Strategic sill pillar design for reduced hanging wall overbreak in longhole mining

Chen, Tuo; Mitri, Hani S.

doi:10.1016/j.ijmst.2021.09.002

Cited by 8 publications

(2 citation statements)

References 15 publications

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“…There are various methods to evaluate mining-induced stresses on coal pillars, such as empirical (3)(4)(5)(6)(7) and numerical methods (8)(9)(10)(11)(12). An empirical method is a method of inductive analysis by collecting some previous cases.…”

Section: Introductionmentioning

confidence: 99%

Hybridizing five neural-metaheuristic paradigms to predict the pillar stress in bord and pillar method

Zhou

Chen

et al. 2023

Front. Public Health

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Pillar stability is an important condition for safe work in room-and-pillar mines. The instability of pillars will lead to large-scale collapse hazards, and the accurate estimation of induced stresses at different positions in the pillar is helpful for pillar design and guaranteeing pillar stability. There are many modeling methods to design pillars and evaluate their stability, including empirical and numerical method. However, empirical methods are difficult to be applied to places other than the original environmental characteristics, and numerical methods often simplify the boundary conditions and material properties, which cannot guarantee the stability of the design. Currently, machine learning (ML) algorithms have been successfully applied to pillar stability assessment with higher accuracy. Thus, the study adopted a back-propagation neural network (BPNN) and five elements including the sparrow search algorithm (SSA), gray wolf optimizer (GWO), butterfly optimization algorithm (BOA), tunicate swarm algorithm (TSA), and multi-verse optimizer (MVO). Combining metaheuristic algorithms, five hybrid models were developed to predict the induced stress within the pillar. The weight and threshold of the BPNN model are optimized by metaheuristic algorithms, in which the mean absolute error (MAE) is utilized as the fitness function. A database containing 149 data samples was established, where the input variables were the angle of goafline (A), depth of the working coal seam (H), specific gravity (G), distance of the point from the center of the pillar (C), and distance of the point from goafline (D), and the output variable was the induced stress. Furthermore, the predictive performance of the proposed model is evaluated by five metrics, namely coefficient of determination (R2), root mean squared error (RMSE), variance accounted for (VAF), mean absolute error (MAE), and mean absolute percentage error (MAPE). The results showed that the five hybrid models developed have good prediction performance, especially the GWO-BPNN model performed the best (Training set: R2 = 0.9991, RMSE = 0.1535, VAF = 99.91, MAE = 0.0884, MAPE = 0.6107; Test set: R2 = 0.9983, RMSE = 0.1783, VAF = 99.83, MAE = 0.1230, MAPE = 0.9253).

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Section: Introductionmentioning

confidence: 99%

Hybridizing five neural-metaheuristic paradigms to predict the pillar stress in bord and pillar method

Zhou

Chen

et al. 2023

Front. Public Health

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“…In the mining of steeply inclined orebodies, Chen et al, conducted research based on the actual design case of the mine and proposed a numerical simulation scheme considering the progressive stope wall damage in order to demonstrate the role of the pillars. The results showed that when the pillar is strategically placed in the lower half of the mining plan, the average overbreak can be reduced by 33% [12]. Bazaluk et al, took the Yuzhno-Belozerskyi deposit as an example and studied the deformation process of unstable hanging-wall rock when mining a thick and steep deposit.…”

Section: Introductionmentioning

confidence: 99%

Study on Stope Stability in Continuous Mining of Long-Dip, Thin Orebody by Room–Pillar Method

Guo

Miao

2022

Sustainability

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In order to analyze the stability of the stope under continuous mining with the room–pillar method for a kind of orebody with a long inclination, but not deep mining, this paper takes the room–pillar method for the continuous mining of a long-inclination orebody in the Mengnuo Lead–Zinc Mine, Yunnan Province as the research background. On the basis of the analysis of the stope mechanical model of a long, inclined, thin orebody with room-and-pillar mining, based on numerical simulation, the nature of the change in stress, displacement and the plasticity zone of the roof and pillar during continuous mining along the inclination are systematically analyzed. The results show that as the mining depth increases, the roof subsidence of the stope in the middle of the current operation increases. With the continuous mining of the lower middle section, the roof displacement of the stope will continue to increase with the subsequent mining of the middle section until the end of all stope operations, and the roof displacement of the stope has an obvious cumulative effect. The stress on the roofs and pillars increases with the gradual downward movement of the mining in each level, and the distribution of the plastic zone also expands. It shows that the stope structural parameters that are set according to shallow mining cannot fully meet the requirements of stability and safety in mining a deeper orebody. Therefore, for the mining of a non-deep orebody with a greater tendency to extend, the structural parameters of a shallow stope should not simply be used in the mining of a deeper orebody, but the pillar size should be appropriately increased or the spacing between the room and pillar should be reduced to ensure the stability and safety of the continuous stope.

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Ground Movement in the Hanging Wall of Underground Iron Mines with Steeply Dipping Discontinuities: A Case Study

et al. 2023

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To ensure the safety of underground mining activities and effectively protect the surface production facilities and houses of the nearby residents, the ground movement caused by the sublevel caving method needs to be studied. In this work, the failure behaviors of the surface and drift of the surrounding rock were investigated based on the results of in situ failure investigations, monitoring data, and engineering geological conditions. The results were then combined with theoretical analysis to reveal the mechanism responsible for the movement of the hanging wall. Driven by the in situ horizontal ground stress, horizontal displacement plays an imperative role in both the movement of the ground surface and underground drifts. Accelerated movement is found to occur in the ground surface which coincides with the occurrence of drift failure. Failure occurs in the deep rock masses and then gradually propagates to the surface. The steeply dipping discontinuities are the main reason for the unique ground movement mechanism in the hanging wall. As steeply dipping joints cut through the rock mass, the rock surrounding the hanging wall can be modeled as cantilever beams subjected to in situ horizontal ground stress and lateral stress due to caved rock. This model can be used to obtain a modified formula for toppling failure. Also, a mechanism of fault slipping was proposed, and the condition required for fault slipping was obtained. Based on the failure mechanism of steeply dipping discontinuities, the ground movement mechanism was proposed considering the horizontal in situ ground stress and caved rock mass: slippage of fault F3, slippage of fault F4, and toppling of rock columns. Based on the unique ground movement mechanism, the goaf surrounding rock mass could be divided into six zones: a caved zone, a failure zone, a toppling-slipping zone, a toppling-deformation zone, a fault-slipping zone, and a movement-deformation zone.

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Strategic sill pillar design for reduced hanging wall overbreak in longhole mining

Cited by 8 publications

References 15 publications

Hybridizing five neural-metaheuristic paradigms to predict the pillar stress in bord and pillar method

Hybridizing five neural-metaheuristic paradigms to predict the pillar stress in bord and pillar method

Study on Stope Stability in Continuous Mining of Long-Dip, Thin Orebody by Room–Pillar Method

Ground Movement in the Hanging Wall of Underground Iron Mines with Steeply Dipping Discontinuities: A Case Study

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