The Qualitative Stability Graph for Open Stope Design – Recent Developments

ABSTRACT: The Stability Graph is an accepted tool for open stope design in the metalliferous underground mining community. Since its development in 1981, it has undergone several modifications and remains active research subject to date. Admittedly, while some of the suggested changes have been called into question for their practical relevance, others have gone a long way to improve the reliability of the method in minimizing dilution in open stope mining. One of the major concerns that has emerged in researching some suggested modifications to the design tool appears to show some authors do not understand the assumptions and purpose behind the tool. Such authors rely on application of statistics to the database with no idea of the practical implications of the outcome of their analysis. The downside of this is that so much confusion has been created in the mining industry as to what is useful in using the method for open stope design. This paper cautions against the misuse of statistics in geo-engineering with emphasis on the Stability Graph and provides recent developments relevant to improving the reliability of the method in reducing dilution in open stope s. Furthermore, the long outstanding question of whether the original Stability Graph number factors or the modified Stability Graph number factors should be used or not is that there is no difference between the two. 1. INTRODUCTION In 1980 the Department of Energy, Mines and Resources of the Canadian Center for Mineral and Energy Technology (CANMET) commissioned Golder Associates Consulting Geotechnical and Mining Engineers to determine the information that is required to predict stable spans for open stopes at mining depths below 1 000 m. The method developed in the report for the design of open stopes by Golder Associates has since been referred to as the Mathews Stability Graph Method (Mathews et al., 1981).