INVESTIGATION OF STOPE WALL CONVERGENCE-BASED BEHAVIOR FOR NARROW VEIN OREBODIES
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Date
2024-04-19
Authors
Abdir, Darkhan
Journal Title
Journal ISSN
Volume Title
Publisher
Nazarbayev University School of Mining and Geosciences
Abstract
Despite the fact that it involves geological complexities like inconsistent vein properties, shear zones, and varied lithological width, narrow-vein mining is an ancient underground mining technique that is currently gaining importance due to the depletion of surface mines. Narrow vein mining targets tabular orebodies known as veins, single or in complex systems that are essential for yielding various minerals like gold and tin. In this thesis, it is suggested that the behavior in deep, hard rock, narrow vein mines is primarily plastic instead of brittle, as the current design tools assume. This is primarily because production demands force stopes to be elongated, leading to stope walls that are significantly longer along the strike than their width. In order to check this hypothesis numerical modeling tool RS2 was used, also, the influence of stress ratio (K=1; K=1.5; K=2; K=2.5), and different stope width (from 1m to 10m) were analyzed. The stope walls deformation and damage increase with mining depth and in-situ stress, as shown by the figures and RS2 simulations. When K=1.5, 𝜎1/𝜎𝑐= 0.15, depth = 65 m, stope wall closure was equal to
0.00210022 m; 𝜎1/𝜎𝑐= 0.4, depth = 750 m, walls converged inside of stope by 0.054073 m; 𝜎1/𝜎𝑐=0.6, depth = 1500 m, the closure of walls was 0.118056 m. Also, it was concluded that the behavior of stope walls changes with changing stress circumstances; greater depth and K values cause displacement to increase and strength to decrease, respectively, resulting in considerable stress damage. The graph indicates that larger stopes often encounter less wall convergence and it shows that the closure percentage increases as the effective stress ratio (K) increases, underscoring the critical role of stress conditions affecting wall stability and the significance of taking both stope width and stress conditions into account when controlling wall displacement in mines.
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Keywords
Type of access: Open access, open stopes, narrow veins, wall closure, horizontal displacement
Citation
Abdir, D. (2024). Investigation of stope wall convergence-based behavior for narrow vein orebodies. Nazarbayev University School of Mining and Geosciences