Before opening new mines, perhaps the old ones should have been looked at better. Not the tunnels, not the lines still to be chased, not the promise of digging another mountain to satiate batteries, solar panels, chips, radars, electric cars and the entire catalog of indispensable modernity. It was enough to stop in front of what remains outside: piles of ground rocks, mud, dust, residues left on the margins of extraction. That stuff that for decades had an inelegant and very practical name: waste.
Now a study published in Science puts those mining wastes back at center stage. The point is almost embarrassing in its simplicity: in the United States many critical minerals are already mined together with copper, gold, zinc, nickel and other metals, only that they often end up separated, set aside and dispersed in waste materials, i.e. the residues of mining processing that must be stored and controlled to avoid environmental damage. The researchers combined data from federally licensed metal mines with geochemical measurements of 70 elements in ore samples, trying to estimate how much strategic material is already being moved and left behind.
The ore already excavated
The word “critical” here must be taken literally. Cobalt, nickel, manganese, lithium, tellurium, germanium and rare earths enter the production of rechargeable batteries, wind turbine magnets, semiconductors, solar panels, medical devices, communications technologies and defense systems. They are small materials in the public narrative and gigantic in the industrial supply chain: when they are missing, entire parts of the economy stop.
The study suggests that a very significant share of these materials is already within the US mining circuit. Except that it is in the wrong position in history: next to the main metal, within processing flows designed to recover more. The mines, in fact, are designed to extract what makes the plant economically sustainable: copper, gold, zinc, nickel, molybdenum. Everything else can become chemical noise, impurities, minor fractions, residues to be managed. Yet right there, in the middle of the part treated as encumbrance, a reserve already torn from the rock can hide.
According to the researchers, if the United States could recover 90% of these byproducts, it could cover almost all of its needs for critical minerals; even a 1% recovery would significantly reduce import dependence for many analyzed items.
The problem may be less “where do we find more minerals” and more “why are we throwing away the ones we have already brought to the surface.” A huge difference, because opening a new mine requires years, authorizations, local opposition, infrastructure, water, energy, roads, plants, promised and often postponed reclamation. Better recovering what already passes into active mines remains complex, but it starts from a less absurd point: the material has already been excavated.
There is also another element that weighs. In many cases, recovering less than 10% of these byproducts could generate greater economic value than the primary metals sold by some U.S. mines today, the analysis found. A sentence like this seems written on purpose to make anyone who has always imagined waste as the worthless back room of the extractive industry jump on their seats.
The waste makes politics
Of course, American politics has already smelled the issue. In July 2025, the Interior Department announced measures to increase recovery of critical minerals from mine tailings, coal tailings, waste materials and abandoned uranium mines, as part of the Trump administration’s strategy to reduce reliance on China-dominated supply chains. The interesting thing is that, under the usual permanent national emergency rhetoric, this time there is a concrete idea: recover what has already been excavated before transforming every critical mineral into a new commercial front. Even a broken watch, every now and then, indicates the right time. Even a broken watch, every now and then, indicates the right time. Then of course, the problem of the watch remains: as soon as he smells rare earths, he starts looking at Greenland again as if it were his own property. And when the dossier moves to Africa, the tone becomes even heavier: we saw it with the Zambia case, where US health aid entered the same negotiating perimeter as copper, cobalt and lithium.
Here there is no need to transform every residue into a geopolitical manifesto. We need to understand if there is a serious way to recover strategic materials while reducing the mass of mining waste, the pressure on new areas to be excavated and some of the vulnerability of supply chains. The USGS, the US geological survey, is already working on this front and defines mining waste as a possible, still underexploited source of essential raw materials. In historic sites, these residues can also represent an environmental and health problem; recovery, if done well, can accompany reclamation interventions.
Concrete examples help more than any slogan. In Tar Creek, Oklahoma, an old lead and zinc mine site left waste where germanium and zinc were redistributed during mineral weathering processes. Germanium is used in defense and communications technologies. At the Bingham Canyon mine in Utah, a significant amount of tellurium ends up in waste materials produced during copper mining; tellurium is used in electronics and steel.
This is the least romantic and most important part. Recovering critical minerals from waste isn’t about sticking a shovel into a pile and pulling lithium out of a Lego box. Mining tailings are complicated mixtures. Useful elements can be found in low concentrations, bound to other minerals, dispersed in different chemical forms, sometimes modified by time, water, oxidation, site conditions. We need mineralogical analyses, separation technologies, industrial processes, energy, investments, environmental controls and clear rules. The same study underlines that the possibility exists, but it requires advanced technologies, additional processing steps and policies capable of making recovery feasible on a large scale.
Mining waste can become a resource, of course. They can reduce the volume and impact of some waste, strengthen industrial safety, ease pressure on imports and perhaps avoid some new extraction. But only within a controlled supply chain, with transparent numbers and systems that do not move the problem from a pile of waste materials to another, more elegant discharge.
The energy transition needs materials. This phrase is now repeated so often that it seems like a tax on common sense. The next step is to decide how to get them without replicating every old vice of mining: digging, selling, abandoning, reclaiming when someone remembers. The United States, at least on this point, displays a perfect paradox. They look for critical minerals in maps, in treaties, in trade wars, in national security speeches. Some of it was already there, in the mine waste. In the form of waste, as often happens with things that matter when no one has yet decided to measure them properly.
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