scholarly journals Research on optimal takeoff positions of UAV integrated GNSS - RTK in producing large scale topological maps for open - pit mines

2020 ◽  
Vol 61 (5) ◽  
pp. 54-63
Author(s):  
Canh Van Le ◽  
Cuong Xuan Cao ◽  
Ha Thu Thi Le ◽  
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Open Pit ◽  
Surface Model ◽  
Open Pit Mines ◽  
Topological Maps ◽  
Accuracy Requirement ◽  
Ground Control Points ◽  
Uav Images ◽  
A Site

Unmanned aerial vehicles (UAV) are widely used for establishing large scale topological maps. Recently, drones have been integrated with high-quality GNSS receivers which allows real time kinematic positioning (RTK), so are called UAV/RTK. This technology is beneficial to surveyors as they do not need to establish many ground control points in mapping such a complex terrain as open-pit mines. DJI Phantom 4 RTK (P4K) is a UAV/RTK which is of much interest due to its small size and low cost. For open-pit mines, the takeoff position of P4K needs to be seriously considered because of its influence on the accuracy of the digital surface model (DSM) and safety of survey flights. This article presents the method of determining the optimal takeoff positions for UAV in large scale mapping for open pit mines. To evaluate this method, a site of steep and rugged terrain with an area of 80 hectares at the Coc Sau coal mine was chosen as the study area. The results indicate that two optimal locations with altitudes of +50 m and +160 m could be used for taking off the P4K. The accuracy of DSM generated from UAV images using the optimal positions satisfied the accuracy requirement of large scale topological maps at the deepest area of the mine (the altitude of -60 m).

scholarly journals UAV PHOTOGRAMMETRY-BASED FOR OPEN PIT COAL MINE LARGE SCALE MAPPING, CASE STUDIES IN CAM PHA CITY, VIETNAM

2020 ◽  
Vol 12 (4) ◽  
pp. 501-509
Author(s):  
Nguyen Long ◽  
◽  
Le Thi Thu Ha ◽  
Tong Si Son ◽  
Kim Thi Thu Huong ◽  
...  
Keyword(s):  
Large Scale ◽  
Coal Mines ◽  
Open Pit ◽  
Ground Control ◽  
Surface Model ◽  
Control Points ◽  
Aerial Photogrammetry ◽  
Ground Control Points ◽  
Active Coal ◽  
Uav Images

The use of lightweight Unmanned Aerial Vehicle with the aerial photogrammetry approach to construct the Digital Surface Model (DSM) has been effectively applied for various types of topography. However, the ability to carry out this approach for huge active open coal mines is insufficiently investigated, furthermore, the influences of topographical factors on the accuracy of DSM are ambiguous. This experiment attempts to apply the UAV method for the two active coal mines with the total area of 7.99 km2 , exploited at a range from -300 m to 300 m altitude to figure out the effect of topographic factors on the accuracy of DEM constructed from UAV images. A total of 972 UAV images and 17 ground control points have been coupled to construct DSM of the mines. Besides, 16 checking points located at different elevations are used to evaluate the accuracy of DEM and to define the influence. DEMs are generated with the maximum RMSE of 0.086 m, 0.099 m, and 0.170 m corresponding to X, Y, and Z dimensional errors. The results show the unclear correlation between the vertical accuracy of DEM and the relative elevation (R2=0.064), the general slope of the mines, and the number of ground control points using in the coal mines as well.

scholarly journals Experimental Investigation on the Performance of DJI Phantom 4 RTK in the PPK Mode for 3D Mapping Open-Pit Mines

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Le VAN CANH ◽  
Cao XUAN CUONG ◽  
Nguyen QUOC LONG ◽  
Le THI THU HA ◽  
Tran TRUNG ANH ◽  
...  
Keyword(s):  
Coal Mines ◽  
Daily Basis ◽  
Open Pit ◽  
Surface Model ◽  
Test Field ◽  
Open Pit Mines ◽  
Ground Control Points ◽  
Aerial Vehicle ◽  
Topographic Surveys

