Mine waste, which includes tailings, waste rock, slags, and acid mine drainage, is a resource that is mainly underutilized but is becoming more and more recognized for its substantial potential for producing sustainable energy. Interest in turning these wastes from environmental liabilities into viable energy resources has increased because of the global energy transition and the increased focus on the concepts of the circular economy. New prospects include growing bioenergy crops like willows on amended tailings to increase soil fertility while producing biomass and improving carbon sequestration, recovering rare earth and other essential minerals from mine residues to support the production of clean energy technologies, and using flooded mine workings as low-enthalpy geothermal reservoirs for district heating and cooling. However, a number of obstacles prevent these opportunities from being realized. Low agricultural yield and soil toxicity in bioenergy applications are examples of technical obstacles, as are maintenance costs, hydraulic unpredictability, and mineral scaling in geothermal systems. Economic and environmental obstacles, especially the high-energy requirements for secondary mineral recovery and the possibility of harmful byproducts or secondary pollution, further complicate feasibility. Widespread adoption is also hampered by socioeconomic and legislative constraints, such as inadequate regulatory frameworks, a lack of financial incentives, and community opposition. Notwithstanding these obstacles, mine waste offers a variety of opportunities to concurrently support resource security, environmental restoration, and the production of renewable energy. Cross-disciplinary innovation in engineering, biotechnology, and policy, in addition to pilot-scale demonstrations and robust governance systems, is necessary to realize this potential. Mine waste can be converted from an environmental hazard to a low-carbon, sustainable asset with integrated approaches.
