## 6 Conclusions  
Mining wastes are strategically important because of the high demand for the new raw materials resources. The characterization and variability maps of compositions for the major and trace elements are the main targets to evaluate the presence of any precious element. However, the artificial spatial variability of mining wastes, which is different from natural spatial variability of deposits, make the characterization complicated and challenging.  
The surface geochemistry of the Vigonzano mining area was coupled with Sentinel-2 image from Copernicus data to study the major element detections. Band ratios related to iron oxides and ferrous iron oxides were used to find a meaningful correlation with the element's concentrations. On the basis of the high correlation coefficients between band ratios and some of the major and trace elements (Fe\({}_{2}\)O\({}_{3}\), Cu, Co, Cr, Ce, La, Rb, and Nb), we obtained composition maps using Co-Kriging method. Results show important concentration within the mining wastes for Fe\({}_{2}\)O\({}_{3}\), Cu, Co, and Cr and depletion for Ce, La, Rb, and Nb compared to the surrounding agricultural soils. The grade estimation for interesting metals such as Co, Cr, and Cu resulted in similar values to worldwide low-grade ore deposits.  
The results confirmed the essential advantage of combining remote sensing and in-situ samples in mapping the major and trace elements. This low-cost approach based on publicly available EO data is an interesting tool for decision makers to assess critical raw material resources and to design projects to remove heavy metal contaminants from abandoned mine sites.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app12041928/s1](https://www.mdpi.com/article/10.3390/app12041928/s1)]([https://www.mdpi.com/article/10.3390/app12041928/s1](https://www.mdpi.com/article/10.3390/app12041928/s1)), Figure S1. Chemical (major elements) stratigraphy of profile P1. Figure S2. Co-Cr-Cu stratigraphy of profile P1. Figure S3. Chemical (major elements) stratigraphy of profile P2. Figure S4. Co-Cr-Cu stratigraphy of profile P2. Tables S1-S4: Major (wt %) and trace element (ppm) bulk composition of samples. All calculations were conducted using ISATIS software, license of Bologna University.  
**Author Contributions:** Conceptualization, S.K. and R.B.; methodology, S.K. and E.D.; software, S.K.; validation, S.K. and R.B.; formal analysis, S.K. and R.B.; investigation, S.K. and R.B.; resources, R.B.; data curation, E.D.; writing--original draft preparation, S.K. and R.B.; writing--review and editing, S.K., R.B. and E.D.; visualization, S.K. and R.B.; supervision, R.B.; project administration, R.B.; funding acquisition, R.B. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by EIT Raw Materials, project no. 18259, \"BioLeach: Innovative Bio-treatment of RM.\" and by by the RawMatCop Programme (2018-2021), funded by the European Commission and EIT RawMaterials, grant agreement number \"271/G/Gro/COPE/\".  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Not applicable.  
**Acknowledgments:** We would like to thank the Associate Editors Gianluca Bianchini and Claudio Natali and four anonymous reviewers for helpful comments that improved the manuscript.  
**Conflicts of Interest:** The authors declare no conflict of interest.