Flexible assessment of slope stability ratings

The extensive and systematic exploration and investigation of any open pit mine gives valuable data on geo-mechanical properties which can be integrated with the optimum slope design for achieving both stable and economically attractive mining. These assessments are important for all open pit mines such as those under planning and currently in operation. In hard rock environments, rock mass classification systems are frequently used as the basis for evaluating slope stability conditions. One of the most prevalent methods is the calculation of Slope Mass Rating (SMR) based on RMR ratings. Important conditions to stability such as jointing characteristics and groundwater behaviour are underrepresented into the formulation of RMR and thereby in SMR. The aim of this manuscript is to provide a flexible and dynamic methodology to calculate SMR values based on local conditions affecting stability. A flexible modification is achieved by deriving weights, or degrees of importance, based on expert judgement and knowledge of specific conditions at the mine from back analysis and field investigations. Weights are consequently derived following the method of pairwise comparison encompassed into the analytical hierarchy process (AHP). Assessments of results based on the conditions observed in the open pit mine is provided in order to depict stability conditions and proficiency of the proposed method. Such integrated evaluation results are believed to be also helpful in assessing mining sequences and blasting for the optimum recovery without the compromise in stability and safety.