Slope Stability In Open-pit Mines Research Articles

GEOMONITORING OF THE OPEN-PIT MINE SLOPES DURING SUBSOIL DEVELOPMENT

The concept of geomonitoring and its role in developing the mining industry as a case study of the development of copper and zinc deposits in central Kazakhstan ("East Saryoba" mine) has been considered. As a crucial element of the geomonitoring concept, the control of the open-pit mine's slope stability has been examined. Geomonitoring is being treated as a combination of geodetic monitoring data and geomechanical properties of the surrounding rocks to analyze the possible slopes' collapses. The refined approach of geomonitoring has been developed to provide appropriate reliability and accuracy. The technology is based on complex knowledge about the geological structure of the object of monitoring and applying state-of-the-art geodetic methods. Research on the geomechanical properties of the open-pit mine has been carried out. The results of these studies have been used to determine the collapse zones of the slopes of the open-pit mine. The limit values for the slopes' collapse zone and inclination angle for the prospective excavation regions in the open-pit mine have been calculated using the equilibrium state equation. Those values, namely, the size of the collapse zone and the slope's inclination angle, were used for the geodetic target setup. As a case study, the displacements of these targets were measured using robotic total stations placed on the control points over the geodetic network. For the installation of both geodetic equipment during the geomonitoring design and accomplishment, the authors developed the permanent measuring station construction, which provides fast and accurate centering. The first results showed that the problem of the geomonitoring design could be solved based on geomechanical rock properties accounting and their combination with the results of geodetic measurements.

Open Pit Mine Slope Stability: Methodological Framework

Open Pit Mine Slope Stability: Methodological Framework

Hyperbolic Sine Similarity Measure of SVNS for Open-Pit Mine Slope Stability Classification and Assessment

Hyperbolic Sine Similarity Measure of SVNS for Open-Pit Mine Slope Stability Classification and Assessment

Current Tectonic Stress State in an Iron Mine District, North China, Based on Overcoring, Hydraulic Fracturing, and Acoustic Emission Stress Measurements

Abstract Full knowledge of the current tectonic stress state is crucial for assessing open-pit mine slope stability and regional tectonic evolution and geodynamic processes. Overcoring, hydraulic fracturing, and acoustic emission in situ stress measurement techniques were adopted to determine the 3D stress tensor in an iron mine district, North China, and 25 sets of stress data ranging from 56 to 490 m were measured. Accordingly, the current tectonic stress state and its relationship to regional geological tectonics were investigated. The results indicated that the stress condition seemed to favor thrust and strike-slip faulting, and the stress field was particularly controlled by the horizontal tectonic stress. A high horizontal tectonic stress considerably influenced the stability of high and steep slopes in this mine district, which requires great attention. The stress directions derived from different methods were almost similar, indicating a dominant NEE–SWW stress field direction or near-E–W direction, comparable to the direction revealed by focal mechanism solutions and other stress indicators around the mine district. According to geological structure analysis, the present-day stress field in this district generally inherited the third-stage tectonic stress field while partially retaining the characteristics of the second-stage tectonic stress field, which is the result of dynamic action and tectonic movement during different geological periods, and the maximum principal stress direction of the tectonic stress field that affects the modern tectonic activity in this area is the NEE–EW direction.

Stability prediction and optimal angle of high slope in open-pit mine based on two-dimension limit equilibrium method and three-dimension numerical simulation

