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.

scholarly journals INSAR COLLABORATIVE MONITORING MODE AND MULTI-MODE COMPUTING SERVICES FOR GEOHAZARDS IDENTIFICATION IN OPEN-PIT MINING AREA

2021 ◽  
Vol XLIII-B1-2021 ◽  
pp. 241-247
Author(s):  
J. Zhang
Keyword(s):  
Time Series ◽  
Surface Deformation ◽  
Underground Mining ◽  
Mining Area ◽  
Deformation Monitoring ◽  
High Density ◽  
Open Pit ◽  
Open Pit Mining ◽  
Mining Areas ◽  
Wide Range

Abstract. InSAR has developed a variety of methods, such as D-InSAR, PS-InSAR, MBAS, CT, SqueeSAR, POT, etc., which have been widely used in land subsidence monitoring. For open pit mining areas, there are usually mining activity, complex terrain features, low coherence, and local large deformation gradients, which makes it difficult for time series InSAR technology to obtain high-density surface deformation information in open pit mining areas. Traditional methods usually only monitor the linear deformation of the surface caused by the mining of a few working zone above the underground mining area, and the temporal and spatial resolution is lower. How to obtain high-precision, high-density, and time-sensitive deformation information is the main difficulty of InSAR monitoring in open pit mining areas. Make full use of the geosensor network monitoring system, optimize monitoring mode of collaborated satellite-to-ground based InSAR, further realize whole calculation and geographic information services, to achieve early identification and discovery of abnormal in large-area macro-monitoring, and accurate monitoring of local areas in real-time early warning, which is the development direction of ground deformation monitoring of mining areas. The study area is Pingshuo open pit mining area. we fully study the application mode and services of InSAR monitoring for geohazards in open-pit mining area, through the establishment of satellite InSAR technology system for large-scale macro-monitoring and forecasting, and GBSAR and GSN for local precision monitoring. The effective mode of InSAR monitoring of geohazard in open-pit mines is summarized. A combination of D-InSAR, POT (Pixel offset tracking), Time Series-InSAR and GB-SAR is used in a wide range, and high-resolution optical images are used to identify localized changes in subsidence areas and open-pit mining areas.

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 Two-Dimensional Modeling of the Influence of Underground Mining Direction on Slope Stability in Coordinated Open-Pit and Underground Mining

2021 ◽  
Author(s):  
Bowen Liu ◽  
Zhenwei Wang ◽  
Xinpin Ding ◽  
Zhitao Wang ◽  
Bin Li
Keyword(s):  
Rock Mass ◽  
Slope Stability ◽  
Underground Mining ◽  
Mining Area ◽  
Two Dimensions ◽  
Open Pit ◽  
Engineering Practice ◽  
Inverse Slope ◽  
Coal Wall ◽  
Mining Face

Abstract Under a background of coordinated open-pit and underground mining engineering practice in the Pingshuo mining area, a combination of numerical simulations and similar-model experiments was used to study the influence of the underground mining direction on slope deformation in two dimensions. The results show that the disturbance caused by inverse-slope mining is more obvious than that caused by along-slope mining. Underground mining presents an asymmetric influence on the open-pit slope; the slope rock mass on the open-off cut side is disturbed more than that on the coal-wall side. Compared with the slope in front of the advancing direction of the underground mining face, the degree of rock-mass damage and stress concentration of the slope of the open-off cut side are more serious. As such, in coordinated open-pit and underground mining practice, an along-slope mining direction is recommended to reduce adverse effects on slope stability and improve the recovery rate of coal resources.

Analysis of the Relative Position of the Slope and Underground Mining Area and its Influence Properties

2013 ◽  
Vol 634-638 ◽  
pp. 3277-3281 ◽  
Author(s):  
Shi Guo Sun ◽  
Hong Yang ◽  
Chun Sheng Li ◽  
Bao Lin Zhang ◽  
Jia Wang ◽  
...  
Keyword(s):  
Slope Stability ◽  
Underground Mining ◽  
Mining Area ◽  
Open Pit ◽  
Stability Factor ◽  
Mining Depth ◽  
Extracellular Region ◽  
Geological Conditions ◽  
Slope Rock ◽  
The Stability

