The mining newspaper for Alaska and Canada's North
The mining newspaper for Alaska and Canada's North
North of 60 Mining News - September 6, 2024
Massive stibnite (antimony mineral) collected from the Stibium prospect on Nova Minerals' Estelle project.
Antimony is a metalloid critical to America's national security.
U.S. Department of Defense is supporting one antimony mine project in Idaho and is looking to Alaska for additional domestic supplies.
A two-meter-thick vein antimony-enriched has been identified at Stibium.
Nova Minerals inspects stibnites samples collected from Estelle before shipments to labs in Alaska and Australia for metallurgical testing.
China's coming state-controlled restrictions on antimony exports has significantly elevated the criticality and price of this semi-metal that is already a top concern from many officials within the U.S. Department of Defense due to its use in military hardware and the dearth of antimony mines in the United States.
An element that has properties that fall between metals and non-metals, antimony has long been considered critical to the U.S. due to its use across a wide array of American industries, including the high-tech, defense, and energy sectors. Unease over reliable supplies of this metalloid, however, became more acute following Russia's invasion of Ukraine.
This is because the U.S., which currently has no antimony mines of its own, is reliant on imports from countries like China, Kazakhstan, and Russia, which produce roughly 82% of global supply.
In a 2022 report, the U.S. House Armed Services Committee said it "is concerned about recent geopolitical dynamics with Russia and China and how that could accelerate supply chain disruptions, particularly with antimony."
This concern is shared by DOD, which has invested in accelerating the development of Perpetua Resources Inc.'s Stibnite gold-antimony mine in Idaho and is looking elsewhere for secure and reliable supplies of this element vital to ammunition, flame-resistant compounds, night vision goggles, laser sighting, and other military applications.
Antimony is a metalloid critical to America's national security.
The search for reliable and secure supplies of antimony has the Pentagon and mineral exploration companies looking north to Alaska, a state that supplied the nation with this metalloid critical to national defense during periods of conflict over the past century.
"The antimony and other critical minerals found at Estelle has drawn major interest from the Department of Defense," Nova Minerals CEO Chis Gerteisen said when talking about the company's gold-antimony project in the West Susitna Mineral District.
Roughly 54 million pounds of antimony is used each year for the manufacturing of fireproofing compounds, batteries, ammunition, ceramics, specialty glass, optical storage, semiconductors, and other military and consumer products in the U.S.
The largest use of antimony is for an alloy called antimonial lead, which is used to make internal combustion engine (ICE) vehicle batteries, ammunition, electrical cable sheathing, printing machines, solders, and other products.
Antimony-based fireproofing compounds applied to personal protective equipment, mattresses, electronic devices, aircraft, and automobile seat covers have saved countless lives – from soldiers in the field to families on a road trip – over the past eight decades.
Another major use for antimony is to make high-quality glass used by both civilians and soldiers. For example, a small amount of antimony oxide has the ability to remove bubbles from super-clear glass used to make lenses for binoculars and similar optical equipment, as well as the glass screens of smartphones and other electronic devices.
"Antimony is a key ingredient in communication equipment, night vision goggles, explosives, ammunition, nuclear weapons, submarines, warships, optics, laser sighting, and much more," U.S. Army Major General (retired) James "Spider" Marks penned in a 2020 column published in The Washington Times.
Roughly 18% of America's annual demand for this strategic and critical metalloid is currently being met by recycling ICE vehicle batteries. Manufacturers in the U.S., however, must rely on imports for the remaining 44 million lb.
The U.S. Geological Survey calculates that 63% of U.S. antimony imports last year came from China.
U.S. Department of Defense is supporting one antimony mine project in Idaho and is looking to Alaska for additional domestic supplies.
While the Pentagon is never completely at ease with relying on a potential adversary for a strategic material like antimony, the August announcement that China is putting government controls on exports of this critical metalloid has increased the discomfort.
In announcing the antimony export restrictions that go into effect on Sept. 15, China's Ministry of Commerce said the government controls are required "to safeguard national security and interests, and fulfill international obligations such as non-proliferation."
The announcement has sent already high antimony prices soaring. At the end of August, the price for antimony had reached a new record high of $11.66 per pound, more than double the $5.60/lb average in 2023.
The mandated government approvals to export antimony out of China follow similar restrictions the communist nation has placed on the exports of gallium, germanium, and graphite – all highly critical to high-tech and clean energy manufacturing.
"China is weaponizing the world's access to critical minerals, and it's never been more urgent to secure the United States' critical mineral supply," said Perpetua Resources President and CEO Jon Cherry. "For a vast, secure source of American-made antimony, Perpetua Resources' Stibnite Gold project is the clear solution."
As large and important as the Stibnite project in Idaho is, it is only expected to produce enough antimony annually to meet about 35% of current U.S. demand, which has DOD officials looking for other secure and reliable supplies.
