Reimagining Australia's mine waste: New resources, new challenges

Meeting the needs of the energy transition is a once-in-a-generation challenge like no other before. To meet the projected metal demand to support things, the global community will produce increased volumes of mine waste requiring best practice management. Mine waste is suspected to be a host of critical metals and minerals (i.e., cobalt, indium, REEs, Ga and Ge have typically been by-products since concentrating in waste streams). If identified as significant resources of critical metals, remining waste can support Australia’s effort to adopt circular economy principles, a notable socio-economic driver.

Whilst this sounds relatively straightforward, practical investigations show this is anything but. From sampling to metal recovery, mine waste materials are complex and heterogenous originating, in some cases, from multiple ore sources, processed by different methods, and eventually subjected to weathering under changing climatic conditions. Therefore, multi-scale multidisciplinary characterisation is required to truly develop a valorisation process which not only recovers critical metals and minerals, but also substantially reduces any associated environmental legacy issues and mining footprints.    

In collaboration with the QLD, NT, NSW and SA State Governments and Geoscience Australia mine waste (i.e., tailings, slag, waste rock and metallurgical residues) at historical and operational mines across the country have been sampled (n= 50 of 77: 2019-2024). Highlights so far include potential for Co resources in QLDs NW Minerals Province with metallurgical studies now being conducted to recover Co from pyrite.  Indium, hosted in a range of sulfides, sulfosalts and cassiterite has been recognised in greisen and VHMS mine waste, whilst Sb (and REE) enrichment has been identified in the sampled NT. New investigations are underway to better understand SAs waste with desktop studies suggesting Ni, REEs and Mn fertility. 

 

Whilst these data will ultimately feed into the national Mine Waste Atlas being developed by Geoscience Australia, opportunities to manage the new waste streams are being explored. With new markets coming online seeking feedstocks which are more enviro-ethically sourced. However, the challenge remains, how to ensure policies are in place to support these activities, whilst ensuring that the right technologies to support valorisation are accessible. As global communities align to tackle these hurdles, mine waste transformation looks certain to be the business model of the future.