The technology sector has experience exponential growth in all areas over the last decade, heavily pushed by the transition to a low-carbon economy future. New technologies such as electric vehicles, solar and wind energy and batteries are driving the shift. The manufacturing of green technology requires requires critical metals including cobalt, tungsten, rare earth elements, indium, gallium and germanium. Traditionally, these metals were not considered to be part of the deposit commodity and consequently can accumulate in mine waste.
Environmental, social and governance (ESG) remains the top risk and opportunity for mining and metals companies in 2023 (EY, 2022). The opportunities of remining mine waste provides a longer-term, more strategic plan as part of mine closure and rehabilitation. The uptake of this concept can be seen by a growing shift in business models in many countries with at least 75 active mine waste reprocessing projects. However, these materials are mineralogically heterogeneous thus, a ‘one approach-fits all’ will not optimise value-recovery. While these wastes are surficially deposited and reduce mining costs, the increased surface area and exposure to the atmosphere make these facilities dynamic environments, so, the geochemical processes, as related to mineralogy, must be studied at each. Further, the concept of remining mine waste can help navigate the critical metal demand but it does not guarantee that the waste is environmentally de-risked. Appropriate characterisation and end use of the secondary mining waste must be considered.
In Australia there has been a growing body of research focused on secondary prospectivity of mine waste. In South Australia there are over 3,000 mine sites classified as abandoned, many of these managed by the government. The ongoing management of some of these sites is costly, but their potential new economy metal content presents a unique opportunity to rehabilitate these sites through reprocessing waste. In this research program, the critical metal fertility and reprocessing potential of mine waste at abandoned mine sites across South Australia is being researched.