Scientists Mine Gold With Alfalfa

Meanwhile, out in California, an entirely different procedure was being used to validate Yacaman's finding. Scientists at the Stanford Synchrotron Radiation Laboratory, part of the Stanford Linear Accelerator Center, bombarded the alfalfa with X-rays to see if those black specks really were gold.

They were, and they were remarkably similar to gold particles produced through much dirtier chemical processes. It was payday again.

But it's hard to spend gold that's buried in alfalfa, so the researchers had to figure out some way to get the gold out of the plant. That turned out to be easier than had been thought. They ground up the plants, and put them in a centrifuge. Since gold is much heavier than any other part of the plant, it was quickly isolated by the spinning machine.

Of course, the gold they ended up with was the gold they added to the soil in the first place, so they weren't any richer. The next test was to see if the alfalfa could mine gold in a real setting.

To test that out, Gardea turned to the people he had known so long ago as a kid growing up in Mexico. He needed dirt from the mining area.

A truckload of dirt soon arrived on the El Paso campus.

"It's real soil," he says, contaminated with all the stuff left over from the mining process, including small amounts of gold.

His alfalfa plants, he says, worked like a charm.

"We're actually mining gold with plants," he says.

Soaking Up Scraps

Alfalfa is never going to replace hard rock mining, of course, but the researchers think it might produce enough gold to satisfy some pressing needs. The electronics industry is lusting after gold because it is an excellent electrical conductor and it doesn't rust. As machines get smaller and smaller, gold is seen as a key player in the nanotechnology industry.

And what could be better than nanoparticles, produced by little factories that pick up what the miners left behind while cleaning up the tailings?

We're talking alfalfa.

Lee Dye’s column appears weekly on A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.

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