Global Navigation Satellite System (GNSS) has been widely used in the field of surveying. When applying the GNSS technology, the positioning could be done by setting up a network of continuous operation reference stations (CORS). Real... more
Global Navigation Satellite System (GNSS) has been widely used in the field of surveying. When applying the GNSS technology, the positioning could be done by setting up a network of continuous operation reference stations (CORS). Real Time Kinematic (RTK) method based on CORS stations, therefore, has been developed. While the accuracy of positioning by the RTK technique depends on the distance from the CORS base to the rover station, it is necessary to determine the most reasonable distance from the CORS station to the rover station to ensure the appropriate accuracy for the establishment of large-scale cadastral maps. In this study, an investigation on a variety of distances between the base and the rover was performed to their influence on the accuracy of positioning. The results showed that when producing cadastral maps with scales of 1: 200, 1: 500, 1:1000, 1:2000 and 1:5000, the maximum distances from the CORS station to the rover station are 2.2 km, 5.3 km, 10.5 km, 20.8 km an...
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In processing of position time series of crustal deformation monitoring stations by continuousGNSS station, it is very important to determine the motion model to accurately determine the displacementvelocity and other movements in the... more
In processing of position time series of crustal deformation monitoring stations by continuousGNSS station, it is very important to determine the motion model to accurately determine the displacementvelocity and other movements in the time series. This paper proposes (1) the general geometric model foranalyzing GNSS position time series, including common phenomena such as linear trend, seasonal term,jumps, and post-seismic deformation; and (2) the approach for directly estimating time decay ofpostseismic deformations from GNSS position time series, which normally is determined based on seismicmodels or the physical process seismicity, etc. This model and approach are tested by synthetic positiontime series, of which the calculation results show that the estimated parameters are equal to the givenparameters. In addition they were also used to process the real data which is GNSS position time series of4 CORS stations in Vietnam, then the estimated velocity of these stations: DANA (n, ...
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The paper is devoted to studying the possibility of using artificial neural networks (ANN) to estimate ground subsidence caused by underground mining. The experiments showed that the most suitable network structure is a network with three... more
The paper is devoted to studying the possibility of using artificial neural networks (ANN) to estimate ground subsidence caused by underground mining. The experiments showed that the most suitable network structure is a network with three layers of perceptrons and four neurons in the hidden layer with the back propagation algorithm (BP) as a training algorithm. The subsidence observation data in the Mong Duong underground coal mine and other parameters, including: (1) the distance from the centre of the stope to the ground monitoring points; (2) the volume of mined-out space; (3) the positions of the ground points in the direction of the main cross-section of the trough; and (4) the time (presented by cycle number), were used as the input data for the ANN. The findings showed that the selected model was suitable for predicting subsidence along the main profile within the subsidence trough. The prediction accuracy depended on the number of cycles used for the network training as well...
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Open-pit mining activities, including blasting, drilling, loading, and transport, often result in the direct emission of particulates and gases into the atmosphere. Occupational exposure to these pollutants is considered as the risk for... more
Open-pit mining activities, including blasting, drilling, loading, and transport, often result in the direct emission of particulates and gases into the atmosphere. Occupational exposure to these pollutants is considered as the risk for health, especially the risk of developing respiratory diseases. An air quality monitoring system and spatial analysis are necessary to identify these potential hazards. In this study, we propose an air quality monitoring system that integrates gas and dust sensors into a small multi-rotor copter or unmanned aerial vehicle (UAV). Different spatial interpolation methods including trilinear interpolation, nearest neighbour, and natural neighbour applied to the monitoring data (CO, SO2, PM2.5, CO2) from our system to derive air concentration levels in the atmosphere of open-pit coal mines were also examined. The results show that the UAV based air quality monitoring system performed efficiently and safely in conditions of deep open-pit coal mines. In add...
