Overlooked tin connects the Digital Age
Critical Minerals Alliances 2022 - September 12, 2022
Last updated 9/13/2022 at 3:04pm
From flashlights to supercomputers, tin is the glue for an electronic age
Lost in the clamor for lithium, nickel and other metals needed for the batteries powering electric vehicles and modern electronics, or the rare earth elements that turn stored energy into motion, is the enormous need for a much more modest metal that is so fundamental to the advancement of technology that it almost goes unseen – tin.
While other technology metals are critical to certain products and sectors of the economy, practically any device with a battery or electrical cord contains tin.
This is because almost half of the tin used in the world today goes into the solder used to make the connections in nearly every electrically powered device imaginable, from the most basic flashlight to the most advanced supercomputer.
A quick look at any printed circuit board will provide a glimpse of how fundamental tin solders are to modern electronics. While on the topside, these mainstays of modern electronics are a mesmerizing metropolis of microchips, transistors, resistors, capacitors, inductors, diodes, and processing units connected by electronic roadways carrying electronic data, a look underneath will reveal a silver-dotted landscape – each shiny dot representing the innumerable electronic connections made with tin alloy solders.
These tiny tin connections are so essential to the Digital Age and beyond that Massachusetts Institute of Technology researchers ranked tin as the metal most likely to be most impacted by new technologies such as autonomous and electric vehicles, advanced robotics, renewable energy, and computers.
Roskill, a world-leading metals consultant based in London, agrees with this assessment, and foresees these same technologies finding new uses for the alloying metal.
"Tin's extensive use in solders makes it the metal that glues the technology revolution together, and new applications, such as in emerging lithium-ion batteries, tend to grow as technology advances and diversifies," Roskill wrote.
Bronze swords to EVs
Whether it be solders gluing together the tech revolution, corrosion-resistant coatings on consumer goods, or the durability it infused into copper during its first rise to criticality during the Bronze Age, tin is nearly always used to bolster the properties of other metals.
"Almost without exception, tin is used as an alloy," the United States Geological Survey penned in the tin section of a comprehensive 2018 report on critical minerals. "The major uses of tin today are for cans and containers, construction materials, transportation materials, and solder."
While these uses provide the foundation for global tin markets, new applications in green technologies could add to the demand for this fundamental metal.
Some consider tin the "forgotten EV metal."
In addition to gluing together the massive maze of circuits in electric cars and trucks, tin is quietly gaining momentum as a performance-enhancing ingredient in the batteries powering these marvels of modern electronics.
In lithium-ion batteries, tin is being considered as an additive to enhance the maximum theoretical capacity of graphite and silicon anodes.
Tin and its alloys are also candidates for anode materials in next-generation rechargeable batteries such as sodium-ion, magnesium-ion, and potassium-ion cells.
Further expanding the frontiers for this fundamental tech metal, researchers have shown tin's potential as a safer and more abundant metal to replace rare and toxic materials used in energy-generating solar technologies, hydrogen production, and fuel cells.
No American tin mines
As traditional uses and new applications drive up the demand for tin, mining companies and recyclers are struggling to keep pace with the growing demand for this alloying tech metal.
As a result, the price for a pound of tin has climbed from US$7.50 (US16,500 per metric ton) in mid-2020 to as high as US$22 (nearly US$49,000/t) in early March. The price, however, had retreated to around $14.75/lb (US$32,500/t) by mid-year.
Currently, however, there are no tin mines in the U.S. or Canada to reap the benefits from strong prices of this overlooked but essential tech metal.
According to the USGS, the U.S. depended on imports for roughly 78% of its tin during 2021. Indonesia (25%), Peru (22%), Malaysia (19%), and Bolivia (17%) were the top suppliers of refined tin. The balance of the roughly 45,000 metric tons used by American industries last year was recycled from domestic and imported scrap.
"Tin has not been mined or smelted in the United States since 1993 and 1989, respectively," USGS inked in its Mineral Commodity Summaries 2022 publication.
This dependence on foreign sources for new supply and scrap, coupled with the alloying metal's fundamental uses across multiple sectors of the economy, is why tin lands on the list of minerals and metals critical to the U.S.
The two best options for establishing a North American supply to break its dependency on imports for this most critical technology metal are to develop some of the more than 100 tin occurrences identified across Alaska or revisit the past-producing East Kemptville Mine in Nova Scotia.
Global miner Rio Tinto, however, is investigating a third North American option.
Alaska's gateway tech metal
Aside from the geopolitical factors that weigh on U.S. dependency on imports for other critical minerals and metals, the primary reason there are not any North American tin mines is that deposits of this alloying metal are rare in both the U.S. and Canada.
Alaska, which hosts more than 100 known tin occurrences, is considered the best place in the U.S. to establish a domestic source of this long-lived critical metal.
"Today, Alaskan tin deposits are known to be widespread, occurring from the central Alaska Range north to the Brooks Range and across Interior Alaska ... Southwest Alaska and the Seward Peninsula," according to Mineral Deposits of Alaska, a 1997 publication that compiles the work of nearly 50 geologists.
And when it comes to technology minerals exploration in Alaska, tin could be considered the gateway metal due to its direct affiliation with nearly 30 of the 50 metals deemed critical to the U.S.
Beryllium, bismuth, chromium, fluorspar, gallium, indium, manganese, niobium, five platinum group metals, 14 rare earth elements, scandium, strontium, tantalum, tungsten, and vanadium, are among the critical metals and groups of elements associated with the placer and lode tin occurrences across the state.
