Topographic modelling using UAVs compared with traditional survey methods in mining

Abstract

The current developments with unmanned aerial vehicles ('UAVs') are revolutionizing many fields in civil applications, such as agriculture, environmental and visual inspections. The mining industry can also benefit from UAVs in many aspects, and the reconciliation through topographic control is an example. In comparison with traditional topography and maybe modern techniques such as laser scanning, aerial photogrammetry is cheaper, provides faster data acquisition and processing, and generates several high-quality products and impressive level of details in the outputs. However, despite the quality of the software currently available, there is an uncertainty intrinsic to the surfaces acquired by photogrammetry and this discrepancy needs to be assessed in order to validate the techniques applied. To understand the uncertainty, different surfaces were generated by UAVs for a small open pit quarry in southern Brazil. Wellestablished topographic surveying methodologies were used for geolocation support and comparison, namely the RTK (real-time kinetic) global navigation satellite system (GNSS) (here called conventional method) and laser scanning. The results showed consistency between the UAV surfaces with a few outliers in when vegetation, water and mobile objects during the flight missions. In comparison with the laser-scanned surface, the UAV results were less erratic surrounding the RTK points, showing that surfaces generated by photogrammetry can be a simpler and quicker alternative for mining reconciliation, presenting low uncertainty when compared to conventional methods.

Accuracy Analysis of a 3D Model of Excavation, Created from Images Acquired with an Action Camera from Low Altitudes

“…Five cross-sections were measured, in which each cross-section contained 3 points evenly spaced. The total area of this test area is 103 m 2 .…”

“…Eight cross-sections of the escarpment were measured on the entire surface of this area, in which each cross-section contained three points. The area of the area was 444 m 2 .…”

“…The use of multi-camera high-resolution video sets in UAV photogrammetry, offers a new range of application in many fields of research related to 3D modelling, production of high-resolution Digital Surface Models (DSMs) and orthophotos. The potential of this type of solution can be found, especially in mining [1][2][3], archeology [4], 3D modelling in an open-pit mine [5,6], 3D mapping, [7], forestry and agricultural mapping [8,9]. The accuracy of DSMs developed based on the UAV photogrammetry, is determined by many factors such as image quality, flight altitude, weather conditions, camera orientation as well as the number and distribution of Ground Control Points (GCPs) [10,11].…”

“…The use of low altitude photogrammetry favours the optimisation of cubic measurement techniques in the areas of opencast mines, and thus reduces the costs of aggregate production while optimising the costs of its extraction. The use of technology of imaging from a low altitude enables the non-invasive development of accurate 3D models of excavations and conducting accurate and detailed analyses [2,3,7,9].…”

Using UAV for automatic lithological classification of open pit mining front

“…In the mining in-dustry, Salvini et al (2016), Hugenholtz et al (2013), Silva et al (2016), Peroni (2016 and Westoby (2012) also use make use of UAVs. Topographic surveying techniques, for instance, are already available and the solutions apply for several uses with similar accuracy and more definition when compared with traditional methods (BERETTA et al, 2017(BERETTA et al, , 2018.…”