The project is in Hudspeth County where the sun shines on average for about 10 hours a day, 292 days a year, making a strong case to use photovoltaics to power the operation.

The company estimates it will require about 15MW to support mining and processing, which it expects will require a solar farm of about 18 hectares, scalable should the company decide to relocate its sintered neo-magnet manufacturing facility and associated infrastructure to the 243,000ha Round Top Mountain site.

Round Top will require either energy storage or trading, supplying excess energy to the grid balanced by drawing power at night and during the region's infrequent periods of low irradiance.

CEO Pini Althaus said the company was committing to extending the "clean-green" approach into the operation's design from the outset. About 60% of the project's output is targeted at clean-tech and green-tech applications, adding weight to the renewable energy commitment and ticking the right boxes for ESG investment purposes.

"Our 100% renewable energy plan means that USA Rare Earth will be producing materials for clean, green, renewable applications - using a process that employs clean, green, renewable power," he said.

A preliminary economic assessment (PEA) projects a pre-tax NPV (at 10% discount) of US$1.56 billion based on a 20-year mine plan based on only 13% of the identified measured, indicated and inferred resources. The PEA calculates an IRR of 70% and average net revenues of $395 million per annum.

Althaus told Mining Journal in April the private rare earths developer had the key pieces in place to re-establish an integrated US supply chain.

USA Rare Earth has an option to earn an 80% interest in the Round Top project from Texas Mineral Resources.

Round Top hosts 16 of the 17 rare earth elements, plus other high-value tech minerals such as lithium and is well placed to serve the emerging North American clean-tech industry.