Loaded for Bear: Coal waste is the new frontier in the critical minerals scramble

Coal waste has long been discarded as trash. But research and development is uncovering the minerals that lie within, potentially transforming this liability into an asset.

Minerals and Petroleum Minister Gwede Mantashe made reference to this last week at the Southern Africa Coal Conference when he unveiled the “Coal Reimagined Programme” of Mintek, South Africa’s national mineral research organisation.

Mantashe said the initiative represented a “strategic intervention aimed at repositioning coal and its derived waste streams as a strategic national asset. This programme builds on Mintek’s long-standing work in characterising South African coal, coal discards and coal fly ash.”

“Through this programme, we intend to transform a historical liability into an engine of economic opportunity, provided that appropriate investment is mobilised to move from research and piloting to industrial deployment.”

According to FutureCoal: The Global Alliance for Sustainable Coal – an umbrella group representing the industry – coal and coal waste contain critical heavy metals including aluminium, cobalt, copper, iron, nickel, zinc, silver and lead.

Ironically, these are essential for renewable energy. And coal and its by-products contain 17 rare earth minerals which are needed for electric vehicles, solar panels and wind turbines, among other things.

Read more: Sibanye, Valterra and JM team up to find new applications and markets for PGMs

Viewed through this prism, this is the latest round of the coal sector’s fightback in defiance of its obituary writers – making itself critical to the scramble for critical minerals needed for the green energy transition.

It also highlights how chemists and other scientists are probing minerals and metals to find new applications and markets from the planet’s resource wealth.

Trash to treasure

University of Texas research indicates that US coal ash has nearly 11 million tonnes of rare earth elements locked within, which is eight times America’s domestic reserves and valued at $8.4-billion.

Coal ash is basically the stuff that is left after coal has been burnt for fuel generation, like the ashes after your braai.

“The US alone produces around 110 million tons of this coal-mining byproduct each and every year. The ponds that house this ash pose a major threat to the environments that host them, but they might also hold the secret to home-shoring vital supply chains for critical minerals,” the university said last year.

“This really exemplifies the ‘trash to treasure’ mantra,” said Bridget Scanlon, co-lead author of the study. “We’re basically trying to close the cycle and use waste and recover resources in the waste, while at the same time reducing environmental impacts.”

This is the kind of bounty that Mantashe is eyeing in South Africa.

“There has to be a reimagining of coal beyond combustion. Coal is a carbon product but we haven’t necessarily thought about everything else that comes in that lump of coal,” FutureCoal CEO Michelle Manook told me in an interview at the Investing in African Mining Indaba in Cape Town.

“Coal waste has effectively been seen as a liability on your balance sheet. But now imagine all of a sudden that you can produce critical minerals, a high-value product... That’s the growing interest we see from investors. It’s not just about mining, it’s about looking at what the end product could look like,” she said.

South Africa certainly has the technical and scientific expertise to drive research on this front. For example, the Coaltech Research Association – a collaborative effort of South Africa’s coal sector – is digging into this issue.

“CoalTech is spending over R10-million with partners over the next two years to try and determine the science behind the extractability of the rare earths from different sources with coal fly ash as the top priority,” Avhurengwi Nengovhela, CoalTech’s CEO, told me at the indaba.

And love it or loathe it, South Africa’s coal sector is not going extinct anytime soon. The renewable energy drive is fast gathering pace here but Eskom still gets the bulk of its power from the fossil fuel, which is also a major export commodity.

So it makes sense to extract more value from coal and minerals that are actually green. This in turn can attract additional investment to South Africa’s mining sector and provide the country with new minerals for export or domestic use.

And on the global stage, coal has confounded its critics.

According to the International Energy Agency’s latest annual coal report, demand for the commodity climbed for the third year on the trot in 2025, reaching a new all-time high.

Read more: Coal demand hit record high in 2025, confounding its obituary writers

This was not in the script a few years ago as a growing number of banks stopped providing finance to new coal projects because of the fossil fuel’s links to rapid and accelerating climate change. But many banks have since dropped out of initiatives such as the Net Zero Alliance.

Plugging coal into the green energy transition will be regarded with scepticism by many, and the alarming smoke signals from our burning planet underline the urgency of phasing it and other fossil fuels out of the global economy.

But that is not going to happen tomorrow and in the meantime, coal trash and ash may yield unexpected treasures. DM