America had 16 copper smelters in 1976. Today it has only two. We still mine a million tonnes of copper a year, but a third of it leaves the country for refining. Last year we imported twice the refined copper we made. China floods the market with refining capacity, so refining pays almost nothing anywhere else. That's a hard problem to solve. Smelters mostly stay open by selling byproducts, and some only with government support. @nrg91720 might have found a way around that. His startup, Determinant Materials, says it can skip the smelter by sorting ground-up ore with flowing liquid, in small refineries at the mine. We do the same at Solugen, where we make smaller versions of chemical plants that sit next to our customers. If Nikhil pulls it off, the US could again own its copper refining. He explains how in this interview with @jrwolfe: goingdirect.substack.com/p/7…