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Comprehensive Monitoring of Tailings Dams : Navigating the Limitations and Blind Spots of Interferometric Synthetic Aperture Radar (InSAR) Technology

Tailings and Mine Waste Conference (2023 : Vancouver, B.C.); University of British Columbia. Norman B. Keevil Institute of Mining Engineering

Interferometric Synthetic Aperture Radar (InSAR) is a remote sensing technology used to identify deformations of the earth over large areas. The use of this technology has become widespread in recent years to obtain information about structural performance and to help identify large-scale movements of tailings dams and other mine structures. Dam owners and consultants have started to specify Trigger Action Response Plan (TARP) thresholds based on deformations detected by InSAR. However, more recent scrutiny of InSAR technology has exposed some “blind spots” or limitations of the technology. These limitations must be understood by all who rely on InSAR technology as part of their performance monitoring programs. In addition, TARP thresholds may not be relevant to InSAR monitoring technology in the same way that they are applied to more conventional geotechnical instrumentation (e.g., piezometers, slope inclinometers). The slope aspect is a critical aspect of InSAR interpretation. InSAR deformation data is typically provided for both the vertical and east-west displacement directions. Measuring east-west deformations on a slope with a north or south facing slope aspect results in a low sensitivity to deformations. However, InSAR pixels are still used to represent movements on these slopes and can provide users with a misrepresentation of potential deformation on these slopes. Caution should be applied when setting TARP thresholds, as the TARP thresholds will depend on the interaction between the slope angle and the imaging direction. It is important that InSAR analysis is supported by ground-based deformation monitoring systems, including visual inspection and instrumentation readings. InSAR data can be used as an indicator of structural performance but should never be relied upon in isolation of other data sources. The data processing algorithms may need to be adjusted and validated multiple times before a good match is made with ground-based monitoring systems. An iterative, site-specific approach to InSAR data analysis must be utilized to assess the accuracy and value of InSAR data as part of a comprehensive monitoring program designed to effectively facilitate informed risk management decisions.

Text

2023-12-08

Attribution-NoDerivatives 4.0 International

http://hdl.handle.net/2429/86845

Unreviewed

http://creativecommons.org/licenses/by-nd/4.0/