Mine Slope Research Articles

Groundwater identification using geophysical tools and its implications for the stability of slopes in an open pit mine

The open pit mining development begins with the opening of pits with the rock mass excavation and formation of slopes and berms for ore exploration. Knowledge about the geological conditions represents an important step in this process, since rock masses generally have heterogeneous characteristics and the presence of discon- tinuities can become an aggravating factor in the safety of operations. The characterization and classification of these discontinuities, as well as the identification of the groundwater in the rock mass, has a great importance to ensure the safety of operations during the mine's production process, in addition to ensure the effectiveness of its decommissioning process. The use of DC resistivity geophysical method has been increasing to characterization and identification lithological types and presence of water, since it is a non-invasive research tool with fast ability to obtain data. DC resistivity together with visual investigation methods, such as obtaining the discontinuities orientation and their alteration characteristics, provides important information for the characterization of the rock mass. Given this importance, the present work aimed to use DC resistivity to identify the presence of water and its correlation with lithology and rock mass structure in order to identify how these variables influence the occurrence of ruptures. To this end, two-dimensional resistivity sections were designed and related to visual inspection data and kinematic analyzes obtained from structural data of the rock mass. The integration of these results indicated that the ruptures present in the investigated mine slopes are related to zones whose predominant lithology is volcanic breccia with the presence of water in the subsurface. These ruptures compromise the stability of the slopes and consequently make the decommissioning mine process difficult.

A Practical Prediction Model for Surface Deformation of Open-Pit Mine Slopes Based on Artificial Intelligence

A Practical Prediction Model for Surface Deformation of Open-Pit Mine Slopes Based on Artificial Intelligence

Stability evaluation of open-pit mine slope based on Bayesian optimization 1D-CNN

As mechanized open-pit coal mining intensifies, assessing and predicting slope stability has become increasingly important. To address the limitations of traditional mechanical calculations, numerical simulations, and physical experiments, this paper identifies the key factors impacting slope stability in open-pit mines and develops a multi-parameter sample data set. The study employs hyperparameters optimized using a Bayesian algorithm, introduces additional convolutional layers, and combines the Adam optimizer with dropout techniques to enhance the feature extraction and performance of one-dimensional convolutional neural networks (1D-CNN). This leads to a Bayesian-optimized one-dimensional convolutional neural network (B-1D MCNN) model for predicting slope stability.The study evaluates the classification performance and accuracy of various models for slope stability, including BP neural networks, genetic algorithm-optimized convolutional neural networks, 1D-CNN, and B-1D MCNN, using accuracy, precision, and F1-score as metrics. The analysis also examines the influence of factor indicators and training set length on the model's output to assess its generalization capabilities.The research findings suggest that: (1) the B-1D MCNN model for evaluating slope stability demonstrates the capability to accurately depict the nonlinear correlation between influencing factors and slope stability. (2) Compared with other models, the B-1D MCNN model has shown enhancements of 10.96% to 27.85%, 10.26% to 28.55%, and 8.98% to 25.05% in terms of Accuracy, F1-Score, and Precision, respectively. (3) As the length of the training dataset increases, the performance of the model improves accordingly. (4) The B-1D MCNN model shows a generalization power of 87.5%.

A Novel Predictive Framework for the Determination of the Threshold Limit Velocity of Open-Cast Mine Slopes

A Novel Predictive Framework for the Determination of the Threshold Limit Velocity of Open-Cast Mine Slopes

Optimized air-ground data fusion method for mine slope modeling

Optimized air-ground data fusion method for mine slope modeling

Developing a Model for the Identification of Onset of Failure of Slopes in Surface Mines

Developing a Model for the Identification of Onset of Failure of Slopes in Surface Mines

Effect of drone flight speed on intensity images in drone-based synthetic aperture radar analysis of mine slopes

ABSTRACT Drone-based synthetic aperture radar (SAR) analysis offers a simple and efficient technique for acquiring observational data from various research areas. However, fundamental research on observation techniques, including the investigation of drone flight parameters, remains insufficient. This study focuses on improving the resolution of intensity images of a single-look complex (SLC) via drone-based SAR observations. By conducting experiments at different flight speeds and analysing the obtained SLC images, we demonstrated that higher drone speeds resulted in enhanced image resolution under the conditions investigated at flight speeds of ≤ 5 m s−1. A comparison with satellite SAR images highlighted the superior performance of drone-based SAR in capturing topographic features. The analysis also suggested that factors including trajectory deviation and Doppler rate affected the resolution and azimuth position. The simulation results supported the experimental findings on the relationship between drone speed and resolution. Our results emphasize the potential of drone-based SAR observations for monitoring slope failures and suggest the importance of the drone flight parameter selection. In the future, drone-based SAR is expected to produce intensity images of slopes and locate slope deformations associated with blasting for mining and earthquakes.

