83 ambient temperatures often require long cycle times. The recovery from conventional heap leaching is also relatively lower than the concentrator circuit due to the larger particle sizes, as the ore being leached is not subjected to the grinding circuit. Innovations with the potential to transform leaching include the following: • Use of oxidants to accelerate the reaction kinetics and temperature which can help overcome the chalcopyrite passivation layer. • Novel use of lixiviants and reagents that acts as solvent and oxidizing agents, facilitating leaching through enhanced dissolution. • Use of catalysts to break through the chalcopyrite passivation layer. • Biological approaches involve the use of microorganisms and bacteria, which are often naturally occurring and can aid the leaching process. Microorganisms can be utilized to trigger the ferric leach process for example. • Hybrid approaches that combine disciplines, including physical and electrokinetic with chemical approaches. • Heap design and operational considerations also influence recovery and cycle time, such as increasing temperature by the addition of heat, and heap leaching system monitoring and optimization. If heap leaching can be transformed to achieve performance similar to the concentrator plants, in terms of cycle time and recoveries, it can provide a significant benefit of reducing water use, waste, and eliminating tailings. Trend Spotlight: Innovations in copper leaching are entering a transformational phase in achieving industrial scale, backed by mining giants such as BHP, Rio Tinto, FreeportMcMoRan, and Vale Base Metals. This is in the context of record prices for copper, more than $13,000 per tonne, spurring interest in R&D to recover metal, including from waste material. Freeport has indicated that two-thirds of its growth in copper production by 2030 could come from the application of new leaching technologies (Hodgson, 2026). 2.5 Recovery through In-Situ Extraction Recovery of minerals through in-situ extraction will not result in waste and mine tailings that conventional mining and processing produce. In-situ extraction is a method of extracting valuable minerals directly from ore deposits without the need for conventional mining. The key process steps for in-situ might include the following: • Drilling of wells into the ore body, which serves as pathways for the injection of the leaching solution into the mineral deposit. • Once the wells are in place, the leaching solution is pumped through the injection wells into the ore body, where it permeates through the rock and dissolves the target minerals. As the solution moves through the ore, it becomes enriched with the dissolved minerals. • This solution is then pumped back to the surface through recovery wells. At the surface, the mineral-laden solution undergoes processing to separate and recover the valuable
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