Gold in herbs

By LIAM DANN PRIMARY, industries editor


It sounds like alchemy but extracting gold from plants could become a commercial reality.

Massey University scientist Dr Chris Anderson, who has developed a process for extracting gold from the soil using plants, has just completed research showing the system can be commercially viable.

His goal is to put the science - called phytomining - into practice on the gold-rich soils of old mining operations in places like Brazil and Africa.

The process requires the soil to be treated with chemicals to break down the gold into water-soluble particles, so plants can suck it out along with the other minerals and nutrients they need.

His research has identified fast-growing herbs, specifically common garden mustard, as the most efficient plants for the task.

But the toughest part of the process is getting the gold out of the plants.

He and his team have developed a processing system using chemical solvents that he now plans to refine into a commercial operation.

His latest research project in Brazil enabled him to set a benchmark of recovering 1kg of gold from a hectare of soil for making the operation profitable.

But it is unlikely that the hills of Waihi will be covered in mustard plants in the near future.

"New Zealand has got a young mining industry that is very efficient. What we're looking for is parts of developing countries where they have mines that were operating 10 or 50 years ago."

In August Anderson completed a three-year research project funded by Foundation for Research Science and Technology and a private Dutch company.

He may seek further public funding, but is already fielding inquiries from interested foreign investors.

"There's a lot of interest there from people in Japan, the United States and Europe," he said.

Finding New Zealand investors was an option but international companies that could can also provide access to suitable sites were the ideal partners.

Anderson said he was hoping to set up a private company to hold the intellectual property, which at the moment was owned by Massey University and the Dutch investors.

It would be a New Zealand company, he said, but it was just a matter of where the money came from.