Gavin M. Mudd

Unresolved Complexity in Assessments of Mineral Resource Depletion and Availability

Considerations of mineral resource availability and depletion form part of a diverse array of sustainable development-oriented studies, across domains such as resource criticality, life cycle assessment and material flow analysis. Given the multidisciplinary nature of these studies, it is important that a common understanding of the complexity and nuances of mineral supply chains be developed. In this paper, we provide a brief overview of these assessment approaches and expand on several areas that are conceptually difficult to account for in these studies. These include the dynamic nature of relationships between reserves, resources, cut-off grades and ore grades; the ability to account for local economic, social and environmental factors when performing global assessments; and the role that technology improvements play in increasing the availability of economically extractable mineral resources. Advancing knowledge in these areas may further enhance the sophistication and interpretation of studies that assess mineral resource depletion or availability.

Global Resource Assessments of Primary Metals: An Optimistic Reality Check

The mining of primary metals is critical for a range of modern infrastructure and goods and the continuing growth in global population and consumption means that these primary metals are expected to remain in high demand. However, metallic deposits are, in essence, finite and non-renewable—leading to some concern that we may run out of a given metal in the future. Here, we address this concern by presenting a brief review of the reporting of mineral resource estimates, compiling detailed datasets for national and global trends in mineral resources for numerous metals, and present detailed case studies of major mining projects or fields. The evidence clearly shows strong growth in known mineral resources and cumulative production over time rather than any evidence of gradual resource depletion. In addition, the key factors that already govern existing mining projects and mineral resources are certainly social, environmental and economic in nature rather than geological or related to physical resource depletion. Overall, there is great room for optimism in terms of humankind’s ability to supply future generations with the metals they will require.

Global platinum group element resources, reserves and mining – A critical assessment

The platinum group elements (PGEs) are used in many technologies and products in modern society, especially auto-catalysts, chemical process catalysts and specialty alloys, yet supply is dominated by South Africa. This leads PGEs to be assessed as critical metals, signalling concern about the likelihood and consequences of social, environmental and economic impacts from disruptions to supply. In order to better understand the global PGE situation, this paper presents a comprehensive global assessment of PGE reserves and resources and the key mining trends which can affect supply. The data shows that global PGE resources have increased from 90,733t PGEs in 2010 to 105,682t PGEs in 2015, a 16.4% increase - despite global production of 2243t PGEs over this period. This suggests that the key issues facing the PGE sector are not geological or resource depletion, but clearly social, economic and environmental in nature - as highlighted by recent social issues in South Africa and volatile global economic conditions. Concerns over PGE supply reliability and the implications of any supply disruption will therefore continue to see the PGEs labelled as critical metals - but certainly not due to resource depletion.

Looking Down Under for a Circular Economy of Indium

Indium is a specialty metal crucial for modern technology, yet it is potentially critical due to its byproduct status in mining. Measures to reduce its criticality typically focus on improving its recycling efficiency at end-of-life. This study quantifies primary and secondary indium resources (stocks) for Australia through a dynamic material-flow analysis. It is based on detailed assessments of indium mineral resources hosted in lead-zinc and copper deposits, respective mining activities from 1844 to 2013, and the trade of indium-containing products from 1988 to 2015. The results show that Australias indium stocks are substantial, estimated at 46.2 kt in mineral resources and an additional 14.7 kt in mine wastes. Australian mineral resources alone could meet global demand (∼0.8 kt/year) for more than five decades. Discarded material from post-consumer products, instead, is negligible (43 t). This suggests that the resilience of Australias indium supply can best be increased through efficiency gains in mining (such as introducing domestic indium refining capacity) rather than at the end of the product life. These findings likely also apply to other specialty metals, such as gallium or germanium, and other resource-dominated countries. Finally, the results illustrate that national circular economy strategies can differ substantially.