Mining and in-situ leach

Uranium occurs in the Earth's crust at very low concentrations. Most of the deposits mined today grade above 0.10% uranium, but the real range is huge: from poor deposits at just 0.02% to exceptional Canadian veins reaching 20%. Whatever the grade, the ore is crushed and leached with acid or carbonate to dissolve the uranium, and the resulting liquid is purified and precipitated as a uranium oxide concentrate, U₃O₈, about 85% uranium by mass. That concentrate, yellowcake (in practice more khaki than yellow), is what gets shipped in 200-litre drums to the conversion plants.

Since the 2000s, most of that process no longer happens at a conventional mine. In in-situ leach mining (ISL or ISR), the deposit is drilled with injection and recovery wells, a leaching solution is circulated through the porous rock that holds the uranium without excavating it, and it is pumped back up already loaded with dissolved uranium. It is cheaper, produces no waste-rock piles or tailings ponds, and works in permeable sedimentary basins. According to the World Nuclear Association, about 52% of the world's uranium now comes out by ISL, 44% from conventional open-pit or underground mines, and 4% as a by-product of other metals.

Kazakhstan is where that shift is concentrated. The country produced about 25,839 tonnes of uranium in 2025, close to 40% of the world total, almost all of it by ISL through Kazatomprom and its thirteen mining projects, including Karatau, Inkai, Akdala and Tortkuduk. It is a process that depends on chemical inputs at massive scale: in 2025 alone Kazakh mining consumed about 1.85 million tonnes of sulfuric acid, and shortages of that acid were behind several production cuts in recent years.

At the other extreme sit the high-grade conventional mines and the very-low-grade, huge-volume ones. Cigar Lake and McArthur River, in Saskatchewan, are underground deposits of extremely high concentration: in 2022 they produced 6,501 and 7,808 tonnes of uranium respectively, 11% and 13% of world output, and are mined with remote drilling and ground freezing because of the ore's radioactivity and instability. Olympic Dam, in Australia, extracts uranium as a by-product of a copper, gold and silver mine. And Namibia shows the opposite case: Rössing, open-pit since 1976, processes 3 million tonnes of rock to yield 1,000 tonnes of U₃O₈, and its neighbor Husab works a 300-million-tonne deposit averaging just 0.04% U₃O₈; together they produce a large share of Namibia's uranium and place the country among the world's largest producers.