scholarly journals A New Mining Scheme for Hanging-Wall Ore-Body during the Transition from Open Pit to Underground Mining: A Numerical Study

2018 ◽  
Vol 2018 ◽  
pp. 1-17
Author(s):  
Baohui Tan ◽  
Fengyu Ren ◽  
Youjun Ning ◽  
Rongxing He ◽  
Qiang Zhu
Keyword(s):  
Underground Mining ◽  
Numerical Study ◽  
Hanging Wall ◽  
Slope Instability ◽  
Open Pit ◽  
Ore Body ◽  
Instability Development ◽  
Induced Caving ◽  
Iron Mine ◽  
Mining Scheme

A new mining scheme by employing the induced caving mining method to exploit hanging-wall ore-body during the transition from open pit to underground mining is proposed. The basic idea is to use the mined-out area generated by the planned mining of the hanging-wall ore-body to absorb the collapsed slope body, so as to avoid the influence of the inner-slope mining to the normal open-pit mining and guarantee mining efficiency during the transition stage. Numerical simulation study on the process of induced caving mining of hanging-wall ore-body is carried out based on the practical engineering setting of the Hainan iron mine, China, by employing the numerical method of discontinuous deformation analysis (DDA). The impact of rock mass structure on the mechanism of slope instability development and the mining hazard assessment in the new mining scheme is investigated. The influence of mining sequence on slope instability development and mining safety is also analyzed by taking the hanging-wall ore-body mining under the southern anti-dip slope at the Hainan iron mine as an example, and eventually a reliable mining scheme via induced caving is obtained. The numerical study proves the feasibility of the proposed new mining scheme for hanging-wall ore-body and provides theoretical and technical support for its application in practical mining activities.

Numerical Study of Plastic Strains on Slope Instability

2012 ◽  
Vol 548 ◽  
pp. 363-366
Author(s):  
Mao Hu Wang ◽  
Zhen Liang Xu
Keyword(s):  
Finite Element ◽  
Slope Stability ◽  
Safety Factor ◽  
Numerical Study ◽  
Limit Equilibrium ◽  
Strength Reduction ◽  
Slope Instability ◽  
Open Pit ◽  
Instability Criterion ◽  
Incremental Search

This article simulates an open pit slope stability using the ANSYS software, which is based on the finite element strength reduction theory, three kinds of slope instability criterion of the strength reduction method are applied to judge whether the slope is on the limit equilibrium state, the incremental search method is used to search the safety factor of the slope stability, and the results show that, the slope body damages when the plastic zone developed from the top to the bottom, in the numerical simulation the finite element iteration calculation didn’t just converge, the corresponding former level of reduction factor is the safety factor, This article can have a guiding significance on the safety production of the open-pit mine.

Impact Assessment on the Ore Body under the Tower Footing of 500kV Transmission Line

2012 ◽  
Vol 594-597 ◽  
pp. 115-120 ◽  
Author(s):  
Chen Zhang ◽  
E Chuan Yan ◽  
Yi Zhou ◽  
Ya Jun Wang
Keyword(s):  
Transmission Line ◽  
Power Transmission ◽  
Additional Stress ◽  
Rock Stress ◽  
The West ◽  
Ore Body ◽  
Iron Mine ◽  
Mining Scheme ◽  
The Impact ◽  
Surrounding Rock Stress

Zhangjiaba-Enshi 500kV Transmission Line is a backbone network in the West to East Power Transmission Project of China, which passes through the factory area of Chongqing Sanxing Iron Mine Factory. According to solving the additional stress on foundation rock produced by tower load based on the Boussinesq theory and the redistribution of surrounding rock stress resulting from iron mining computed by using the calculation formula for redistribution stress on circular chamber in rock mass, this paper analyzes and demonstrates the impact of Zhangjiaba-Enshi Line N327 tower footing pressure mine on mining within the range of mining scheme, and determines that there is no mutual impact between the Zhangjiaba-Enshi Line N327 tower and exploitation of Sanxing ore horizon.

Study of the Effect of Mining with Transition from Open-Pit to Underground and without Protective Coal Pillar on Slope Stability

2014 ◽  
Vol 1010-1012 ◽  
pp. 1475-1481
Author(s):  
Shi Guo Sun ◽  
Yanan Yi ◽  
Lu Jin ◽  
Jia Huan Shi
Keyword(s):  
Slope Stability ◽  
Slope Failure ◽  
Underground Mining ◽  
Coal Pillar ◽  
Simulation Method ◽  
Mining Area ◽  
Control Measures ◽  
Open Pit ◽  
Rock Body ◽  
Mining Scheme

As this mining area has a shallow coal seam and a dump, therefore, the mining for the deep resources uses the method of transition from open-pit to underground without protective coal column. In this paper, the numerical simulation method is used to analysis the surface subsidence and slope stability from the two different mining schemes which are from inside to outside, and from outside to inside, in order to obtain the optimization of mining scheme. And settlement and slope stability of rock body are further analyzed from two aspects of fully exploit from the tendency and from toward, the result of an overall slip slope failure caused by underground mining is found. So that in the process of exploitation, corresponding prevention and control measures to the slope safety has been put forward, ensuring smooth production.