The optimization design of the open pit slope can ensure safety in production at the same time bring considerable economic benefits, so it is necessary to evaluate the stability of the initial excavation scheme of the high slope in an open-pit mine and optimize the initial slope angle according to the evaluation results. In this paper, an exhaustive study of Anyi open-pit mine in mouding County Yunnan province China has been made, and the following results have been achieved: (1)Confirmed the geological factors which affected the slope stability of open-pit mine; (2)Quantified the stability of the open-pit mine slope; (3) Under the premise of safety, the angle of the open pit high slope has been optimized on the base of the calculations of the open-pit mine high slope stability so as to ensure the maximum economic benefit. In this paper, the study area was divided into six zones. Firstly, qualitative analysis of slope stability was made by analogy method of engineering geology and stereographic projection method according to the orebody location, the properties of rock and soil in slope, the height of slope, and so on. The analysis shows that the preliminary design of slope angle is so large to ensure safety. Secondly, the stability of different slopes of a high slope is the quantitative analysis of different zones in high slope was made by two-dimensional limit equilibrium method and the finite difference method. In this paper, the mechanical parameters of rock are obtained by a laboratory test, and the stability of the high slope is quantitatively analyzed by two-dimensional limit equilibrium and three-dimensional numerical simulation.

SVNN-ANFIS approach for stability evaluation of open-pit mine slopes

The stability of the open-pit mine slope has an important impact on the safe operation and benefits of the mining company. This paper proposes a single-valued neutrosophic number-based adaptive neuro fuzzy inference system (SVNN-ANFIS) approach to evaluate the open-pit mine slope stability. In the method, it utilizes the single-valued neutrosophic number concept for expressing the truth, indeterminate, and falsity information of influencing factors/indices (slope height, slope angle, potential slip plane angle, cohesion, internal friction angle and rock density) of the open-pit mine slope stability by truth, indeterminate, and falsity membership functions. Then, three ANFISs are used to obtain the corresponding relations between the influencing factors and the slope stability in truth, indeterminate, and falsity situations. Finally, the truth, indeterminate, and falsity output of the three ANFISs, i.e., a SVNN output, whose score value can be used to evaluate the slope stability through a score function of SVNN. The application results of the proposed approach have reflected that the training accuracy reaches 99.20% and the testing accuracy reaches 97.62%. Therefore, the established SVNN-ANFIS method provides a new effective way for evaluating open-pit mine slope stability in the uncertain environment.

Toward state-of-the-art techniques in predicting and controlling slope stability in open-pit mines based on limit equilibrium analysis, radial basis function neural network, and brainstorm optimization

Toward state-of-the-art techniques in predicting and controlling slope stability in open-pit mines based on limit equilibrium analysis, radial basis function neural network, and brainstorm optimization

Research on Slope Stability Evaluation Based on Improved Set Pair Analysis Method: A Case of Tonglvshan Open-Pit Mine

In this paper, combined with fuzzy analytic hierarchy process (FAHP), information entropy theory, and set pair analysis (SPA) theory, an improved set pair analysis model (EFAHP-SPA) for open-pit mine slope stability evaluation based on entropy method and FAHP is proposed. Taking the east-side slope of Tonglvshan north open-pit mine in Daye as an example, the proposed method is verified. First, an open-pit mine slope stability evaluation index system with 14 indicators in 4 categories, namely the topography and geomorphology, geological structure, hydrogeology, and other factors, have been constructed. Second, the objective weight and subjective weight of each evaluation index are calculated by entropy and fuzzy analytic hierarchy process, and then the comprehensive weight of the evaluation index is estimated based on subjective weight and objective weight. Afterward, the single-index connection degree between the evaluation index and the evaluation standard of the secondary subsystem is evaluated considering the improved set pair analysis theory, and the comprehensive connection degree of the system is obtained by combining it with the comprehensive weight of each evaluation index. Finally, the confidence criterion is established to discern the risk grade of slope stability in the east-side slope of the north open pit in Daye Tonglvshan mine. Moreover, case studies and comparisons of the proposed model with fuzzy comprehensive evaluation method and Entropy-SPA model were performed to confirm the validity and reliability. The results show that the evaluation results of the proposed EFAHP-SPA model are consistent with the actual situation of open-pit mines and the evaluation results of entropy-SPA model and are somewhat different from those of fuzzy comprehensive evaluation method. It indicates that the proposed EFAHP-SPA evaluation model can objectively evaluate the slope stability of the open-pit mine.