A comparative slope stability analyses of heavily jointed open-pit slopes using 3D limit equilibrium and finite element methods: a case study from Bingöl, Türkiye

ABSTRACT This study investigates the slope stability of Bingöl open-pit iron mine slopes using 3D limit equilibrium and finite element methods. The pit benches are 3 m wide and 6 m high, with an overall slope angle of 38°. The geological composition comprises slightly to moderately weathered and heavily jointed phyllite, micaschist, and gneiss. Shear strength parameters were determined through back analyses of already failed sections using the Hoek-Brown failure criterion and Geological Strength Index (GSI). Factor of safety values for static and dynamic conditions were calculated using 3D limit equilibrium and 2D finite element analyses. Results show good agreement between the two methods, with benches in the northern section exhibiting a significant decrease in safety factor under dynamic conditions, indicating near-limit equilibrium slopes.

MINE SLOPE DESIGN SIMULATIONS USING SLIDE 6.0 SOFTWARE OF POST-MINING SLOPE STABILITY

Post-mining slopes are susceptible to landslides due to factors such as slope geometry, rock structure, physical and mechanical properties of rocks, and groundwater content. Monitoring of these slopes is essential to prevent broader environmental issues. This research aims to determine the stability of former mining slopes using soil samples from the Mataraman District, Banjar Regency. The technical analysis method focuses on the physical and mechanical properties of soil, supplemented with mine slope design simulations using Slide 6,0 software to ascertain the safety factors from various slope angles. Safety factor analysis considers the smallest cohesion and bulk density values to represent the material strength of the slope. Findings indicate that the post-mining slopes would remain stable and safe provided no additional destabilizing factors are introduced. The slopes maintain a safety factor greater than 2, implying stability even with a steepness up to 70°. Keywords: mining slope stability, safety factor

Imagining black feminist geographies of Johannesburg through Senzeni Marasela’s creative (un/re)mapping of Johannesburg’s mine slopes

ABSTRACT Part of the project of philosophy is to problematise how the world is known, including destabilising geography as one of the dominant imperialist discourses. In the Afropolis, legacies of colonialism and Apartheid still work to uphold spatial inequality within urban spaces in ways that are both racialised and gendered. Black feminist scholar, Katherine McKittrick, provides a fruitful theoretical foundation to consider postcolonial cities from a renewed epistemological perspective. In the 2006 book Demonic Grounds: Black Women and the Cartographies of Struggle, McKittrick works alongside and across traditional geographies through critical black geographies that centre a black feminist sense of place. In considering ‘a black sense of place’, McKittrick demonstrates how transatlantic slavery enforced and naturalised the connection between blackness and placelessness. She writes to document black women geographies and provides a narrative that locates and draws on black histories and black subjects to ‘make visible social lives which are often displaced, rendered ungeographic’. This paper places McKittrick in conversation with the work of South African artist Senzeni Marasela through their selected literary and artistic works to explore alternative feminist geographies of Johannesburg’s decommissioned mine slopes/dumps, and to emphasise the liberatory potential of a black feminist point of departure in relation to the mining–industrial complex. The argument is not merely that Johannesburg needs to become more inclusive to black feminist understandings of place, but rather that the centring of black feminist geographical knowledges has the subversive ability to reshape how the city is known in the first place. In doing so, this paper hopes to ‘raise questions about the ground beneath our feet, and how we are all implicated in the production of space’.

