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.

scholarly journals Modelisation of fractured rock mass for open pit mining in Vietnam

2020 ◽  
Vol 61 (5) ◽  
pp. 80-96
Author(s):  
Tuan Anh Nguyen ◽  
Viet Van Pham ◽  
Nam Xuan Bui ◽  
Hoa Thu Thi Le ◽  
Hai Thi Le ◽  
...  
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Construction Materials ◽  
Mining Operation ◽  
Open Pit ◽  
Open Pit Mining ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Fractured Rock Mass ◽  
Mass Data

In open pit mining, besides the value of the minerals obtained, the cost of waste rock removal determines the efficiency of the mining operation. The paper introduces the rock mass data processing method and modelisation of fractured rock mass to serve the optimal calculation of technological stages in mining. This code is a discrete fracture network (DFN) code that couple geometrical block system construction based on modelisation stochastic with RESOBLOK simulations. The method of three-dimensional modeling (3D) of the fractured rock mass in the quarry is based on the rock mass data, the geometrical parameters of the open pit mine. From there, the rock mass simulation models were used in the analysis of the stability analysis of open pit benches, the optimization of the blast design parameters at overburden benches, project construction materials, and technology projects for block stone extraction. An application in some open pit mines such as quarries of Vietnam is presented.

Prediction of the Ground Vibration Rate during Large-scale Explosions in the Underground Conditions

2021 ◽  
pp. 41-45
Author(s):  
V.N. Tyupin ◽  
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Underground Mining ◽  
Calculated Data ◽  
Ground Vibration ◽  
Open Pit ◽  
Vibration Velocity ◽  
Earth Surface ◽  
Seismic Safety ◽  
The Earth

At present, to ensure seismic safety in massive explosions, the analytical dependence of the determination of the vibration velocity of M.A. Sadovsky rock mass is mainly used. This dependence is widely used in the creation of seismic-safe technologies for mineral deposits open-pit and underground mining. However, scientific research and production experience showed that the rate of oscillation depends on the energy parameters of the explosive, the diameter and length of its charges, the number of simultaneously exploded charges, the number of deceleration stages, the deceleration interval, etc. The purpose of this article is to predict the speed fluctuations of the massif on the earth surface when conducting the underground explosions depending on the parameters of large-scale explosions and physical-technical properties of the rock masses in the areas of explosion of the protected object. The formulas for calculating the velocity of rock mass on the earth surface during large-scale explosions in the underground conditions are substantiated and presented. The formulas were used for calculating the vibration velocities of the rock mass on the earth surface in accordance with the parameters of drilling and blasting operations during large-scale explosions in the mines of GK VostGOK. Comparison of theoretical (calculated) data and the results of actual measurements indicates their convergence. By changing the controlled parameters in the calculation formulas, it is possible to quantitatively reduce the seismic effect of a large-scale explosions on the protected objects. Further research will be aimed at studying the influence of tectonic faults, artificial contour crevices, filling massif or mined-out space on the rate of seismic-explosive vibrations during blasting operations in the mines. The research results can be used in the preparation of rules for conducting large-scale explosions at the underground mining.

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

Rock Mass Deformation Characteristics in High-Steep Slopes Influenced by Open-Pit to Underground Mining

2016 ◽  
Vol 34 (3) ◽  
pp. 847-866 ◽  
Author(s):  
Chuanbo Zhou ◽  
Shiwei Lu ◽  
Nan Jiang ◽  
Dingbang Zhang ◽  
Zhihua Zhang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Underground Mining ◽  
Open Pit ◽  
Deformation Characteristics ◽  
Rock Mass Deformation ◽  
Steep Slopes ◽  
Mass Deformation

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.

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.

Prediction of ground surface collapse by instrumental observation data on rock mass movements during underground mining

2020 ◽  
pp. 264-274
Author(s):  
O. D. Kharisova ◽  
T. F. Kharisov
Keyword(s):  
Rock Mass ◽  
Underground Mining ◽  
Ground Surface ◽  
Local Area ◽  
Observation Data ◽  
Local Cluster ◽  
Instrumental Observation ◽  
Geological Conditions ◽  
Deformation Processes ◽  
Surface Collapse

