In situ recovery of gold: Column leaching experiments and reactive transport modeling

The Mineral Question: How Energy and Technology Will Determine the Future of Mining

“…Hence, the limits to mining derive mainly from the limits to the amounts of energy which we may assume to be available in the future. Seen in this light, the problem of depletion will become serious much before actually "running out" of any mineral, as already noted in early depletion studies (Jevons, 1866;Meadows et al, 1972).…”

“…In other cases, a solid mineral can be separated by the matrix by "in situ" solubilization processes, e.g., by means of acid leaching. It is a method of mining used, for instance, for uranium (Eligwe et al, 1982) and gold (Martens et al, 2012). Generally speaking, the energy cost of all these operations is expected to be proportional to the volume that needs to be processed and, therefore, it is inversely proportional to the grade of the resource.…”

“…In modern times, quantitative models based on the same concepts were proposed, for instance, by Jay Forrester and by the group of researchers who performed the 1972 study titled "The Limits to Growth" (Forrester, 1971;Meadows et al, 1972). These models did not take into account energy as a disaggregated parameter; rather, energy was embedded into the more general "non-renewable resources" stock, assumed to be finite.…”

“…Over the years, two poles of thought have developed. One emphasizes the limited amount of the available mineral resources and proposes that depletion will lead to a reduction of the supply in times short enough to be object of concern today (see e.g., Jevons, 1866;Meadows et al, 1972;Bardi and Pagani, 2007;Bardi, 2011;Mason et al, 2011). The other emphasizes technology and human ingenuity, arguing that depletion is not a fundamental problem, at least for the foreseeable future (see e.g., Zimmermann, 1933;Lambert, 2001;Bradley, 2004Bradley, , 2007.…”

Numerical modelling of column experiments to investigate in-situ bioleaching as an alternative mining technology

“…Leaching is commonly applied on the surface in tanks or heaps [Sullivan, 1931;Riekkola-Vanhanen, 2013;Wang, 2005], but is more interestingly applied in-situ when geological settings are favourable. Even if uranium remains the most common commodity mined by insitu recovery, this technique has recently received a growing interest for a wide range of other metals, e.g., gold [Martens et al, 2012], and could bring a similar technological breakthrough as it triggered for uranium in the beginning of the twenty-first century [Seredkin et al, 2016]. In addition to its potential for reducing Capital Expenditures (CapEx) for infrastructure and mine development, in-situ recovery represents a formidable avenue for reducing environmental impact and needs for remediation.…”