How Imaging Spectroscopy is Tracking Mine Residue in Italy

A 2026 study published in the journal Remote Sensing tested Germany’s EnMAP hyperspectral satellite to see if it could identify and map acid mine drainage (AMD) and associated mineral residues from a legacy sulfide mine in Sardinia, Italy.¹ This study, which was led by Susanna Grita, a researcher at the University of Rome La Sapienza and the Polytechnic University of Turin, collaborated with other researchers from the Polytechnic University of Turin, University of Cagliari, and the GFZ German Research Centre for Geosciences, demonstrated how imaging spectroscopy can locate AMD sources in vegetation-covered mining environments. The remote-sensing workflow outlined here could help regulators and remediation teams monitor thousands of abandoned European mines more efficiently.¹

Sardinia, Italy, is located off the mainland, and it has an extensive mining history. Because the island has numerous mineral deposits of zinc, silver, copper, and lead deposits, mines and quarries emerged starting in the pre-Roman era.² Although these mines are no longer in operation, they are still standing, becoming a defining feature of the island’s landscape.² Some of these mines have also become the focus for tourism and research. Some of the most popular mines in Sardinia are in Argentiera, Montevecchio, and Ingurtosu.³

In their study, the researchers investigated the Montevecchio lead–zinc mining district. Many of the mines here have been restored, and many containing tailings that contaminate land and waterways and pose risks to human health.^1,3 By integrating laboratory reflectance spectroscopy with EnMAP satellite imagery, the team mapped mineralogical indicators of AMD and tracked the downstream dispersion of contaminated sediments along the Rio Irvi river system.¹

Small mine sites are difficult to survey on the ground. The methodology used in the study helped identify and delineate pollution from these sites.¹ Hyperspectral satellites such as EnMAP measure reflected light across hundreds of wavelengths, allowing specific minerals to be recognized from space.¹ Although hyperspectral methods have been applied to large or sparsely vegetated mines previously, it was unclear whether these methods would be effective when analyzing sites that were significantly smaller.¹

Of the 85 field samples collected from mine dumps, tailing impoundments, and river sediments, 31 samples underwent mineralogical characterization by powder X-ray diffraction (XRD), while all samples were analyzed in the laboratory with a VNIR–SWIR spectroradiometer.¹ Then, the researchers used a polynomial spectral-fitting technique to EnMAP imagery (30-m spatial resolution) to map the distribution of diagnostic minerals across the landscape.¹

This method allowed for the detection of jarosite and compositional variations in iron hydroxides, which are key indicators of AMD conditions. Spatial patterns derived from EnMAP corresponded with field observations and laboratory analyses, confirming that Fe- and Zn-bearing sulfates and oxyhydroxides extend from tailings piles into downstream sediments along the Rio Irvi.¹

What are the implications for environmental monitoring and remediation?

This study demonstrates that EnMAP data can provide preliminary mineralogical maps and pollution indicators without extensive field campaigns. Even with 30-m pixels, the approach identified AMD sources and dispersion pathways in a complex, vegetated terrain.¹

The authors note that satellite resolution limits detection of targets smaller than roughly 15–20 m, and vegetation cover can obscure mineral signatures. They mitigated these issues by integrating field sampling and laboratory spectra to calibrate the satellite analysis.¹ The resulting maps can guide targeted ground surveys, prioritize remediation sites, and monitor contaminant spread over time.

What are the key takeaways from this study?

The study establishes a baseline spectral framework for AMD minerals in carbonate-buffered Pb–Zn mine environments. As a result, the researchers concluded that EnMAP can resolve subtle mineralogical differences linked to pH and water chemistry.¹ For remote-sensing and geoscience practitioners, this confirms that medium-resolution hyperspectral satellites can support environmental assessment of small legacy mines.¹

“This study has broader implications for mapping and monitoring mining activities across Europe, where many current and historic mining operations are of similar small to medium scale, contributing to better management and remediation of mining-impacted landscapes throughout the continent,” the researchers wrote in their study.¹

The authors added that future studies will look at constructing a spectral library to improve metal sulfate identification.¹

References

1. Grita, S.; Sedda, L.; Casu, M. et al. Tracking the Environmental Impact of Mine Residues and Tailings in Sardinia (Italy) Using Imaging Spectroscopy. Remote Sens. 2026, 18 (3), 499. DOI: 10.3390/rs18030499
2. Archaeology Travel, Industrial Heritage & Mining in Sardinia. Archaeology Travel. Available at: https://archaeology-travel.com/destinations/europe/italy/sardinia/industrial-heritage/ (accessed 2026-02-16).
3. Tavani, C. 9 Sardinian Mines Truly Worth Visiting. Strictly Sardinia. Available at: https://strictlysardinia.com/sardinian-mines/ (accessed 2026-02-16).