Inside Freeport-McMoRan’s only copper smelter in the US, on the outskirts of Miami, Arizona, concentrated molten metal are transformed into neat, purified slabs, which are then shipped to a refinery in El Paso, Texas — a rare example of entirely made-in-America copper.
The process of converting raw materials into their purest forms via smelters and refineries has become almost prohibitively expensive in the US because of regulation, energy costs, labor and a glut of cheap Chinese competition.
The Freeport smelter in Arizona was one of several industrial processing facilities built near the turn of the 20th century. Today it stands almost alone, one of the very last copper smelters operating in the country. The plant costs about 3 times more to operate than the company’s smelters outside the US. Instead of processing copper in the US, many miners now turn abroad, where there’s more than enough capacity.
The Freeport facility has remained afloat by processing ore from the company’s nearby mines and boosting production of sulfuric acid. But the economic pressure from China’s army of smelters has been constant over the years and caused the US industry to downsize in the late 2000s and mid-2010s while demand for US copper dwindled. Demand is now back but the US capacity isn’t.
The US has plenty of copper in the ground — with reserves of ~47 million metric tons, #7 globally and ahead of China. There are copper projects across the US, such as the Resolution Copper project (a giant deposit in Arizona owned by Rio Tinto Group and BHP Group), that could, in theory, add about 1.5 million tons to the country’s annual production — enough to fulfill almost all domestic demand.
Still, it takes an average of 29 years from the discovery of a US copper deposit to the start of production — the longest development time in the world after only Zambia. And the US lacks the key smelting and refining operations to process all that ore domestically.
The US copper industry has been shrinking for decades. It peaked around 1997, producing 1.9 million tons of the metal from the roughly 35 mines and 11 smelters that were then operating. Now there are 25 mines and only two smelters that process mined ore — Miami and Rio Tinto’s Kennecott in Utah — plus a third dedicated to anodes and scrap. China produces about 13 times more refined copper than the US and operates more processing facilities than anywhere else in the world, part of a nationwide project that began in the ’90s to meet demand for copper.
China now has so much smelting capacity that treatment and refining charges have gone negative — smelters are effectively paying more for their concentrate than the value of the metal it contains.
The last smelter for mined copper built in the US was Kennecott, which began operations in 1995. The current cost to construct a domestic smelter would be around $3B.
One of the world’s top copper producers, Freeport owns or co-owns 3 smelters globally, including a new one in Indonesia, which came about only after the government there ordered mining companies to build domestic processing plants as part of a government-led push to onshore its minerals supply chain.
In the desert town of Hayden, ~95 miles southeast of Phoenix, an idled smelter owned by Asarco LLC, a unit of Grupo México, collects dust while the company contemplates its future. The plant was mothballed in 2019 following a labor dispute that devolved into a strike. Even after the issue was resolved, the plant remained shut, as competing Chinese facilities came online, tightening margins for existing plants.

“We just don’t have all the subsidies or the lack of environmental controls that countries like China do.”
Copper processing isn’t pretty work. Smelters belch sulfurous exhaust from smokestacks that can expose nearby residents to arsenic and lead.
In 2015 the EPA announced a settlement with Asarco after discovering toxic pollution spewing from the facility.
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