Concept Feasibility and Predicted Behavior of Mining a Rock Tower with Drill-and-Blast Undermining Using Dynamic Three-Dimensional Discontinuum Numerical Models
Authors: Abousleiman, R.1, Contreras, C.I.2, Cremeens, J.3, Worsey, T.4, Rouse, N.5
Conference: 58th US Rock Mechanics / Geomechanics Symposium
Date: June 23-26, 2024
1 Knight Piésold and Co., Denver, Colorado, USA
2 Stantec, Lima, Lima, Peru
3 Knight Piésold and Co., Fort Collins, Colorado, USA
4 DynoConsult, New Castle, NSW, Australia
5 Thoroughbred Drill and Blast Consultants, Thurles, Tipperary, Ireland
ABSTRACT
The safety and efficacy of a proposed novel mining method - felling a mineralized rock tower away from an adjacent river and towards an existing open pit using a wedge-shaped “key-cut” blast pattern and post-split hinge – was analyzed by integrating site-specific and site-adjacent data to develop a into a dynamic three-dimensional discrete element method numerical model. These data included historic laboratory testing and geomechanical core logging from the adjacent open pit, Lidar scans and geomechanical spot mapping of the rock tower, local signature blast seismic data, and proposed blast-pattern. Static and dynamic model stages were run to assess the pre-blast, syn-blast, and post-blast deformation of the mineralized rock tower. Model sensitivities to mesh size, dynamic time-step, block size, and joint strength were assessed. Ultimately, model results indicated that the proposed mining method would likely result in 97 percent retention of the blasted material within the existing open-pit, and only 3 percent of material would be cast towards the adjacent river.
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