From Waste to Asset: Can Tailings Take Miners To and Beyond Net-Zero?

One month before COP25, some of the world's top miners committed to a goal of net zero direct and indirect carbon emissions by 2050 or sooner.

One month before COP25, some of the world's top miners committed to a goal of net-zero direct and indirect carbon emissions by 2050 or sooner. A pledge that will require more than words to achieve.

The mining industry has long been criticized for its environmental impact but advances in research and technology may make the industry’s waste an indispensable part of the solution to go beyond net zero. 

In October, the International Council on Mining and Metals (ICMM) CEO Rohitesh Dhawan published an open letter with the signatures of 28 chiefs of the world’s largest miners, committing to net zero scope one (direct) and two (indirect) greenhouse gas emissions by 2050.

The ICMM has 28 members with operations that span 650 sites over 50 countries and will report annually on their progress to decarbonize annually. The industry is currently a heavy contributor to greenhouse gas emissions.  

According to McKinsey, it is estimated that greenhouse gas emissions associated with primary mineral and metal production are ~10% of the total global energy-related greenhouse gas emissions in 2018.

McKinsey points out further that the problem for copper mining is even graver. Fuel consumption increased by 130% and electricity consumption increased by 32% per unit of mined copper in Chile from 2001 to 2017, largely due to decreasing ore grade. 

There has been a lot of talk around the use of renewable tech to reduce fossil fuel consumption at operations and shipping, but this could only get you so far in reducing carbon emissions.

There is an opportunity for mining sites to go beyond net-zero with carbon sequestration, using waste or what is known as tailings to store carbon dioxide (CO2) at scale.

According to Greg Dipple in an interview with CIM Magazine, a professor and carbon capture researcher at the University of British Columbia believes efforts to reduce emissions alone will not solve the carbon problem and requires removal of CO2 from the atmosphere.  

For over a decade, he has been researching a process by which tailings (mine waste) naturally pull CO2 from the air and capture it into new rock formations

In the lab, Dipple fed air with 10% CO2 similar to what a power plant emits, to highly reactive material and made rock in 200 hours. 

Dipple discovered that BHP’s Mouth Keith open-pit nickel mine in Australia was passively capturing 40,000 tonnes of CO2 per year by direct capture from air and turning it into minerals.  

That mine’s total emissions are ~350,000 tonnes, so it was unwittingly producing an 11% offset on its total mine greenhouse gas emissions with its tailings. This is just one mine and one method. 

Dipple is also looking into creating a strategy to actively pump carbon into tailings or the appropriate geology to host carbon dioxide emissions. His research could be a breakthrough for a global problem and a bonus to current mining operations. 

The ICMM published a series of papers that tracked a total of 1,743 unique facilities containing 44,540,000,000 cubed metres of tailings. This dataset represents only 30.2% of global commodity production.

However, not all tailings are equal in their ability to store CO2. Nickel, platinum, diamond, and asbestos are typically hosted in magnesium silicate rocks which can provide the “labile” magnesium that reacts with CO2 to form new minerals, capturing CO2.  

Ultimately the geology of ore deposits and operations will determine their ability to sequester carbon, but in a world that is teetering on the adoption of carbon offsets across the value chain, some mines may offer a competitive advantage to sell their carbon credits or reduce carbon liabilities on their balance sheet once carbon sequestration at mines is recognized as a valid method to store carbon.  

Mine waste could become an asset. 

Check out Prospector Portal to research for the specific geology and/or projects that could store carbon dioxide.

[Source: CIM Magazine, Reuters, VC Elements, ICMM]

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