ICGCM Papers:
Pillar and Mine Design II
 
 
The Evaluation of Empirical Coal Pillar Strength Formula Based on Uncertainty Criterion
31st International Conference on Ground Control in Mining
The Evaluation of Empirical Coal Pillar Strength Formula Based on Uncertainty Criterion
by
Navid Hosseini, Islamic Azad University, South Tehran Branch, Tehran, IranBehdeen Oraee-Mirzamani, Centre For Environmental Policy, Imperial College London, London, United KingdomKazem Oraee, University of Stirling, Stirling, United Kingdom
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[Conference] 31st International Conference on Ground Control in Mining
[Price] Free  [Comments] 0
[Topical Area] Pillar and Mine Design II
[Author] Navid Hosseini, Islamic Azad University, South Tehran Branch, Tehran, IranBehdeen Oraee-Mirzamani, Centre For Environmental Policy, Imperial College London, London, United KingdomKazem Oraee, University of Stirling, Stirling, United Kingdom
[Abstract] 
Problem Statement:
Several empirical equations for estimation of coal pillar strength have been presented in academic studies so far. Determining the amplitude with accuracy is one of the most important limitations present. Based on the basic principles of statistical engineering, the correlation coefficient (R2) is one of the best criteria for evaluation of such equations, however it has some limitations. In order to compare the equations of coal pillar design using correlation coefficient, access to the initial data is necessary. On many coal pillar strength formulae however such access is not possible.
Objective of the Paper:
For evaluation of the coal pillar strength formula a dataset using field data has been created. Subsequently the curve of the equation of each coal pillar strength formula has been drawn using the Curve Fitting toolbox of MATLAB. Then, using these data, the uncertainty is studied. These curves are drawn using the equation of coal pillar strength formula based on adjusting the constants coefficient. In order to determine uncertainty, the upper and lower prediction bounds of each coal pillar strength formula are drawn. Overall, the uncertainty of each coal pillar strength formula is shown by distance of upper and lower bounds from the fitting curves. Therefore, the closer the upper and lower bounds are, the higher the confidence of coal pillar strength formula, and vice-versa.
Key Findings:
Providing the new approach to prediction of certainty and confidence of coal pillar formulae are key finding in this research.
Key Conclusions:
According to the results, while considering the field data of coal pillar strength, the prediction certainty and confidence level of the coal pillar formulae decrease when the width-to-height ratio of coal pillar is increased. Therefore according to field characteristics, operational conditions and geomechanical properties of the appropriate coal pillar strength formula for each area, i.e. the equation with highest certainty, can be selected. In other words, the uncertainty can be used as a guide to select the appropriate coal pillar strength formula.