High-grade antimony deposits in Alaska are on their radar.
For well over a century, geologists have known that many of Alaska's famed gold districts also host rich stores of high-grade antimony.
"It has long been known that stibnite, the sulphide of antimony and the principal source of that metal, is widely distributed in Alaska," USGS Geologist Alfred Brooks penned in a 1917 report, "Antimony deposits of Alaska."
Brooks' early 20th-century investigation identified 67 stibnite occurrences in Alaska, most of which are found in areas also rich in gold – namely Nome, Fairbanks and Iditarod.
Some of these deposits, such as the Sliscovich Mine northeast of Nome and the Scrafford Mine north of Fairbanks, provided the U.S. with a domestic source of antimony during World War I.
"WWI created considerable demand for antimony," James Barker, who investigated much of Alaska's critical minerals potential while working as a geologist for the U.S. Bureau of Mines, told Mining News.
Small but very high-grade mines around Fairbanks represented the largest source of antimony out of Alaska during World War I.
"In 1915 antimony ore was mined on four properties in the Fairbanks district at the Scrafford, in Treasure Creek basin; the Stibnite, in Eva Creek basin; the Gilmer, in Vault Creek basin; and at Chatham Creek mine," Brooks wrote. "All the operations were on a small scale and consisted chiefly of open cuts. The total shipments of stibnite from the district during 1915 were 685 tons, which probably averaged 58% antimony."
Barker said the lump antimony mined from Scrafford "was sacked and transported by cable tram up to the ridge top and then by horse drawn wagons into Fairbanks to be shipped south by river steamer."
Intermittent mining of Scrafford and other deposits within the Treasure Creek basin also supplied small amounts of antimony during World War II, as well as during the Korean and Vietnam wars.
Today, Felix Resources Ltd. is exploring the Treasure Creek property where the historic Scrafford Mine is located. While this exploration has primarily focused on gold, the Australia-based company is investigating the idea of reviving the Interior Alaska property as a domestic source of antimony.
"With widespread high-grade antimony across the Treasure Creek Project area, which is surrounded by infrastructure and includes one of Alaska's largest historic antimony mines, Felix Gold is well-positioned to contribute meaningfully to the U.S.'s critical metal needs while also advancing our gold exploration efforts," said Felix Gold Executive Director Joe Webb.
It is estimated that a total of 1.08 million kilograms (2.4 million pounds) of antimony in 2,800 metric tons of ore averaging 38.6% stibnite, was extracted from nine seasons of small-scale underground mining at the Scrafford Mine between 1915 and 1977.
"Unlike lower-grade antimony often associated with larger gold systems, the high-grade antimony at Treasure Creek – exemplified by the Scrafford Antimony Mine, with historical production grades up to 58% Sb (the periodic table symbol for antimony) – presents a unique opportunity for stand-alone antimony production," Webb added.
Historical and modern exploration indicates that high-grade antimony and associated gold are widespread at Treasure Creek.
"The Scrafford antimony deposit is affiliated with an east-west, south-dipping shear zone of the same name that can be followed for at least six miles," Barker, who was project manager of the Treasure Creek Partnership prior to Felix Gold's 2021 acquisition of the project, told Mining News.
The Goodwin Mine, about 1,500 meters east of Scrafford, also supplied the U.S. with antimony during World War I, but the quantities and grades of the antimony produced from this underground mine are unknown.
Felix has also discovered high-grade antimony associated with its NW Array gold deposit about 2,000 meters west of Scrafford.
Drilling carried out by Felix Gold during 2022 and 2023 has confirmed both the precious metal and critical mineral potential of Treasure Creek.
Based on this drilling, an initial 25 million metric tons of Australian Joint Ore Reserve Committee- (JORC) compliant inferred resource averaging 0.58 grams per metric ton (467,000 oz) gold has been outlined so far in a near-surface deposit at NW Array.
Recognizing that the drilling was also cutting through antimony mineralization, Felix has resubmitted selected samples from its gold resource drilling at NW Array for antimony.
Highlights from antimony assays include:
• 1.5 meters averaging 15.99% antimony from a depth of 88.9 meters in hole 22TCRC041.
• Three meters averaging 14.24% antimony from a depth of 7.6 meters in hole 22TCRC071.
• 7.5 meters averaging 3.3% antimony from a depth of 141.7 meters in hole 22TCRC122, including 1.5 meters averaging 28% antimony.
• 1.5 meters averaging 26% antimony from a depth of 38.1 meters in hole 23TCRC135.
• 15.2 meters averaging 5.5% antimony from a depth of 21.3 meters in hole 23TCRC155, including 6.1 meters averaging 13% antimony.
• 6.1 meters averaging 7.7% antimony from a depth of 3.1 meters in hole 23TCRC176, including 1.5 meters averaging 28% antimony.
