There’s rare earth in them thar hills


Photo of rare-earth oxides. Clockwise from top center: praseodymium, cerium, lanthanum, neodymium, samarium, and gadolinium. Photo by Peggy Greb, USDA.

The elements, crucial to high-tech applications and usually extracted abroad, exist west of Boulder, and a team of scientists is banding together to determine how they might be concentrated in Rocky Mountain granite

By Clay Evans

Some 70 years ago, scientists examined and reported on veins of highly concentrated “rare earth elements” (REE) just 10 miles as the crow flies from the University of Colorado campus in Boulder. And that, as they say, was that.

Julien Allaz

Research associate Julien Allaz

Now research associate Julien Allaz, manager of CU-Boulder’s electron microprobe facility, and colleagues have been awarded a $46,000 grant from the U.S. Geological Survey to return to the site to conduct further study using modern analytical instrumentation.

Strictly speaking, rare earth elements — a group of heavy elements critical to many high-technology applications, from alternative energy to cell phones to defense — are not particularly rare.

All high-tech industries need these elements. ‘The biggest problem, for the U.S. and the world, is that we heavily depend on China for providing them. But there is new attention to U.S. soil, which has a lot of potential for a lot of these rare earth elements.”

“They are actually much less rare than gold, and about as common as lead or zinc,” Allaz says. But they also are rarely concentrated in mineable ore deposits, and the veins embedded in granite formations around Jamestown, he says, are “abnormally rich” in “REE.”

“The veins in Jamestown … are in many respects unique in all the world,” says Charles R. Stern, professor of geological sciences at CU-Boulder, co-principal investigator with Allaz, along with Associate Professor of Physics Marcus Raschke, Assistant Professor of Geological Sciences Kevin Mahan and Senior Research Associate Alexandra Skewes.

Allaz learned about the local deposits shortly after coming to CU two years ago. Raschke, together with undergraduate student Philip Persson, had rediscovered the site and suggested that the microprobe lab use state-of-the-art instruments to update data collected seven decades ago.

The local deposits are important not so much for their economic value — though some REE can fetch up to $1,000 a kilogram — but “what they might tells us about how (they) are concentrated, transported and deposited during crystallization of granite plutons and pegmatites such as those that make up much of the rocks in the Rocky Mountain Front Range,” Stern says.

But the research also taps into global economic concerns.

“All high-tech industries are in need of these elements. They are essential for lasers, magnets, solar-cells, batteries, or catalysis,” Raschke explains.

“The biggest problem, for the U.S. and the world, is that we heavily depend on China for providing them. But there is new attention to U.S. soil, which has a lot of potential for a lot of these rare earth elements,” Allaz says.

Global Production of Rare Earth Oxides

Global Production of Rare Earth Oxides. Chart by USGS.

Among the first tasks will be to analyze the formations to get a clear understanding of which rare earth elements are present. The researchers also hope to gain a better understanding of just how far the Jamestown REE veins extend, focusing on the surrounding public lands.

And by helping to unravel the mystery of how such concentrations are formed, the research could have enormous economic, even strategic, implications for the future, by providing data on how and where such deposits are likely to occur.

“It’s good to understand how these elements got enriched,” Allaz says. “It is unlikely that this specific field will ever be mined. It’s really exceptional in terms of enrichment, but it’s extremely local. … This research is important, because you don’t want to start a million mines and discover only one ton of elements.”

The research will provide “a contribution to understanding how (REE) are formed, where other such deposits might be found and what they tell us about the behavior of REE in the natural environment,” Stern says.

Clay Evans is  director of public relations for CU Presents.

June 24, 2014

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