Block caving

Irazu Simulation of a block caving operation in a conceptual model with undercut depth and length equal to 100m. The rock mass fabric is modelled with a Discrete Fracture Network characterized by a 45º inclined joint set (crack length = 10 ± 1 m, bridge length = 6 ± 1 m, spacing = 6 ± 1 m).

The block caving method has been used for many years to mine lower grade ore bodies economically. Estimates of the magnitude and extent of surface subsidence are needed to better understand the risk to surface infrastructures. The use of sophisticated numerical models has recently started to provide an opportunity to analyze the factors governing caving mechanisms and to develop improved methodologies for the prediction of associated surface subsidence.

Geomechanica’s Irazu simulation software can simulate the propagation of a block caving operation to surface. Due to the ability of FEM/DEM of explicitly simulating fracture propagation, within one model, the progressive excavation of an undercut can be realized and the subsequent initiation and propagation of the caving front (primary fragmentation) and many mechanisms of secondary fragmentation of the fallen blocks can be simulated as ore is drawn.

Further Reading:

  • Lisjak A, Tatone B, Mahabadi O and Grasselli G (2012). "Block caving modelling using the Y-Geo hybrid finite-discrete element code". In Proceedings of the 6th International Conference on Mass Mining. Sudbury. 10-14 June, 2012.
Simulation highlights

  • Elastic models including isotropic and transversely isotropic
  • Isotropic and anisotropic strength models
  • Model heterogeneity with arbitrary number of material types
  • Staged undercut excavation
  • Dynamic removal of caved material with either continuous or staged flow extraction
  • Discrete Fracture Network (DFN) capability with frictional or cohesive discontinuities
  • Micro-seismic monitoring function