Assessment of rock fall hazards and optimisation of rock support for deep underground mines

Important results from the project

The aim of this project was achieved. Methods for assessing the rockfall hazards based on deterministic (forensic investigation) and statistical (DFN modelling) analyses were developed. The knowledge of the performance characteristics of rock support (bolt-shotcrete arches and mesh overlap) were improved. Design guidelines for bolt-shotcrete arches, mesh and mesh overlaps were proposed. By implementing the methodologies and guidelines in practice, the number of production disturbances, and the risk for personnel injury and production losses could be reduced.

Expected long term effects

Improved understanding of rockfall mechanisms, A new methodology for assessing the rockfall hazards based on deterministic and statistical analyses, Improved rock support strategy to prevent large rockfalls controlled by geological structures and seismic loading, Improved performance of bolt-shotcrete arches based on the improved understanding of the performance characteristics of bolt-shotcrete arches, Improvement of welded mesh application by new design layout and guidelines, and Educated rock engineering personnel for the mining industry.

Approach and implementation

Five damaging seismic events were investigated and the developed deterministic and statistical numerical methods were used to assess the rockfall hazards. Comprehensive field monitoring was conducted and the collected data were used to calibrate the numerical model and investigate the performance of bolt-shotcrete arches. The performance of welded mesh under various loading and boundary conditions were tested and evaluated. The results were analysed and integrated to develop new methods to evaluate rockfall hazards and to improve design guidelines of rock support.