Exploitation
Samia Chaoui; Adel Djellali; Benghazi Zied; Sarker Debojit
Abstract
This study aims to investigate the stability of rooms and pillars along the inclined zinc orebody at the Chaabet El Hamra underground mine (Setif, Algeria). Stability was initially assessed using an analytical shear strength model, with the results subsequently validated through numerical modeling. Geomechanical ...
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This study aims to investigate the stability of rooms and pillars along the inclined zinc orebody at the Chaabet El Hamra underground mine (Setif, Algeria). Stability was initially assessed using an analytical shear strength model, with the results subsequently validated through numerical modeling. Geomechanical characterization revealed low interstitial porosity, strong to very strong uniaxial compressive strengths ranging from 50.4 MPa to 129 MPa, and significant fracture-related secondary porosity. Rock Mass Rating (RMR89) and Geological Strength Index (GSI) values suggest fair to good rock quality. The mine design features square pillars inclined at 10°, with walls originally oriented perpendicular to the orebody dip, measuring 5 m in width and 3 m in height. The rooms, situated under a cover depth of 145.3 m, are 9 m wide. This configuration yielded an effective extraction rate of 87.24% and a safety factor of 1.63, indicating stable mining conditions. Phase 2D finite-element simulation confirmed these findings, showing a maximum displacement of 3.96 mm, surface subsidence of 0.57 mm, and a safety factor of 1.66, suggesting minimal environmental impact and long-term stability. Shear/compressive stress results from tributary area theory, aligning with numerical results and validating both approaches for inclined orebodies. Finally, the pillar walls, originally perpendicular to the orebody dip, were modified to be vertical relative to the horizontal plane, while maintaining the same pillar and room dimensions and cover depth. This adjustment improved stability by enhancing stress distribution and pillar core confinement, increasing the safety factor to 1.85.
V. Mwango Bowa; W. Samiselo; E. Manda; Y. Lei; W. Zhou; A. Shane; S. Chinyanta
Abstract
The influence of variable groundwater has been overlooked in the available literature. Yet, wedge failure induced by variable groundwater is still commonly experienced in sedimentary rock formation in many commercial dams, highways, and surface mine slopes around the world. In this article, a robust ...
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The influence of variable groundwater has been overlooked in the available literature. Yet, wedge failure induced by variable groundwater is still commonly experienced in sedimentary rock formation in many commercial dams, highways, and surface mine slopes around the world. In this article, a robust analytical model for stability analysis of the rock slopes subjected to wedge slope failure induced by variable groundwater is presented. This involves modifying the existing analytical model for estimating the safety factor of the rock slope subjected to wedge failure by incorporating the effects of variable groundwater. The proposed analytical model is validated using a numerical simulation model using the Fast Lagrangian Analysis of Continua in 3 Dimensions (FLAC3D) software. Furthermore, a real wedge slope instability at the Chingola Open-Pit Mine (COP F&D) induced by the presence of variable groundwater case history is studied in order to illustrate the effectiveness of the presented analytical model. The investigation results indicate that the presence of variable groundwater has a direct impact on the computed factor of safety of the rock slope subjected to wedge failure. The results obtained entail that the presented analytical model can provide a robust analytical model for the stability analyses of the rock slope subjected to wedge failure considering the presence of variable groundwater.