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W ciągu ostatnich lat problemy szkod poeksploatacyjnych na terenie gorniczym Quang Ninh stają sie coraz powazniejsze. W artykule zastosowano pewne metody prognozowania wplywow eksploatacji w tym funkcje wplywow Budryka-Knothego. Na... more
W ciągu ostatnich lat problemy szkod poeksploatacyjnych na terenie gorniczym Quang Ninh stają sie coraz powazniejsze. W artykule zastosowano pewne metody prognozowania wplywow eksploatacji w tym funkcje wplywow Budryka-Knothego. Na przykladzie podziemnej kopalni wegla Thong Nhat (Wietnam) przeanalizowano wyniki i dokonano porownania wartości wskaźnikow deformacji zaprognozowanych i uzyskanych z pomiarow terenowych w świetle funkcji czasu wedlug teorii S. Knothego.
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Lightweight Unmanned Aerial Vehicle (UAV) for 3D topographic mapping in mining industry has been raised significantly in recent years. Especially, in complex terrains such as in open-pit mines in which the elevation is rapidly undulating,... more
Lightweight Unmanned Aerial Vehicle (UAV) for 3D topographic mapping in mining industry has been raised significantly in recent years. Especially, in complex terrains such as in open-pit mines in which the elevation is rapidly undulating, UAV-based mapping has proven its economical efficiency and higher safety compared to the conventional methods. However, one of the most important factors in UAV mapping of complex terrain is the flight altitude, which needs to be considered seriously because of the safety and accuracy of generated DEMs. This paper aims to evaluate the influence of the flight height on the accuracy of DEMs generated in open-pit mines. To this end, the study area is selected in a quarry with a complex terrain, which is located in northern Vietnam. The investigation was conducted with five flight heights of 50 m, 100 m, 150 m, 200 m, and 250 m. To assess the accuracy of resulting DEMs, ten ground control points (GCPs), and 385 checkpoints measured by both GNSS/RTK and...
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Surface subsidence due to underground mining is a frequent problem that mine surveyors normally deal with. When some indicators like ground cracks occur, it is necessary to have a quick assessment of surface subsidence. In this case, the... more
Surface subsidence due to underground mining is a frequent problem that mine surveyors normally deal with. When some indicators like ground cracks occur, it is necessary to have a quick assessment of surface subsidence. In this case, the similar zone method proposed by D. A. Kagacovski is commonly used. By this method, the borehole data of overburden strata is used to estimate angles of movement of the subsidence trough. This article presents the result of the initial assessment of surface movement due to excavation at the Khe Cham underground mine, Quang Ninh province. With movement angles of subsidence trough estimated using stiffness coefficients of the overburden strata, it is obvious that the Khe Cham washing plant is within the dangerous deformation area due to the underground mining activities. The assessment in this study can be used to choose a reasonable solution of excavation for the safety in both underground working and surface areas. Index Terms Subsidence, underground...
Open-pit coal mines’ terrain is often complex and quickly and frequently changes. Therefore, topographic surveys of open-pit mines are undertaken on a daily basis. While these tasks are very time-consuming and costly with traditional... more
Open-pit coal mines’ terrain is often complex and quickly and frequently changes. Therefore, topographic surveys of open-pit mines are undertaken on a daily basis. While these tasks are very time-consuming and costly with traditional methods such as total station and GNSS, the unmanned aerial vehicle (UAV) based method can be more efficient. This method is a combination of the “Structure from motion” (SfM) photogrammetry technique and UAV photogrammetry which has been widely used in topographic surveying. With an increasing popularity of RTK-enabled drones, it is becoming even more powerful method. While the important role of ground control points (GCP) in the accuracy of digital surface model (DSM) generated from images acquired by “traditional” UAVs (not RTK-enabled drones) has been proved in many previous studies, it is not clear in the case of RTK-enabled drones, especially for complex terrain in open-pit coal mines. In this study, we experimentally investigated the influence of...
