Slope stability analysis and evaluation of further major failure in Angooran open-pit mine

Summary
In this research, stability analysis and probability assessment of the further failure for Angooran lead and zinc mine have been investigated. To investigate its geomechanical properties precisely, main joints and available faults were appraised and some samples of the mine limestone zone were prepared to determine strength properties of rocks using laboratory tests. Then, the 3DEC code was used to construct a three dimensional model. According to the initial displacements from the software and geomechanical properties of the eastern wall and its concave shape, this wall was supposed to be stable. Further analyses were focused on the western wall. For stability analysis of the western wall, the model was constructed based on different cohesions and internal friction angles. It was observed that the magnitudes of displacements were higher than in the eastern wall. So, statistical analysis was performed on the toe of the wall and the probability of the failure calculated to 35.2 percent, according to the obtained displacements.
 
Introduction
Slope stability is one of the major and determiner parameters in the economy and safety of open pit mines. Failure and consequently rupture of the slope caused no compensable economic and humanity losses. So, probability assessment of the further failure for presentation of damages and additional costs is of prime importance. In this research, stability analysis and probability assessment of the further failure for Angooran lead and zinc mine have been investigated.
 
Methodology and Approaches
To investigate geomechanical properties precisely, main joints and available faults were appraised and some samples of the mine limestone zone were prepared to determine strength properties of rocks using laboratory tests. Then, the 3DEC code was used to construct a three dimensional model. According to the initial displacements from the software and geomechanical properties of the eastern wall and its concave shape, this wall was supposed to be stable. Further analyses were focused on the western wall. For stability analysis of the western wall, the model was constructed based on different cohesions and internal friction angles.
 
Results and Conclusions
In this research, field and laboratory studies were carried out in order to achieve accurate data of Angooran lead and zinc open pit mine. According to the obtained displacements of the model, probability of heavy failure was evaluated. The results are listed below: