It is five years since the giant trucks hauling ore around the Mountain Pass mine in California’s Mojave desert fell silent. Molycorp, the only major rare earths producer in the US, had just collapsed under the weight of a $1.7bn debt. The bankruptcy burnt investors and left the nation almost entirely reliant on China for the supply of 17 metallic elements that are embedded in most high-tech products from wind turbines to electric vehicles and F-35 fighter jets.

Now, as relations between Washington and Beijing deteriorate further the US government is supporting the resurrection of Mountain Pass, which until the 1980s was the world’s biggest producer of rare earths. Disruption to supply chains during the Covid-19 pandemic has underscored the need for the US and other nations to ensure they are not reliant on a single country or company for vital supplies of raw materials and goods.

The Pentagon has agreed to fund MP Materials — a private equity backed company, which bought the mine for $20.5m in 2017 and restarted excavations — to design the first heavy rare earths processing facility in the US at the site. It is also backing a similar project in Texas proposed by Australian company Lynas, amid concerns that China could disrupt US defence and other industries by withholding supplies of rare earths. In July, it handed $29m to Urban Mining Company in Texas which manufactures rare earths magnets by recycling electronic waste.