Rio Tinto has commenced the production of tellurium, a critical mineral used in advanced thin-film photovoltaic (PV) solar panels, at its Kennecott copper mining operation in Utah, US.

The tellurium produced will be refined by speciality semiconductors and performance materials producer 5N Plus in North America, under an agreement signed with Rio Tinto.

5N Plus will refine tellurium at its facility in Montreal, Canada, and primarily supply the refined tellurium to First Solar, under an existing supply contract between the two parties.

Furthermore, 5N Plus will use the tellurium to produce ultra-high purity semiconductor materials at its facility in St George, Utah, to serve customers in the security and medical imaging markets.

Tellurium is one of the ten metals and products that are being recovered from ore extracted at the Kennecott operation.

It produces around 15% of copper in the US with the ‘country’s lowest carbon footprint’.

Rio Tinto copper chief operating officer Clayton Walker said: “We are proud to deliver a new domestic supply of tellurium to support the manufacturing of solar panels and other critical equipment here in the United States.

“Approximately 90% of the world’s tellurium resource is contained in copper ore and no other metal has more critical mineral by-products than copper.”

Rio Tinto plans to produce 20t of tellurium annually through a new $2.9m circuit built at the Kennecott refinery.

Utah Governor Spencer Cox said: “Utah continues to play a key role in domestic production of critical minerals. With operations in our state like Rio Tinto Kennecott, we are able to demonstrate to the world how to responsibly make use of our natural resources to move toward a sustainable future.”