The Prediction of Northern Slope Deformation and Failure Caused by the Transformation of Open-Pit to Underground Mining in the Yanqianshan Iron Mine

2014 ◽  
Vol 580-583 ◽  
pp. 364-370
Author(s):  
An Lin Shao ◽  
Hai Long Feng
Keyword(s):  
Slope Failure ◽  
Underground Mining ◽  
Limit Equilibrium ◽  
Failure Process ◽  
Open Pit ◽  
Northern Slope ◽  
Body Distribution ◽  
Ore Bodies ◽  
Sublevel Caving ◽  
Iron Mine

<span><p class="TTPAbstract"><span lang="EN-US">The Yanqianshan<a name="OLE_LINK94"></a><a name="OLE_LINK93"></a> iron mine is preparing to transform from an open-pit mine to an underground mine. We adopt the <a name="OLE_LINK104"></a><a name="OLE_LINK103"></a>non-pillar sublevel caving approach to exploit the particularly thick steep ore bodies within the range from -183 m to -500 m from top to bottom. According to the features of ore body distribution and the approaches of exploitation, we expect that underground mining will result in <a name="OLE_LINK102"></a><a name="OLE_LINK101"></a>the loss of stability on the northern slope of the open pit, causing traction-type landslides. Moreover, along with increasing the depth of the mining operation, the range of slope failure will continue to expand and further affect the safety of drainage features and roads distributed on the north side of the open pit. For this purpose, we select f</span><span lang="EN-US">our</span><span lang="EN-US"> sections along the trending direction of ore bodies and apply the limit equilibrium method to predict the failure process and characteristics on the northern slope according to the stratified mining process.</span><span lang="EN-US"><o:p></o:p></span></p>

scholarly journals Research on the Evolution Characteristics of Rock Mass Response from Open-Pit to Underground Mining

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jiabo Geng ◽  
Qihang Li ◽  
Xiaoshuang Li ◽  
Tao Zhou ◽  
Zhifang Liu ◽  
...  
Keyword(s):  
Underground Mining ◽  
Vertical Direction ◽  
Mining Area ◽  
Open Pit ◽  
Measuring Point ◽  
Deformation And Failure ◽  
Ore Body ◽  
Evolution Characteristics ◽  
The Impact ◽  
Overlying Strata

This study is based on the engineering background of pit no. 2 in Jinning Phosphate Mine, China. In order to systematically analyze the movement, deformation, and failure laws of surrounding rocks in underground stopes. The room and pillar method is used to excavate and stop the ore bodies in the mining area. Combined with the similar physical model experiments and discrete element MatDEM numerical simulations, it reveals the deformation and failure laws and evolution characteristics of the surrounding rock of the stope in the process of converting from open-pit to underground mining. The results show the following: (1) Along the inclination of the ore body, the farther the horizontal and vertical displacements are from the underground stope, the less the impact of mining stress. On the other hand, along the inclined vertical direction of the ore body, the farther the measuring point is from the stope, the smaller the range of mining influence will be. (2) In the process of ore body recovery, the rupture of the overlying strata of the stope has an obvious layered structure, with collapse zones, fissure penetrating zones, and microfracture loosen zones appearing from the bottom to top. In addition, the movement and destruction of the overlying strata of the entire stope is an “elliptical arch.” Therefore, the results of similar simulation experiments and numerical simulation are basically consistent.

Prediction of failure of south slope caused by underground mining in the Yanqianshan open-pit iron mine

2013 ◽  
pp. 391-397
Author(s):  
Xuebing Pei ◽  
Renjie Zhou ◽  
Nengxiong Xu ◽  
Xiaoqiang Liu ◽  
Jingping Liu
Keyword(s):  
Underground Mining ◽  
Open Pit ◽  
Iron Mine ◽  
South Slope

scholarly journals Peculiarities of the underground mining of high-grade iron ores in anomalous geological conditions

2019 ◽  
Vol 28 (4) ◽  
pp. 706-716
Author(s):  
Mykhailo V. Petlovanyi ◽  
Vladislav V. Ruskykh
Keyword(s):  
Iron Content ◽  
Underground Mining ◽  
Hanging Wall ◽  
Slope Angle ◽  
High Grade ◽  
Ore Deposit ◽  
Ore Body ◽  
Subsequent Decrease ◽  
Geological Conditions ◽  
The Difference