Study on Open-pit Mine Slope Stability Based on Improved TOPSIS Method

In order to evaluate the slope instability risk of open-pit mine more accurately, this paper establishes a slope instability risk evaluation model based on Improved TOPSIS method according to the hierarchical holographic modeling method and entropy method. In this paper, the hierarchical holographic modeling method is used to establish the evaluation index system of open-pit slope stability, and 11 main indexes which have great influence on the stability are selected. The weights of 11 main indexes are calculated by using entropy method, and then applied to TOPSIS method. Finally, the positive and ideal solution distances of 5 typical open-pit slopes are calculated and the destabilization risk of 5 open-pit slopes is reasonably evaluated. The evaluation results were compared with those of other evaluation models to verify their rationality. The results show that the slope evaluation method based on improved TOPSIS can effectively evaluate the slope stability, which provides a new method for determining the high risk slope and effectively rating the slope risk.

Monitoring active open-pit mine stability in the Rhenish coalfields of Germany using a coherence-based SBAS method

With the recent progress in synthetic aperture radar (SAR) technology, especially the new generation of SAR satellites (Sentinel-1 and TerraSAR-X), our ability to assess slope stability in open-pit mines has significantly improved. The main objective of this work is to map ground displacement and slope instability over three open-pit mines, namely, Hambach, Garzweiler and Inden, in the Rhenish coalfields of Germany to provide long-term monitoring solutions for open-pit mining operations and their surroundings. Three SAR datasets, including Sentinel-1A data in ascending and descending orbits and TerraSAR-X data in a descending orbit, were processed by a modified small baseline subset (SBAS) algorithm, called coherence-based SBAS, to retrieve ground displacement related to the three open-pit mines and their surroundings. Despite the continuously changing topography over these active open-pit mines, the small perpendicular baselines of both Sentinel-1A and TerraSAR-X data were not affected by DEM errors and hence could yield accurate estimates of surface displacement. Significant land subsidence was observed over reclaimed areas, with rates exceeding 500 mm/yr, 380 mm/yr, and 310 mm/yr for the Hambach, Garzweiler and Inden mine, respectively. The compaction process of waste materials is the main contributor to land subsidence. Land uplift was found over the areas near the active working parts of the mines, which was probably due to excavation activities. Horizontal displacement retrieved from the combination of ascending and descending data was analysed, revealing an eastward movement with a maximum rate of ∼120 mm/yr on the western flank and a westward movement with a maximum rate of ∼ 60 mm/yr on the eastern flank of the pit. Former open-pit mines Fortuna-Garsdorf and Berghein in the eastern part of Rhenish coalfields, already reclaimed for agriculture, also show subsidence, at locations reaching 150 mm/yr. The interferometric results were compared, whenever possible, with groundwater information to analyse the possible reasons for ground deformation over the mines and their surroundings.

The slope creep law for a soft rock in an open-pit mine in the Gobi region of Xinjiang, China

The lithology of the strata in the Gobi region of the Xinjiang autonomous region of China is mainly composed of mudstone, silty mudstone, and other soft rocks. Because of the low strength of the rock mass and the serious effects of physical weathering in this area, the slope stability in open-pit mines is poor, and creep deformation and instability can readily occur. Taking the Dananhu No. 2 open-pit mine as a typical example, the creep test of a mudstone sample under different stress levels was studied. Then, based on a bottom friction experiment and a FLAC3D numerical simulation, the deformation and failure processes of the slope were analyzed. The stress–displacement curve and the displacement–time curve for the monitoring points were plotted to obtain the relationship between the stress and displacement for the slope of the soft rock. The results showed that the long-term strength of the mudstone was between 8.0 and 8.8 MPa, and that stable creep occurred when the slope was under low stress. The potential failure mode for this type of slope is that the front edge creeps along the weak layer and then a crack is formed at the trailing edge of the slope. When the crack penetrates the weak layer, cutting bedding and bedding sliding occur. The deformation process of the stable creep slope includes an initial deformation stage, an initial creep stage, a constant velocity creep stage and a deceleration creep stage.