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 GCP regarding its numbers and distribution on the accuracy of DSM generation from images acquired by RTK-enabled drones in open-pit coal mines. In addition, the Post Processing Kinematic (PPK) mode was executed over a test field with the same flight altitude. DSM generation was performed with several block control configurations: PPK only, PPK with one GCP, and PPK with two GCPs. Several positions of GCPs were also examined to test the optimal locations for placing GCPs to achieve accurate DSMs. The results show that the horizontal and vertical accuracy given by PPK only were 9.3 and 84.4 cm, respectively. However, when adding at least one GCP, the accuracy was significantly improved in both horizontal and vertical components, with RMSE for XY and Z ranging between 3.8 and 9.8 cm (with one GCP) and between 3.0 and 5.7 cm (with two GCPs), respectively. Also, the GCPs placed in the deep areas of the open-pit mine could ensure the cm-level accuracy.

scholarly journals Brown Coal in Victoria, Australia and Maddingley Brown Coal Open Cut Mine Batter Stability

2020 ◽  
Vol 9 (3) ◽  
pp. 109-118
Author(s):  
Lei Zhao ◽  
Greg You
Keyword(s):  
Coal Seam ◽  
Brown Coal ◽  
Large Scale ◽  
Low Cost ◽  
Three Dimensional ◽  
Open Pit ◽  
Open Pit Mining ◽  
Mining Operations ◽  
Power Generators ◽  
Three Dimensional Finite Element

Brown coal is young, shallowly deposited, and widely distributed in the world. It is a fuel commonly used to generate electricity. This paper first reviews the resources and characteristics of brown coal in Victoria, Australia, and its exploitation and contribution to the economy or power supply in Victoria. Due to the shallow depth of the brown coal seam, e.g. very favorable stripping ratio, open pit mining is the only mining method used to extract the coal at low cost for power generators. With the large-scale mining operations, cases of batter failure were not rare in the area. From the comprehensive review of past failures, overburden batter tends to fail by circular sliding, coal batter tends to fail by block sliding after the overburden is stripped due to a weak water-bearing layer underneath the coal seam and tension cracks developed at the rear of the batter, and batter failure is typically coincided with peak raining seasons. Secondly, the paper reviews the case study of Maddingley Brown Coal (MBC) Open Cut Mine batter stability, including geology, hydrogeology, and hydro-mechanically coupled numerical modelling. The modelling employs three-dimensional finite element method to simulate the MBC northern batter where cracks were observed in November 2013. The comprehensive simulation covers an overburden batter, a brown coal batter, two rainfall models, and a buttressed batter. The simulated results agree well with observed data, and it is found that the rainfall at the intensity of 21mm substantially lowered the factor of safety of the coal batter.

scholarly journals Arbuscular mycorrhizal fungi promote the growth of plants in the mining associated clay

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ziheng Song ◽  
Yinli Bi ◽  
Jian Zhang ◽  
Yunli Gong ◽  
Huihui Yang
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Structural Equation ◽  
Large Scale ◽  
Low Cost ◽  
Eastern China ◽  
Arbuscular Mycorrhizal ◽  
Open Pit ◽  
Open Pit Mining ◽  
Amf Inoculation

Abstract It is urgent to restore the ecological function in open-pit mining areas on grassland in Eastern China. The open-pit mines have abundant of mining associated clay, which is desirable for using as a soil source for ecological restoration. The mining associated clay in Hulunbuir district, Inner Mongolia was selected and mixed with a sandy soil at a ratio of 1:1 (S_C soil). Also, effects of arbuscular mycorrhizal fungi (AMF) inoculation on soil functions were studied. The aboveground and underground biomass of maize in S_C soil was 1.49 and 2.41 times higher than that of clay soil, respectively. In the topsoil and S_C soil, the growth hormone (IAA) and cytokinin (CTK) levels of maize were higher than that of clay, while abscission acid (ABA) levels were lower. The inoculation with AMF could significantly improve the biomass of maize and enhance the stress resistance of plants. Through structural equation model (SEM) analyses, it was found that the soil type and AMF inoculation had the most direct impact on maize growth and biomass content. These finds extend our knowledge regarding a low-cost method for physical and biological improvement of mining associated clay, and to provide theoretical support for large-scale application in the future.

