion of the relative importance of bolt tension and the resultant immediate roof compression. The focus is on roof conditions encountered in coal mines however the discussion may be extended to hard rock mines as well. The theoretical bases for both systems are presented, with the analysis focused on the bolt's ability to actually fulfill the theoretical assumptions. Of specific concern are assumptions about bolt tension upon installation and the likelihood of maintaining useful bolt tension over time. The usefulness of tension roof bolting is limited by the mechanical interaction of roof bolt assembly and the rock, which may be valid at the time of installation only. Ambient mine atmosphere and fluctuation in moisture content changes the physical condition of rock, which may have a significant impact on the effectiveness and longevity of bolt tension. Changes in the material properties of the surface of the immediate roof can invalidate the assumptions, which were made in the design stage of roof support system. This means that the roof support in the long term excavations may be inadequate requiring costly rehabilitation. The presented arguments are illustrated with the examples of some relevant experimental data. Tension primary roof bolting is recommended where the immediate roof is: ? Stiff with a high modulus of elasticity ? Surface layers are continuous and fairly thin ? Not easily weathered
Full Article Download:
(1480 kb)

Additional chapters/articles from the SME-ICGCM book 23rd International Conference on Ground Control in Mining (ICGCM) 23rd

Geomechanical Criteria of Longwall Face Support Selection at
Rock Fracture, Caving and Interaction of Face Supports Under
Effect of the Approaching Longwall Faces on Barrier and Entr
Computer Simulation of Ground Behaviour and Rock Bolt Intera
lnterpanel Barriers for Deep Western U.S. Longwall Mining
Application of Yieldable and Cuttable Pump Crib in Longwall
Field Testing of a Real Time Roof Mapping Drilling Display S
Problems in "Void" Detection in Coal Mine Water Hazards
Violent Coal Pillar Collapse -A Case Study
Stooping Low Safety Factor Pillars at Goedehoop Colliery - 1
Laboratory Strength Testing of Coal from Selected Illinois S
Downhole Overcoring Stress Measurement at a Western Undergro
Effect of In Situ Stresses on the Stability of Coal Mine Dev
SOMA: A New Method to Calculate the Operative Stress Field:
Numerical Modeling for Increased Understanding of the Behavi
Evaluation of Rockburst Hazard from Core Testing
Investigation of Electromagnetic Emissions in a Deep Undergr
Development and Application of Geotechnical and Rockmechanic
Laboratory Testing of Rib Straps
The New Two-Dimension LaModel Program
Risk Assessment: Multiseam - Single Seam Mining
A Method To Determine Expander Spacing For Steel Pipelines I
A Case Study Of Abandoned Mine Subsidence At Dominion, Nova
Spatial Trends In Rock Strength - Can They Be Determined Fro
Development And Demonstration Of An Alternate Mining Geometr
Evaluation Of Polyurethane Injection For Beltway Roof Stabil
Application Of Ground Penetrating Radar To Evaluate The Exte
A Risk Assessment Tool For Open Cast Mining In South Africa
Analysis Of Practical Ground Control Issues In Highwall Mini
Preventing Falls Of Ground In Coal Mines With Exceptionally
Geo-Mechanical Property And Failures Of Weak Roof Shales In
Eclipse System Bolting In The Illinois Basin
Variation In The Load Transfer Of Fully Encapsulated Rockbol
Bolt Load Changes During Initial Face Advance And Cross-Cut
Coal Mine Primary Support Selection: Tension Versus Non Tens
Improving Stope Support At Modikwa Platinum Mine
3D FEM Simulation For Fully Grouted Bolts
An Investigation Into The Effectiveness Of Support Systems C
Hydraulic Prestressing Units: An Innovation In Roof Support
Improving Roof Truss Performance
Coal Combustion Byproducts-Based Artificial Mine Supports -
The Influence Of Horizontal Stress On Pillar Design And Mine
Investigation Of Pillar-Roof Contact Failure In Northern App
Mapping Hazards With Microseismic Technology To Anticipate R
Practical Detection Of Underground Mine Roof Failure
Heat-Imaging Experimental Study Of Reducing Local Gas Accumu
Microcirculation Theory Analysis Of Spontaneous Combustion O