recomine: Technologies and concepts for a holistic mine waste treatment made in Saxony

recomine is an alliance of predominantly regional partners from industry, science and society in the Erzgebirge (Saxony/Germany). The alliance is funded by the German Federal Ministry of Education and Research (BMBF) since 2018 with a total of €12.7 million and is coordinated by the Helmholtz Institute Freiberg for Resource Technology. With the vision of developing innovative and holistic solutions for mining waste, recomine supports R&D projects that address the intersection of environmental technology, resource technology, Industry 4.0 and social issues. The aim is to bring regional know-how at real development sites together. The Davidschacht tailing in Freiberg is such a site that allows testing new solutions under real conditions. The necessity of innovative technologies is illustrated the new Global Industry Standard on Tailings Management published in 2020 by the International Council on Mining & Metals (ICMM). It was developed in response to recent devastating tailings accidents (e.g. Brumadinho/Brazil in 2019) and is based on the "Zero Harm" principle. Numerous activities of large mining companies (e.g. BPH, Vale, Rio Tinto) started to promote the development of new approaches as a consequence of the new standard. In 2021, for example, the BHP Tailings Challenge called the global raw material community to submit concepts for the recycling and reduction of mining waste from a large copper mine. recomine succeeded in being among the ten selected from over 150 teams. These teams had to proof their submitted recycling concept in a first phase of the challenge. This success is now being continued, e.g. in a project for Amira, a global not-for-profit organization representing members from the resources industry, which is currently being prepared. Direct R&D agreements with mining companies are also under negotiation. recomine's long-term goal is to act as a bridge between regional know-how providers and the global mining industry. The developed technologies can be divided into four groups: analysis, avoidance, remining and transformation. While new technologies for the characterization of tailings or mine water play a role in the area of analysis, the area of avoidance deals with technologies to minimize fine-grained tailings in primary ore processing (e.g. machine-learning optimized sensor-based sorting). In remining, processing technologies are developed to recover the remaining metals, even from the previously undevelopable grain size ranges, e.g. by further development of pneumatic flotation. The Transformation then deals with the use of mining waste, e.g. in the building materials sector, and also provides new approaches to renaturation.