scholarly journals Evaluating the potential of post-processing kinematic (PPK) georeferencing for UAV-based structure- from-motion (SfM) photogrammetry and surface change detection

2019 ◽  
Vol 7 (3) ◽  
pp. 807-827 ◽  
Author(s):  
He Zhang ◽  
Emilien Aldana-Jague ◽  
François Clapuyt ◽  
Florian Wilken ◽  
Veerle Vanacker ◽  
...  
Keyword(s):  
Change Detection ◽  
Structure From Motion ◽  
Low Cost ◽  
Post Processing ◽  
Positional Accuracy ◽  
Surface Change ◽  
Ground Control Points ◽  
Single Lens ◽  
Surface Representations ◽  
Uav Images

Abstract. Images captured by unmanned aerial vehicles (UAVs) and processed by structure-from-motion (SfM) photogrammetry are increasingly used in geomorphology to obtain high-resolution topography data. Conventional georeferencing using ground control points (GCPs) provides reliable positioning, but the geometrical accuracy critically depends on the number and spatial layout of the GCPs. This limits the time and cost effectiveness. Direct georeferencing of the UAV images with differential GNSS, such as PPK (post-processing kinematic), may overcome these limitations by providing accurate and directly georeferenced surveys. To investigate the positional accuracy, repeatability and reproducibility of digital surface models (DSMs) generated by a UAV–PPK–SfM workflow, we carried out multiple flight missions with two different camera–UAV systems: a small-form low-cost micro-UAV equipped with a high field of view (FOV) action camera and a professional UAV equipped with a digital single lens reflex (DSLR) camera. Our analysis showed that the PPK solution provides the same accuracy (MAE: ca. 0.02 m, RMSE: ca. 0.03 m) as the GCP method for both UAV systems. Our study demonstrated that a UAV–PPK–SfM workflow can provide consistent, repeatable 4-D data with an accuracy of a few centimeters. However, a few flights showed vertical bias and this could be corrected using one single GCP. We further evaluated different methods to estimate DSM uncertainty and show that this has a large impact on centimeter-level topographical change detection. The DSM reconstruction and surface change detection based on a DSLR and action camera were reproducible: the main difference lies in the level of detail of the surface representations. The PPK–SfM workflow in the context of 4-D Earth surface monitoring should be considered an efficient tool to monitor geomorphic processes accurately and quickly at a very high spatial and temporal resolution.

scholarly journals A Historical Earthquake-Induced Landslide Damming Event at the Qiaojia Reach of the Jinsha River, SE Tibetan Plateau: Implication for the Seismic Hazard of the Xiaojiang Fault

2021 ◽  
Vol 9 ◽  
Author(s):  
Mengmeng Hu ◽  
Zhonghai Wu ◽  
Klaus Reicherter ◽  
Sajid Ali ◽  
Xiaolong Huang ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Active Faults ◽  
Source Area ◽  
Surface Model ◽  
Jinsha River ◽  
Highly Active ◽  
Uav Images ◽  
A Site ◽  
River Valleys ◽  
Xiaojiang Fault

In bedrock mountainous areas where active faults and deep river valleys interact, earthquake-induced landslides can be used to explore local seismic hazards. The intersection of the highly active Xiaojiang Fault and the Jinsha River and its main tributaries in southwest China is a site of abundant earthquake-induced landslides. We found some boulders inappropriately scattered on the east bank of the Qiaojia reach of the Jinsha River, where the Qiaojia Segment of the Xiaojiang Fault passes through. We investigated the lithology and topography nearby and confirmed its source area, as well as the existence of a landslide damming event in the field. A high-resolution Digital Surface Model (DSM) generated from Unmanned Aerial Vehicle (UAV) images was used to analyze its characteristics and calculate its parameters. Optically Stimulated Luminescence (OSL) and 14C dating methods on the related dammed lake sand shows the age of the landslide, which is not later than 878 AD. The characteristics of large size with limited depositional extent, spatial relevance between the landslide and Xiaojiang Fault, and temporal-coincidence of the landslide with 624 AD earthquake support the seismic origin of this landslide. Moreover, the 624 AD earthquake was reanalyzed for its magnitude and macro-epicenter based on the coseismic displacement of the Heishui River floodplain. It was calculated to be Mw7.7 or Ms7.9 and relocated to the Qiaojia area. No M ≥ 7 earthquakes have occurred on the Qiaojia Segment for nearly 1,400 years since 624 AD. The elapsed time is close to the average recurrence interval of large earthquakes on the Qiaojia Segment. Therefore, the seismic hazard of the Qiaojia area should be considered in the future.

