China has been quietly cornering the rare earth market, but North Dakota may be getting its boot in the door to that global market, all thanks to its “brown” coal.
North Dakota’s lignite layers have long been considered the lowest rank of coal due to their relatively low heat content, high inherent moisture content and above average ash content. The economics of that has driven co-location of power plants with lignite mines, so that transportation expenses are minimized.
While lignite might not be the highest grade of coal when it comes to fuel, there is new evidence it may have some of the highest concentrations of rare earth elements in the nation, according to a 104-page study out this week from the North Dakota Geological Survey.
The two-year study was based on samples collected from several locations in southwestern North Dakota counties, starting in McKenzie County and extending down into Bowman.
Of 352 rock samples analyzed from the area, 277 averaged 120 parts per million total rare earth elements. That is twice the published average for U.S. coal, according to North Dakota Survey Geologist Ned Kruger.
One of the samples was at 603 ppm, which was twice the potential economic threshold identified by Department of Energy in its grant funding requirements, and it was the fifth highest recorded in the nation for coal. Overall, the samples ranked in the top 20 of coal samples nationwide.
The elements contained in the samples also trended toward the heavier, more valuable ones, such as scandium. Scandium, as an example, is selling for about $4,600 per kilogram or 2.2 pounds right now, Krueger said. Terbium is $410 to $425 per kilogram and dysprosium $183 to $186 per kilogram.
North Dakota’s study follows on the heels of a United States Geological Survey study also just out that says the U.S. has become dependent on foreign nations for 20 of 23 critical minerals, among them, several rare earths.
Interior Secretary Ryan Zinke called that troubling and said it poses a national security risk. President Donald Trump, meanwhile, issued an executive order titled, “Federal Strategy to Ensure Secure and Reliable Supplies of Critical Minerals.”
The president’s order calls for streamlining permitting processes to expedite exploration, production, processing, reprocessing, recycling and domestic refinement of critical minerals, among other actions.
The mining industry lauded the administration’s actions.
“This administration correctly recognizes that a reliable, secure minerals supply chain is of utmost importance to addressing America’s national security, infrastructure and manufacturing needs,” National Mining Association President and CEO Hal Quinn said. “Our country’s dependence on mineral imports has doubled over the past 20 years. Today, less than half of the mineral needs of U.S. manufacturing are met from domestically mined minerals, and we are 100 percent import-dependent for 20 key minerals. These trends will only worsen if we do not advance policies that enable U.S. mining to perform to its potential.”
The U.S. had only one mine that was producing a substantial amount of rare earth elements, and that has since shut down amid financial difficulties. Montana has a platinum mine, but it does not produce anywhere near the quantity the United States needs for its manufacturing.
Many of the rare earths produced at the Mountain Pass Mine were the lighter, less valuable rare earths, Kruger said, and that may have contributed to its demise.
“If you look at our lignites in North Dakota, we compare favorably to what was seen in Mountain Pass in California,” he said. “We are more favorable. (Our lignite) tips the scale toward the heavier, more valuable elements.”
Kruger and state geologist Ed Murphy became interested in examining lignite’s rare earth potential after seeing a few papers in 2012 examining coal in other regions. In 2015, they succeeded in getting the state legislature to fund a study to look at how well North Dakota’s lignite layers would stack up.
They chose the area in southwestern North Dakota because its lignite coal outcroppings are exposed to the surface. Expensive drilling of core samples wouldn’t be required just to take a peek at whether there’s anything there. They could just walk right up to the outcroppings and take samples. And they could take notes on what other types of geological indicators might appear in the outcrops to help them figure out if there are trends pointing to which areas are likeliest to have higher concentrations.
The results have been very encouraging so far, Murphy said, and show that more study is warranted. These studies will extend the sampling in the higher concentration areas to get a handle on how big those areas are.
“How economic it is to get (rare earths) out is a question that still has to be answered,” Murphy said.
North Dakota actually has two studies already delving into that, which were funded by the Department of Energy. One study is with the North Dakota Institute for Energy Studies and the other with the Energy and Environmental Research Center. Among possibilities being examined is extraction of rare earths from the ash residue after the coal is burned.
“The work we are doing with UND and others is crucial to finding an economic means of extracting these rare earths from our coal,” Murphy said.
If researchers are successful in finding an economic means of liberating rare earths from coal, it could create a whole new value chain for the coal sector, which has been struggling amid increased regulation and a glut of cheap natural gas.