A novel artificial intelligence technique for analyzing slope stability using PSO-CA model

This study aims to develop a new artificial intelligence model for analyzing and evaluating slope stability in open-pit mines. Indeed, a novel hybrid intelligent technique based on an optimization of the cubist algorithm by an evolutionary method (i.e., PSO), namely PSO-CA technique, was developed for predicting the factor of safety (FS) in slope stability; 450 simulations from the Geostudio software for the FS of a quarry mine (Vietnam) were used as the datasets for this aim. Five factors include bench height, slope angle, angle of internal friction, cohesion, and unit weight were used as the input variables for estimating FS in this work. To clarify the performance of the proposed PSO-CA technique in slope stability analysis, SVM, CART, and kNN models were also developed and assessed. Three performance indices, such as mean absolute error (MAE), root-mean-squared error (RMSE), and determination coefficient (R2), were computed to evaluate the accuracy of the predictive models. The results clarified that the proposed PSO-CA technique was the most dominant accuracy with an MAE of 0.009, RMSE of 0.025, and R2 of 0.981, in estimating the stability of slope. The remaining models (i.e., SVM, CART, kNN) obtained poorer performance with MAE from 0.014 to 0.038, RMSE 0.030–0.056, and R2 0.917–0.974.

A comparison between effects of earthquake and blasting on stability of mine slopes: a case study of Chadormalu open-pit mine

Dynamic slope stability in open-pit mines still remains a challenging task in the computational mining design. Earthquake and blasting are two significant sources of dynamic loads that can cause many damages to open-pit mines in active seismic areas and during exploitation cycles. In this work, the effects of earthquake and blasting on the stability of the NW slope of Chadormalu mine are compared by a numerical modeling method. The dynamic results show that the maximum displacement under earthquake and blasting loads within the slope are 844 mm and 146 mm, respectively. According to the shear strain results, both the earthquake and blasting waveforms are destructive, while the earthquake waveforms cause more damages to the slope. Moreover, the deterministic and probabilistic seismic hazard analyses are carried out to assess the seismicity of the mine area. The experimental results indicate that the maximum values for the vertical and horizontal accelerations are 0.55 g and 0.75 g, respectively. The maximum calculated acceleration is then scaled to the selected earthquake accelerograms. In order to show the effective impact of the established scale, the model is executed using the original accelerograms. The results obtained show that the established scale prevents overestimation and underestimation of the displacement and strain. Therefore, applying scaled accelerograms in a dynamic slope stability analysis in mine slopes leads to more reliable and robust results. The overall results show that a strong earthquake causes plenty of damages to the slope, and consequently, interrupts the mining cycle. Hence, the seismic study and dynamic slope stability should be considered as a part of the computational mining design.

Integrating Rock Engineering Systems device and Artificial Neural Networks to predict stability conditions in an open pit

Stability performance of newly open pit slopes are is affected by many factors, namely, overall complex geological environment, water flow, in situ and induced rock stresses, continuous blasting effects and construction methods. It is therefore important to identify the critical parameters affecting slope stability, as well as their interactions, in order to reduce the associated uncertainty and risk. In this paper, we extend a worldwide open pit slope stability database further and build on the use of an open pit mine slope stability index to predict the stability conditions, coupling Rock Engineering Systems (RES) and artificial neural networks, namely, Back Propagation and Self Organising Maps. The Open Pit Mine Slope Stability Index (OPMSSI) can be computed as a simple weighted sum of ratings for all parameters involved in the RES. The basic device used in the Rock Engineering Systems approach is the Generic Interaction Matrix (GIM). By coding the GIM cause-effect coordinates, relevant cause-effect plots are generated indicating interaction intensity and dominance. We propose the coding of the GIM using scatter plots produced by an unsupervised, trained, self-organising map and a comparison with GIM coding through connection weights resulting from a trained back propagation neural network. Depending on the resulting OPMSSI, the approach informs on low, medium and high susceptibility levels associated with stable status, failure at set of benches or overall slope failure, respectively. Verification of results suggests that OPMSSI, resulting from self-organising maps, appears to be superior to a back propagation algorithm in prediction capacity and that the SOM proves to be an informative knowledge extraction tool.