Most of Alaska's tin occurrences are placer deposits of cassiterite, the primary tin mineral, found across the breadth of the state. This follows a global trend – most of the world's production comes from alluvial deposits rather than the hardrock sources that provide ore for the large-scale production of most minerals.
"Placer deposits have traditionally been an important source of tin; in 2012, they accounted for about 70% of the world output of cassiterite concentrates," USGS penned in its 2018 critical minerals report.
There are a couple of advantages that make placer deposits an intriguing source of tin – Mother Nature has completed the first stage of mineral processing – eroding cassiterite from the hard rock sources and concentrating the tin mineral in deposits that can be mined with simple gravity recovery systems – and these rich sources of Alaska tin are almost always associated with an array of other metals critical to the U.S.
The best-known placer tin regions in Alaska are at Tin City, near the gold rush town of Nome, and the Tofty Tin belt, about 90 miles northwest of Fairbanks.
Placer tin was mined from both these areas early in the 20th century but has had very little modern exploration or production.
In addition to the alluvial deposits, Alaska hosts hardrock tin deposits, including one associated with the Tin City placers.
"One of the few primary hard-rock tin deposits in the United States is the Lost River tin-tungsten-fluorine deposit in the Seward Peninsula, Alaska," the USGS wrote in its 2018 critical minerals report.
Other Alaska hardrock tin deposits include Kougarok, which is located about 90 miles east of Tin City; Sleitat Mountain, found in Southwest Alaska; and Coal Creek, a tin-silver-lithium deposit about mid-way between Anchorage and Fairbanks.
Work in the 1980s estimated a portion of the tin-bearing granites there hosts some six million lb of tin in 240,000 tons of historical resource averaging 1.3% tin. Some of the cassiterite deposits at Kougarok also host considerable amounts of critical metals beryllium, tungsten, fluorspar, niobium, and tantalum.
When it comes to hardrock sources of tin in Alaska, the Coal Creek prospect on Discovery Alaska Ltd.'s Chulitna project roughly midway between Fairbanks and Anchorage shows great promise due to its proximity to rail and grid power, which is a narrow band in the Last Frontier state.
Drilling in the 1980s outlined a historical deposit with roughly 4.8 million metric tons averaging 0.27% (roughly 28.6 million lb) tin, along with silver and zinc.
A 2022 reanalysis of core from the historical drilling at Coal Creek has identified lithium associated with the tin.
Discovery Alaska, an Australia-based mineral explorer, says its initial scan detected lithium across broad zones in all twelve holes.
"The company is excited to identify the first lithium prospect in Alaska, with access to extensive historic drill core that will allow us to rapidly expedite exploration works at Coal Creek, and in a strategic location close to the major Parks Highway and the state-owned Alaska railroad," said Discovery Alaska Director Jerko Zuvela.
These lithium-bearing zones are also prospective for tantalum, niobium, and other critical minerals.
"The company will accelerate works to test the remaining prospective drill core to determine potential scale of the lithium bearing zone," Zuvela added.
Revisiting East Kemptville
The best place in Canada to look for tin is Nova Scotia, where Avalon Advanced Materials is considering the economics of re-establishing a tin mine at East Kemptville, which was operated by Rio Algom from 1985 until 1992.
Avalon, which entered into an agreement for limited surface access to East Kemptville in 2014, has completed limited drilling to affirm the historical resources. Based on this drilling, the company has outlined 22.97 million metric tons of measured and indicated resources averaging 0.153% (roughly 77.5 million lb) tin, and 14.25 million metric tons of inferred resource averaging 0.139% (roughly 43.7 million lb) tin.
While this resource is substantial, Avalon's immediate interest is in the tailings and ore stockpiled on the property.
The company says that only about half the tin and none of the copper, zinc, and other metals were recovered during the early years of previous operations at East Kemptville.
Much like Coal Creek in Alaska, the tin-bearing rocks on this Nova Scotia property also contain significant lithium, with the potential for indium, gallium, and germanium.
Avalon proposes using ore-sorting technology to recover the high concentrations of critical and base metals contained in the ore stockpiles at East Kemptville. By doing so, the company would be remediating the old mine site while producing metals needed for modern technologies.
In 2018, Avalon published a preliminary economic assessment outlining its tin-producing rehabilitation plans for East Kemptville.
"Avalon strives to be a leader in adopting sustainability best practices and innovative project designs," Mark Wiseman, a sustainability consultant to Avalon, said at the time. "This approach will create an early revenue stream and a platform for growth, while providing a solution for the long-term environmental liability on site."
The company says it is in discussions with several parties interested in new sources of supply of tin concentrate or interested in tin development opportunities. The East Kemptville project, however, is currently inactive until Avalon secures full surface rights to the property.
Third option – Montana
While revisiting East Kemptville or unlocking the potential of more than 100 tin occurrences across Alaska are currently the best options for North American supplies of tin, Rio Tinto believes there may be a third option – Montana.
Toward the end of 2021, the global mining company partnered with the USGS to survey an area of southwestern Montana highly prospective for rare earths, tellurium, tin, tungsten, copper, molybdenum, and gold.
To further explore this potential, Rio Tinto is providing support to airborne magnetic and radiometric surveys being carried out as part of the USGS' Earth Mapping Resources Initiative (Earth MRI), a nationwide program to enhance domestic mineral supplies and decrease America's heavy reliance on foreign sources of minerals that are fundamental to economic and national security.
This marks the first partnership between a mining company and Earth MRI.
"By working together, we are sharing expertise, resources, and knowledge to make the search for critical minerals more efficient," said Rio Tinto Exploration Director Chris Welton.
The Earth MRI data collected through this partnership will be available to the public.