Rare earth elements are not as scarce as their name implies, but a mine producing these strategic minerals outside of China is uncommon. So, when the Far East country dramatically cut its REE exports, the rest of the world scrambled to discover alternative sources of these much needed metals. With dozens of REE prospects scattered across its expanse, Alaska may help supply the United States’ growing need of these strategic elements.
“We cannot afford to be dependent on foreign sources of rare earth elements — and we believe Alaska’s subsurface contains vast quantities,” Alaska Gov. Sean Parnell said when rolling out his proposed Fiscal Year 2012 budget.
Gov. Parnell has asked the Alaska Legislature to approve funding for a comprehensive 3-year project to determine the potential of REEs deposits on state lands. This project will include conducting geologic field work and developing Alaska specific REE mineral-deposit models.
Parnell has also urged President Obama to consider directing the U.S. Geological Survey to conduct a similar inventory and geological program on federal lands in the Far North state.
“Alaska has already identified some of the most promising REE sites in the nation and we should be working to find more,” Parnell informed Obama.
Due to the growing focus on these technological metals, Alaska Department of Natural Resources Division of Geological & Geophysical Surveys (DGGS) has already begun compiling information on the state’s rare earth element potential.
In their initial assessment, DGGS has identified 71 known REE occurrences in the state and millions of acres of Alaska real estate prospective for these minerals.
“Our nation can look ‘North to the Future,’ to Alaska, for solutions on REEs,” Parnell touted in his letter to Obama.
Bokan highlights SE potential
Alaska’s REE potential is underscored by the discoveries made by Ucore Rare Metals Inc. at its Bokan Mountain property on Prince of Wales Island in Southeast Alaska.
An inaugural NI 43-101-compliant resource calculated for Bokan earlier this year estimates the deposit hosts an inferred mineral resource of 3.7 million metric tons grading 0.75 percent total rare earth oxides.
Though not particularly large or high-grade, 39 percent of the TREO found at Bokan are the more valuable heavy rare earth oxides.
Technology Metals Research co-founder Jack Lifton – considered to be the leading authority on the sourcing and end-use trends of rare and strategic metals – said Bokan Mountain is key to securing a domestic supply of the critical heavy REEs.
“Because of its proportion of heavy rare earths, (Bokan) is the most desirable deposit to be developed in the United States,” Lifton said. “For the future of this country, this development in Alaska is very important. I am hoping it comes to the attention of the national government.”
Amongst the HREEs found in the deposit at Bokan are dysprosium and terbium; two metals considered to be especially vital to the high-tech and green industries.
Dysprosium has been ranked by the U.S. Department of Energy as the number one most critical strategic metal to the United States. In 2004, dysprosium was valued at US$30/kg, compared to current values of more than US$450/kg.
The mineral resource at Bokan Mountain contains an estimated 0.29 kilograms of dysprosium per metric ton. Of the remaining four rare earth metals DOE deemed critical, Bokan contains an estimated 1.08 kilograms per metric ton neodymium, 0.05 kilograms per metric ton terbium, 0.03 kilograms per ton europium and 1.88 kilograms per metric ton yttrium.
In its initial assessment, DGGS has identified a trend of REE prospects stretching along the entire 135-mile-, or 220-kilometer-, length of Prince of Wales Island; many of which display characteristics similar to Bokan.
Based upon preliminary work carried out by the United States Geological Survey and subsequently reviewed by Fairbanks-based Avalon Development Corp., Contango Ore Inc. snatched up Salmon Bay and Stone Rock Bay — two of the island’s REE prospects.
The 980-acre Stone Rock Bay property is located about 12 miles, or 19 kilometers, south of Bokan Mountain project and the 2,540-acre Salmon Bay is located on the northern shores of the island.
Dora Lake, located some 20 miles, or 30 kilometers, north of Bokan Mountain is another interesting REE prospect unveiled in the initial DGGS assessment. Geological investigations in 1990 discovered REE-bearing pegmatites along a two-mile trend from the head of Dora Bay to Dora Lake. The geologists that conducted the survey estimate a 1-meter-thick vein dike near Dora Lake contains an inferred resource of about 500,000 tons of material with 442 parts per million niobium, 71 ppm uranium, 1,775 ppm yttrium, 1.53 percent zirconium, and 2,816 ppm REE. And, like Bokan, nearly half of the REE content of this prospect is estimated to be the highly sought after HREEs.
