China provides more than 90 per cent of the rare-earth metals used in products from mobile phones and laptops to missile guidance systems, and the metals are now at the core of geo-political tensions involving both global trade and defence issues.

In August there was a rumour that China was about to restrict export of some of the more difficult to find rare earths; elements like Terbium, Europium and Dysprosium.

The Pentagon is concerned about possible restrictions because many rare-earth metals are vital ingredients in several US military applications such as missile guidance systems.

China's stranglehold on supply is why the United States, the Europeans and the Japanese are looking for alternative sources.

A few weeks ago US President Barack Obama approved a defence budget that asked for a report by April next year on how the US might secure supplies of rare-earth metals.

Australia has plenty of rare-earth metals, but it is no easy process to get them out of the ground.

The continent used to supply about 25 per cent of the world's rare earths but that came to a stop in the early 1990s when the fact that they were mixed with radioactive elements became an issue.

Australia's largest rare-earth mine is Mt Weld, near Laverton in Western Australia, where radioactivity is relatively low - the mine will soon be in production.

Another mine about 150 kilometres from Alice springs is Arafura's Nolan's Bore.

The mine still has to complete its Environmental Impact Statement and needs final approval from the Federal Government, but environmentalists are raising concerns.

Ironically, one of the reasons for investor interest in rare-earths mining is the wave of global enthusiasm for everything green.

Green technologies such as solar panels and wind turbines depend for their efficiency on rare-earth metals.

Alistair Stephens of Arafura Resources says it presents a conundrum for green groups.

"These rare earths are going to be extremely important for delivering energy efficiency, yet they are going to be associated with radiation," he said.