scholarly journals Assessment of DSM Based on Radiometric Transformation of UAV Data

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1649
Author(s):  
Muhammad Hamid Chaudhry ◽  
Anuar Ahmad ◽  
Qudsia Gulzar ◽  
Muhammad Shahid Farid ◽  
Himan Shahabi ◽  
...  
Keyword(s):  
Point Cloud ◽  
Accuracy Assessment ◽  
Low Cost ◽  
Image Data ◽  
Flying Height ◽  
Surface Model ◽  
Lidar Data ◽  
Local Accuracy ◽  
Uav Images ◽  
Uav Image

Unmanned Aerial Vehicle (UAV) is one of the latest technologies for high spatial resolution 3D modeling of the Earth. The objectives of this study are to assess low-cost UAV data using image radiometric transformation techniques and investigate its effects on global and local accuracy of the Digital Surface Model (DSM). This research uses UAV Light Detection and Ranging (LIDAR) data from 80 meters and UAV Drone data from 300 and 500 meters flying height. RAW UAV images acquired from 500 meters flying height are radiometrically transformed in Matrix Laboratory (MATLAB). UAV images from 300 meters flying height are processed for the generation of 3D point cloud and DSM in Pix4D Mapper. UAV LIDAR data are used for the acquisition of Ground Control Points (GCP) and accuracy assessment of UAV Image data products. Accuracy of enhanced DSM with DSM generated from 300 meters flight height were analyzed for point cloud number, density and distribution. Root Mean Square Error (RMSE) value of Z is enhanced from ±2.15 meters to 0.11 meters. For local accuracy assessment of DSM, four different types of land covers are statistically compared with UAV LIDAR resulting in compatibility of enhancement technique with UAV LIDAR accuracy.

scholarly journals Methodology for a dump design optimization in large-scale open pit mines

2017 ◽  
Vol 4 (1) ◽  
pp. 1387955 ◽  
Author(s):  
Jorge Puell Ortiz ◽  
Sanjay Kumar Shukla
Keyword(s):  
Design Optimization ◽  
Large Scale ◽  
Open Pit ◽  
Open Pit Mines

scholarly journals Accuracy assessment of open - pit mine’s digital surface models generated using photos captured by Unmanned Aerial Vehicles in the post - processing kinematic mode

2021 ◽  
Vol 62 (4) ◽  
pp. 38-47
Author(s):  
Long Quoc Nguyen ◽  
Keyword(s):  
Accuracy Assessment ◽  
Open Pit ◽  
Ground Control ◽  
Surface Model ◽  
Control Points ◽  
Post Processing ◽  
Ground Control Points ◽  
Satellite Positioning ◽  
Surface Models ◽  
Aerial Vehicle

To evaluate the accuracy of the digital surface model (DSM) of an open-pit mine produced using photos captured by the unmanned aerial vehicle equipped with the post-processing dynamic satellite positioning technology (UAV/PPK), a DSM model of the Deo Nai open-pit coal mine was built in two cases: (1) only using images taken from UAV/PPK and (2) using images taken from UAV/PPK and ground control points (GCPs). These DSMs are evaluated in two ways: using checkpoints (CPs) and comparing the entire generated DSM with the DSM established by the electronic total station. The obtained results show that if using CPs, in case 1, the errors in horizontal and vertical dimension were 6.8 and 34.3 cm, respectively. When using two or more GCPs (case 2), the horizontal and vertical errors are at the centimetre-level (4.5 cm and 4.7 cm); if using the DSM comparison, the same accuracy as case 2 was also obtained.

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