Mitigating the carbon intensity of resource production

The mining and processing of mineral ores is a small but significant contributor to global CO2 emissions. The sources of carbon pollution from this industry are largely derived from the electricity generation required to power large, fixed plant such as grinding mills and crushers, and from diesel combustion in mobile plant such as haul trucks. Consequently, reducing the carbon intensity of resources production has the dual benefits of lessening the industry’s global impact on climate change, while also potentially shielding the industry against rising energy and fuel costs. Mine waste storage also presents opportunities for carbon sequestration, where in some instances, mine tailings products are chemically amenable to bonding with atmospheric CO2. Projects completed within this theme of Resourcing Decarbonisation cover these facets, with particular focus on developing strategies to minimise grinding energy inputs during the processing of copper ore.

Core to float – Making sense of a massive dataset related to floatability

The project focuses on applying network analysis as a form of data analysis to study the nature of the variables related to pyrite floatability. In particular, how significant correlations between those variables are interconnected, and to study the topology of that correlation network. This will provide insights into subsequent experimental design to explore causal mechanisms of pyrite floatation. The intention is to use these insights to improve the operational efficiency of copper floatation circuits, a key step on the journey to decarbonising minerals processing operations.

Project leads: Benjamin Seligmann, b.seligmann@uq.edu.au and Liza Forbes, l.forbes@uq.edu.au

High voltage pulse enhanced leaching of mineral ores

The JKMRC is developing High Voltage Pulse (HVP) Technology for ore pretreatment. HVP uses short-pulsed high voltage discharges, which act like a lightning strike to selectively break mineralised ores whilst keeping barren rocks intact. This selectivity makes it possible to choose the material which should go to the processing plant and leaving behind material which contains little or no metal. HVP has many benefits, including pre-weakening, pre-concentration and improved mineral liberation and recoveries. These factors all have the potential to lower the energy intensity and carbon footprint of the minerals processing circuit, reducing both costs and environmental impact.

This technology functions by the electrical current generating microcracks along mineral grain boundaries. This means that HVP can enhance processes that are typically limited by restricted access, such as ore leaching. Funding from the Resourcing Decarbonisation program has supported the development of an HVP application aimed at improving ore leachability. The project seeks to deliver a proof of concept for HVP-assisted leaching and evaluate its applicability across different ore types.

Project lead: Christian Antonio, c.antonio@uq.edu.au

Workshop – Path to net-zero: Carbon emissions within the mining industry

This one-day workshop provided a comprehensive view of mining decarbonisation. It explored emission sources, the complexities of scope 1, 2 and 3 emissions, energy transition, and emerging technologies shaping the future. Participants discussed case studies and best practices, engaged in interactive workshops, and networked with peers. This workshop provided knowledge on sustainable mining practices and carbon reduction strategies by reviewing sources of greenhouse gas emissions and net-zero targets within the mining industry, as well as looking at sustainable decarbonisation practices that exist within the industry.

Workshop overview: Path to net-zero: Carbon emissions in the mining industry

Project leads: Kristy Nell, k.nell@uq.edu.au and Mohsen Yahyaei, m.yahyaei@uq.edu.au

Improving coarse particle flotation in conventional flotation cells (PhD)

Coarser particle flotation has the potential to both increase the supply of critical metals as well as reduce the carbon intensity of resource production. The aim of this project is to develop retrofit solutions which can enable coarser particle flotation in existing flotation cells already being used in brownfield mining operations. Tens of thousands of conventional flotation cells are being operated in mining operations around the world.  Being able to retrofit these existing cells would enable mining operations to more quickly achieve coarser particle flotation without the need for major equipment installation. This will have the benefits of reducing energy of grinding and enable higher throughput during comminution as well as increasing mineral recovery by reducing loss of mineral in coarse particles that report to tailing.  Coarser grinding also makes downstream dewatering more efficient.

Project leads: German Lastra Yanez, g.lastra@uq.edu.au and Kym Runge, k.runge@uq.edu.au

Carbon negative mines – mineral carbonation of mine waste

Mining operations in Queensland generate large volumes of waste, which poses environmental risk such as acid and metalliferous drainage (AMD). Current remediation technologies, such as lime neutralization have high operational costs and carbon intensities. This study evaluates an integrated mineral carbonation strategy to neutralize acidity and sequester arsenic within gold and copper mine tailings, which are abundant in Queensland. By utilizing alkaline brine lixiviants derived from mine affected water (MAW), reactive waste minerals are transformed into secondary carbonate minerals such as magnesite and dolomite, facilitating carbon storage and tailings stabilization.

Related publications:

Project lead: Eric O Ansah, e.oansah@uq.edu.au