The stability state of slope rock mass is relating to each other’s relative location during the transformation from open-pit to underground mining, it’s the most disadvantageous influence on the slope stability when the underground mining area is located in the toe of slope, and it’s the best influence as in the slope extracellular region. Slope stability factor changes with the geometric dimensions of underground mining increased, but not in direct proportion. Under the condition of constant geometric dimensions of mining area, the influence on slope stability is changing with the mining depth increased. Thus indicating that the influence on slope stability by underground mining has its spatial property, and to determine the specific influence value requires a combination of many factors, such as the relationship of relative spatial position, the geometric dimensions of mining area, engineering geological conditions and so on.

scholarly journals Mapping Annual Land Disturbance and Reclamation in a Surface Coal Mining Region Using Google Earth Engine and the LandTrendr Algorithm: A Case Study of the Shengli Coalfield in Inner Mongolia, China

2020 ◽  
Vol 12 (10) ◽  
pp. 1612 ◽  
Author(s):  
Wu Xiao ◽  
Xinyu Deng ◽  
Tingting He ◽  
Wenqi Chen
Keyword(s):  
Inner Mongolia ◽  
Land Reclamation ◽  
Underground Mining ◽  
Surface Mining ◽  
Mining Area ◽  
Google Earth ◽  
Open Pit ◽  
Open Pit Mining ◽  
Landsat Images ◽  
Google Earth Engine

The development and utilization of mining resources are basic requirements for social and economic development. Both open-pit mining and underground mining have impacts on land, ecology, and the environment. Of these, open-pit mining is considered to have the greatest impact due to the drastic changes wrought on the original landform and the disturbance to vegetation. As awareness of environmental protection has grown, land reclamation has been included in the mining process. In this study, we used the Shengli Coalfield in the eastern steppe region of Inner Mongolia to demonstrate a mining and reclamation monitoring process. We combined the Google Earth Engine platform with time series Landsat images and the LandTrendr algorithm to identify and monitor mining disturbances to grassland and land reclamation in open-pit mining areas of the coalfield between 2003 and 2019. Pixel-based trajectories were used to reconstruct the temporal evolution of vegetation, and sequential Landsat archive data were used to achieve accurate measures of disturbances to vegetation. The results show that: (1) the proposed method can be used to determine the years in which vegetation disturbance and recovery occurred with accuracies of 86.53% and 78.57%, respectively; (2) mining in the Shengli mining area resulted in the conversion of 89.98 km2 of land from grassland, water, etc., to barren earth, and only 23.54 km2 was reclaimed, for a reclamation rate of 26.16%; and (3) the method proposed in this paper can achieve fast, efficient identification of surface mining land disturbances and reclamation, and has the potential to be applied to other similar areas.

scholarly journals Numerical modeling of open pit (OP) to underground (UG) transition in coal mining

2016 ◽  
Vol 38 (3) ◽  
pp. 35-48 ◽  
Author(s):  
Phu Minh Vuong Nguyen ◽  
Zbigniew Niedbalski
Keyword(s):  
Numerical Modeling ◽  
Coal Mining ◽  
Surface Deformation ◽  
Underground Mining ◽  
Primary Objective ◽  
Open Pit ◽  
Open Pit Mining ◽  
Original Experiment ◽  
Surface Stability ◽  
The Impact

Abstract The primary objective of the present paper is an attempt at evaluating the influence of sub-level caving operations on the slope stability of a still-functioning open pit coal mine in Vietnam. Initially, various methods of predicting the impact of underground mining on surface stability are discussed. Those theoretical considerations were later utilized in the process of constructing a Flac-2D-software-based numerical model for calculating the influence of underground operation on the deformation and possible loss of stability of an open pit slope. The numerical analysis proved that the values of open pit slope displacements were affected mainly by underground exploitation depth, direction of operation (i.e., from one slope to the other) and the distance from the slope plane. Real geomechanical strata parameters from the Vietnamese coal basin of Cam Pha were used in the modeling process. The paper is, therefore, a critical review of the hitherto proposed methods of predicting the impact of underground operation (UG) on open pit mining (OP), illustrated with selected examples of case studies on OP-UG interaction, followed by an original experiment based on numerical modeling method. This is first such study for the genuine conditions of the coal mining in Vietnam. The obtained results, however, should not be generalized due to a highly specific character of the analyzed phenomenon of mining-induced surface deformation. The practical implications of the study may occur extremely useful in the case of an UG-OP transition. Such a transition is often necessary for both technical and economical reasons, as in some coal basins open pit operations at greater depths occur unfeasible, which calls for a proper selection of parameters for a planned underground operation.

scholarly journals Planetary fracturing and lineaments revealed in the Kovdor magnetite–apatite ore deposit by open pit mining

