Mining spectral signatures for mineral resource exploration. Results from the EU S34I Project.

The combination of mineralogical, geochemical, and spectroscopy data in the visible, near-infrared, and shortwave infrared (VNIR-SWIR) wavelength ranges provides the determination of mining spectral signatures. These signatures enable the identification and classification of geological materials present in a specific mineral deposit. Beyond their use in remote sensing studies focused on the studied area, mining spectral signatures have broader applications in exploration and extraction processes. They provide a rapid, cost-effective way to classify samples according to ore content, without the need for reagents or harmful chemicals.

 

This paper presents the methodology and the results of the determination and validation of the mining spectral signatures during a pilot study conducted in the Aramo Plateau (northern of the Iberian Peninsula), included in the S34I project (Secure and Sustainable Supply of Raw Materials for EU Industry). Mineralization of Co, Cu, and Ni in this area have been known since the last century, associated with the alteration of carbonates due to fluid circulation linked to tectonic activity in the region.

 

Through the analysis of 133 samples, 11 mineralogical associations were identified. Of these, 9 (7 corresponding to rocks and 2 to soils) were distinguishable from one another using VNIR-SWIR spectroscopy, so each association was assigned a characteristic spectral signature. Three of these groups were related to the higher Co content. These spectral signatures were subsequently validated through X-ray diffraction analysis of the samples. The validated spectral signatures enabled the fast mineralogical characterization of 550 samples and their classification according to their Co, Cu and Ni content.

 

 The methodology developed here is easily transferable to other mineral resource exploration studies.