The worker was a construction supervisor on the development of a borefield suppling water to the mine and was an employee of a contracting firm.
OZ said the site had been shut down for half a day out of respect - the accident occurred at the borefield, around 35km from the mine, and involved a single light vehicle.
WorkSafe SA has been notified and will be on site today to carry out further investigations following police investigations yesterday.
OZ has not released the employee's name, but in a statement said its sympathies were with the worker's families and friends.
The death follows on from an accident at OZ's Century zinc mine last week in which a worker, also a contractor, suffered a serious head injury.
Shares in OZ were last at $1.34, down 1c this morning.
