The growing demand for metals worldwide has led to the recognition of a large class of elements essential to long-term economic stability and energy security. Due to the combination of high industrial demand, unpredictable geological resource availability, and economically and geopolitically motivated supply risk, they are referred to as critical or strategic, and as elements, metals or materials. They include, but are not limited to, the rare earth elements, rare metals (Nb, Ta, Li, Be, Rb, Cs, Zr, Hf, W, Sn), rare dispersed metals (In, Cd, Te, Ge, Ga, Se, Re, Tl) and other precious metals (PGE, Cr, Co). Most are required in various high-technology applications, especially in those designed to create a carbon-neutral future to mitigate and react to the consequences of climate change. Hence, they may also be referred to as Hi-tech or green metals. Many have had only a recent exploration and research focus and therefore knowledge of the various processes that govern their distribution and behaviour in mineralising systems and in the environment is often rather limited. 

The following group of five sessions individually focus on specific aspects of the critical metals, mainly their different deposit types and formation processes.

Nathan Fox¹, Richard Valenta¹ and Paul Gow^1
1WH Bryan Mining & Geology Research Centre, Sustainable Minerals Institute, The University of Queensland, Australia
Email: nathan.fox@uq.edu.au

The resources sector is faced with a significant challenge to meet the projected future demand for commodities including copper, nickel, rare earth elements and critical metals (e.g. Co, Li) which are essential for the global transition to low-carbon technologies. 

To meet this increasing demand, future commodities will need to be sourced from a combination of existing mines, new discoveries and currently undeveloped deposits. The natural complexity of ore systems necessitates that technical factors can render these ‘complex orebodies’ as economically unviable. These may include low ore grade, geotechnical issues, problematic metallurgy and geoenvironmental factors. 

This session will focus on key topics related to orebody knowledge and geometallurgy that bridge the technical challenges facing existing, future and undeveloped resources to unlock value from these complex systems. This session seeks submissions that will address:

• Applied mineralogical and chemical analytical methods for enhanced orebody knowledge and geometallurgical characterisation (including drill core scanning and microanalysis);  
  
• Geometallurgy case studies implemented at both strategic planning and operational levels;
  
• Novel mineral processing techniques for improved recovery of low-grade/problematic ores and new economy minerals;
  
• Geological linkages to geotechnical issues related to mass mining methods (e.g. block/panel caving);
  
• Novel approaches and technologies for coarse waste rejection.
  

Arianne Ford¹ and John Carranza^2
1Geoscience Australia, Australia,  ²University of Kwazulu-Natal, Durban, South Africa
Email: arianne.ford@ga.gov.au; carranzae@ukzn.ac.za

The mineral exploration industry and government organisations acquire massive volumes of geoscience data annually. Often the data collected remain underutilised due to lack of time, budget, or inhouse expertise – or some combination thereof. This session will describe new ways of generating mineral exploration targets through optimised spatial data analysis and integration, with a focus on greenfields and regional- to district-scale studies. The session welcomes contributions on:

• Integration, analysis, and interpretation of spatial geoscience (geological, geochemical, geophysical) data for mineral exploration;
  
• Case studies of exploration success stories aided by spatial data analysis/integration;
  
• Quantifying and managing geological uncertainty in spatial data analysis;
  
• Challenges facing spatial data analyses and their possible solutions.
  

Michael Gazley¹ and Shawn Hood^2
1RSCMME, Wellington, New Zealand, ²GoldSpot Discoveries Corp, Montreal, Canada
Email:  m.gazley@rscmme.com; shawn@goldspot.ca

This session will focus on the role of techniques such as machine learning and multivariate data analysis methods with relation to ore deposit studies or exploration settings to explore large, multi-dimensional datasets that are increasingly generated by geologists. The uptake of machine learning and multivariate data analysis techniques are all around us, especially to complete monotonous jobs rapidly or to find complex relationships in datasets with high degrees of dimensionality. Unfortunately, these techniques are often applied naively or with limited oversight from a domain expert (i.e. a geologist). We invite contributions from across commodities and ore deposits-styles (including exploration settings) that highlight novel applications of these techniques to enhance geological understanding based on all the available data.

Renee Birchall¹, Tobias Schlegel¹ and Jessica Stromberg^1
1CSIRO Mineral Resources
Email: renee.birchall@csiro.au; tobias.schlegel@csiro.au; jessica.stromberg@csiro.au

Understanding the mineral zonation related to magmatic and hydrothermal ore deposits and the development of novel approaches to exploration vectoring using mineralogy are critical for future discoveries in an increasingly challenging exploration climate, especially in terrains where ore deposits are deeply buried below thick sequences of cover. This session aims to bring together researchers and industry professionals who develop or apply mineralogical vectors that help mineral exploration in the discovery of ore deposits. The techniques and approaches may range from trace element contents in indicator mineral and SEM-based quantitative mineralogy to hyperspectral mineralogy. We invite contributions from across commodities and ore deposits-styles highlighting analytical techniques and novel applications for mineral exploration, as well as case studies which contribute to the greater understanding of economic mineralisation.

