Numerical Simulation of Crown Pillar Behaviour in Transition from Open Pit to Underground Mining

2021 ◽  
Author(s):  
Tumelo K. M. Dintwe ◽  
Takashi Sasaoka ◽  
Hideki Shimada ◽  
Akihiro Hamanaka ◽  
Dyson N. Moses ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Underground Mining ◽  
Open Pit ◽  
Crown Pillar

Numerical Simulation Analysis on the Collapse of Slope in Iron Mine

2014 ◽  
Vol 926-930 ◽  
pp. 593-596
Author(s):  
Fang Wang ◽  
Chong Shi ◽  
Kai Hua Chen ◽  
De Jie Li ◽  
Ke Han
Keyword(s):  
Numerical Simulation ◽  
Shear Failure ◽  
Safety Management ◽  
Simulation Analysis ◽  
Underground Mining ◽  
Tensile Failure ◽  
Open Pit ◽  
Open Pit Mining ◽  
Roof Fall ◽  
Rock Movement

The process of open-pit mining can lead to high slopes in iron mines, and natural slopes should be rebuilt by the method of roof fall as the exploitation style turns from open-pit mining to the underground mining. So the slope can be steep, deep and may has the characteristics of collapse. It is difficult to describe the stabilization of the mining slope by a conventional safety factor method. Through the numerical simulation of underground mining process, this paper analyzes the result of distortion stress and rock movement rupture range. Studies have shown that the failure mode is dominated by tensile failure as a pattern of collapse and few is dominated by shear failure. The failure zone is controlled by rock mass parameters and structures. The results can be helpful for the proposition of exploitation program and safety management design.

scholarly journals Determination of the Ultimate Underground Mining Depth considering the Effect of Granular Rock and the Range of Surface Caving

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Rongxing He ◽  
Jing Zhang ◽  
Yang Liu ◽  
Delin Song ◽  
Fengyu Ren
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Mechanical Model ◽  
Surface Deformation ◽  
Underground Mining ◽  
Mining Area ◽  
Open Pit ◽  
Open Pit Mining ◽  
Mining Depth

Continuous mining of metal deposits leads the overlying strata to move, deform, and collapse, which is particularly obvious when open-pit mining and underground mining are adjacent. Once the mining depth of the adjacent open-pit lags severely behind the underground, the ultimate underground mining depth needs to be studied before the surface deformation extends to the open-pit mining area. The numerical simulation and the mechanical model are applied to research the ultimate underground mining depth of the southeast mining area in the Gongchangling Iron mine. In the numerical simulation, the effect of granular rock is considered and the granular rock in the collapse pit is simplified as the degraded rock mass. The ultimate underground mining depth can be obtained by the values of the indicators of surface movement and deformation. In the mechanical model, the modified mechanical model for the progressive hanging wall caving is established based on Hoke’s conclusion, which considers the lateral pressure of the granular rock. Using the limiting equilibrium analysis, the relationship of the ultimate underground mining depth and the range of surface caving can be derived. The results show that the ultimate underground mining depth obtained by the numerical simulation is greater than the theoretical calculation of the modified mechanical model. The reason for this difference may be related to the assumption of the granular rock in the numerical simulation, which increases the resistance of granular rock to the deformation of rock mass. Therefore, the ultimate underground mining depth obtained by the theoretical calculation is suggested. Meanwhile, the surface displacement monitoring is implemented to verify the reasonability of the ultimate underground mining depth. Monitoring results show that the indicators of surface deformation are below the critical value of dangerous movement when the underground is mined to the ultimate mining depth. The practice proves that the determination of the ultimate underground mining depth in this work can ensure the safety of the open-pit and underground synergetic mining.

