CSIRO pours Australia’s first eco-friendly gold bar produced without toxic cyanide
You might pay more for single origin, ethically-produced coffee beans for your morning brew, but what about environmentally friendly gold in your wedding ring?
Highly-toxic cyanide has been used in commercial gold production in Australia since the gold rush.
But the CSIRO have successfully poured Australia’s first gold bar using the less-harmful alternative, thiosulphate.
A demonstration plant in Menzies, in Western Australia’s Goldfields region, was the site of the first pour of ‘green gold’.
CSIRO chief executive Larry Marshall said green gold was better for the environment and society.
“We really believe that over time companies will value more and more the importance of social responsibility,” he said.
“Green gold has a 20 per cent price premium over gold produced using less environmentally-friendly technologies.
Dr Larry Marshall, CSIRO chief executive
Dr Larry Marshall said cyanide-free gold production could boost corporate responsibility. (ABC News: Tony King)
“So it is not just good for the environment, it is good for the bottom line.”
WA-based Eco Minerals Research, which partnered with CSIRO on the project and setting up the processing plant in Menzies, is planning to expand the production method on a commercial scale.
The company’s managing director Paul Hanna said the new technology could be a gamechanger for smaller gold producers.
“You’ve got to have special licenses to handle cyanide, you’ve got to have special equipment to handle it, whereas we don’t need to do that,” he said
Mr Hanna said overseas governments are becoming increasingly strict on the use of cyanide in gold production, which meant there was a lot of demand for the technology.
Cyanide is used as a reagent in 90 per cent of the world’s gold production.
It is used to leach or dissolve the pure gold out of the ore.
For decades, industry has been trying to find a better alternative that is less harmful to workers and the enviroment.
That push been largely driven by industrial accidents that have had dire environmental impacts.
One of those incidents was a spill in 2000 when a dam at the Baia Mare gold mine in Romania overflowed, sending a flood of toxic cyanide down riverways, accompanied by a tide of dead fish.
A better alternative?
Not everyone in the gold industry is convinced by CSIRO’s green gold technology.
Bill Staunton, an adjunct professor at Curtin University’s School of Mines, said if managed well and safely, the impact of using both cyanide and thiosulphate interchangeably would be same.
Although thiosulphate is far less toxic than cyanide, the ongoing hurdle in its use in gold production is the economics of its use.
“Economically and technically it can’t compete with cyanide, usually,” Mr Staunton said.
“The cyanide process is a much more robust process and is very easy to operate and run. And you get very good recoveries from the ore.
“The thiosulphate is much more complex and therefore more expensive to run. And often you get a lower recovery from the ore.”
Mr Staunton said the cost of producing gold using thiosulphate could be an extra 10-20 per cent, depending on the ore.
That could be balanced by a price premium, but Mr Staunton said he was not aware of one.
“I am not sure what [Dr Marshall] means by a 20 per cent premium,” he said.
“I’ve never heard of any suggestion that people would pay 20 per cent more for an ounce of gold if they thought it was being produced ethically, or if it was green, so to speak.”
The CSIRO’s Paul Bruer is lead scientist on the project, and said the initial demonstration plant was about proving the merits of the method to industry.
“The industry needs to see the technology proven, in the field, and then from there it can look at how it assess that against the current cyanide process,” he said.
“Directly comparing the cyanide, we haven’t got the numbers around that yet. That’s part of the demonstration plant — [understanding] where we sit.”
CSIRO’s Dr Marshall said it was a great opportunity to add value to a uniquely Australian piece of science, and a uniquely Australian industry.
Australia’s gold production is expected to plummet to generational lows by 2022.
S&P Global Market Intelligence mining analyst Chris Galbraith said he expects production to drop from a 26-year high of 10.2 million ounces to just 6.8 million ounces by 2022.
Mr Galbraith said the potential 33 per cent drop was driven by the gradual depletion of Australia mines.
“Australia does have quite a few large and medium-sized mines that are expected to close over the next few years,” he said.
“We do see a number of projects in development that can offset a bit of that fall, but nothing large enough that it’s going to offset it that significantly.”