Analysis of the Influence of Groundwater Level on Slope Stability at Highwall PT. X, South Kalimantan

Mine slope design is an important part of mining operations because it is used to determine the balance between mine economy and operational safety. In the mine slope design there will also be a groundwater level design, the groundwater level is one of the triggers for a slide to occur. Therefore, this study aims to determine the effect of the groundwater level on the stability of the highwall slope cross section A-A’ as well as to determine the factor of safety value and probability of slope failure under various conditions of high groundwater levels. This research method uses quantitative methods because there are numerical data that will be used to calculate the value of slope stability. Slope stability analysis uses the “morgenstern-price” boundary equilibrium and the “monte-carlo” landslide probability. From the research results it is known that the higher the groundwater level, the lower the safety factor value because the presence of groundwater can reduce slope stability causing a decrease in soil shear strength due to increased pore water pressure. In addition, the weight of the material will increase due to the presence of groundwater, which causes the driving force on the slope to also increase. In addition, the movement of air in the soil can cause seepage forces which can affect slope stability. The lowest safety factor value is at the groundwater level 100% of the overall slope height, in conditions of 100% of the overall slope height, the deterministic safety factor value is 1.337, the mean safety factor is 1.358, and 0% hazard susceptibility.

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.

Analysing Slope Stability in Response to Blast-Induced Dynamic Loading by Pseudo-Static Approach

Regular blasting in opencast coal mines generates significant ground vibrations, impacting mine slope stability and posing risks to life and property. This study focuses on monitoring ground vibrations in an opencast coal mine through near-field monitoring and investigating the impact of blast-induced seismic loading on slope stability. The approach involves a pseudostatic method utilising Strength Reduction Factor (SRF), based on Finite Element (FE) numerical modelling software. The study examines a pit slope with a tension crack under seismic loading, varying the intensity of seismic coefficients (Ks) from 0 to 0.5. These coefficients are determined through field vibration monitoring during production blasts. In numerical modelling, seismic loading is considered in both horizontal (outward of slope face) and vertically downward (in-line with gravity). Numerical modelling incorporates dimensionless horizontal seismic coefficient (Kh) and vertical seismic coefficient (Kv), and both directions which is expressed as Seismic Coefficient Ratio (SCR) which is the ratio of Kv and Kh for interpretation of results. Although SCR induces changes in the Factor of Safety (FoS), its impact is minimal compared to seismic loading solely in the horizontal direction. Consequently, increasing SCR leads to a decrease in FoS. The study observes that Peak Ground acceleration (PGA) in the longitudinal direction has greater dominance than in the transverse direction. Additionally, the seismic wave in the horizontal direction destabilises the slope more than the corresponding vertical seismic wave. These findings are elucidated in the context of the Critical Slip Surface (CSS).

Slope instability mechanism with differential rock mass structure along a fault: a mine landslide from Southwest China

Mine slope stability and mining sustainability are related to the local geological structures, which could change the rock mass structure in deep mining. After 20 years mining in a mudstone mine, western China, the slope structure transforms from anti-dipping structure into a bedding structure by a recently discovered fault (F1), further inducing the two landslides (Landslide #I and Landslide #II). Landslide investigation suggested the residual deposits in Landslide #I first slid over 100 m and overburdened the rear of Landslide #II. The bedding rock with weak interlayers at footwall is separated from the anti-dipping rock at the hanging wall by F1. After excavation, a weak interlayer was exposed and softened by rainfall, resulting in the slip of footwall rock mass and further inducing large scale toppling deformation. The fragmented rock mass sliding along a weak interlayer triggers consequent deformation of adjacent slope, reducing safety reserve of the open mine. The discrete element analysis reveals that the bedding rock mass of footwall slid once the weak interlayer was exposed by mining. And retrogressive deformation transmitted to the hanging wall and induced bending and toppling deformation of anti-dipping rock mass. Mine feasibility assessment should recognize the potential deep geological structures as important in the future.

A Comprehensive Evaluation of Resilience in Abandoned Open-Pit Mine Slopes Based on a Two-Dimensional Cloud Model with Combination Weighting

The stability of abandoned open-pit mine slopes and their ecological environment are threatened owing to their fragile, complicated, and uncertain characteristics. This study establishes a novel evaluation indicator system for enhancing mine design and environmental protection insight. The weights in the system are assigned using a combined method, which consists of the game theory, the interval analytic hierarchy process (IAHP), and the entropy weight method (EWM). The IAHP is optimized by the improved radial movement optimal (IRMO) algorithm and the simulated annealing (SA) algorithm to ensure calculation stability and efficiency. Meanwhile, a two-dimensional cloud model (TDCM) is developed to obtain the slope resilience level and visualize the result. This comprehensive evaluation method is applied to three abandoned mine slopes in the Yellow River Basin, and the results demonstrate that the method can provide crucial insights for rational mine slope stabilization and ecological restoration.

