Uranium is found on every continent, in most types of rock, in soil, in seawater, and even in the phosphate fertilizer spread on farmland. It is far more common than most people assume. The average concentration in ordinary soil is about 3 parts per million, making it roughly 500 times more abundant in the Earth’s crust than gold. But only a handful of countries have deposits concentrated enough to mine profitably, and three geological deposit types account for over 70% of the world’s known reserves.
Top Uranium-Producing Countries
Kazakhstan dominates global uranium production and holds 75% of the world’s cheapest-to-extract reserves. Its deposits sit in porous sandstone layers that can be mined by pumping solution underground and recovering uranium-bearing fluid at the surface, a technique called in-situ leaching. This method is far cheaper than digging conventional mines, which is why Kazakhstan’s resources fall into the lowest cost category.
Canada is the second-largest producer, home to two of the world’s richest mines. The McArthur River/Key Lake complex in northern Saskatchewan produced about 7,808 tonnes of uranium in 2024, roughly 13% of global output. Nearby Cigar Lake added another 6,501 tonnes (11%). These are deep underground mines sitting in ore grades that dwarf anything found elsewhere on Earth.
Namibia rounds out the top three, with the Husab open-pit mine in the Namib Desert producing around 4,437 tonnes in 2024 (7% of global output). Australia, Uzbekistan, Niger, Russia, China, India, and South Africa also contribute meaningful production. Australia holds some of the world’s largest reserves but limits mining through strict policies, so its output is smaller than its geology would suggest.
The Three Main Deposit Types
Uranium deposits form through a surprisingly simple process: water dissolves trace uranium from rock, carries it until conditions change, and drops it in a new location where the chemistry favors concentration. The details vary, but that redox cycle (uranium dissolving when exposed to oxygen and precipitating where oxygen is absent) explains nearly every major deposit on the planet.
Sandstone deposits are the most widespread type, holding about 40% of known global resources. They formed over the last 400 million years, after land plants evolved and created layers of organic-rich sediment. Groundwater carried dissolved uranium through sandy aquifer rock until it hit pockets of decaying plant material, which stripped the oxygen and caused uranium to drop out of solution. These deposits are common across Central Asia, the western United States, and parts of Africa. Because the ore sits in porous rock, many sandstone deposits can be mined with in-situ leaching rather than excavation.
Unconformity-related deposits are rarer but spectacularly rich. They form at the boundary between ancient basement rock and younger sedimentary layers, typically in formations more than a billion years old. Canada’s Athabasca Basin in Saskatchewan hosts the world’s premier examples, with ore grades 10 to 100 times higher than sandstone deposits. The McArthur River and Cigar Lake mines both exploit this deposit type.
Quartz-pebble conglomerate deposits are the oldest, dating back more than 2.2 billion years to a time before Earth’s atmosphere contained significant oxygen. Uranium eroded from rocks and settled in riverbeds without dissolving, much like gold placer deposits. South Africa’s Witwatersrand Basin and Canada’s Elliot Lake district are classic examples, though most are no longer actively mined for uranium alone.
Uranium in the United States
The western U.S. contains the country’s most significant uranium resources, concentrated in sandstone deposits across a handful of states. Wyoming’s Powder River and Wind River basins hold the largest share, followed by deposits in New Mexico’s Grants mineral belt, Arizona’s northern strip country, Utah, Colorado, Nebraska, and Texas. Most active U.S. production today uses in-situ leaching in Wyoming and Nebraska, where the geology is well suited to that approach. Conventional mining has largely wound down, though some underground and open-pit operations in Arizona and Utah have restarted or are under review as uranium prices rise.
Uranium in Everyday Environments
You do not need to be near a mine to encounter uranium. Granite countertops, garden soil, well water, and commercial fertilizer all contain trace amounts. Typical soil concentrations hover around 3 parts per million. Rocks vary more widely: ordinary sedimentary and igneous rocks might contain 3 to 9 milligrams per kilogram, while granite and certain volcanic rocks can reach the higher end of that range.
Phosphate rock, mined worldwide for fertilizer production, is a particularly notable source. Sedimentary phosphate ore generally contains 80 to 120 milligrams of uranium per kilogram, with some deposits reaching 180. Certain East African phosphate deposits are far higher: rock from Matongo in Burundi measured 632 mg/kg, and Minjingu in Tanzania reached 446 mg/kg. Finished phosphate fertilizers made from these ores retain a portion of that uranium, with measured concentrations ranging from about 108 to 281 mg/kg. This means agricultural soils receiving heavy phosphate fertilization accumulate small but measurable amounts of uranium over decades.
The minerals that carry uranium in these settings go by names like uraninite (also called pitchblende), carnotite, coffinite, and autunite. Uraninite is the most important ore mineral and the one found in high-grade deposits like those in Canada. Carnotite, a bright yellow mineral, is common in the sandstone deposits of the Colorado Plateau.
Uranium Dissolved in Seawater
The world’s oceans contain an estimated 4.5 billion tonnes of dissolved uranium, roughly 1,000 times more than all known land-based reserves. The catch is concentration: seawater holds only about 3.3 parts per billion, so extracting it requires filtering enormous volumes of water.
Researchers have spent decades developing materials that selectively grab uranium ions from seawater. The most promising approach uses adsorbent fibers that attract uranium while ignoring the many other dissolved elements around it. Recent work published in Nature Communications demonstrated a seaweed-like adsorbent material that captured about 14.6 milligrams of uranium per gram of material after 56 days in natural seawater. That is a significant improvement over earlier designs, but practical challenges remain: marine organisms foul the adsorbent surfaces, ocean currents limit contact time, and the cost per kilogram of recovered uranium still far exceeds conventional mining. Seawater extraction is not commercially viable today, but the sheer size of the resource keeps it on the table as a long-term supply option.
How Global Reserves Stack Up
The most recent international assessment, published in 2024 by the Nuclear Energy Agency and the International Atomic Energy Agency, estimated total reasonably assured resources at about 4.78 million tonnes of uranium when including all cost categories up to $260 per kilogram. At the cheapest extraction costs (under $40/kg), only about 365,000 tonnes qualify, and just four countries report reserves in that bracket, with Kazakhstan holding three-quarters of the total. Stepping up to the under-$130/kg category, which covers most currently operating mines, the figure rises to about 3.87 million tonnes spread across dozens of countries.
Low-cost reserves have been declining. The latest data showed a 20% drop (about 92,000 tonnes) in reserves recoverable below $80/kg compared to previous estimates, largely because existing mines are drawing down their richest ore. Higher-cost categories held steadier, suggesting that plenty of uranium remains in the ground but will cost more to get out. At current consumption rates, identified resources at the $130/kg level represent roughly 70 years of supply for the world’s reactor fleet, though that number shifts with demand, new discoveries, and extraction technology improvements.