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The US Department of the Interior has added copper, silver and metallurgical coal to its list of “critical minerals”, increasing the likelihood that these materials could be included in future tariff policies.
The three materials are among 10 elements added on Thursday to the list, which is updated every three years by the US Geological Survey. The list determines which minerals are included in the upcoming Section 232 tariff review of levies applied for national security purposes. It also plays a role in determining which domestic projects may receive federal support.
The Trump administration has made it a top priority to secure the supply chains of critical minerals used in the US, and greatly expanded the definition of what constitutes a “critical” mineral.
Several of the additions are materials that the US already produces in large quantities and exports, such as metallurgical coal and boron. The USGS said boron was added after input from industry producers in California.
“This list is a signal to the market about what the US government is prioritising,” said Gracelin Baskaran, director of the critical minerals security programme at the Center for Strategic and International Studies. “It will be easier to line up government support for a mineral designated as ‘critical’.”
While the addition of copper and coal was widely expected, the inclusion of silver has the potential to upend the market for the white metal if tariffs are introduced.
Suki Cooper, an analyst at Standard Chartered, said the question of whether the US would tariff silver was “murky”. The inclusion of silver on the list is the “first step in that process”, she noted.
However, the US has already included some customs codes for silver on its list of tariff exemptions, implying certain types of silver are unlikely to be hit.
Fears of potential silver tariffs have led to a huge build-up of inventories in New York — where stockpiles hit record levels last month — and caused temporary shortages of silver in London.
The US imports about two-thirds of its silver, which is widely used in electronics and solar panels, as well as in jewellery and for investment purposes. Silver prices hit record levels above $50 per ounce in October due to increased demand from industry as well as from investors.
Other additions to the list include lead, phosphate, silicon, uranium and rhenium, which is used in jet engines.
The USGS also identified certain elements that have the “highest risk” of disruption in supply chains — including rhodium, gallium, germanium, tungsten, several rare earth elements, and potash, which is primarily imported from Canada.
USGS defines a critical mineral as “those commodities which are essential to the economic or national security of the US; have a supply chain that is vulnerable to disruption; and serve an essential function in the manufacturing of a product, the absence of which would have significant consequences for the economic or national security of the US”.
A similar list is maintained by the Department of Energy, which includes 41 elements and was last updated in 2023.