Slope stability analysis of an open pit mine with considering the weathering agent: Field, laboratory and numerical studies

Freezing-thawing (F-T) processes can affect the slope instability of open pit mine wall in cold regions, resulting the increase of mining operations cost and decrease the safety of personnel and equipment. Therefore, estimating the degradation of rockmass geomechanical properties under the weathering agent is crucial for slope stability analysis of an open pit mine in mountain areas. Accordingly, for optimal slope stability analysis of Angouran open-pit mine in this research, variations of physico-mechanical properties of pit wall schist rock including dry density, and uniaxial and triaxial compressive strengths were firstly measured during the defined F-T cycles. Then, the related properties of slope rock mass were determined using the generalized Hoek-Brown criterion. Based on the estimated rock mass characteristics, a numerical model of mine slope was constructed and pit stability conditions was analyzed. According to the obtained results, the displacement of slope rock mass varied from 0 to 14.6 m, occurred in highly weathered schist, indicating the low probability of large collapses. To validate the achieved results, 30 prisms were installed in the north-west wall of mine and in-situ displacements were recorded three times in week for one year. Results indicated that the measured displacements from in-situ monitoring and numerical model are in good agreement, so that the determination coefficient (R2) was obtained 0.80.

Mine Landslide Management Sustainability Model in Kutai Kartanegara Regency, East Kalimantan, Indonesia

This research aims to identify the geological and lithological structures of mine land, determine the slope stability of the land, and determine the sustainability of landslide management in Kutai Kartanegara Regency, East Kalimantan, Indonesia. This present research was conducted in Samboja and Sebulu sub-districts, Kutai Kartanegara Regency, East Kalimantan, Indonesia. Data collection concerning the geological structure, lithology, and sustainability of coal mine landslides was carried out. Rock data, such as its physical and mechanical properties, were taken from complete coring drilled and then analyzed in a geomechanics laboratory. This procedure was carried out in three locations, with the first and second samples collected in the Kampungbaru Formation representing the youngest formation. In addition, the third taken in the Pulubalang Formation represents the oldest coal-bearing formation. The data relating to the avalanche condition were collected through surveys, interviews, and filling out questionnaires using a purposive sampling method. The respondents were 13 mining engineering heads from various mine sites in Kutai Kartanegara Regency, three mining environmental experts, and four academics. The results showed that of the 50-joint data, those with potential positions for landslides were located at N333°E/61° and N110°E/74°. The most dominant lithology in the study area was claystone, followed successively by sandstone, siltstone, and shale, with a specific gravity between 2.55 and 2.66. The dominant claystone indicated a relatively prone area. Meanwhile, the strength of the mechanical properties of the rock (direct shear) cohesion ranged from 17.80 and 174.53 kPa, with shear angles ranging from 10.88° to 42.01°. Based on the design of the slope stability in the three locations, this study demonstrated the maximum slope angle ranging from 29° to 37°, a height of 50.17 to 70.16 meters, a single slope height of 10 meters with an angle ranged from 32° to 44°, and a factor of safety (FOS) ranging from 1.326 to 1.452 with stable conditions. Multi-dimensional scaling (MDS) simulation results of the sustainability status comprised of a total of 49 attributes derived from five dimensions, namely ecological, economic, social, law, institutional and technological, demonstrated a score fell of 50.01. Furthermore, to increase the sustainability score, this study identified some sensitive factors as follows: condition of the slope of the mine slope, MSME business of residents, role of NGOs in mine landslides, concern of pit supervisory personnel for mine landslides, and mastery of mine landslide technology. Hence, the projection sustainability score increased to 82.00, which was achieved in the good category.

