Application of Synthetic Rock Mass modeling to veined core-size samples

Abstract

Rock masses of the primary copper ore at the El Teniente mine fail mainly through the infill of preexisting veins during the caving processes, especially through those composed of less than 35% hard minerals (quartz and pyrite). In this study, the Synthetic Rock Mass (SRM) approach is used to reproduce the results of ten uniaxial compression tests on veined core-size samples of El Teniente Mafic Complex (CMET) lithology, from El Teniente mine, Codelco-Chile. At the scale of the tested samples it is observed that veins composed mostly of quartz dominate the failure process. The developed methodology considers generating a deterministic Discrete Fracture Network (DEN) based on the veins mapped at the surface of each core sample. Then, the micro-parameters of the Bonded Particle Model (BPM) are calibrated to represent the macro-parameters of the average block of intact rock within all samples. Next, the micro-parameters of the Smooth-Joint Contact Model (SJCM), which represent the mechanical properties of veins, are calibrated to reproduce the stress-strain curves and the failure modes of the veined coresize samples measured during the laboratory tests. Results show that the SRM approach is able to reproduce the behavior of the veined rock samples under uniaxial loading conditions. The strength and stiffness of veins, as well as the vein network, have an important impact on the deformability and global strength of the synthetic samples. Contrary to what was observed in the laboratory tests, synthetic samples failed mainly through weak veins. This result is expected in the modeling given that anhydrite veins are considered weaker than quartz veins. Further research is required to completely understand the impact of veins on the behavior of rock masses.