The presentation by mining geotechnical engineer Fungai Kwangwari of SRK Consulting recently earned the Best Technical Presentation award at the Zimbabwe National Institute of Rock Engineering (ZINIRE) symposium in Bulawayo.
In an event held at the Zimbabwe School of Mines, in July 2024, Kwangwari presented on ‘A Stability Assessment and Support Design of Drift and Fill Layouts for an Underground Operation’.
“An assessment was carried out to determine the stability of different drift sizes and their extraction sequences, identifying any potential safety risk posed by each of the proposed sequences and recommend on secondary support requirements for final drifts,” she explains.
“The aim was to ensure that drifts were well supported during all stages of mining to ensure safety of exposed personnel.”
The study made recommendations on the safest practical extraction options. The excavation stability analysis and optimisation were conducted using three-dimensional finite element elastoplastic numerical modelling techniques to evaluate the condition of the drifts, and to investigate hangingwall stability.
The extent of hangingwall damage for different drift spans and extraction sequences was determined from the numerical modelling results.
“Furthermore, a kinematic analysis was carried out to determine the stability of potential wedges formed along the excavation perimeter when the drifts intersected with structural discontinuities,” says Kwangwari, a member of SRK’s Mining Geotech team. “The wedge analysis was conducted for different recommended primary patterns for wedge stability support to ensure that the design factor of safety is achieved, thereby limiting uncontrolled falls of ground.”
