3/20/2023 0 Comments The black masses mineConsequently, the current mining paradigm can be considered inherently unsustainable, and there is a recognized need for the development of new approaches for more sustainable exploitation of known but currently unviable metal deposits ( 18). Similar considerations also apply for many other commodities. Moreover, the economic viability of processing such diminishing grade material relies on a continual improvement in the efficiency of mining technologies and/or the economy of scale, i.e., the use of large infrastructure to deal with high throughput ( 17), using more energy, water, and land per unit mass of extracted Cu ( 5). Under these circumstances, conventional Cu mining becomes increasingly challenging because of the necessity to remove, process, and store large quantities of waste rock. For example, many Cu deposits currently deemed “Tier 1”, such as the Pebble East giant copper-gold deposit in Alaska (USA) ( 15) and the deeper ore zones at the Escondida porphyry Cu deposit in Chile ( 16), are buried by hundreds of meters of overburden. During the past decade, there has been a major decline in the discovery of shallow (e.g., <100 m cover depth) Cu ore deposits while the average ore cutoff grade has also decreased by ~25% ( 14). In recent years, Cu demand has burgeoned and has been predicted to increase by a further 275 to 350% by 2050 ( 13). Major tailings dam failures in the past decade include the 2019 Feijão dam disaster (Brazil Fe ore, 32 million to 80 million m 3 tailings released ≥237 deaths) ( 7), the 2015 Fundão dam disaster (Fe ore, 32 million to 60 million m 3 tailings released ≥19 deaths) ( 8, 9), the 2019 Cobriza dam failure (Peru Cu ore, 67,488 m 3 tailings released over 41,574 m 2) ( 10), and the 2018 Cadia dam failure (Australia Au-Cu ore, 1.3 million m 3 tailings released and contained by southern dam) ( 11).Ĭu currently plays a crucial role in our concurrent low-carbon energy transition it is also used in a wide range of products and materials across industry and society ( 12). The hauling and storage of vast quantities of geological material often result in human, ecological, and financial catastrophes, for example, the collapse of underground mines or tailings dams ( 6). Within this, copper (Cu) mining and refining were among the most intensive GHG emitters with approximately 6 × 10 10 kg of CO 2 released ( 4). It is estimated that in 2018, greenhouse gas (GHG) emissions associated with primary mineral and metal production amounted to 3.6 × 10 12 kg of CO 2 (excluding energy carriers, such as coal and uranium, and mineral aggregates), which was equivalent to ~10% of the total annual energy-related GHG emissions ( 5). Such metal recovery is also intrinsically energy intensive the mining industry is among the most important individual contributors to the climate emergency ( 4). Global estimates are of the order of 100 Gt per year ( 3), substantially larger than any other anthropogenic waste form and estimated to be several times more than the natural riverine transport of sediment to our oceans ( 4). The process results in the generation of inexorably large quantities of solid waste. The ore then invariably requires removal of gangue material, often representing >99 wt %. This requirement to haul ore to the surface dictates that large volumes of overburden must first be excavated, transported, and safely disposed. This remains true today such processes are responsible for more than 99 weight % (wt %) of all metals extracted from Earth each year ( 2). Throughout this time, one fundamental component has remained constant: Mining activities have almost exclusively occurred via physical excavation, i.e., the process of physically removing solid ore-bearing minerals from the subsurface. Mining technology has since undergone transformative change, both in terms of our ability to mine at scale and autonomously. Industrial-scale metal and metalloid (hereafter metal) mining can be traced back several thousand years and marked the beginning of the Bronze Age ( 1).
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