Differing paths for critical twin metals
Niobium-tantalum typically found with tin, REEs in Alaska Critical Minerals Alaska 2020 – Published October 29, 2020
Last updated 12/23/2020 at 4:32am
Niobium and tantalum are nearly identical critical mineral twins with unique personalities that takes them on separate career paths in the defense, energy, high-tech and medical sectors.
"The leading use of niobium is in the production of high-strength steel alloys used in pipelines, transportation infrastructure, and structural applications," the United State Geological Survey penned in a 2018 report on the indispensable twins. "Electronic capacitors are the leading use of tantalum for high-end applications, including cell phones, computer hard drives, and such implantable medical devices as pacemakers."
Not only are niobium and tantalum difficult to distinguish due to shared physical and chemical properties, their close bonds mean that where you find one of the twins you typically find both.
"Niobium and tantalum are transition metals that are almost always found together in nature because they have very similar physical and chemical properties," the U.S. Geological Survey wrote in a 2018 paper on the twin metals.
Niobium and tantalum share two more traits that place these indispensable twins firmly on the list of minerals and metals the USGS has deemed critical to the security and economic wellbeing of the United States – the U.S. is 100% import reliant for both, and you cannot find a good substitute for either without sacrificing performance and increasing costs.
When exploring for niobium and tantalum in Alaska, you can usually find the twins hanging out with a whole family of critical minerals, including tin and rare earths.
Tough, resistant to corrosion and a high melting point, niobium tends to be the blue-collar working twin.
Roughly 78% of the 11,000 metric tons of niobium imported into the U.S. last year was used as an alloy in high-strength steel.
"As little as 0.1% of this metal can considerably enhance the strength and stability of structural steel," according to Admat Refractory Metals, a Pennsylvania-based supplier of specialty metals.
This strength and stability are crucial to industrial applications such as pipelines and automotive sheet metal.
Niobium's extreme resistance to heat and corrosion also makes this exceptionally strong metal an important ingredient for iron-, nickel- and cobalt-based superalloys that need to stand up to high temperatures.
Roughly 22% of the niobium consumed in the U.S. is used to make high-temperature superalloys used in parts that go into jet engines, rockets, gas turbines and turbochargers.
Adding to its résumé of "super" properties, niobium is among the most powerful superconducting metals.
Superconducting magnets made from niobium-germanium, niobium-tin and niobium-titanium alloys are used in a range of important devices, from imaging equipment to particle accelerators.
The magnetic resonance imaging (MRI) scanners, which use niobium superconducting magnets, along with radio waves and a computer to create detailed images of the inside of a human body – is among the applications of this critical metal's special characteristics.
Niobium superalloy magnets also play a crucial role in the Large Hadron Collider, a 17-mile circular tunnel deep under the border between Switzerland and France that physicists use to collide particles together at near the speed of light. These high-energy collisions of protons help scientists investigate dark matter, antimatter, and other secrets of the universe.
Niobium plays a key role in creating the powerful magnetic fields that guide and squeeze the particle beams that generate these volatile collisions.
Niobium-titanium magnets currently being used to produce these powerful fields are being replaced with even more powerful niobium-tin magnets used in the search for dark matter and other cutting-edge experiments at the Large Hadron Collider.
International scientists are now floating the idea for the Future Circular Collider, a 62-mile successor that would be 10 times more powerful than the Large Hadron Collider. This massive US$27.5 billion project, including initial and upgrade costs, would need a whole lot more niobium and a slew of other metals considered critical to the United States.
Beyond its "super" characteristics, niobium is also hypoallergenic and inert, making it a good candidate for uses inside the human body, such as pacemakers and prosthetics.
Niobium is also one of the few metals that can be heated to produce a wide array of iridescent colors. The heat creates anodized oxide layers on the surface of niobium that creates this color changing effect by diffracting the light that bounces off it.
This ability, coupled with being hypoallergenic, makes it a popular for creating colorful jewelry, especially for body-piercing.
In addition to sharing many of niobium's traits, tantalum has an exceptional capacity to store and release energy that takes it down a high-tech career path.
Much of the tantalum mined globally goes into powerful capacitors and resistors.
Because it is so good at storing and releasing energy, tantalum capacitors and resistors can be exceptionally small. This is crucial in the shrinking of modern electronics, such as smartphones, hearing aids, personal computers, and automobiles.
Tantalum oxides are also used to make lighter weight glass camera lenses that produce a brighter image.
