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A Stope Mining Design with Consideration of Hanging Wall When Transitioning from Open Pit Mining to Underground Mining for Sepon Gold Mine Deposit, Laos
Phaisopha, S.; Shimada, H.; Sasaoka, T.; Hamanaka, A.; Pongpanya, P.; Shorin, S.; Senthavisouk, K. A Stope Mining Design with Consideration of Hanging Wall When Transitioning from Open Pit Mining to Underground Mining for Sepon Gold Mine Deposit, Laos. Mining2023, 3, 463-482.
Phaisopha, S.; Shimada, H.; Sasaoka, T.; Hamanaka, A.; Pongpanya, P.; Shorin, S.; Senthavisouk, K. A Stope Mining Design with Consideration of Hanging Wall When Transitioning from Open Pit Mining to Underground Mining for Sepon Gold Mine Deposit, Laos. Mining 2023, 3, 463-482.
Phaisopha, S.; Shimada, H.; Sasaoka, T.; Hamanaka, A.; Pongpanya, P.; Shorin, S.; Senthavisouk, K. A Stope Mining Design with Consideration of Hanging Wall When Transitioning from Open Pit Mining to Underground Mining for Sepon Gold Mine Deposit, Laos. Mining2023, 3, 463-482.
Phaisopha, S.; Shimada, H.; Sasaoka, T.; Hamanaka, A.; Pongpanya, P.; Shorin, S.; Senthavisouk, K. A Stope Mining Design with Consideration of Hanging Wall When Transitioning from Open Pit Mining to Underground Mining for Sepon Gold Mine Deposit, Laos. Mining 2023, 3, 463-482.
Abstract
This study investigates the transition from surface to underground mining at the Sepon Gold mine. The stability of surface slopes is assessed prior to commencing underground operations. Stope mining is adopted based on ore body characteristics and geological features. Finite element numerical analysis, employing the Generalized Hoek-Brown criterion, evaluates slope stability for surface slopes and opening stopes. The pit design comprises a 70° slope angle, 20 m height, and 10-15 m safety berm, meeting stability requirements with a factor of safety of 2.46. Underground mining design includes a 62° ore body dip, 50 m thick crown pillar to prevent surface subsidence, and 5 m wide, 5 m high stopes. Sill pillars are left for support after each level excavation. Rock bolts are employed in specific stope areas where is necessary, with continuous monitoring for surface deformation. The study analyzes the influence of stope sizes on pit wall and pit bottom stability, identifying slope failures near the hanging wall close to the pit bottom during underground mining. A slight increase in the displacement zone is observed on the upper crest of the top footwall. Overall, the findings demonstrate successful stability in the transition from surface to underground mining at Sepon Gold mine.
Keywords
open pit slope stability; finite element analysis; generalized Hoek-Brown criterion; underground stopping stability; surface subsidence
Subject
Engineering, Mining and Mineral Processing
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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