The REE-trend on Prince of Wales Island is a subset of a 350-mile-, or 560-kilometer-, belt prospective for these strategic metals that spans Southeast Alaska. All told, more than two dozen prospects have been identified along the panhandle.
“Those things like Bokan Mountain, those alkaline granitic complexes, occur in groups and there are a number of those in Southeast Alaska,” explains DGGS Senior Minerals Geologist Dave Szumigala.
Beyond Bokan
REEs have been discovered in anomalous amounts all across the state, but most of these prospects have not been investigated.
“In Southeast they (REE prospects) are better explored because there is better access overall,” Szumigala explains.
A band of prospects about 90 miles, or 135 kilometers, east of Nome is strikingly similar to the geology that hosts the REE deposits on Prince of Wales Island.
“It is the same sort of geology as far as we know right now. It is one of those unusual type granites that tend to have these types of elements in them – uranium, thorium and the rare earths.
Not only is the geology right, but a dozen REE-bearing occurrences have been identified along a 50-mile-, or 80-kilometer-, long trend of this prospective area.
Mount Prindle in Interior Alaska is a particularly exciting prospect due to the high concentrations of REEs discovered there.
The property — Located about 60 miles, or 90 kilometers, north of Fairbanks — was staked for uranium by MAPCO Inc. in 1978. Subsequent exploration identified several small deposits with extremely high concentrations of REEs and thorium. Rock samples taken from Mount Prindle returned grades of 15 percent REE and 0.1 percent uranium oxide.
The downside to this high-grade REE prospect is it lies within the White Mountain National Recreation Area. Though it is located in a region off limits to mining, a further understanding of this high-grade deposit could lead geologists to other similar prospects in Interior Alaska.
Other Interior Alaska occurrences include Hot Springs Creek, about 50 miles, or 80 kilometers, east of Mount Prindle; and Spooky Valley, about 100 miles, or 160 kilometers west of the high-grade prospect.
Core, the company that staked two of the REE prospects on Prince of Wales Island, has also laid claim to Spooky Valley and three other Interior Alaska REE properties.
Avalon Development — which has compiled its own database of Alaska REE prospects — will deploy a geological team to conduct mapping, geochemical sampling and other tasks designed to determine the presence and magnitude of rare earth element mineralization at Spooky and Core’s five other REE properties in Alaska.
Characterized by DGGS as a slightly different type of occurrence, REEs discovered near Manley Hot Springs in Interior Alaska have particularly high concentrations of niobium, a metal used in high-grade structural steel, super alloys and superconducting magnets.
A reserve of about 100,000 pounds of niobium is estimated to be present in placer tailings at Idaho Gulch. Known as Tofty Ridge, this niobium prospect is near a 12-mile-, or 19-kilometer-, long group of cassiterite- and gold-bearing placer deposits known as the tin belt, and the area is underlain by Cretaceous and Tertiary granitic plutons.
NURE outlines prospects
The National Uranium Resource Evaluation (NURE) program was originally charged with evaluating domestic uranium potential when initiated by the U.S. Atomic Energy Commission in 1973. Later NURE was expanded to test for REEs and other strategic metals, which led to the identification of a number of large REE prospective areas across Alaska.
Between 1975 through 1979 this extensive geological initiative blanketed about 80 percent of Alaska with stream sediment, soil and rock samples.
Though little work has been done to follow-up on the discoveries made under NURE, several large swaths of REE anomalies were discerned by the program. Areas of note are a 175-mile-, or 280-kilometer-, long trend stretching along the southern slope of the Alaska Range and a region stretching about the same distance west from the Cook Inlet.
As long as the Western World could depend on China as a low cost REE-supplier there was little incentive to investigate Alaska’s potential as a source of these metals important to high-tech and green technologies. With the Far East nation restricting global supply and prices skyrocketing, exploration companies and government agencies will surely look “North to the Future” to secure a domestic source of these vital metals.
