It might be the second most common element in the observable universe but until very recently, Earth, it was thought, was running out of helium. Aside from its obvious uses in balloons given out at children’s parties by pizza restaurants, the noble gas actually has a number of vital medical and scientific applications—and in recent decades we’ve burned through most of our once-enormous reserves.

Helium is used mostly as a coolant, especially in MRI scanners, which use around one fifth of the world’s reserves in liquid form to cool the machines’ superconducting magnets. The semiconductor industry also uses it to grow crystals, while modern materials science also uses its high-yield cooling properties, as do certain advanced telescopes. Despite its uses, however, Earth was believed to be coming to an end of its reserves, having been allowed to squander what was once considered a fairly useless resource.

Researchers from Durham and Oxford universities, however, have surprised the scientific world by discovering a huge new reserve in Tanzania’s Rift Valley in east Africa—using a new technique which could be used to find even more. It turns out that volcanic activity helps release the gas from the ancient rocks which usually hold it, allowing it to rise to shallower gas fields.