The main data collection for the RESEM project was carried out during Summer and Autumn 2016 at 3 different case study sites.
Site 1: Monitoring possible movement in mine tailings.
The tailings are deposited using the paste technique, whereby mine tailings are dewatered prior to deposition. Research is needed to investigate the stability of the material and the slope angles.
A tailing pond, which has not been in operation since 2014, was surveyed for the second time (first survey was in 2015) in August 2016, using a fixed wing UAV carrying a Canon EOS M digital camera. Prior to the flight, 15 target sheets were put out as ground control points and measured by dGPS. The photos were stitched using Agisoft Photoscan software, which uses the Structure-from-Motion technique to create an orthorectified photomosaic and a DEM. The created orthophoto has a spatial resolution of 5 cm and the DEM 10 cm. In addition, the pond was equipped with frost measurement points and GPS-reference points to monitor movement due to freeze-thaw processes during the winter. A third UAV flight is planned for summer 2017.
Figure 1: Digital elevation model of the tailings surface from the 2016 campaign downsampled to 1 m resolution.
Site 2: Investigating the role of ground water in mining areas.
Several areas in and around a mine site were surveyed: a peatland adjacent to a mine wastewater pond in order to detect locations of ground water upwelling; and dams around a tailing pond to better understand different water sources and hydrological processes. A fixed wing UAV was used carrying a normal digital camera (Canon Powershot S100), a modified digital camera that measures near infrared (NIR) (Canon Powershot SX260HS), and a FLIR Tau thermal imaging camera.
Fig. 2. An example of a thermal image showing part of a dam surrounding a tailing pond.
Site 3: Satellite-based mapping of ground deformation and dam stability.
An important issue for the mining industry is the monitoring of the stability of the dams that surround the tailing ponds, as dam failure can have major environmental consequences. Mining can also cause ground deformation in the surrounding area as large volumes of rock are moved. This case study site is used to investigate the possibility to use satellite data to map ground deformation in and around mine sites.
Time series of freely available high-resolution (Sentinel-1) and commercial very high-resolution (TerraSAR-X) satellite data were collected over a mining area, including a large tailing pond, during the snow free season from June to October 2016. The satellite data was processed using the InSAR technique to produce maps of ground deformation and estimates of the deformation rate during the season.
Last updated: 13.10.2017