This paper is dedicated to research into the geological peculiarities, shape of the ore body and the occurrence of the host rocks in the hanging wall of the Pivdenno-Biloz- erske deposit , as well as their influence on the degrees and quality of high-grade iron ore extraction. It is noted that in the interval of 480 – 840 m depths, a decrease is observed in the stability of the natural and technogenic massif, which is caused by the increase in rock pressure with depth, the influence of blast- ing operations on the massif and the difference in geological conditions. This has led to the collapse of hanging wall rocks and backfill into the mined-out space of chambers in certain areas of the deposit, the dilution of the ore and deterioration of the operational state of the underground mine workings. Attention is focused on the causes and peculiarities of consequences of the collapse of the hanging wall rocks during ore mining, which reduce the technical and-economic indexes of the ore extraction from the chambers. A 3D-model of an ore deposit with complex structural framework has been developed, which makes it possible to visually observe in axonometric projection the geological peculiarities and the shape of the ore body. The parameters have been studied of mining chambers in the 640 – 740 m floor under different changing geological conditions of the ore deposit and hanging wall rocks occurrence – the northern, central and southern parts. The difference in the iron content in the mined ore relative to the initial iron content in the massif has been defined as an indicative criterion of the influence of changing conditions on the production quality. The reasons have been revealed which contribute to the collapse of the rocks and the subsequent decrease in the iron content of the mined ore in ore deposit areas dif- fering by their characteristics. It has been determined that within the central and half of the southern ore deposit parts with a length of 600 m, an anomalous geological zone is formed, the manifestation of which will be increased with the depth of mining. It was noted that within this zone, with the highest intensity and density of collapse of hanging wall rocks, the influence of decrease in the slope angle and change in the strike direction are of greatest priority, and such geological factors as a decrease in hardness, rock morphology, deposit thickness increase this influence significantly. To solve the problems of the hanging wall rocks’ stability, it is recommended to study the nature and direction of action of gravity forces on the stope chambers in the northern, central and southern parts, as well to search for scientific solutions in regard to changes in the geometric shapes of stope chambers and their spatial location, improving the order of reserves mining in terms of the ore deposit area, the rational order of breaking-out ore reserves in the chambers with changing mining and geological conditions of the fields’ development.

scholarly journals Numerical Simulation of Surface Subsidence and Backfill Material Movement Induced by Underground Mining

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Xibing Li ◽  
Dongyi Wang ◽  
Chongjin Li ◽  
Zhixiang Liu
Keyword(s):  
Underground Mining ◽  
Hanging Wall ◽  
Ground Surface ◽  
Surface Subsidence ◽  
Mining Method ◽  
Backfill Material ◽  
Ore Body ◽  
Sublevel Caving ◽  
Lead Zinc ◽  
Zinc Mine

Surface subsidence induced by underground mining is one of the challenging problems in mining engineering, which can destroy ground surface buildings and cause huge economic losses to the mine. In this study, a two-dimensional numerical model, established by the discrete element method code PFC2D, was adopted to investigate the mechanical mechanism of surface subsidence and backfill material movement induced by underground mining in the Hongling lead-zinc mine. In the first simulation case, the ore body was excavated from the ground surface to the mining level 705 m by the sublevel caving mining method, and the stress evolution during the mining process was analyzed to reveal the mechanical mechanism of surface subsidence. In the second and third simulation cases, the mined-out areas above 905 m were backfilled by the noncemented tailings and an insulating pillar was reserved beneath the backfill material, and then the deep ore body was excavated by two different mining methods to study the movement law of the backfill material and rock strata induced by underground mining. The numerical simulation results show that when the sublevel caving mining method is adopted, underground mining can induce toppling failures in the hanging wall and lead to a large collapse pit in the ground surface. After the toppling failures in the hanging wall, the collapsed waste rock in the mined-out area can provide support force for the surrounding rock and restrict the further collapse of the hanging wall. Furthermore, when the cut-and-fill mining method is adopted for the excavation of deep ore body, the insulating pillar can restrict the horizontal displacement of surrounding rock and maintain the stability of the backfill material. The cut-and-fill mining method can efficiently control the surface subsidence and prevent the occurrence of collapse pit in the ground surface and is recommended for the Hongling lead-zinc mine to solve the surface subsidence problem.

The Study on Key Issues of Slope Instability during Turning Open-Pit into Underground Mining

2012 ◽  
Vol 594-597 ◽  
pp. 70-75
Author(s):  
Shi Guo Sun ◽  
Hong Yang ◽  
Chun Sheng Li ◽  
Bao Lin Zhang ◽  
Ai Wei Miao ◽  
...  
Keyword(s):  
Slope Stability ◽  
Underground Mining ◽  
Outer Region ◽  
Central Area ◽  
Geometric Dimension ◽  
Slope Instability ◽  
Open Pit ◽  
Open Pit Mining ◽  
Stability Coefficient ◽  
Mining Depth

During turning open-pit into underground mining, the state of slope stability is related to the relative space positional relationship between open-pit mining and underground mining. The toe area of slope is the most unfavorable area to slope stability and the outer region of slope is the most favorable area, while the central area of the slope has the most complicated effect on slope stability so that the mechanism of its influence can be understood only by the means of calculation. The slope stability coefficient decreases with the augment of underground mining geometric dimension. But it remains constant when the underground mining area is fully extracted. With the increase of mining depth, its range of influence on slope stability increases, which results in the decrease of slope stability coefficient. However, the slope stability coefficient tends to unchanged when the mining depth increases to some certain value.

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