Date of Graduation


Document Type


Degree Type



Statler College of Engineering and Mineral Resources


Mining Engineering

Committee Chair

Keith A. Heasley.


In the Analysis of Retreat Mining Pillar Stability (ARMPS), Analysis of Longwall Pillar Stability (ALPS) and LaModel programs, the magnitude of the abutment loading adjacent to a gob area is calculated using an "abutment angle" concept, and the extent of the abutment loading is determined as solely a function of depth from an empirically derived equation. However, the latest in-situ stress measurements of abutment loading performed in the United States and Australia have shown that there can be significant deviations in the measured abutment magnitude and extent as compared to the predicted values from the empirical formulas used in ARMPS, ALPS and LaModel.;In this dissertation, stress measurements from U.S. and Australian mines were back analyzed by using analytical and numerical methods to investigate the measured abutment extent and loading. Ultimately, it was determined that the original empirical abutment extent formula in conjunction with the original ALPS square-decay stress distribution function was supported by the case histories reviewed in this dissertation. Also, for depths less than 900 ft, the average 21° abutment angle was supported by the case histories; however, at depths greater than 900 ft, the abutment angle was found to be significantly less than 21° and should be calculated with a new proposed equation.