In addition to traits that set it apart from its twin, tantalum shares many of niobium's characteristics and is often used for similar applications. Being substantially more expensive, however, tantalum typically imbues its properties as a coating on other metals.
One such parallel is devices going inside the human body, where tantalum-coated blood vessel stents, plates, bone replacements, suture clips and wire are often used.
In the chemical industry, tantalum's corrosion resistance makes it useful as a lining for pipes, tanks, and vessels.
While deposits of both niobium and tantalum are found in the United States, it has been nearly six decades since either of these critical minerals have been produced domestically.
"Primary production of niobium or tantalum in the United States has not been reported since the late 1950s; therefore, the United States has to meet its current and expected future needs by importing primary mineral concentrates and alloys, and by recovering them from foreign and domestic alloy scrap," USGS inked in its 2018 report on the indispensable twins.
As a result, the U.S. imported an estimated 24.3 million pounds of niobium, valued at US$460 million, to meet the needs of U.S. manufacturers in 2019.
Accounting for roughly 67%, Brazil was by far the United States' largest source for niobium. Canada (23%), Russia (3%) and Germany (2%) accounted for most of the balance.
NioCorp Developments Ltd. plans to produce niobium, along with scandium and titanium, at its Elks Creek mine project in Nebraska.
While tantalum consumption in the U.S. is less than 10% that of niobium, the higher price this energy storing metal fetches makes up much of the differential.
According to the USGS, about 1.9 million lb of tantalum, valued at US$270 million, was used in the U.S. during 2019.
Rwanda, at 39%, was the largest supplier of tantalum ores and concentrates to the U.S., followed by Brazil (20%) Australia (17%), and Congo (10%).
When it comes to tantalum metal, China, at 39%, was America's largest supplier last year, followed by Germany (19%), Kazakhstan (14%), and Thailand (12%).
Because the U.S. is wholly dependent on foreign sources for both niobium and tantalum, it is vulnerable to potential supply disruptions from swings in the metal markets, such as the recent downturn that interrupted operations at several mines, and global economic instability that could create supply problems.
"Other possible disruptions include war, civil unrest, political changes, natural disasters, environmental issues and market manipulation," the USGS penned in its niobium-tantalum paper. "For example, rebel sales of 'conflict coltan' (coltan is a niobium-tantalum mineral) in the Democratic Republic of Congo, amidst a civil war, have led to discussions about supply-line transparency and traceability as tools for excluding illegal columbite-tantalite while keeping the market open for legitimate, small-scale artisanal mining in central Africa."
Increased global competition for niobium and tantalum is expected to drive up the competition for these strategic twins.
"Niobium and tantalum are considered critical and strategic metals based on the potential risks to their supply (because current production is restricted to only a few countries) and the significant effects that a restriction in supply would have on the defense, energy, high-tech industrial, and medical sectors," according to the USGS.
Alaska is home to potential domestic supplies of both indispensable metals.
Twins found at Kougarok
The Kougarok prospect about 90 miles north of Nome on the Seward Peninsula is one Alaska locale where both niobium and tantalum are known to exist.
Situated on the north side of Kougarok Mountain, this prospect is best known for its tin, another of the 35 metals considered critical to the United States.
While an official resource estimate is not available for Kougarok, work carried out by Anaconda Mining Company in the 1980s has outlined potentially large and critical mineral-rich deposits at Chuck's dike, Main plug and Roof greisen, the main targets identified so far.
The richest tantalum and niobium concentrations were identified in Main plug. According to preliminary calculations, this portion of the larger Kougarok prospect hosts 1.4 million metric tons averaging 0.45% (12.6 million lb) tin and 0.1 to 0.3% (2.8 million to 8.4 million lb) combined niobium and tantalum.
Navigator Exploration Corp. and Chapleau Resources, Ltd., which optioned Kougarok in 2001, took a closer look at the prospect's tantalum potential. These explorers found elevated tantalum values across the wider prospect area.
Numerous other tin deposits are found on the Seward Peninsula, making this region of western Alaska highly prospective for the niobium and tantalum that is associated with the specialized granites that host this critical metal.
Interior placer niobium
The Tofty tin belt in Interior Alaska is rich in placer tin deposits and hosts intriguing clues of at least a third of the 35 minerals and metals critical to the U.S., including niobium and tantalum.
The tin potential of the Tofty area became readily apparent to the early placer miners that discovered gold in this area about 90 miles northwest of Fairbanks.
Niobium is also present in the gold- and tin-rich placers mined in this area. Pan concentrates from the tailings at Idaho Gulch and Miller Gulch, gold producing creeks in the area, turned up 0.2 to 7% niobium bearing minerals.