Slope monitoring and stability analysis of open pit mine based on fiber Bragg grating sensing technology

With the further development of resources, it is urgent to carry out on-line safety monitoring and early warning for high and steep slopes. Fiber Bragg grating technology used in the slide force monitoring can achieve the slope stability evaluation and the landslide pre-warning. The design and development of the fiber Bragg grating cable force sensor was carried out and achieved the automatic temperature compensation of fiber Bragg grating cable force measurement sensor in this paper, the center wavelength and the stress, temperature has a good linear relationship, the practice showed that the fiber Bragg grating anchor cable force sensor could meet the needs of open pit mine slope stability monitoring.

A field investigation of application of digital terrestrial photogrammetry to characterize geometric properties of discontinuities in open-pit slopes

In order to analyze the slope stability in open-pit mines, the structural parameters of rock mass such as persistence and spatial orientation of discontinuities are characterized through field surveys, which involve spending high costs and times as well as posing high risks of rock toppling and rock fall. In the present work, a new application of terrestrial digital photogrammetry is introduced for characterizing the rock mass structural parameters through preparing photogrammetry images from open-pit walls and building stereomodels. The data extracted from processing the stereo-model generations using photogrammetry images with different focal distances are highly consistent with the data collected through field surveys. However, it must be noted that the weather conditions, natural lighting angle, and applied observation scale may considerably affect the results obtained from stereomodel processing. Nevertheless, by taking into account the parameters such as time, cost, and full access to the required data, this new method can effectively be used in the estimation of rock mass structural parameters for analysis of steep slopes in open pits.

Rational Research of Deep Concave Open-Pit Slope Angle of Lower Part

With the rapid advance of industrialization,the consumption of mineral resources is increasing.For open pit mine,many of them went into deep mining.The current,widespread adoption of open pit slope angle makes deep concave mining has a huge stripping ratio.So many mines in trouble,on the premise of guarantee the deep sunken open pit slope stability increase slope toe can bring huge economic benefits,and a lot of research work has been done.This paper describes the factors affecting the stability of open-pit mine slope,the slope rock mass stress analysis,to calculate the lower steep slope economic benefits,puts forward reasonable suggestions the future research direction of the slope stability of open-pit mine.

Pemali open pit mine slope stability problem : Manaf, M H; Bhattacharyya, A K Proc 2nd Conference on Large Open Pit Mining Latrobe Valley, 3–6 April 1989P13–17. Publ Melbourne: AusI M M, 1989

Pemali open pit mine slope stability problem : Manaf, M H; Bhattacharyya, A K Proc 2nd Conference on Large Open Pit Mining Latrobe Valley, 3–6 April 1989P13–17. Publ Melbourne: AusI M M, 1989

Influence of strata stress state on openpit mine slope stability (in Serbo-Croat) : Milanovic, P Rud Glas, N3, 1980, P15–P18

Influence of strata stress state on openpit mine slope stability (in Serbo-Croat) : Milanovic, P Rud Glas, N3, 1980, P15–P18

Open pit mine slope stability. The Berkeley pit. Symposium. In Stability of rock slopes : Pariseau, WG Montana Coll. Miner. Sci. Techn. Butte, USA Stout, K Montana Coll. Miner. Sci. Techn. Butte, USA 11F, Refs. 13th Symposium on rock mechanics ASCE, New York, 1972, P367–395

Open pit mine slope stability. The Berkeley pit. Symposium. In Stability of rock slopes : Pariseau, WG Montana Coll. Miner. Sci. Techn. Butte, USA Stout, K Montana Coll. Miner. Sci. Techn. Butte, USA 11F, Refs. 13th Symposium on rock mechanics ASCE, New York, 1972, P367–395