Protestors at Australia's Olympic Dam mine, which is perched on top of the world's largest known deposit of uranium, have managed to smash through the perimeter gate of the BHP Biliton mine and enter the site itself.
According to a news report by Radio Australia, a group of around 350 people managed to breach the mine's exterior fence by smashing the lock.
The protestors were unable to reach the mine itself, however, as they were blocked by a reinforced steel gate.
Police have introduced additional horse-mounted officers and officers on foot in response, although they have said they are trying to run the protest without generating confrontation.
12 protestors were arrested this afternoon, according to Sydney's Daily Telegraph, for refusing to abandon a human roadblock in front of the mine.
This is the third day of the protest, staged in opposition to a planned expansion of the uranium mine.