Assessment of rock mass caveability in block caving mining method, using Rock Engineering Systems (RES)

Assessment of rock mass caveability is one of the important factors in the success of the block-caving mining. prediction of rock mass caveability is complicated due to the wide range of effective factors and the lack of complete knowledge of the impact of each factor on the rock mass caveability. Existing methods do not consider all the factors affecting the caveability process. This study uses the Rock Engineering systems (RES) approach to assess the rock mass caveability. After the implementation of the rock engineering system and ranking the influencing factors, the caveability index for selected mines was calculated. The results of this study have shown the sufficiency of RES approach in taking into account of all effective parameters.
Introduction In mining methods based on caving of ore such as block caving and sublevel caving, caveability of ore and surrounding rocks is of great importance. If the caveability of ore, would not properly evaluated it will impose high cost and losing of time on mining companies.
A major challenge in developing of existing caveability predicting methods is the taking into account of the values related to geomechanical, environmental, geometric and operational factors of rock mass, with a simple yet efficient method.
Methodology and Approaches RES is a powerful system approach to study the effect of influencing factors on the performance of an engineering system. The first step of the method is to establish interaction matrix and coding of the matrix. The principal factors considered relevant to the caveability have listed along the leading diagonal of a square matrix and off-diagonal terms have been coded by ESQ method. Then by Using RES approach the effective parameters on caveability have ranked. In the next step caveability index of Elteniente, Kemess and Ironcap mines, determined and compared with the results of well-known experimental methods, as the Laubscher caving chart, the extended Mattew’s stability graph and Stewart and Forsyth methods.
Results and Conclusions The results of this study have shown that Geomechanical factors are the most dominant and geometric factors are the most subordinate factors in the system. In addition, geomechanical and environmental factors have the highest and the least interaction on the system, respectively. Furthermore, although the hydraulic radius is different in experimental methods, but follows the same trend and there is a good agreement between the results of rock engineering systems and experimental methods there. At last a classification for the caveability index has introduced.