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Open-pit or underground mining both causes environmental impacts such as air, soil, water pollution, etc., especially causing land subsidence of mines and surrounding areas. Research on mining subsidence is often carried out by field... more
Open-pit or underground mining both causes environmental impacts such as air, soil, water pollution, etc., especially causing land subsidence of mines and surrounding areas. Research on mining subsidence is often carried out by field survey, the advantage of this method is high accuracy, but it is usually applied in a small scale. Recently, with the development of radar technology, there have been many studies applying this Radar Interferometry technique to determine surface subsidence over a wide range with a few millimeters accuracy. In this paper, 24 Sentinel-1 images were used as input materials, using the Permanent Scatter Interferometry (PSInSAR) method to determine the land subsidence of the Tan My-Thuong Tan quarries and surrounding areas. The results were compared with the average annual subsidence of 20 surveying points using GNSS technology from 1/2018 to 3/2020. The correlation coefficient of annual average land subsidence of the two methods is 0.83, showing the feasibil...
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Flash floods induced by torrential rainfalls are considered one of the most dangerous natural hazards, due to their sudden occurrence and high magnitudes, which may cause huge damage to people and properties. This study proposed a novel... more
Flash floods induced by torrential rainfalls are considered one of the most dangerous natural hazards, due to their sudden occurrence and high magnitudes, which may cause huge damage to people and properties. This study proposed a novel modeling approach for spatial prediction of flash floods based on the tree intelligence-based CHAID (Chi-square Automatic Interaction Detector)random subspace, optimized by biogeography-based optimization (the CHAID-RS-BBO model), using remote sensing and geospatial data. In this proposed approach, a forest of tree intelligence was constructed through the random subspace ensemble, and, then, the swarm intelligence was employed to train and optimize the model. The Luc Yen district, located in the northwest mountainous area of Vietnam, was selected as a case study. For this circumstance, a flood inventory map with 1866 polygons for the district was prepared based on Sentinel-1 synthetic aperture radar (SAR) imagery and field surveys with handheld GPS. ...
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Aerosol optical depth (AOD) can be retrieved accurately with sequential ground-based measurements of direct and diffuse solar radiance. However, spatial coverage and location frequency cause certain limitations. Hence, satellite image... more
Aerosol optical depth (AOD) can be retrieved accurately with sequential ground-based measurements of direct and diffuse solar radiance. However, spatial coverage and location frequency cause certain limitations. Hence, satellite image data are a proper tool for obtaining aerosol optical depth products with more spatial information and patterns of aerosol distribution. Currently, aerosol remote sensing may enhance our understanding of the optimal approach to AOD retrieval over urban and rural areas, and how it differs due to the characteristics of surface reflectivity. The article deals with the concepts of contrast reduction, and dark target approaches are examined using Landsat imaging and the observation of a sun photometer for integrating aerosol optical depth distribution over the city of Taipei in Taiwan. For areas with bright surfaces, such as urban areas, the above concepts were applied using the dispersion coefficient method with a sun photometer, in order to reduce errors c...
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Dust is one of the components causing heavy environmental pollution in open-pit mines, especially PM10. Some pathologies related to the lung, respiratory system, and occupational diseases have been identified due to the effects of PM10 in... more
Dust is one of the components causing heavy environmental pollution in open-pit mines, especially PM10. Some pathologies related to the lung, respiratory system, and occupational diseases have been identified due to the effects of PM10 in open-pit mines. Therefore, the prediction and control of PM10 concentration in the production process are necessary for environmental and health protection. In this study, PM10 concentration from drilling operations in the Coc Sau open-pit coal mine (Vietnam) was investigated and considered through a database including 245 datasets collected. A novel hybrid artificial intelligence model was developed based on support vector regression (SVR) and a swarm optimization algorithm (i.e., particle swarm optimization (PSO)), namely PSO-SVR, for estimating PM10 concentration from drilling operations at the mine. Polynomial (P), radial basis function (RBF), and linear (L) kernel functions were considered and applied to the development of the PSO-SVR models i...
