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Rock mined in Greenland for green manufacturing also found in Alaska

Published: Oct. 25, 2021 at 8:31 PM AKDT

ANCHORAGE, Alaska (KTUU) - Miners in Greenland are extracting anorthosite, a rock that some scientists are calling climate-changing. And it’s also found in Alaska.

Anorthosite is found is many northern countries and even on the moon, but in Alaska, it’s rare.

“It’s relatively small, but in terms of potential mining ... I think, would be more than enough to exploit, but whether or not it could be mineable, there’s a lot of other questions,” U.S. Geological Survey Research Economic Geologist George Case said.

Case said he knows of two documented locations: in the area of Kobuk and northeast of Slana.

“It’s a pretty unusual type of plutonic igneous rock,” Case said. “That’s what we call a rock that crystallized from a magma below the below the surface.”

It has a lot of aluminum in it, which is one reason it’s been mined.

“Anorthosite comes in many versions. Our anorthosite is one-third of aluminum, and the rest is calcium and silica,” Claus Stoltenborg, the CEO of Greenland Anorthosite Mining, said.

The company sells the anorthosite to manufactures to make things like aluminum, fillers for the paint and ceramics industry, and fiberglass.

Stoltenborg said using anorthosite can be a greener method. For example, the fiberglass industry uses kaolin clay in the process.

“They had to heat (the kaolin) up to like 600 to 800 degrees and then get rid of the water content,” he said.

Another part of the process is to mix the material with calcium, but “when you’re using an anorthosite, first of all, we have the calcium in it, and there’s no water whatsoever,” Stoltenborg said.

Using anorthosite instead of kaolin would make the process more environmentally friendly, he said.

“If you take 100,000 tons of material and heat 100,000 tons or 200,000 or 300,000 tons up to perhaps 800 degrees, it actually requires a lot of energy, a lot of energy,” Stoltenborg said. “So, of course, that’s a lot of emissions for that.”

But Case said he wouldn’t say Alaska’s deposits could be “climate saving.”

“I am hesitant to go as far as to call it that,” he said. “... If anorthosite was more prevalent, I would say yes there’s more potential for it to replace these traditional methods.”

He said there’s a lot of other questions about mining it in the state, such as the purity of the rock and how to transport it to buyers from remote areas of Alaska.

“To my knowledge, nobody and has investigated the economic feasibility of these in Alaska,” Case said.

The USGS is also studying critical minerals and commodities that could be sourced in Alaska to achieve a low carbon economy, Case said.

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