Use of an artificial crown pillar in transition from open pit to underground mining

2019 ◽  
Vol 117 ◽  
pp. 118-131 ◽  
Author(s):  
Shuai Xu ◽  
Fidelis T. Suorineni ◽  
Long An ◽  
Yuan Hui Li ◽  
Chang Yu Jin
Keyword(s):  
Underground Mining ◽  
Open Pit ◽  
Crown Pillar

Analysis of the Open-Pit to Underground Mining Slope Stability

2014 ◽  
Vol 484-485 ◽  
pp. 599-603
Author(s):  
Guang Ming Bao ◽  
Juan Chang ◽  
Zhi Gang Liu
Keyword(s):  
Numerical Simulation ◽  
Slope Stability ◽  
Underground Mining ◽  
Open Pit ◽  
Maximum Displacement ◽  
Modeling Software ◽  
Stability Of Slope ◽  
Computer Numerical Simulation ◽  
The Stability ◽  
Mining Slope

This paper uses the simulation technology of computer numerical simulation, combined with the GAMBIT numerical modeling software and ANSYS structure analysis software, we carry out an in-depth research and analysis on the stability of engineering simulation, at the same times establish the mathematical model of ANSYS numerical simulation displacement stability and design the ANSYS command stream program algorithm. Finally, this paper uses the open-pit to underground mining slope stability as an example, to verify the reliability of the model and algorithm. Through the numerical simulation, we get the displacement of slope in the Y direction and Z direction. In the Y direction, the maximum displacement is 0m, the negative maximum displacement is 5.88m and displacement is relatively large; in the Z direction, the maximum displacement is 1.32M, the negative maximum displacement is 1.08M and the stability of slope is different in different position. The numerical simulation provides the theory reference for the safety of mining engineering.

Numerical Simulation of the Deep Mining of Phosphate Ore Body Based on Digital Image Processing

2012 ◽  
Vol 616-618 ◽  
pp. 521-527
Author(s):  
Jun Wei Yao ◽  
Sheng Zhou Li ◽  
Ming Hui Li
Keyword(s):  
Numerical Simulation ◽  
Image Processing ◽  
Digital Image Processing ◽  
Digital Image ◽  
Underground Mining ◽  
Grid Cell ◽  
Open Pit ◽  
Triangular Grid ◽  
Uniform Mesh ◽  
Object Of Study

Based on digital image processing, use Matlab mathematical software to write Flac3D modeling interface program, and suppress noise transported from CAD software, for establishing numerical simulation model rapidly. With the No.59 exploration line profile picture of Yunnan Phosphate Group Jinning mine as the object of study, which is transformed from the open pit to deep underground mining, to establish Flac3D model mined with the way of room and pillar method study, it shows that: (1) using the method of multi-threshold segmentation, build the appropriate mask to suppress image noise effectively; (2) with controlling the horizontal grid cell size, achieve uniform mesh of the model; mesh at the strata border with the triangular grid, for weakening the jagged edges; (3) as the stopes excavated gradually, the movement extent of roof and floor is increasing influenced by mining; the roof is relatively stable, while the stress concentration factor of room pillars is bigger, therefore some measures should be taken to prevent the mine wall caving. The numerical simulation results provide a reference for the design feasibility study of phosphate mining and have a guiding significance for parameter optimization as well.

Estimation of open-pit / underground mining cross-effect in complicated geomechanical conditions

2021 ◽  
pp. 58-63
Author(s):  
I. E. Semenova ◽  
◽  
I. M. Avetisyan ◽  
Keyword(s):  
Rock Mass ◽  
Underground Mining ◽  
Ground Surface ◽  
Mining Operation ◽  
Open Pit ◽  
Design Parameters ◽  
Cross Effect ◽  
Stress Strain ◽  
Tectonic Stresses ◽  
Crown Pillar

The paper presents the results of prediction model studies of the stress–strain behavior in Gakman field of Yukspor deposit during hybrid open pit/underground mining under conditions of high tectonic stresses. The mountainous relief, rock mass faulting with a series of weak structures, geometry of the ore body, the actual and design parameters of stopes, and mining operation under the uncaved overlying stratum with three-sided support are taken into account. Based on the multivariate threedimensional stress–strain modeling using the finite element method, geomechanical substantiation of simultaneous open-pit and underground mining was carried out. It has been established that the geomechanical determinants in Gakman field are: – gravitational and tectonic stresses with a significant excess of the tectonic component over the gravitational component; – mountainous relief of ground surface with a significant elevation difference in the study area; – location of underground mining under the uncaved overlying stratum with three-sided support; – faulting of rock mass with a series of weak structures (Gakman fault); – formation of the open pit and crown pillar above underground mine; – significant lag of the mining front on the underlying levels of level + 320 m. The dimensions of the cross-effect zone and crown pillar when the underground operations approach the open pit mine are determined.

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