Australia: How a tiny radioactive capsule was found in Australia’s vast outback

On 25 January, when mining company Rio Tinto reported that one of their Caesium-137 radioactive capsules had gone missing, Western Australian authorities faced a seemingly impossible task.

They had to locate a pea-sized capsule anywhere along a 1,400km (870 mile) route stretching from the Gudai-Darri mine in the north of the state to a depot just north of Perth’s city centre.