Mining provides us with the building blocks of modern society. Think about all the commonplace objects that contain metals – washing machines, laptops, power lines, and even fertilizer. Metals are also key to our transition to less polluting energy. Technologies like solar panels and electric cars rely on metals like aluminum or lithium, so we will need to do a lot more mining in the future to create a low-carbon energy system.

But much of the energy used to get minerals out of the ground, and process them, today comes from fossil fuels, and releases greenhouse gases into the atmosphere. Forty-four percent of all carbon dioxide (CO2) emissions from industry come from producing steel and non-metallic mineral products like cement (1).

It takes many steps for the metal from a mineral to go from an ore below the ground to a steel beam or an aluminum frame, and every step takes a toll in carbon emissions. To extract mineral ore, large chunks of earth have to be removed with explosives or heavy machinery. Those machines run on fossil fuels that release CO2 and other pollutants, while explosives produce carbon monoxide, which also contributes to global warming. Once extracted, the ore is pulverized – a step that accounts for 40% of mining's energy use (1). Water is often used to separate desired minerals from ore, and it must be treated before and after use. This, too, requires a lot of energy, and means a large amount of water is not then available for other uses like agriculture.

The chemical reactions used to refine minerals also contribute to climate change. For example, one of the first steps in making steel is to heat a mixture of iron ore, limestone and coke, a coal product, to extremely high temperatures. This purifies iron by removing oxygen, but it also creates CO2 and carbon monoxide as a byproduct. Industrial steel plants also use tremendous amounts of energy overall. A typical steel plant uses over 2,000 megawatts of energy a year – enough to take up all the energy produced by a standard nuclear power plant.

Mining and metals companies are working to lower their greenhouse gas emissions, but they are not on track to get to net-zero emissions. A key way for this industry to emit less CO2 is to swap out fossil fuels with low-carbon electricity. Some companies are building solar farms near their mines and manufacturing plants to do this, but to complete this transition, more heavy equipment also needs to be redesigned to run on electric power. Another way to lower emissions is to cut down on transportation, by using or refining metals closer to where they’re mined.

The metals industry could drastically lower emissions by using renewable electricity instead of carbon-containing chemicals to extract metals from minerals. More reductions can come from cutting down on energy use. For example, we could improve the quality of ore going into mills by changing the way it's blasted from the earth and sorted, which would reduce the energy needed to crush and grind that ore.

Meeting our global climate goals will not be possible if the mining and metals industry does not invest heavily in renewable energy and in new low-carbon technologies.

Published October 19, 2020.

Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International license (CC BY-NC-SA 4.0).

Photo Credit: Hasin Hayder via Unsplash

FOOTNOTES

1 Fischedick, Manfred, et al. “Industry.” Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, edited by Roland Clift, Cambridge University Press, Cambridge, United Kingdom, 2014. www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_chapter10.pdf.