Alcoa's Pinjarra alumina refinery shut down after gas outage

An unexpected disruption to gas supply at Alcoa's Pinjarra refinery on Tuesday morning triggered a loss of power and numerous spills of caustic liquid at the refinery with a return to full production expected to take about a week.

An Alcoa spokesman said the incident impacted process flow, and clean-up of the spills commenced immediately.

"One worker came into contact with a small amount of caustic material and immediately returned to work after onsite medical assessment," he said.

Pinjarra is Alcoa's largest alumina refinery, contributing 44 per cent of the $16 billion company's operating capacity.

Alcoa moves future mining away from dams ‘for now’

Alcoa has made last minute changes to its planned expansion of mining in WA’s jarrah forest and wants to reenter a previously mined area, potentially triggering a new major federal environmental assessment.

Boiling ColdPeter Milne

A spokesman for the WorkSafe petroleum safety and dangerous goods section said Alcoa reported the incident immediately.

"The spill was contained within the bunded area, and once power was restored, the discharge was returned to the system," he said.

"One worker received a minor injury and WorkSafe is making enquiries into this issue."

 Alcoa is working to restore refining operations at the site investigating the cause of the incident, which occurred a year after five workers at the refinery were injured in another spill, with two requiring hospital treatment.

It is understood from sources not permitted to speak to the media that a return to full production is expected to take a further seven to ten days.

 In June, the US aluminium specialist ended production at its oldest WA refinery in Kwinana, citing poor returns at the 61-year-old facility.

Update: Reference to 2023 spill incident added.