Using the data of long-term surveying at the Saranovsky chrome iron ore deposit, movements of rock mass were analyzed with a view to identifying potential early signs of ground surface collapse. The research findings are unique as one of the instrumental observation series was accomplished on the eve of the ground surface sinking above non-backfilled voids of earlier stoping. It was found that the test area experienced vertical alternating movements, and sinking was preceded by upheaval of ground surface. However, the further analysis revealed no clear cause-and-effect between the event and insufficiency of its study. The subsequent research identified a local cluster of rock mass subsidences at gradually increasing velocities, which showed up a few years before the sink appeared on ground surface above its initiation source. The absence of this cluster zone in the period before the collapse is explained by the damage of check points in this site. Finally, the conclusion is drawn that in certain geological conditions, deformation processes are localized and manifest no visible signs of impact on the enclosing rock mass and ground surface. Manifestations of these processes from the instrumental observations concentrate directly in the local area of their development, which should be taken into account in the analysis and prediction of movements. It is emphasized that the existing and new criteria of hazardous deformation processes should be corrected and updated for geomechanical monitoring of mineral mining objects.

scholarly journals Rock Mass Blastability Classification Using Fuzzy Pattern Recognition and the Combination Weight Method

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Shuangshuang Xiao ◽  
Kemin Li ◽  
Xiaohua Ding ◽  
Tong Liu
Keyword(s):  
Pattern Recognition ◽  
Rock Mass ◽  
Wave Impedance ◽  
Open Pit ◽  
Design Parameters ◽  
Rock Density ◽  
Fuzzy Pattern Recognition ◽  
Fuzzy Pattern ◽  
Weight Method ◽  
Strength Rock

Rock mass blastability classification provides a theoretical basis for rock mass blasting design, which is used to select blasting explosives, to estimate the unit explosive consumption, and to determine blasting design parameters. The primary factors that affect rock mass blastability were analyzed by selecting five indexes for rock mass blastability classification, that is, the rock Protodyakonov coefficient, rock tensile strength, rock density, rock wave impedance, and integrity coefficient of rock mass, and by identifying standards for the rock mass blastability classification and a method for testing the blasting classification indexes. The index weights were calculated using the combination weight method, which is based on game theory. A model for rock mass blastability classification was developed in combination with a fuzzy pattern recognition method. This classification method was applied to a Heidaigou open-pit coal mine, where mudstone, fine sandstone, medium sandstone, and coarse sandstone were determined to have a blastability degree of II, which corresponds to a blastability characterization of “easy,” and the unit explosive consumption of mudstone, fine sandstone, medium sandstone, and coarse sandstone was determined to be 0.44, 0.42, 0.40, and 0.36 kg/m3, respectively. These results were used to develop a loose blasting design that was effective for loose blasting.

scholarly journals Ensuring Wall Stability in the Course of Blasting at Open Pits of Kyzyl Kum Region

2020 ◽  
Vol 5 (3) ◽  
pp. 235-252
Author(s):  
Sh. Sh. Zairov ◽  
Sh. R. Urinov ◽  
R. U. Nomdorov
Keyword(s):  
Rock Mass ◽  
Strain State ◽  
Boundary Integral Equations ◽  
Video Recording ◽  
Splitting Method ◽  
Boundary Integral ◽  
Open Pit ◽  
Open Pit Mining ◽  
Stress Strain ◽  
Stress Strain State

Involvement of deep deposits in mining predetermined the trend of development of open pit mining towards increasing the depth of open pits. The main limitation imposed on drilling and blasting in the near-contour zone of an open pit is the need to protect the pit walls and engineering structures on the walls from seismic effects of huge blasts. As practice shows, the most effective and proven method of protecting pit walls is the use of blasting by presplitting method, creation of a shielding gap and a shielding layer of blasted rock mass, i.e. pre-splitting of the pit walls, preceding the huge blast. Therefore, the study of stress-strain state of the near-contour rock mass, determination of the parameters of blastholes for edge pre-splitting (preliminary shielding gap formation) in open pits is an urgent task. The analysis of the pit wall design and stress-strain state of rock mass at Kokpatas deposit exploited by Navoi Mining and Metallurgical Combine allowed to determine the model, as well as the method for calculating stress-strain state of the rock mass. When assessing stability of the pit walls, an approach known as the displacement method was used. Applying the boundary integral equations method allowed to develop an algorithm for calculating stresses in the rock mass for the conditions of Kokpatas deposit. A technique has been developed for experimental studies of blasting contour blasthole charges (blasting by pre-splitting method) using models, allowing to study fracturing on volumetric models and wave interaction by the method of high-speed video recording of the blasting process in transparent models, as well as to determine the parameters of stress waves during blasting in samples of real rocks. A method for formation of stable pit wall slopes, an excavator method for bench pre-splitting on ultimate envelope (contour) of a pit, and a method for initiating blasthole charges in the near contour zone of a pit have been developed and implemented in the industry.

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