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Landslide and subsidence in waste dump is a major problem which most mining industry countries is facing, Viet Nam is not an exception. To reduce the effects of disasters such as subsidence, there have had many developed subsidence... more
Landslide and subsidence in waste dump is a major problem which most mining industry countries is facing, Viet Nam is not an exception. To reduce the effects of disasters such as subsidence, there have had many developed subsidence prediction methods. In this paper, prediction function of Knothe was presented. Based on Knothe function, the authors built a subsidence prediction module and applied it for Nam Deo Nai waste dump, Quang Ninh, Viet Nam. The predicted values from this module was compared to the actually measured data, the smallest difference of subsidence is-0.003 m, equivalent to 5.3%, the largest difference is 0.011 m, equivalent to 4.3%. The small disparity between the largest and smallest difference shows the result has a high convergence. As the final result, it is found that the developed module is powerful and effective tool for waste rock dumps subsidence prediction.
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Mining-induced subsidence is often determined by field survey methods, e.g., using total station or global navigation satellite system (GNSS) technology. The advantage of these methods is high accuracy, but they are usually employed in a... more
Mining-induced subsidence is often determined by field survey methods, e.g., using total station or global navigation satellite system (GNSS) technology. The advantage of these methods is high accuracy, but they are usually employed in a small-scale areas. Radar technology has been developed and applied to determine surface subsidence over a large area at a few millimeters accuracy. In this paper, 24 Sentinel-1B SAR images are used with the Permanent Scatter Interferometry (PSInSAR) method to determine the land subsidence of the Tan My-Thuong Tan quarries and surrounding areas in Binh Duong province, Vietnam. The results are compared with the average annual subsidence of 20 GNSS surveying points from January 2018 to March 2020. The correlation coefficient of annual average land subsidence of the two methods is bigger than 0.8, indicating the feasibility of applying the InSAR Sentinel-1 data processed by the PSInSAR method to determine the mining-induced subsidence of ground surfaces...
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In this scientific report, a new technique of artificial intelligence which is based on k-nearest neighbors (KNN) and particle swarm optimization (PSO), named as PSO-KNN, was developed and proposed for estimating blast-induced ground... more
In this scientific report, a new technique of artificial intelligence which is based on k-nearest neighbors (KNN) and particle swarm optimization (PSO), named as PSO-KNN, was developed and proposed for estimating blast-induced ground vibration (PPV). In the proposed PSO-KNN, the hyper-parameters of the KNN were searched and optimized by the PSO. Accordingly, three forms of kernel function of the KNN were used, Quartic (Q), Tri weight (T), and Cosine (C), which result in three models and abbreviated as PSO-KNN-Q, PSO-KNN-T, and PSO-KNN-C models. The valid of the proposed models was surveyed through comparing with those of benchmarks, random forest (RF), support vector regression (SVR), and an empirical technique. A total of 152 blasting events were recorded and analyzed for this aim. Herein, maximum explosive per blast delay (W) and the distance of PPV measurement (R), were used as the two input parameters for predicting PPV. RMSE, R2, and MAE were utilized as performance indicators ...
Observation lines set up on the ground play an important role in the determination of rock deformation caused by underground mining, issuing timely warning notices and alleviating any impacts on surface engineering constructions. The main... more
Observation lines set up on the ground play an important role in the determination of rock deformation caused by underground mining, issuing timely warning notices and alleviating any impacts on surface engineering constructions. The main purpose of this study is to design three monitoring lines above the working (tunnel) with exact location of observation and control points on the topographical map as well as the profiles along the strike and dip directions. The initial determination of surface areas where the influence of coal extraction occurred based on geological parameters, extraction planning, topological maps, and limit angles of study areas is necessary before designing observation lines in order to accurately determine the deformation area. While common design methods have a problem of inaccurate control points, the method proposed in this study suggested adding a value to the angle of draw to solve the problem. The proposed method is applied to the seam G9 in the Mong Duong colliery to obtain the optimal design of monitoring lines. After taking several real conditions into account, the result design with the maximum and minimum distances between monitoring points of 28.5 m and 17.25 m, respectively, satisfied the standard requirement in Vietnam National Specifications on Mine Surveying.