Where uranium comes from

Uranium is not rare. It is about as common in the earth's crust as tin, and more common than silver. What is rare is uranium concentrated enough to be worth extracting, and the economics of a mine turn almost entirely on ore grade.

That is why Canada matters out of proportion to its output. The McArthur River deposit averages over 6% uranium, roughly a hundred times the grade of a typical mine. The ore is so intensely radioactive that it cannot be mined by people standing next to it; it is cut remotely and handled behind shielding. Cigar Lake, the second-richest deposit, sits in water-saturated sandstone and is mined by freezing the ground solid and jet-boring through it.

Kazakhstan took the opposite route and won on cost. In-situ leaching pumps a weak acid solution through a permeable orebody and recovers dissolved uranium at the surface. There is no pit, no shaft and no tailings dam, and the capital cost is a fraction of conventional mining. This is how a country with unremarkable ore grades came to supply two fifths of the world.

The milling step turns ore into uranium oxide concentrate — U3O8, "yellowcake" — which is stable, shippable, and the form uranium trades in. Everything downstream begins here.