Page 46 - 100 years of Anglo American

Step 1: Step 2: Step 3: Step 4: Step 5:
Assess mine Assess unintentional carbon storage Implement technologies to Monitor carbon storage Rehabilitate
emissions and additional storage potential increase carbon storage in tailings amounts over time tailings

t’s not science fiction: there’s a very real
possibility that De Beers could be MINING
operating at least one carbon-neutral
mine within the next 10 years.
And, if successful, the technology
Icould revolutionise the mining industry goes green
by safely trapping harmful carbon dioxide
emissions in rock, thereby dramatically reducing
its carbon footprint.
Dr Evelyn Mervine is leading a sustainable
development research project for De Beers that’s
testing the viability of capturing and storing De Beers sets out to offset carbon emissions by
greenhouse gases in the waste kimberlite ore trapping them in rock, writes Christina Kennedy
tailings found at diamond mines.
“We think it’s quite realistic because the
potential of kimberlite is huge,” says Mervine. scale pilot on a mine site in Venetia and/or
“It’s potentially a very cost-effective way to Gahcho Kué,” she says. “We hope to find a
reduce carbon emissions. The technology exists – solution to suit both environments.”
now it’s a matter of finding out how best to The De Beers-funded research comes amid
modify it to work on mining sites.” revised emissions targets set in the Paris Climate
This research was prompted by a natural Agreement, and the moral and social imperative
process called mineral carbonation, whereby for mines to increasingly “green” their operations.
surface rocks interact with carbon dioxide in the It also comes when several countries (including
atmosphere and lock it away in solid form. This South Africa and Canada) are implementing
happens more quickly in ultramafic rocks such carbon pricing to charge companies a tax for
as the kimberlite from which diamonds are Dr Evelyn Mervine is testing the viability of each ton of greenhouse gas emitted.
extracted, but still too slowly to offset man-made capturing and storing harmful greenhouse The De Beers researchers are looking at three
carbon emissions. gases produced during the mining process possible technologies: spreading the waste
De Beers is now looking at ways to accelerate tailings more thinly to increase carbon
this natural process to safely store the carbon 2019 extraction from the atmosphere; injecting carbon
dioxide released as a byproduct from mining dioxide into the rock; or adding microbes to the
operations in tailings dams containing previously THE YEAR WHEN DE BEERS tailings to accelerate the mineral carbonation
mined waste rock. Kimberlite tailings turn into a PLANS TO HAVE A process.
solid compound when mixed with carbon SMALL-SCALE CARBON Mervine says it’s possible that the carbon-
dioxide, effectively trapping the gas in rock. CAPTURE PILOT PROJECT storage technology could be extended to other
Mervine says academics have been looking at types of mining.
the potential of mineral carbonation for years, AT VENETIA MINE IN “Mineral carbonation occurs in other
but De Beers has now given the green light to LIMPOPO AND GAHCHO ultramafic rocks and the potential for carbon
scientists to start exploring this process in depth. KUÉ IN CANADA storage there is enormous.”
With her team’s desktop research completed, She says past research on carbonating
assessments will be carried out at two De Beers R135 - R270 ultramafic rocks has focused on storing the
sites – the Venetia mine near Musina in carbon dioxide off site, which is expensive.
Limpopo and the Gahcho Kué open-pit mine in THE ESTIMATED “Now, the research is shifting to seeing what
Canada’s Northwest Territories – to gauge the PRICE PER TON OF STORED technologies work to do this in situ in a tailings
potential of their kimberlite tailings for carbon pile or rock outcrop. This method will work out
storage. CARBON DIOXIDE IN much cheaper – as low as $10 (R135) to $20 per
Tests will also begin in Botswana next year, KIMBERLITE ROCK ton of carbon dioxide stored.”
Mervine says, explaining that it’s vital to assess TAILINGS When carbon pricing is factored in, such
different sites because “kimberlite varies in technology makes good economic sense for
composition and there are subtle differences in mining operations. Mervine says carbon dioxide
The process will entail laboratory experiments, 1 000 000s to millions of years”.
minerology”. can be locked away in kimberlite for “thousands
conducted in association with Anglo American’s THE NUMBER OF YEARS It makes sense to invest in a greener product.
Technical team, the University of British CARBON DIOXIDE COULD “It’s really exciting. It’s important to reduce our
Columbia in Canada and other research social and environmental footprint, but I think it
partners. BE LOCKED AWAY IN will also position De Beers as a leader in
“We are targeting early 2019 to have a small- KIMBERLITE reducing carbon emissions.”
46 ANGLO AMERICAN 100 YEARS