2020 ◽  
pp. 30-34
Author(s):  
I. B. Agarkov ◽  
◽  
I. M. Ignatenko ◽  
V. A. Dunaev ◽  
I. S. Kryuchkov ◽  
...  
Keyword(s):  
Rock Mass ◽  
Hard Rock ◽  
Laser Scanner ◽  
Open Pit ◽  
Open Pit Mining ◽  
Mining Operations ◽  
Structural Mapping ◽  
Remote Assessment ◽  
Tectonic Origin

The analysis of the studies into fracturing of Zhelezny pitwall rock mass over the period from 1989 to 2019 proves that planetary fracturing is represented by faults, carbonatite dykes and single fractures oriented in the same direction as the prevailing regional lineaments on the Kola Peninsula. Planetary fracturing is assumed as a system of regular-oriented fractures. The planetary fracturing also includes lineaments of tectonic origin. The scientists think the faults registered in the pitwall rock mass and codirectional with the lineaments will accompany mining operations down to the full depth of the pit, up to the full extraction of magnetite–apatite ore reserves. While preparing this article, the authors have collected, generalized and analyzed the data of geological and structural mapping implemented by VIOGEM’s experts over the period from 1989 to 2019. VIOGEM’s procedure of geological and structural mapping ensures continuous documentation of extensional tectonics at high referencing accuracy (to 50 cm), as well as determination of inaccessible azimuths and angles of fractures by remote assessment of their orientations in pit walls using a laser scanner and photographic techniques to study the structure of hard rock mass and the behavior of permanent benches.

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.

scholarly journals Digitalization in Open-Pit Mining: A New Approach in Monitoring and Control of Rock Fragmentation

2021 ◽  
Vol 11 (22) ◽  
pp. 10848
Author(s):  
Natalia Koteleva ◽  
Sergei Khokhlov ◽  
Ilia Frenkel
Keyword(s):  
Rock Mass ◽  
Digital Technologies ◽  
Open Pit ◽  
Open Pit Mining ◽  
Monitoring And Control ◽  
New Approach ◽  
And Control ◽  
The Relationship ◽  
Operational Component

Mining enterprises are widely introducing digital technologies and automation is one of such tools. Granularity monitoring, namely, the size determination of rock mass pieces is a common operational component of the processes that extract minerals by open-pit mining. The article proposes an approach that, in addition to the lump size distribution, makes it possible to estimate the lump form distribution as well. To investigate the effectiveness of monitoring the form of blasted rock mass lumps, the authors conducted experiments in four stages related to the rock condition. They include geological occurrence, explosive crushing, trommelling, and mill crushing. The relationship between these stages is presented and the change in the lumps fragment form is traced. The present article proposes an informational and analytical model of the processes at mining enterprises, extracting minerals by open-pit mining, as well as an algorithm for determining the lumps form and obtaining their distribution in the rock mass.

scholarly journals Study on Blasting Technology for Open-Pit Layering of Complex Mine Adjacent to High and Steep Slope

2021 ◽  
Vol 9 ◽  
Author(s):  
Menglai Wang ◽  
Xiaoshaung Li ◽  
Qihang Li ◽  
Yunjin Hu ◽  
Qiusong Chen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Oblique Line ◽  
Field Tests ◽  
Mining Area ◽  
Open Pit ◽  
Blasting Vibration ◽  
Mass Rate ◽  
Propagation Law ◽  
Steep Slopes

In China, mining blasting vibration has seriously threatened the safety and stability of high and steep rock slopes. In this paper, taking the east mining area of Jianshan Phosphorus Mine as the research background, combined with field survey, field blasting test, numerical simulation and theoretical analysis, we systematically studied the adjacent high-steep rock slope and the layered blasting technology of complex ore. Based on wide hole spacing blasting numerical simulation and field tests, the use of 8 × 4 m hole network parameters, oblique line hole-by-hole initiation method, detonator delay using 35 ms between holes, 65 ms between rows and 500 ms within the holes, the rock mass rate was reduced and the drilling workload was decreased. In addition, regression analysis was carried out on a large amount of vibration test data, and the attenuation law and propagation law of blasting vibration of adjacent high and steep slopes were predicted, which provided a reference for mine production blasting. By establishing a mathematical model of cumulative damage of rock mass blasting, it shows that the depth of impact of mining blasting on the slope of Jianshan open-pit was 0–3.6m, but the blasting did not cause overall damage to the adjacent high and steep slopes. In the future, this model can be used to predict rock damage caused by subsequent blasting.

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