BHP Billiton Ltd. (BHP.AU) said the main haulage shaft at its giant Olympic Dam mine in South Australia state has been damaged and is shut down.

The miner said a mechanical failure Tuesday damaged the Clark Shaft, which is the main shaft hauling ore from the underground mine to the surface for processing.

A secondary haulage system, which has less capacity than the main system, continues to operate and a spokeswoman said it is too early to say what impact the incident may have on production.

No one was injured in the incident at the copper, gold and uranium mine and BHP said it was investigating the cause of the failure and the extent of the damage.

"The safety of our workforce will take priority in determining any restart of haulage operations," the miner said in a statement.

-By Alex Wilson, Dow Jones Newswires; 61-3-9292-2094; alex.wilson@dowjones.com