Metals found in the United States—from aluminum to zirconium—occur naturally in sufficient supply to meet the nation’s industrial needs. Surprised? I was until reading a recent research paper titled “By-product recovery from US metal mines could reduce import reliance for critical minerals”. Researchers from the Colorado School of Mines published this article (Holley et al., 2025); their study quantifies critical minerals that currently are not recovered at active mines in the United States—but that could be separated and available to meet domestic demand.
For many materials, including the cobalt, manganese, nickel and lithium used in rechargeable batteries and the rare earth elements for electric vehicle and wind turbine magnets, demand is increasing. The US Geological Survey and the US Department of Energy have designated 60 of these minerals and chemical elements as critical for energy technologies, for national security, and/or for the overall economy. Some are currently imported from countries where supply chains are vulnerable to disruption, such as from China and the Democratic Republic of Congo.
Niobium crystals, fabricated, and a 1 cm3 cube; niobium increases the toughness and strength of high-grade structural steel and is an important addition in applications such as modern automobile structures; Brazil is the leading producer (Wikipedia)
Usually, we don’t find critical minerals in high concentrations, as they occur in small amounts in rocks rich in another mineral. At active mines, additional processing and metallurgical steps can enable recovery of an array of elements, known as by-product recovery, besides separating the primary product. This is occurring at a few mines in the United States, including at a copper mine in Utah where tellurium and rhenium are also being recovered, and at platinum-palladium mines in Montana where nickel and cobalt are also processed. At the vast majority of mines, however, by-products are discarded into the waste stream, contributing to mine waste such as tailings, which require storage and, ideally, continuous environmental monitoring. Meanwhile, in the United States, billions of dollars are spent annually to import these minerals and elements.
Critical Minerals and Chemical Elements
The US Geological Survey considers the minerals and elements that are used in over 230 sectors of the economy to identify those vital to the US economy and national security, and that also face potential risks from disrupted supply chains. The November 2025 final List of Critical Minerals contains 60 materials, shown below. USGS reviews the list at least every two years to reflect new data and changing supply conditions.
In my research about critical minerals, I came across interesting information. From the USGS: the United States spent an estimated $178 billion on 2024 net imports of processed mineral materials, including metals and chemicals (USGS, 2025, Figure 1—The Role of Nonfuel Mineral Commodities in the US Economy). And also: “The United States is 100 percent import-reliant for 12 of the minerals deemed “critical” by the U.S. Geological Survey and over 50 percent reliant for another 29. China dominates production or processing for 29 of these, including rare earths, antimony, cobalt, copper, graphite, and lithium. Even when mined elsewhere, many of these materials still flow to China for processing due to its unmatched midstream infrastructure.” (Neville, 2025, Global Policy Watch.) Not a bright picture, IMO.
In addition to mapping new domestic deposits of minerals and elements, for many years the USGS also has been inventorying mine waste, as it is possible to reclaim critical minerals from these wastes. Re-mining of abandoned sites and tailings collections, however, poses significant engineering and regulatory challenges. Direct by-product recovery at active mines is much more efficient.
The Colorado School of Mines Study
The study by the Colorado School of Mines researchers quantifies the critical metals that currently go unrecovered at active US mines and shows that by-product recovery from these existing mines could meet domestic demand. The researchers obtained data from 26,838 ore samples, each analyzed for 70 elements, along with production data from permitted mining operations on United States federal lands. Impressively, the six co-authors of the study provide a multi-disciplinary approach to a clearly complex technical and computational problem, as they are from four different School of Mines departments: Mining Engineering, Geology and Geological Engineering, Applied Mathematics and Statistics, and Economics and Business.
The United States has about 162 sites that produce metals, with about one third active hard-rock mines with open pit or underground operations. In decreasing order of total annual production of the main product, the mines are producing iron, copper, zinc, rare-earth elements, nickel, molybdenum, silver, gold, and platinum-palladium. Recoverability of by-products is determined by where the element is found in the mine and the characteristics of the surrounding rock, plus the extractive metallurgy comprising the processes, energy, reagents, and water required for mineral processing and metal extraction.
For most of the critical elements, the School of Mines researchers found that the estimated amount of each that is mined annually—but not recovered—exceeds US imports and US manufacturing demand. Of the elements, a few could not be assessed, but the data show that only two—platinum and palladium — are not found in sufficient quantities to meet United States manufacturing demand. There are uncertainties in the data from some of the ore samples—but the authors believe these are modest when compared to expected uncertainties in mineral demand projections.