Behnam Sadeghi^1,2, Franco Pirajno³ and Huayong Chen^4
1EarthByte Group, School of Geosciences, University of Sydney, Australia, ²Earth and Sustainability Research Centre, University of New South Wales, Sydney, Australia, ³Centre for Exploration Targeting (CET), The University of Western Australia, Perth/Crawley, Australia, ⁴Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
Email: z5218858@zmail.unsw.edu.au

One of the main objectives in the analysis of data in geochemical exploration programs (including elements, minerals, lithology, and/or other related agents) is the selection and application of suitable classification models to separate signals related to the effects of mineralisation from other processes or sources, as well as controls on variation in background geochemical distributions. Various mathematical and statistical models have been applied to regional geochemical data to reveal subtle geochemical patterns related to the effects of different styles of mineralisation or variations in parent lithologies. Conventional statistical methods such as exploratory data analysis, weights of evidence, and probability plots used for anomaly detection or the isolation of geochemical signals and patterns related to the effects of mineralisation on regolith geochemistry have a number of limitations. This has encouraged the investigation of less conventional alternatives to conventional parametric methods, including fractal modelling and geostatistical simulation to isolate such signals or patterns. All studies related to advanced methods and developments in geochemical anomaly classification in mineral exploration, using advanced classification models such as fractal/multi-fractal models, and geostatistical simulations, particularly those works study on the validity, robustness, and uncertainty of the models, are welcome.

Walid Salama¹, David Cohen² and Ryan Noble^1
1Australian Resources Research Centre (ARRC), Kensington, Australia, ²University of New South Wales, Sydney, Australia
Email: walid.salama@csiro.au

One of the fundamental challenges for mineral exploration industry is targeting deeper concealed mineral deposits in deeply weathered and covered terrains. Although the geochemical footprints of the buried mineralisation can be obscured, weathering processes can produce secondary mineral deposits within the weathering profile by supergene enrichment and metal dispersion through the overlying transported cover.

In this session we invite submissions on the following:

• Processes of metal dispersion in the weathering profile and transported cover;
  
• Exploration techniques for vectoring buried mineral deposits in weathered terrains including bio-/hydo-geochemical, geophysical, hyperspectral, remote sensing and machine learning methods;
  
• Supergene and lateritic ore deposits;
  
• Indicator minerals in areas of transported cover.
  

Nigel J. Cook^1
1University Of Adelaide, Adelaide, Australia
Email: nigel.cook@adelaide.edu.au

Paul Weber
Mine Waste Management, Christchurch, New Zealand
Email: paul.weber@minewaste.com.au

The process of mining and sourcing of minerals and materials is essential to support societies demands for a low carbon clean-green technological future.  To deliver these materials all current and future mining operations must address environmental, social, governance (ESG) requirements by undertaking planning, operations, and closure activities using best practicable methodologies coupled with transparent stakeholder engagement.  ESG expectations can be greater than regulatory requirements and also change with time and all projects need to address these expectations.  This session explores ESG requirements for exploration and mining operations and invites contributions that focus on understanding environmental geochemical risks for projects, management of these risks and uncertainty, environmental geochemistry risk communication and engagement, adaptive management, and planning for closure.

Marie Forget¹, Magali Rossi¹ and Kristina Maud Bergeron^2
1Savoie Mont Blanc University, Le Bourget-du-lac, France, ²Université du Québec à Montréal, Montréal, Canada
Email: marie.forget@univ-smb.fr; magali.rossi@univ-smb.fr; kristinamaud@gmail.com

Building sustainable mining territories requires questioning the independent and interdependent relationships between the ore deposit, the mining industry, the environment, culture and society. This session expects contributions from the humanities, environmental sciences, social geology and interdisciplinary studies to explore past and present-day territorial trajectories. Topics of interest include:

• The inheritance of past mining activities on the environment and on society;
  
• The role of local, regional, national, global governance and policy-making in framing trajectories;
  
• The integration of mining activities within a sustainable development framework: best practices and lessons learned;
  
• Integrated, co-existing or conflictual territorial uses or values;
  
• The evolution of the social licence to operate;
  
• Interactions of stakeholders in conjunction with territorial development;
  
• Other historical and socio-environmental aspects of territorial trajectories.
  

Contributions showing the trajectories of various mining territories are welcome, focussing on areas where mines are closed, regions with large or developing operations, as well as those with artisanal and small-scale mining.

Marie-Odile Simonnot¹, Antony van der Ent² and Agnes Samper^1
1Universite De Lorraine - Labex Ressources21, Nancy, France, ²University of Queensland - Sustainable Minerals Institute SMI, Brisbane, Australia
Email: Marie-Odile.Simonnot@univ-lorraine.fr; a.vanderent@uq.edu.au; agnes.samper@univ-lorraine.fr

Rising expectations for environmental and social performance in the minerals sector are strongly affecting research needs and trends. The environmental footprint of mines can be reduced at all stages of the mine life cycle, from exploration stages to extraction and closure, and achieved through innovative technologies and collaborative research.

