Mine Waste as a possible source of Strategic and Critical Raw Materials: Advancing the Knowledge for some Case Studies in Italy

Recent European policies are designed to stimulate the growth of domestic production of Strategic Raw Materials (SRMs) and Critical Raw Materials (CRMs). These regulations actively support the recovery of mining waste to obtain CRMs, along with their core objectives (1). Waste rocks and mining dumps could contain relevant quantities of valuable minerals that were overlooked in past industrial operations (2). Despite Italy having an important mining industry during the 1900s, today there are no active base metals mines. Primary production centres around industrial minerals and ornamental stones (3). As of 2022, there were more than 500 abandoned mine waste sites documented in the Italian National Storage Facilities registry (4). Nevertheless, the information reported on these databases is typically too vague for action definitions and more detailed information is needed from other sources (5). We are currently developing a multi-step approach for selected case studies to bridge the existing information gap. This approach merges publicly available information from governmental sources, scientific literature, and field information aiming at individuating and characterizing the tailings or mine waste bodies. Further site information is also implemented in a Geographical Information System (GIS) model using processed open-source satellite images or remote sensing data. This tool is used to preliminary plan on-field sampling and characterization campaigns in order to collect representative samples that will undergo lab-scale mineral processing tests for mineral recovery estimation. Collected information suggests that SRMs or CRMs could potentially be found within some of the waste volumes considered. Upon successful validation of this multi-step approach on a restricted set of cases, the methodology may be extended to a broader context encompassing several mine waste facilities in Italy. Enhanced knowledge of mining dump sites might improve strategies for CRMs recovery and environmental restoration.