Looking to the future: mining’s journey to decarbonise

It has been two years since 28 of the world’s largest miners made a collective commitment to net zero emissions by 2050, and expectations from stakeholders are only growing. File

It has been two years since 28 of the world’s largest miners made a collective commitment to net zero emissions by 2050, and expectations from stakeholders are only growing. File

Published Jan 17, 2024


By Vis Reddy, Andrew van Zyl and Philippa Burmeister

It has been two years since 28 of the world’s largest miners made a collective commitment to net zero emissions by 2050, and expectations from stakeholders are only growing. With the mining sector now firmly in the implementation stage of this mission, where are the advances going to come from?

As an intensive energy user, it is important that the industry has grasped this nettle. On November 17, 2023, the planet crossed a climatic threshold. For the first time since humans industrialised, the average air temperature near the Earth’s surface was 2 degrees Celsius higher than the baseline. This occurred again the following day. These findings by the Copernicus Climate Change Service were preliminary, but experts consider the model reliable.

Pressure rising

The temperature is also rising in the relationships between corporates, communities and interest groups. The same month saw the annual results presentation of a major South Africa-based petrochemical multinational abandoned, as environmental demonstrators took the stage.

While there is growing pressure on companies in relation to their carbon emissions, there are also considerable opportunities for decarbonisation in the mining sector that should generate both hope and progress. In South Africa, the electricity crisis has been perversely advantageous to the pace of positive change towards a lower carbon future. The country’s challenge – like much of Africa – is as much to produce more power as it is to render our power supply less environmentally harmful.

Less carbon, more output

The point is often made that mining remains a cornerstone of the greener technologies that promise to eventually replace carbon-based fuels. The real task of mining, therefore, is to reduce its carbon intensity – and not just the volumes of carbon it emits. This is necessary for it to continue producing the vital commodities that the energy transition is demanding. It serves no purpose for the sector to reduce carbon emissions by actually producing less – although this would in theory be the quickest solution. The world relies on mining today as much as ever – importantly also for food production through the mining of fertiliser and the materials needed to provide water.

Perhaps the greatest opportunities lie immediately in the realm of renewable energy supply. Pressed by the unreliable grid supply and rising electricity costs in South Africa, mines have moved as quickly as they have been allowed, to address their energy risks by funding new supply from renewable sources.

While still reliant on baseload from the grid, mining has been an important contributor to kick-starting the roll-out of solar and wind energy in the country. As uptake on renewable energy alternatives increases, however, even the reliance on the grid for baseload could decrease as renewable energy transition offers increasingly attractive returns on the investment. The transition to renewable energy alternatives is no longer driven by environmental imperatives only but rather economic factors as well.

Impact of replacing

Increasing the proportion of renewables in electricity supply – whether on site or through a wheeling arrangement – can reflect in mines’ sustainability reporting within a matter of years. This makes it a quick win to address stakeholder and shareholder expectations, often without disrupting any basic operations. A process plant, including its crushing and milling phases, can readily make use of renewable energy as most of its functions are electrically driven.

In fact, it would be difficult to decarbonise an existing plant in any other way. Various valuable optimisations can be considered and applied, but these are unlikely to achieve more than 10–20% greater energy efficiency. Consider also the considerable (though unintended) energy implications and carbon footprint of closing and dismantling an existing plant which still has lifespan, only to replace it with another plant – albeit more efficient.

Clean but flexible

Opencast mines, where loading and hauling are generally diesel powered, require further technical solutions before they can switch over to renewable energy. There are many reasons for this, including the flexibility of these load-haul methods as the mining face moves. While there are more efficient options using technologies such as overhead trolley lines or even conveyor belts, suitable conditions are usually rare. This is understandable but unfortunate, as opencast mining is generally preferred as a mining method where it is possible, not least because it is less capital intensive.

Nonetheless, where opencast mines have a long life and where owners are visionary and well resourced, modern technologies are being tested in exciting applications. The ongoing trials of hydrogen-powered mining trucks at a leading South African platinum producer is testament to this. The success of such a technology would not only obviate the emission of significant volumes of carbon, but would provide another valuable off-take channel for platinum. Hydrogen fuel cells use platinum catalysts in proton exchange membrane (PEM) technology.

Growing awareness

Mining is viewed as an industry that changes slowly, and the risks involved with every operational and strategic decision certainly highlight why every change must be carefully considered. What is clear, though, is that the ranks of mines today are increasingly filled with younger professionals, managers, technicians, operators and other staff who have their eyes on the future.

This cohort is lending its weight to efforts by the industry’s leadership to implement the kinds of environmental, social and governance (ESG) changes that the energy transition demands. This is vital, as the journey towards decarbonisation will not be made by a dedicated ESG department or official. Every operation and individual will be called upon to integrate these concerns into the role they perform. The good news is that this journey has begun and it will bring both challenges and opportunities in mining and in society more broadly.

SRK Consulting’s Vis Reddy, chairman and principal environmental geochemist; Andrew van Zyl, managing director and principal consultant; and Philippa Burmeister, partner and principal environmental scientist.