Monitoring subsidence of open pit mine slope based on GNSS/CORS technology - case study at the Coc Sau open-pit coal mine

Subsidence value is one of the important parameters to evaluate the stability of open pit mine slope. The subsidence is determined from height values measured at different times using different methods and equipment. When applying GNSS/CORS technology to monitor displacement, landslides, ground subsidence or structures, a specialized monitoring system is needed to ensure the necessary accuracy. This article presents the results of research on subsidence monitoring of open pit mine slope based on CORS technology and a self-developed GNSS receiver. The CORS station is set up with Trimble's Zyphir 2 Geodetic antenna and Stonex GNSS receiver located in Cam Pha city, Quang Ninh. The GNSS receiver for monitoring station is designed and developed based on the Trimble's GNSS BD970 board and integrated with a 4G wifi modem, allowing the transmission of monitoring data in standard NMEA0183 format to the CORS station's host computer. Decoded monitoring data and error filtering have improved the accuracy of height determination achieved at the mm level. Results of simulation experiments and experiments with actual monitoring data at Coc Sau coal mine, Cam Pha, Quang Ninh have proven the effectiveness and reliability of the method. With simulated experimental monitoring results, it shows that the largest subsidence difference is 16 mm and the smallest is 6 mm.

Monitoring and Analysis of the Collapse at Xinjing Open-Pit Mine, Inner Mongolia, China, Using Multi-Source Remote Sensing

The collapse of open-pit coal mine slopes is a kind of severe geological hazard that may cause resource waste, economic loss, and casualties. On 22 February 2023, a large-scale collapse occurred at the Xinjing Open-Pit Mine in Inner Mongolia, China, leading to the loss of 53 lives. Thus, monitoring of the slope stability is important for preventing similar potential damage. It is difficult to fully obtain the temporal and spatial information of the whole mining area using conventional ground monitoring technologies. Therefore, in this study, multi-source remote sensing methods, combined with local geological conditions, are employed to monitor the open-pit mine and analyze the causes of the accident. Firstly, based on GF-2 data, remote sensing interpretation methods are used to locate and analyze the collapse area. The results indicate that high-resolution remote sensing can delineate the collapse boundary, supporting the post-disaster rescue. Subsequently, multi-temporal Radarsat-2 and Sentinel-1A satellite data, covering the period from mining to collapse, are integrated with D-InSAR and DS-InSAR technologies to monitor the deformation of both the collapse areas and the potential risk to dump slopes. The D-InSAR result suggests that high-intensity open-pit mining may be the dominant factor affecting deformation. Furthermore, the boundary between the collapse trailing edge and the non-collapse area could be found in the DS-InSAR result. Moreover, various data sources, including DEM and geological data, are combined to analyze the causes and trends of the deformation. The results suggest that the dump slopes are stable. Meanwhile, the deformation trends of the collapse slope indicate that there may be faults or joint surfaces of the collapse trailing edge boundary. The slope angle exceeding the designed value during the mining is the main cause of the collapse. In addition, the thawing of soil moisture caused by the increase in temperature and the reduction in the mechanical properties of the rock and soil due to underground voids and coal fires also contributed to the accident. This study demonstrates that multi-source remote sensing technologies can quickly and accurately identify potential high-risk areas, which is of great significance for pre-disaster warning and post-disaster rescue.

Analisis Stabilitas Lereng Tambang Nikel Kabupaten Morowali

Central Sulawesi Province is a province that has quite high mining activities, so an evaluation of the stability of open pit slope excavations needs to be carried out to prevent collapses during the exploration process which could result in loss of life. Analysis using the finite element method is one method that can be used to analyze slope deformation and stability during the excavation process. This research simulates excavation of a mine slope in 4 stages with a height of 5 m and a slope of 500. The analysis was carried out based on the results of the N-SPT test at three locations (GT-15617, GT-19125 and GT-19841) which are the slopes with the most extreme slopes. The analysis results show that at GT-15617 the maximum deformation occurred at stage 4 of the excavation at 0.18 m with a safety factor of 1.43, the maximum deformation at the GT-19125 location occurred at stage 4 at 0.21 m with a safety factor of 1.26 and at location GT-19841 maximum deformation occurred at stage 4 of 0.21 with a safety factor of 1.21. The overall safety factor analysis results do not meet the required minimum safety factor criteria.