Helium-free MRI scanners have been developed in the last few years. But He is still used in the earlier generation of these critically important pieces of medical equipment. It’s also used in semiconductor manufacture and other applications. Known reserves have been dwindling alarmingly – mostly due to lack of viable gas exploration strategies. This Oxford/Durham group claim to have solved this with discovery that geologically ancient helium in deep rock in Tanzania has been released by volcanic heat to form massive gas fields (estimated at 3xUS reserves) at viable depths.