Safety alert issued after pontoon pump accident

The New South Wales Resources Regulator has issued a safety alert after a maintenance contractor had to swim to shore when a pontoon pump overturned and sank his boat.

The contractor was working at Ravensworth coal handling processing plant (CHPP) in the New South Wales Hunter Valley when tasked with servicing a pump on a pontoon on 17 August 2022.

The worker used a boat to access the pontoon.

Pontoon on the dam before the incident

The pontoon and pump configuration had a dry weight of about 15.7 tonnes and a wet weight (fuel/water in pump line) of about 17 tonnes. The pontoon had a cube container filled with water on one side as a ballast control.

While doing the service, the worker identified that a pulley on the primer pump (vacuum) was faulty.

He had taken off his floatation device to carry out his work, as it was not required by the mine operator.

The primer pump was removed while draining the water line and put into the boat.

The subsequent change in the centre of gravity of the whole unit caused the pontoon to overbalance and overturn.

Within minutes, the worker noticed the pontoon tilt and jumped in the water to swim 30m to the bank, without a floatation device. The pontoon then overturned and dragged the boat under the water with it.

Fortunately, the worker was not injured.

Initial investigations by the mine operator identified:

The site standard for working on or near water was not complied with
The work authorisation for pump maintenance did not identify any additional controls associated with a body of water
No operational risk assessment was in place that identified the floatation characteristics of the pontoon and pump

The New South Wales Resources Regulators recommends that mine operators should:

Verify awareness of the roles and responsibilities for maintaining compliance to their site’s standards for working on or near water
Review the use of work authorisation standards
Review safe work systems for this type of task considering:
- The requirement for wearing flotation devices on pontoons
- The requirement for a spotter while undertaking maintenance activities on water
- Emergency response capability around water
- The suitability of boats for transporting workers and equipment
Consider building a jetty for long-term access to pumps on dams