Evaluation of rockburst energy capacity for the design of rock support systems for different tunnel geometries at El Teniente copper mine

Abstract

Rockburst events have been a serious problem for many years in many mines worldwide, and in particular at El Teniente mine in Chile. El Teniente is the largest copper mine in the world, located in the Andes Cordillera where high stress levels are present due to intensing mining activity in addition to complex geology. Consequently, the study and management of the rockburst threat are necessary. In this work, the case of the Diablo Regimiento (DR) mine within El Teniente is studied. The energy capacity of dynamic support systems is determined for different tunnel geometries based on two kinetic methodologies, using data from DR. Initially, rockburst potential is determined by means of a stress analysis around different tunnel geometries through the boundary elements method. In the first methodology a yielding zone (YZ) is estimated for each excavation geometry using the finite element method FEM. The second methodology involves the definition and determination of a critical strain energy (SE) around each excavation geometry using a FEM numerical analysis. In both cases, peak particle velocity PPV is estimated by a scaling law, which is subsequently adjusted due to tunnel amplification effects. According to the results, and knowing the working energy capacity applied in DR mine, it was found that the values of energy capacity for the rock dynamic supports were better estimated by the YZ-PPV approach than by the SE approach.