ICGCM Papers:
Numerical Modeling Developments and Applications
 
 
A Stability Factor for Supported Mine Entries Based on Numerical Model Analysis.
31st International Conference on Ground Control in Mining
A Stability Factor for Supported Mine Entries Based on Numerical Model Analysis.
by
Gabriel S Esterhuizen, National Institute For Occupational Safety and Health, Pittsburgh, United States
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Author's Presentation PPT
[Conference] 31st International Conference on Ground Control in Mining
[Price] Free  [Comments] 0
[Topical Area] Numerical Modeling Developments and Applications
[Author] Gabriel S Esterhuizen, National Institute For Occupational Safety and Health, Pittsburgh, United States
[Abstract] 
Problem Statement:
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At present support systems in coal mines are designed on an empirical basis which largely relies on a trial-and-error approach. The empirical method does not allow a designer to assess the margin of safety of a particular support design or how each support unit is contributing to stability.
Objective of the Paper:
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To present an analtytical method for assessing the safety margin and reliability of a support design, based on numerical model analysis.The impact of modifications to the support design can be evaluated by comparing the reliabilitiy of each option. The models also report the contribution and failure mode of each support element, which allows the weak-link in a design to be identified.
Key Findings:
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- The study showed that the reliability of a support design can be estimated by considering the variability of the rock mass properties, as characterized by the Coal Mine Roof Rating. - The point of collase is identified in the models by progressive reduction of the rock mass cohesion until excessive closure or downward accelleration of the roof is identified. The reliability is expressed as the probability that the rock mass will be weaker than that required for collapse to occur. - It is also possible to express the reliability of a supported entry as a safety factor.
Key Conclusions:
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The study shows that supported entries have a high reliability, which is in agreement with the fact that only a small percentage of the roof collapses in operating mines. - Changes to the reliability by support modifications can be readily assessed using this technique.