The study concludes that we could replace imports by recovering less than 10 percent, and sometimes less than 1 percent, of what is currently available during mining operations, rather than discarding it. These materials include lithium, cobalt, iron and aluminum, along with rare earth elements; tellurium for solar energy and metal alloy production; and gallium for semi-conductors. Impressive!
Periodic table showing 35 out of 60 of the minerals on the 2025 List of Critical Minerals that are produced as byproducts or coproducts, highlighted in orange. (USGS)
Looking Forward
New United States policies are being promoted to stimulate domestic mining. Many potential new mines, however, face considerable opposition for social and environmental reasons. And even when there are no conflicts, the average timeline for exploration, permitting, and development of a new United States mine is a daunting 29 years (Holley et al., 2025).
By-product recovery presents advantages of waste reduction and utilization of existing mining infrastructure and environmental footprints, and it produces a wider range of needed materials by leveraging the energy and emissions already expended in mining. If widely used, by-product recovery could make other recently proposed extreme measures, including deep-sea mining, unnecessary.
To harvest by-products from rock that is already being mined, significant advancements are needed. Research to identify efficient recovery processing technologies is essential—along with a policy framework and regulatory reforms to incentivize research and implementation of by-product recovery. Government mandates or incentives may be required. Given the billions of dollars the United States is spending on importing critical minerals, as well as the significant concerns associated with some supply chains, unlocking the by-product resources that are available at domestic mines is a logical step forward.
Related Posts on My Website
Recovering Not-So-Rare Rare Earths
Metals, Mines, and Moves Toward Sustainability
Essential Metals From Antiquity to AI
Do We Really Need Deep-Sea Mining?
If you liked this post, please share it and/or leave a comment or question below, and I will reply—thanks! And if you’d like to receive a message when I publish a new post, scroll down to the bottom of this page, and leave your email address on my website. Join now to learn more about geology, geography, culture, and history.
Thank you for another interesting, timely post.
I appreciate hearing this — thank you!
Thank you!
Thank you for the comment!
Great article, Roseanne. I wonder… was this research funded by the government of Greenland by chance?
Good one, Steve! I was tempted to make snarky comments about Greenland, etc., but resisted. Glad you did!
Thanks for such an informative post on a far more sane and cheaper alternative to importing minerals from other countries or attacking them for their use them. What a concept!
Thanks, Paula! I agree — and I appreciate your comment.
The strategic supply chain benefits from pursuing this are apparent. But many unanswered questions in the above overview. For example: How long might it take, and at what cost to develop the recovery processing technologies. Does it actually make economic sense to develop this capability domestically. What assurances can be provided that domestic processors won’t be stuck in an endless series of legal, environmental and regulatory challenges. How confident are we that rare earth minerals critical today will remain so as new technologies come on board.
Thanks, Steven—interesting questions. One reason I trust the information in the Holley et al. paper is that the authors have multi-disciplinary expertise, e.g., coauthor R. Eggert is from the Dept of Economics and Business. I’m a geologist, so beyond knowing that rocks can contain many minerals and elements, I don’t have definitive answers, but I’ll share a few thoughts, in the order that you asked the questions. First, the speed of developing new recovery processing technologies probably depends heavily on the amount of funding for research; hindering university research will slow development (no surprise there!). Yes, it makes sense to develop domestic capacity since countries upon which the US is highly dependent, like China, could completely cut off supplies, or to limit terrible human rights abuses in countries like the DRC. (Also not new news: global politics keep shifting in unexpected ways!) Financial and regulatory incentives to encourage domestic processing will be required. And yes, there could be legal, environmental, and regulatory challenges, but mines that are permitted and active are already way ahead. New technologies could certainly make rare earth minerals, as well as other critical minerals including lithium, less in demand—time will tell. In the meantime, at least some other critical minerals almost certainly will be needed—for a clearer view of current status, check out Figure 9 – 20-Year Trend of US Net Import Reliance for Critical Minerals (time series 2004 -2024; USGS, 2025, Mineral Commodity Summaries; link included in my post “Sources”). This table shows there is currently 100% reliance on imports for several critical minerals, including manganese, cesium, and rubidium, and high (>50%) reliance for titanium, cobalt, barium, magnesium, zinc, and many others. Definitely not a bright picture, IMO.