Probabilistic Block Theory Analysis for a Rock Slope at an Open Pit Mine in USA


A new formulation is given to conduct a probabilistic block theory analysis. A new computer code (PBTAC) is developed to perform both deterministic and probabilistic block theory analysis. The variability of the discontinuity orientation and shear strength is incorporated in the probabilistic block theory analysis. Discontinuity orientation is treated as a bivariate random variable including the correlation that exists between the dip angle and dip direction. PBTAC code was applied to perform both deterministic and probabilistic block theory analyses for a part of an open pit mine in USA. Needed geological and geotechnical data for the analyses were obtained from field and laboratory investigations. The variability of the discontinuity orientations resulted in important differences between the probabilistic and deterministic block theory analyses results. The results confirmed that the design value selected for the maximum safe slope angle (MSSA) for a particular region in the open pit mine based on the deterministic block theory analysis can be on the unsafe side. In summary, the results showed clearly the superiority of probabilistic block theory analysis over the deterministic block theory analysis in obtaining additional important information with respect to designing rock slopes. The calculated values agree very well with the existing almost stable bench face angles reported by the mining company.


Mining Engineering


The work was partially funded by the Centers for Disease Control and Prevention of USA (Contract No. 200-2011- 39886), National Basic Research Program of China (973 Program No. 2010CB732005) and the National Natural Science Foundation Project of China (No. 51079093).

Keywords and Phrases

Block theory; Instability probability; Open-pit mine; Probabilistic analysis; Rock slope

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Article - Journal

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© 2014 Elsevier Ltd, All rights reserved.

Publication Date

01 Sep 2014