The REMinE project aims to evaluate whether re-processing of historical mining waste is favorable from technical, economic and environmental perspectives. The mine sites included in the project are tailings from Sasca Romania (Cu, Ag, Au), Panasqueira in Portugal (W) and Yxsjöberg in Sweden (W, Cu and fluorite). Detailed geochemical characterization and risk assessment of the mine waste will be carried out to study whether re-processing and extraction or remediation of these sites is the best option. To extract metals and minerals from complexly oxidized and already processed ores requires site-specific and innovative extraction methods that have to be identified and developed. The decision to extract mine waste must be based on an integrated approach that includes environmental and economic considerations, technical feasibility as well as safety aspects and social acceptance. The residue remaining after extraction should be less harmful than before extraction. It is important to separate harmless minerals, thereby reducing the amount of harmful residue that must be stabilized and stored safely. Geochemical characterization and risk assessment therefore includes not only the mine waste, but also of the remains after the extraction. This is necessary to be able to take decisions if re-processing is to be implemented and is in line with the development of a sustainable mining industry. The methods developed, the way of thinking and the methodology will be suitable for ongoing mining operations as well.