This session, organised by the international multidisciplinary UQ-UL SUCRE research group (Sourcing Unconventional Critical Resource Elements), is calling for contributions with examples of innovative research, designed specifically for building more practical and efficient sustainability in the minerals sector by:

• Improving the understanding of the diversity of mineralogical assemblages and the geochemical distribution of metals in the ore;
  
• Developing efficient solutions in extractive chemistry (in-process extraction, ore enrichment, process engineering, purification processes);
  
• Deriving economic value from mine waste through eco-engineering;
  
• Identifying the potential for biological processes to assist with mine remediation (hyper-accumulator plants);
  
• Creating adaptive solutions for specific mine sites and wastes, or “soft-mining” of non-conventional substrates;
  
• Enhancing participatory processes with all stakeholders;
  
• Approaching undeveloped ore deposits with a vision including Environmental, Social and Governance considerations;
  
• Enhancing more significant collaborative inter-disciplinary research, including with industry partners.
  

Jenny Stauber¹, Lisa Golding¹ and Farid Juillot^2
1CSIRO Land and Water, Lucas Heights, Australia, ²French National Research Institute for Sustainable Development, Noumea, New Caledonia
Email: farid.juillot@ird.fr; jenny.stauber@csiro.au; lisa.golding@csiro.au

In the last two decades, nickel production has shifted from temperate sulfides to tropical laterite deposits to meet the strong increase in global demand. Laterite nickel deposits now represent two thirds of the nickel resources and they account for about 60% of the nickel production, which emphasises the need for a dedicated assessment of the environmental impacts and health effects of laterite nickel mining. Such an assessment relies on a full understanding of the physical and biogeochemical processes that drive mobility, bioaccumulation, bioavailability and (eco)toxicity of nickel and associated trace metals (Cr, Mn, Co) in soils, sediments, freshwaters, coastal marine waters and the atmosphere around laterite nickel deposits.

This session will focus on understanding the interplay between nickel and associated trace metal geochemistry, ecology and human health, by gathering studies dedicated to source identification and apportionment, fate and transport modeling, speciation characterisation, ecotoxicity and ecological risk assessment, as well as human health risk assessment.

Considering the large proportion of laterite nickel resources in New Caledonia, The Philippines, Indonesia, Papua New Guinea and Australia, studies focused on the Southeast Asia and Melanesia region will be particularly welcome.

Anita Parbhakar-Fox¹ and Gavin Mudd^2
1University of Queensland, Indooroopilly, Australia; ²RMIT University, Melbourne, Austrlia
Email: a.parbhakarfox@uq.edu.au; gavin.mudd@rmit.edu.au

A global challenge faced by the mining sector is how to effectively rehabilitate and relinquish mine sites. This is a complex and costly challenge if conventional rehabilitation practices are practiced. Further, the effectiveness of such traditional management techniques in reducing long-term chemical or stability risks has been contested.

An alternative management strategy is challenging the linear economy approach and instead regarding mine waste as a potential resource i.e., adopting a circular economy management approach. This has potential to reduce the environmental footprint of mining. Recent focus has been on battery or technology metals (e.g., Co, In, W, Te, V, REEs) recovery however, a more holistic approach towards mine waste valorisation (i.e., using gangue minerals as construction materials) is starting to emerge. This session seeks submissions that will:

• Introduce effective techniques for metal exploration (with a focus on battery or technology metals) in a range of mine waste materials (e.g., tailings, slag, waste rock, spent heap leach);
  
• Discuss case studies where potential secondary resources, both metals and other gangue minerals, have been identified;
  
• Describe new mineral processing technologies developed to unlock these complex ore bodies;
  
• Document valorisation of new waste streams.        
  

Nico Thebaud¹, Mark Jessell¹ and Luc Siebenaller^2
1Centre for Exploration Targeting, School of Earth Sciences, University of Western Australia, Crawley, Australia, ²Le Soleil dans la Main, Winseler, Luxembourg
Email: nicolas.thebaud@uwa.edu.au; mark.jessell@uwa.edu.au; luc.siebenaller@asdm.lu

In many emerging nations, mineral resources and mining activities account for large portions of their total export revenues. Yet the ability of local geoscientists and through them local communities to fully benefit from this economic revenue may be impeded by the lack of specialised training. This lack of training is also critically apparent in artisanal mineral extraction activities and contributes to large scale environmental and social challenges that have further negative impacts on other human activities. In this symposium we solicit contributions that may relate to:

• Mining in populated regions – Contemporary and future challenges;
  
• Sustainability and international cooperation;
  
• Geosciences education models for developing nations; 
  
• Geoscientists and environmental protection;
  
• Role of women geoscientist in natural resources development.