Surface deformation monitoring of the Baiyinhua open-pit mine based on time-series InSAR

Using 36 Sentinel-1 images acquired over the Baiyinhua open-pit mine in Inner Mongolia, China, from January 2022 to November 2024, surface deformation rates and time-series cumulative deformation were derived by means of the Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) technique. The reliability of the monitoring results was validated based on internal accuracy, and the spatiotemporal evolution of deformation was analyzed. The results show that surface deformation in the Baiyinhua open-pit mine is dominated by subsidence. The total deformation area is approximately 85.06 km², of which the subsidence area is about 76.18 km² and the uplift area is about 8.88 km², accounting for 89.55% and 10.45%, respectively. Uplift is mainly concentrated in the western parts of the No. 1 and No. 2 open-pit mining areas, while the remaining areas are largely characterized by subsidence. The most severe subsidence is observed in the No. 3 open-pit mining area, with a maximum subsidence rate of 116 mm/a and a maximum cumulative subsidence of 334 mm. An analysis of deformation trends at ten feature points reveals that localized deformation will continue to worsen and likely spread further, and the affected area will take a long time to approach relative stability.