## 1 Introduction  
In the energy transition time, there is an effort towards a society less dependent on oil and gas. The energy transition requires critical metals to sustain a low-CO\({}_{2}\) economic and social development. Electric mobility, for example, requires cobalt, copper, nickel, and silver, key ingredients in batteries that power e-vehicles [1]. In fact, many strategic metals are now termed critical raw material (CRM), listed in a catalog regularly updated by the European Commission [2]. The CRM supply can derive from primary and secondary sources such as extraction mining wastes (stockpiles and tailings) stored at mine sites. Hence, the recovery of CRM from mining wastes has gained attention because (1) mining and quarrying waste represents about a quarter of the total waste production in Europe [3]; (2) hundreds to thousands of abandoned mine sites occur in many countries, creating a European-scale concern [4]; (3) mining and quarrying waste is an economic cost; and (4) they contain hazardous substances prone to polluting the environment. The recovery of secondary raw materials has the additional benefit of adding value to mining residues and reducing their environmental risks [5]. The old mining wastes could represent a significant raw material source considering the deficiency of the old extraction and processing methods. Therefore, prospecting new raw material resources nearby abandoned mines can be prompted for reuse or removal of remained CRM. The main bottleneck towards the recovery of secondary raw materials is the lack of knowledge on the available resources [5]. There are few case studies with the available database for prefeasibility studies of resources. The preliminary information needed is chemical and mineralogical composition, as well as volume of mining wastes deposits [6]. The national registries mainly provide basic information about mining sites location and the main materials extracted [4]. However, for the preliminary characterization of mining waste, there is the need of on-site geological and geophysical surveys, sampling, material preparation for laboratory analyses, and the acquisition of quality compositional and mineralogical data. Obtaining this information is time-consuming and expensive, especially for large storage facilities. Up until now, the main attention on mining wastes deals with environmental issues [7; 8], acid mine drainage [9], and stability monitoring [10]. Recently, the recovery of metals and precious elements have become a new aspect to study the mining wastes [11; 12; 13]. In all mentioned studies, the main challenges are sampling and data collection from mining wastes. A possibility of overcoming these issues could be through the use of earth observation (EO) data, as already performed in some cases [14; 15]. Hence, remote sensing (RS) methods have a high potential to explore mineral deposits and mining residues, with continuity of data in space and time. The European Union's Copernicus [16] EO program is an efficient free data source for mineral mapping, environmental monitoring, urban area management, regional and local planning, etc. RS approaches benefit from the high amount of data and high-tech facilities with minimum ground disturbances. In mining applications, RS techniques can be used for volume evaluations and to detect and classify different mineral formations and alterations on the surface [17]. On the basis of the objective, different RS methods can be used to detect and map ground features, such as band ratio analysis, principal component analysis, spectral angle mapper, spectral unmixing, etc. Sentinel-2 images are part of the Copernicus program and are widely used in mining applications and mining waste studies [18]. Sentinel-2 images are chosen since they are freely accessible, with spatial resolution (10 m) and 5-day global revisit periodicity appropriate for mining wastes. In this research, the exploitation of EO data was highlighted to map elements of potential interest in the Vigonzano mining wastes.