Mines Safety Significant Incident Report No. 269 Structural failure of a corrugated steel water tank

Last updated: 17 March 2025

In May 2018, a 600,000-litre raw water tank failed. It was a rubber-lined steel construction. At the time of failure, the tank was near full capacity. The outrush of water affected an operational area of 24,000m², displacing pumping infrastructure, ladders and associated debris.

There were no personnel in the vicinity at the time of failure.

Water tank that failed
Water tank that failed
Corroded steel wall of tank
Corroded steel wall of tank

Direct causes

  • The structural integrity of the water tank had deteriorated substantially due to corrosion.

Contributory causes

  • Inadequate inspection and maintenance management of the water tank.
  • Failure to ensure the condition of the structure remains within the design limits.
  • Failure to assess the structural integrity of the tank by a competent person with appropriate training and experience.