Slope stability study in open pit and underground mines by means of forensic analysis and radar interferometry

摘要

This paper demonstrates the capabilities of satellite radar technology to generate complete ground deformation maps of an open pit mine, to follow and detect movement intensities ranging from millimetric to metric scales. Several vulnerable parts of the mine have been studied and monitoring of these very small to very large instabilities has provided valuable information for risk and exploitation management at the mine. A forensic analysis has been also performed and validated with these interferometric radar measurements.Images from the X-band high resolution images of TerraSAR-X satellite have been acquired between 2008 and 2012 to monitor ground displacement evolution. Two types of ground markers, natural reflectors providing backscattering of the terrain and trihedral artificial reflectors installed on certain areas of the mine have been used. Measurement quality depends on the temporal changes, and several radar Interferometric techniques, including persistent scatterer interferometry (PSI) and Altamira Information developments (stable point network and non-coherent technique) have been used to detect displacement intensities. Phenomena caused by mine activities have been detected, showing a perfect temporal correlation with the mine evolution. The project has also been very useful for the control and analysis of a strong slope instability affecting the open pit, where displacements have been more than 10 m in some months.