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Mining For Gold With Farm Crops
It's like panning for gold but using plants instead of water, says New Zealand researcher Chris Anderson, who has come up with a process called "phytomining" that lets plant roots pull gold and other precious metals out of the ground. Anderson is a researcher at Massey University. He's using corn and other farm crops t
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Mining For Gold With Farm Crops CROPS New Techniques 30-2-32 It's like panning for gold but using plants instead of water, says New Zealand researcher Chris Anderson, who has come up with a process called "phytomining" that lets plant roots pull gold and other precious metals out of the ground. Anderson is a researcher at Massey University. He's using corn and other farm crops to "hyper accumulate" gold from mine wastes that would otherwise be costly to mine.
"We're still not at a commercial level, but we are getting closer," says Anderson, founder of Tiaki International, the first gold farming company in the world.
To "mine" gold with plants, he seeds corn, canola or mustard in a plot layered with waste from a gold mine. The heavier the concentration of gold particles present in the soil, the greater the eventual uptake. As the crops mature, he sprays the soil around them with low levels of ammonium thiocyanate that induces the plants to take up the gold. After a few days, the leaves turn brown indicating the plants are ready for the gold harvest. Anderson then incinerates the plant material at 923 degrees and extracts the gold from the ash.
The gold is captured in the plant tissue as nanoparticles of pure gold, which can be sold to the medical and electronic industries. At current prices, he estimates the need for a kilogram of gold per hectare (2.5 acres) to be competitive. However, niche uses for nanoparticle gold could reduce the necessary yield to only 250 grams per hectare.
In addition to gold, Anderson is working on ways to extract other minerals and chemicals with plants. For example, so far he has identified about 350 plant species that will take up more than 1,000 milligrams of nickel per kilogram of dry weight plant material. Some take up more than 10,000 mg/kg. Other plants take up large amounts of arsenic, cadmium, zinc, thallium and boron.
Anderson continues to work on both the growing and processing sides of the equation. "We are in advanced planning to run a couple of extensive trials here in the southern hemisphere," says Anderson.
Contact: FARM SHOW Followup, Chris Anderson, Institute of Natural Resources, College of Sciences, Massey University, P.O. Box 11 222, Palmerston North, New Zealand (ph 64 6 350 5799 ext. 7584; fax 64 6 350 5632; C.W.N.Anderson@massey.ac.nz; http://soils-earth.massey.ac.nz).
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