REMinE (Improve Resource Efficiency and Minimize Environmental Footprint) is an ERA-MIN project with three collaborating partners; Luleå University of Technology (LTU) in Sweden, University of Porto in Portugal, and the Research and Development National Institute for Metals and Radioactive Resources (INCDMRR) in Romania. The project vision is to “clean up” historical mine sites by extracting critical metals and separating minerals, thereby minimizing the amount of harmful mine waste. The Smaltjärnen tungsten ore tailings repository in Yxsjöberg is the case study site in Sweden, funded by VINNOVA. Historical tailings characterized by comparatively high metals and minerals content due to less efficient extraction methods and/or relatively low metal prices at the time. Repositories of such tailings pose environmental impact risks but could also become metals and minerals resources. For Work Package 3 (WP3) in which new processing methods for mine waste are to be identified, the aim is to develop methods for the separation of minerals and extraction of metals and metalloids, which will be useful in today’s industry.