Por: J. Ramírez Castañeda, Inersia Monitoring Perú, y P. Fornes, Inersia SAR Monitoring. 

Abstrac

Problem. Geotechnical risk management for critical mining infrastructure, tailings dams, and slopes in general requires monitoring systems capable of detecting instability precursors with continuous spatial coverage and sufficient operational lead time. Conventional methods (inclinometers, piezometers, extensometers, and GNSS) provide only point-based coverage, involve high field maintenance costs, and are subject to access limitations in steep terrain. The failures at Brumadinho (Brazil, 2019; 270 fatalities), Samarco (Brazil, 2015; 19 fatalities), and Mount Polley (Canada, 2014) highlight the catastrophic consequences of deficiencies in early warning systems.

Objective. To evaluate the operational complementarity of Satellite Radar Interferometry (InSAR–PSI) and the Normalized Difference Water Index (NDWI) as an integrated early warning system for detecting surface deformation and hydrological variations at the Mina Portugal Mining Unit, with an operational predictive capability of 12 to 18 days, for application in the mining industry.

Methodology. SAR images acquired by Sentinel-1 satellite (ESA) were processed using the Persistent Scatterer Interferometry (PSI) technique, with a resolution of 3 × 15 m, for two historical periods: March 2015-January 2020 and January 2022-July 2025. Additionally, the NDWI was applied to Sentinel-2 imagery (10 m resolution) for five representative dates. The layers were integrated within a georeferenced 3D environment by correlating saturation patterns with InSAR acceleration fronts.

Main Results. At the BEABAC-Jazigo Moinho dam, cumulative displacements of up to 8.4 cm (2022-2025) and 8.8 cm (2015-2020) were recorded, concentrated in the northwestern sector. At the Barragem de Agua Industrial (BAI), the maximum cumulative displacements reached 8.9 cm (2022-2025) and 5.3 cm (2015-2020). The NDWI-InSAR correlation established that increases in the moisture index of ≥15-20% in areas with NDWI > 0.3 consistently preceded InSAR acceleration events by 12 to 18 days.

Conclusion. The InSAR-NDWI integration constitutes a continuous, non-invasive satellite-based geotechnical monitoring protocol with broad spatial coverage, capable of reducing response times to instability precursors. Its adoption as a complement to Supreme Decree No. 034-2023-EM in Peru represents a high-value tool for the proactive management of risk in critical infrastructure and constitutes an original methodological advancement with no documented precedent in the Peruvian or global mining industry.