UAV Remote Sensing Surveillance of a Mine Tailings Impoundment in Sub-Arctic Conditions

Anssi Rauhala,Anne Tuomela,Pekka Rossi,Corine Davids

doi:10.3390/rs9121318

Anssi Rauhala, Anne Tuomela + Show 2 more

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https://doi.org/10.3390/rs9121318

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Journal: Remote Sensing	Publication Date: Dec 15, 2017
Citations: 34	License type: CC BY 4.0

Affiliation: University of Oulu, Northern Research Institute

Abstract

Mining typically involves extensive areas where environmental monitoring is spatially sporadic. New remote sensing techniques and platforms such as Structure from Motion (SfM) and unmanned aerial vehicles (UAVs) may offer one solution for more comprehensive and spatially continuous measurements. We conducted UAV campaigns in three consecutive summers (2015–2017) at a sub-Arctic mining site where production was temporarily suspended. The aim was to monitor a 0.5 km2 tailings impoundment and measure potential subsidence of tailings. SfM photogrammetry was used to produce yearly topographical models of the tailings surface, which allowed the amount of surface displacement between years to be tracked. Ground checkpoints surveyed in stable areas of the impoundment were utilized in assessing the vertical accuracy of the models. Observed surface displacements were linked to a combination of erosion, tailings settlement, and possible compaction of the peat layer underlying the tailings. The accuracy obtained indicated that UAV-assisted monitoring of tailings impoundments is sufficiently accurate for supporting impoundment management operations and for tracking surface displacements in the decimeter range.

Highlights

Mining produces significant amounts of waste materials, and the volume of waste products is expected to increase in the future as lower grades of ores are utilized in mining [1,2]
The main purpose of the present study was to determine the potential for utilizing unmanned aerial vehicles (UAVs) in monitoring a tailings impoundment
UAVs and Structure from Motion (SfM)-generated digital elevation models were utilized in monitoring a tailings impoundment and movement of the tailings surface during three consecutive summers (2015–2017)

Summary

Introduction

Mining produces significant amounts of waste materials, and the volume of waste products is expected to increase in the future as lower grades of ores are utilized in mining [1,2]. One option to reduce unwanted impacts on the surrounding environment is to store tailings in a drier format, using paste or cake techniques. Several authors discuss such techniques [4,5,6,7,8], the general principle of which is to decrease the water content of tailings using thickeners or filters. The paste technique is claimed to have numerous advantages compared with conventional slurry deposition, such as increased deposition angle, decreased land footprint, less frequent need to raise the embankments, fewer seepage and stability issues, and less segregated material [8,9]. Deposition of tailings using the paste technique requires more investment and a higher degree of mine management compared with the conventional slurry storage approach [2,8]

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