GRSG Conference 2022: Orbit to Outcrop
Title: Integration of satellite SAR with multispectral data for mining risk mitigation
Author: Jennifer Scoular
The process of mining, surface or subsurface excavations are liable to induce ground movements. Unanticipated movements may lead to endangerment of personnel, destruction of equipment, environmental impacts and halt in production. As well as the mine pit, Tailings Storage Facilities (TSF) also pose a number of geotechnical risks. Some of these risks include: sinkholes on the crest of the dam, bulging of the toe due to exerted pressure on the TSF wall, seepage, overtopping, foundational failure and structural inadequacies.
By using a combination of satellite Synthetic Aperture Radar (SAR) and multispectral data, many of these geotechnical risks at mine sites can be successfully monitored and therefore reducing the risks by identifying potential failure precursors.
Interferometric Synthetic Aperture Radar (InSAR) displacements of the mine pit and TSF walls is used to monitor slope instabilities and alert on areas that exceed displacement threshold set in conjunction with the mine site team and to identify areas of acceleration. Coherence, which is a measure of the local spatial correlation between two SAR acquisitions, is used to track areas of surface change and potential areas of fast displacements.
SAR amplitude data combined with the multi spectral data are used to assess the distance of tailings water accumulation from the TSF dam, which serves as an indicator of potential overtopping or seepage. Additionally, high resolution orthoimagery can also be integrated, acquired from either from drones or satellites, to provide regularly updated site context to aid interpretation of results.
These multiple sources of earth observation data are checked against thresholds based on engineering criteria, mine site experience and historical baselines of displacement. The outcomes are then combined into a simplified risk report. The report is then shared with mining staff who can take the appropriate actions and report back to SkyGeo with site information.