Slope and Ground Stability monitoring in Open Pit and Underground mines with Advanced Radar Interferometry
This paper presents the monitoring results of an open pit and underground mine obtained over the course of several years using X-band high-resolution images from the TerraSAR-X satellite.
This high resolution monitoring project began in 2008, studying ground stability until 2013. Several Radar Interferometric techniques have been used in order to detect all ranges of displacement intensities, from millimetric to metric movements. A number of phenomena have been detected, mostly caused by the evolution of the mine, showing temporal correlation with exploitation activities. This project has also been very useful for the observation and analysis of slope failures in the open pit, which has experienced displacements of more than 10 meters in just a few months.
Several critical areas of the mine have been studied, taking into account the presence of infrastructures and other facilities. Two types of measurements have been performed based on the point nature:
- Natural reflectors: Those natural points located on the surface of the mine, i.e. buildings, rocks, arid surface, etc. Measurement quality depends on the temporal changes of these areas.
- Corner reflectors: Trihedral structures have been installed in several areas of the mine in order to ensure that there are measurement points in areas that require precise and continuous monitoring.
A combination of natural and artificial points provides a dense grid of measurement data, even in an ever changing study area such as an open pit mine.
InSAR data allows for precise delimitation of the perimeter of the motion and its different gradients or magnitudes. This case study illustrates the capability of InSAR to measure different magnitudes of motion, from millimetric to metric, with very high accuracy.