EVALUATION OF GEOMECHANICAL RISKS ASSOCIATED WITH THE CUT & FILL MINING METHOD FOR NARROW VEIN MINING CONDITIONS

Abstract

The main objective of this research project is to delve into geomechanical risks associated with the cut & fill mining method for narrow vein mining conditions. The cut-and-fill method is a highly selective underground mining method based on removing horizontal slices and filling the mined stopes with backfill. Controlling geotechnical design parameters and operational factors, affecting the method for a given underground mining condition, will be considered from a risk assessment point of view. Given the complicated nature of the rock mass in-situ, and complicated boundary conditions and operational complexities associated with cut and fill mining at depth, the selection of a safe and economic mining operation is of paramount significance. Rock failure at varying scales within the underground mining openings is always a threat to mining operations and causes human and capital losses worldwide. Geomechanical design is a major design component of all underground mines and dominates the safety of an underground mine. With regard to the uncertainties exist in rock characterization prior to mine development, there are always risks associated with inappropriate design as a function of mining condition and the selected mining method. Uncertainty often results from the inherent variability of rock mass, which in turn is a function of both geological materials and rock mass in-situ conditions. In this study a typical cut and fill mining condition at high depth will be simulated numerically. For this research, the 2D numerical modelling using the finite element method is implemented to assess the effect of the parameters on the stability of the mine. The focus of this research is to conduct a comprehensive analysis looking into key design parameters associated with the method and assess risks associated with geomechanical design parameters. The obtained results will be verified against field data and risk proneness of key geomechanical design parameters will be discussed. As a result, the developed evaluation of geomechanical risks will offer a more complete way of assessing the stability of the underground working environment in terms of industry knowledge of ground behavior and stress distributions.