Alcoa’s mountains of red mud fail to pass stability checks

Alcoa is storing enough caustic bauxite residue to fill Perth’s Optus Stadium more than 350 times, in areas that have failed to be certified as stable, at three refineries in Kwinana, Pinjarra and Wagerup.

The 368 million cubic metres of waste from extracting alumina from bauxite, often called red mud, that have “failed to be confirmed or certified as stable” in recent years was revealed in an annual disclosure from the US miner.

Tailings residue stretches more than three kilometres in two directions, dwarfing the nearby town of Pinjarra.Credit: Google Maps

The waste stored without confirmed stability amounts to three-quarters of the red mud Alcoa has produced in Western Australia over the past six decades.

Alcoa is one of 28 global miners that voluntarily committed to meeting the requirements of the Global International Standard for Tailings Management (GISTM) standard by August 2025.

The recent disclosure revealed 21 tailings areas across Alcoa’s three WA sites have failed stability checks, including at least seven in an audit this year and at least six in 2023.

An Alcoa spokesman said the reporting of 21 areas with unconfirmed stability was largely a result of the company’s work with independent geotechnical experts to assess its tailings facilities and determine what work was required for them to meet the new standard. He said the results did not indicate an increase in risk.

“Our tailings storage facilities are regularly inspected by the regulator and independent geotechnical experts and the most recent inspections did not identify any significant issues,” he said.

A Department of Energy, Mines, Industry Regulation and Safety spokesman said the department was aware of the findings and work was under way to fix the problems.

In August, WorkSafe geotechnical inspectors visited the sites and reviewed the 2024 third-party audit reports.

“No breaches of work health and safety laws were identified with respect to the tailings storage facilities,” the spokesman said.

Rusty Geller, president of the Peel Environmental Protection Alliance, said the results confirmed the group’s concerns.

Tailings storage at Pinjarra are about 14km from Peel Inlet seen in the background.Credit: Peter Milne

“How has Alcoa been allowed to let this hazard develop?” he said, and called for the miner to stop adding tailings to storage until it was safe to do so.

The miner plans to add about 10 million cubic metres to its stockpiles annually.

Geller is concerned extreme rain, such as that Cyclone Seroja caused around Kalbarri in 2021, could cause a wall holding back tailings to fail.

In recent years Alcoa has assessed the stability of the tailings under the impact of more regular extreme weather events due to climate change.

Using the updated, more extreme weather data, Alcoa has conducted dam-break studies for all its WA facilities that analyse the impact on communities, ecosystems and critical infrastructure in the event of catastrophic failure. These studies have been used to produce emergency response plans.

Mike Walmsley, president of the Shire of Waroona where the Wagerup refinery is located, said the shire was concerned about the stability of the tailings facilities.

“The Shire has toured the site at the invitation of Alcoa and discussed the compliance measures that Alcoa is taking to meet standards for dam wall stability,” he said.

Walmsley said stability was the responsibility of the department, but the council had to manage the local response to emergencies. He said Alcoa had not provided its emergency response plan to the shire, but the shire had asked for and anticipated receiving it.

Vince Puccio has campaigned for more than 20 years against the effect of pollution from Alcoa’s Wagerup refinery on nearby Yarloop.

“If these walls breach, there is a looming potential for a catastrophic event,” he said.

A 2010 failure of bauxite residue tailings storage in Hungary was labelled “one of the most severe ecological disasters ever to take place in Europe” in a 2018 study of the incident that said red mud was a “complex mixture of contaminants due to its extreme alkalinity and the presence of potentially toxic trace elements.”

A spokeswoman for the Shire of Murray, home to the Pinjarra refinery, said Alcoa had not provided it with the emergency response plan, but the shire was “very interested” in seeing it.

Alcoa’s oldest tailings storage in WA is at Kwinana, where Alcoa refined bauxite from 1963 to a few months ago when operation was suspended.

Area F at Kwinana, which stores 71 million cubic metres of red mud and is higher than Perth’s Bell Tower, is the only Alcoa area in WA rated as likely to cause “very high” consequences if it failed.

The City of Kwinana did not respond to questions put to it.

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