Given the high-grade antimony potential at NW Array, coupled with the wider potential indicated by previous mines and other targets identified across the wider property, Felix is assessing the viability of a standalone, near-term, high-grade, and low-capex antimony mine at Treasure Creek.
"Our focus is on advancing this potential rapidly, leveraging the strategic location of our assets in the U.S., where significant government support is available to secure supply chains for critical metals like antimony, which has strategic importance for U.S. national security," said Webb.
Much like Felix, Australia-based Nova Minerals Ltd. was drawn to Alaska for its gold potential but cannot ignore the high-grade antimony it has discovered alongside the precious metal.
Exploration carried out by Nova since 2018 has outlined 244 million metric tons of Securities and Exchange Commission's (SEC) S-K 1300-compliant measured and indicated resources averaging 0.3 g/t (2.72 million oz) gold, plus 231 million metric tons of inferred resource averaging 0.3 g/t (2.45 million oz) gold.
This resource is divided into two project areas at Estelle: the large bulk-tonnage Korbel area at the north end of the 198-square-mile (514 square kilometers) property and the higher-grade RPM area about 16 miles (25 kilometers) to the south.
A property-wide surface sampling and mapping program carried out last year, however, discovered widespread high-grade antimony mineralization across the district-scale Estelle land package.
A two-meter-thick vein antimony-enriched has been identified at Stibium.
This reconnaissance program led by Nova Minerals Head of Exploration Hans Hoffman discovered:
• High-grade antimony and gold at the newly discovered Stibium and Styx prospects about six miles (10 kilometers) southeast of the Korbel deposits.
• High-grade gold, antimony, silver, and copper in the Train and Trumpet resource target area in the southern part of the Estelle property.
• High-grade gold, antimony and copper at the Shoeshine and Shadow prospects about 1,000 meters east of Train.
• High-grade copper and gold at the Discovery and Muddy Creek targets immediately north of Train.
• Thick gold-bearing veins with associated antimony and copper at the Wombat target about midway between Korbel and Trumpet and Train.
"While Nova's primary focus continues to be on the gold, the discovery of high-grade stibnite, a primary ore source for antimony, associated with the gold system emerging at Estelle, represents a significant development for the company as antimony is listed as a critical and strategic mineral to US economic and national security interests by the US Department of Interior," Gerteisen said as the high-grade antimony results from the 2023 program rolled in.
China's export restrictions, which are slated to go into effect in less than two weeks, coupled with the corresponding spike in the price of antimony, have substantially elevated the need and desire to take a closer look at developing an antimony mine at Estelle.
Nova sees Stibium as the most compelling prospect for establishing such an antimony mine.
"At the Stibium prospect our field crews are continuing to find near surface, massive stibnite veining and gold-antimony zones, which present opportunities to assess the stand-alone potential of a quick start antimony operation, particularly with the China export restrictions," Gerteisen said during a late-August update on exploration at Estelle.
To gain a better understanding of Stibium's potential, Nova's geological team is carrying out extensive surface sampling to follow up on a two-meter-wide antimony-enriched surface vein that was traced for over 30 meters along strike during the 2023 sampling and mapping program.
"What we see there is massive stibnite veins all over the surface," said Gerteisen.
This includes the collection of a 2,500-kilogram sample from Stibium and a 500 kg sample from Styx for metallurgical testing at laboratories in Alaska and Australia.
"We are hitting the new Stibium prospect with intensity," said Hoffman.
Nova Minerals inspects stibnites samples collected from Estelle before shipments to labs in Alaska and Australia for metallurgical testing.
As field crews collect this bulk sample to test the quality of the Stibnite at Stibium, Gerteisen is in talks with high-level DOD officials about the potential of developing a pilot-scale operation at this target, as well as potentially building an antimony processing plant in Alaska that could process stibnite from Estelle and other projects like Treasure Creek.
A domestic processing plant capable of upgrading stibnite into antimony products for defense, high-tech, and clean energy is as important to DOD as the high-grade ore sources Estelle has the potential to offer. They see Alaska as an ideal place to locate such a facility.
"The company is working closely with various U.S. government agencies, including the Department of Defense, to potentially receive grant funding for fast tracking the Estelle antimony production," said Gertiesen. "The company believes its proposal applications already submitted for available grant funding will be taken under serious consideration, particularly in light of the recent announcement of China export restrictions."
The Nova Minerals CEO has been invited to discuss Estelle's antimony potential and what role the company could play in helping the U.S. shore up secure supplies of this critical metalloid during a DOD-related conference to be held later this month.
"We will update the market as we progress," said Gertiesen.
Over his more than 16 years of covering mining and mineral exploration, Shane has become renowned for his ability to report on the sector in a way that is technically sound enough to inform industry insiders while being easy to understand by a wider audience.
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