In order to ensure the stability of roadways Anglo American Metallurgical Coal (AAMC) has developed an advanced roof support design methodology that integrates analytical, numerical and empirical modelling. This methodology currently is based on a deterministic approach (a single factor of safety against failure is calculated). However, an improved methodology, based on stochastic modelling technique, has also been developed and currently being evaluated. The main advantage of this methodology is that as the design is based on the probability distributions of input parameters, the outcome is based on a distribution of factors of safety rather than a single factor of safety. Evaluation of factors of safety may also be used to determine the likelihood of failure which in turn may be utilised to determine and evaluate the associated risks quantitatively in decision making process. This methodology has been evaluated at Grasstree and Moranbah North Coal Mines in the designs of roof support in various critical areas and has been proven to be successful and a better way of determining the roof support requirements.

A demonstration of application of this methodology in a design of an install road roof support at Moranbah North Mine, where the “world’s highest rated longwall” has recently been installed, is presented in this paper.