Critical and Strategic Raw Materials European Union’s policies are targeting the production of fundamental raw materials from internal sources, fostering the recovery of relevant quantities of materials from the existing mining facilities in Europe. Northwest Italy was an important mining area until the mid-1900s, as reported by the Italian inventory of closed mining waste storage facilities, referring to 92 mining waste facilities. Three sites were chosen to better define their historical and bibliographical framework. The selected sites comprise the Traversella Mine (Piedmont), Libiola Mine (Liguria) and Herin Mine (Aosta Valley). Currently, there are relevant amounts of abandoned mining waste in the surrounding areas of these closed mines. The potential recovery of the residual valuable fraction of these materials could be crucial for both critical raw materials’ recovery and environmental valorization of the involved territories.

Every mining operation is followed by a beneficiation process aimed at delivering quality materials to the transformation industry. Mainly, in order to separate valuable minerals from gangue in mineral processing, the crushing and grinding of extracted ore are crucial operations for the following separation steps. Comminution is the most energy-consuming operation in mining, and the quality of the results is strictly related to the characteristic of the material under treatment, the type of equipment used in comminution, and the circuit design adopted. A preliminary study was performed in order to understand the crushing behavior under different comminution forces of a high-grade mixed Zn-Pb sulfide ore sample, collected in a Mississippi-Valley Type (MVT) deposit, and the distribution of the target minerals among the products of the process. Ore samples were examined and characterized through thin section observation and SEM analyses for the determination of grain size and texture features, while X-ray powder diffraction (XRPD) quantitative analyses were performed for the definition of target mineral concentrations of comminuted product samples. The selected crushing and grinding circuit comprised lab-scale equipment. For each stage of the process, products below the estimated free-grain size threshold were collected, and particle size analyses were carried out. Comminution products were divided into size distribution classes suitable for further separation operations, and XRPD analyses showed a mineral-grade distribution varying with the dimensions of the products. Characterization of the ore material after crushing and grinding force applications in terms of the distribution of target minerals among different-sized classes was achieved. The important trends highlighted should be considered for further investigation related to an efficient separation.

The growing demand for green and, therefore, sustainable technologies present new challenges for our society. The European Union (EU) identified the critical raw materials (CRMs) and strategic raw materials (SRMs) necessary for these technologies and introduced policies to reduce reliance on external suppliers, which includes investigating the recovery of CRMs from extractive waste. This study assesses the recovery potential of mine waste collected in the Traversella mine district (Piedmont, Italy), known for its polymetallic Fe-Cu-W deposit. The characterization of waste rock samples involved chemical and mineralogical analyses, revealing metallic-bearing minerals such as magnetite and scheelite. Laboratory-scale magnetic and gravity separation tests were carried out and compared. Magnetic separation resulted in a recovery of 75.4% of Fe, 72.3% of Cu, and 83.7% of W, with a weak concentration. Instead, gravity separation produced high-grade Fe (67.6%) and W (1289 ppm) concentrate with lower recovery rates.

Every mining operations is followed by a beneficiation process aimed to deliver quality material to the transformation industry. Mainly, in mineral processing comminution and grinding of extracted ore, are crucial operations for the following separation steps in order to obtain valuable minerals from gangue.Comminution is the most energy consuming phase and the quality of the results is strictly related to the characteristic of the material under treatment.A preliminary study has been performed in order to understand the crushing behaviour of a mixed sulphide ore, containing galena and sphalerite, and the distribution of the two target minerals among the different sized products of the process.Ore samples have been examined and characterized by means of thin sections observation and SEM analyses for the determination of the free grain size, while XRD quantitative analyses have been performed for the definition of the grades.The selected crushing circuit comprises lab-scale impact crusher, jaw crusher, disk mill and rod mill. For each stage of the process products below the free grain size threshold have been collected and particle size analyses have been carried out.Comminution products were divided in dimensional classes suitable for flotation separation, ranging between 0.250 and 0.075mm and XRD analyses showed a variable mineral grade distribution varying with the reduction in dimension of the products.This important trend should be considered for further investigation related to an efficient froth flotation separation.

The growing demand for Critical and Strategic Raw Materials (CRMs, SRMs) and the limited availability of primary resources in Europe have renewed regulatory and scientific interest in mine waste and tailings as secondary raw material sources (European Critical Raw Materials Act 2023; Hool et al. 2024). Accordingly, efficient and environmentally sustainable extraction technologies are necessary to minimize both environmental impact and processing costs (Whitworth et al. 2022). Among emerging solutions to conventional acidic leaching, glycine has been attracting attention as a non-toxic and biodegradable amino acid capable of forming stable complexes with calcophile elements under alkaline conditions and low temperatures, enabling low-cost, possible industrial applications for recovering precious and critical metals from mine waste and tailings (O’Connor et al. 2018; Barragán-Mantilla et al. 2024; Eksteen et al. 2018). This study investigated the application of glycine leaching as a green chemical approach for the recovery of copper from fine-grained historical tailings samples from the Fenice–Capanne mine, Tuscany, Italy.Historical tailings samples were preliminarily characterised in terms of granulometry, geochemical and mineralogical composition using multiple methodologies, such as ICP-MS, HH-XRF, SEM-EDS and SEM-MLA for the definition of metal grades and the identification of metal-bearing minerals. Batch leaching tests were conducted using a glycine solution under controlled conditions, including alkaline pH, a constant liquid-to-solid ratio, and progressively increasing leaching times. The performance of glycine as a lixiviant was evaluated in terms of metal extraction efficiency and selectivity using HH-XRF on solid residues and ICP-OES on leaching liquors. Particular focus was addressed on Cu and associated Zn extraction. As a term of comparison, the same samples were leached using sulphuric acid leaching.Preliminary results indicated that glycine leaching enabled the selective extraction of Cu and minor Zn while limiting the dissolution of Fe, and competitive recovery rates when compared to traditional sulphuric acid leaching. It highlighted its potential as an environmentally friendly leaching agent. The outcomes of this study could contribute to the assessment of sustainable options for the recovery of CRMs and SRMs from mine tailings within a sustainable and circular economy approach.