September quarter production was a record 11,998 tonnes, eclipsing the previous quarter's then-record output of 10,305t, with sales volumes jumping 36% partly due to the timing of shipments.

Revenue was up 143% year-on-year to US$99.8 million, adjusted EBITDA rose 488% to $68.3 million and adjusted net income was up 617% to $52 million, MP Materials said.

It said higher demand was driving increased market prices, which meant a 127% increase in its realised sale price to $7,693/t REO for the quarter, against a production cost of $1,449/t.

The high prices are prompting companies to eye expanding downstream, as the US looks to reduce its reliance on China which dominates the rare earths market.

MP Materials chairman and CEO James Litinsky said the company "continued to march toward our goal to restore the full rare earth supply chain to the United States, including progress on our Stage II optimisation project and Stage III downstream expansion into magnetics."

It expected to announce a location for Stage III before year-end.

The company said it had a long-term focus on neodymium-praseodymium (NdPr), a crucial input to powering electric vehicles, wind turbines, drones, robots and other advanced technologies.

Its output is currently further processed in China by circa 8% shareholder Shenghe Resources.

MP Materials said it had produced approximately 15% of the rare earth content consumed in the global market in 2020.

Shares in the company (NYSE: MP) have risen 220% since listing a year ago.

They last traded at $36.61, valuing it at $6.5 billion.