Mining Engineering’s Weekly Rundown: Episode 32

First, Perpetua Resources has announced a major step forward in securing America’s domestic critical mineral supply chain. The Idaho-based company is partnering with the Idaho National Laboratory to host and run a modular pilot plant that will test the recovery of key defense-related minerals. This includes antimony, from Perpetua’s Stibnite Gold Project. This pilot plant aims to prove the feasibility of producing high-quality, military-grade antimony trisulfide, which is an essential material used in munitions and other advanced defense systems. This is part of a broader effort with the U.S. Army to establish a fully domestic “ground-to-round” supply chain for antimony. The project has received up to $22.4 million in Defense Ordnance Technology Consortium funding, which strengthens America’s mineral independence and Idaho’s role as a hub for workforce development in critical materials. The Stibnite Gold Project could eventually supply up to 35 percent of America’s antimony demand.

Next, copper giant Freeport-McMoRan is taking a cautious stance amid the industry’s ongoing merger and acquisition frenzy. Speaking at the Reuters NEXT conference in New York, CEO Kathleen Quirk said the company would only consider an acquisition if, quote, “the stars and the moon aligned.” Freeport, the world’s largest publicly traded copper producer, remains focused on internal growth rather than chasing deals. The company plans to expand production through new leaching technology in the U.S. This technology could yield the equivalent of a new mine’s output but at lower cost and with fewer regulatory hurdles. Quirk emphasized Freeport’s opportunity to grow   by up to 50 percent through internal organic growth within five years, while calling for stronger federal support to protect domestic copper producers.

Finally, BHP and Rio Tinto are marking a major milestone in sustainable mining. The two companies have received the first Caterpillar 793 XE “Early Learner” battery-electric haul trucks for testing at BHP’s Jimblebar iron ore mine. This industry-first collaboration with Caterpillar aims to reduce diesel dependency and accelerate the shift toward zero-emission mining fleets. The trucks are now entering on-site trials to evaluate performance, charging infrastructure, and power management. Both mining giants are targeting net-zero operational emissions by 2050, and this collaboration represents a key move toward that vision.

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