It has been estimated that the placer tailings in the upper portion of Idaho Creek contain roughly 100,000 lb of niobium.
While investigating the lode source of the prolific tin found in the streams of the Hot Springs District, the Alaska Division of Geological and Geophysical Surveys found interesting quantities of many of the minerals and metals considered critical to the United States, including bismuth, chromium, gallium, manganese, niobium, rare earth elements, scandium, strontium, tantalum, and vanadium.
About 60 miles north of the cassiterite-bearing streams at Tofty, Ucore Rare Metals has found that the rare earths-rich placer deposits on its Ray Mountains property contain appreciable amounts of tin and other critical minerals.
Concentrates from gravity separation of placer samples collected at Ray Mountains returned up to 50% tin; 10% rare earths; and 0.01 to 1% tungsten, tantalum, and niobium.
A definitive lode source of the 100-meter-deep bed of critical mineral-bearing gravels at Ray Mountains has yet to be found.
With SE rare earths
Niobium is also found with the rare earths at Ucore's Bokan Mountain project on Prince of Wales Island in Southeast Alaska.
"REE prospects at Bokan Mountain may have the greatest immediate potential for development of an REE resource in the state," USGS penned in its 2017 report on Alaska's critical mineral potential.
A rare earth mine here has the potential to provide a by-product supply of niobium, zirconium, beryllium, hafnium, titanium, and vanadium.
According to a late-2019 calculation, the Dotson Ridge deposit at Bokan hosts 4.79 million metric tons of indicated resource averaging 460 parts per million (2,205 metric tons) niobium; 1,880 ppm (9,001 metric tons) zirconium; 48 ppm (231 metric tons) beryllium; 37 ppm (178 metric tons) hafnium; 0.37% (17,715 metric tons) titanium dioxide; 97 ppm (464 metric tons) vanadium; and 0.6% (31,722 metric tons) total rare earth oxides.
At the same cut-off grade, this deposit also hosts 1.05 metric tons of inferred resource averaging 470 ppm (493 metric tons) niobium; 1,897 ppm (1,992 metric tons) zirconium; 46 ppm (48 metric tons) beryllium; 35 ppm (37 metric tons) hafnium; 0.44% (4,652 metric tons) titanium dioxide; 112 ppm (118 metric tons) vanadium; and 0.6% (6,979 metric tons) total rare earth oxides.
Dotson Ridge, however, is only one of numerous REE occurrences radiating from Bokan Mountain. Back in the 1980s, the U.S. Bureau of Mines estimated that these occurrences contain some 374 million lb of rare earths plus yttrium; another 638 million lb of zirconium, another critical metal; 96 million lb of niobium; and an unquantified amount of tantalum.
While this resource estimate does not comply with modern reporting standards, it does provide a sense of the critical mineral potential at Bokan Mountain and similar rare earth targets across Alaska.
A stretch of Southeast Alaska, extending 200 miles northwest from Bokan Mountain, is known to host additional rare earth prospects such as Salmon Bay at the northern end of Prince of Wales Island.
Where to find the twins
The good news for explorers seeking niobium and tantalum in Alaska is the two deposit types – tin-bearing granites and REE-bearing intrusive rocks – are typically found close to each other across the state.
Working with the Alaska Division of Geological & Geophysical Surveys, USGS has identified 10 areas of Alaska that are highly prospective for tin-rich granites that typically also host tantalum, niobium and a suite of other critical minerals.
Besides the Kougarok area on the Seward Peninsula, the Tofty and Ray Mountains area of Interior Alaska, and the Southeast Alaska Panhandle, other regions that are good hunting grounds for niobium and tantalum are:
• Northern Alaska Range, an area arcing about 220 miles west from the town of Tok in eastern Alaska.
• Western Alaska Range, a 15,000-square-mile very high potential region of Southwest Alaska centered on the Revelation Mountains.
• Yukon-Tanana, a large swath of Interior Alaska extending from the Yukon-Alaska border to the Roy Creek rare earth prospect north of Fairbanks.
• Kuskokwim-White Mountains, which stretches about 500 miles southwest from Yukon-Tanana.
• Darby Hogatza, an area of know uranium and REE occurrences that arcs 200 miles east from the Seward Peninsula.
• Porcupine, an area centered on Spike Mountain in far northeastern Alaska.
The areas that show promise for tin-bearing granites and rare earth deposits may also provide domestic sources for the indispensable twins – niobium and tantalum.