Alcoa's plans to mine WA's jarrah forest for 20 more years released

Alcoa's plans to expand mining around Serpentine Dam to feed its Pinjarra alumina refinery until 2045 have been released for public comment by WA's environmental watchdog.

The WA Environmental Protection Authority also released details of Alcoa's current mining, and the public now has 12 weeks to comment on both plans.

Alcoa started the approval process for the expansion of its Huntly mine in 2020 and four years ago agreed on the scope of the Environmental Review Document released on Thursday.

The US company's current mining plan out to 2027 will also be assessed by the EPA after it accepted a referral from the WA Forests Alliance.

Alcoa's expansion would clear 75 square kilometres of jarrah forest and increase the volume of caustic tailings stored each year at the Pinjarra refinery by 1.6 million tonnes a year to 11.6 million tonnes.

EPA chair Darren Walsh said they were both complex environmental impact assessments with many thousands of pages submitted by Alcoa for review.

“The sheer volume, the unique biodiversity of the Northern Jarrah Forest, and the number of environmental factors to consider means a 12-week public consultation period is entirely appropriate,” he said.

Strong opposition to both proposals is expected due to concerns about the future of the northern jarrah forest, which is at risk of collapse from hotter, drier conditions with more fires, according to the Intergovernmental Panel on Climate Change.

Alcoa has strip-mined more than 280 square kilometres of jarrah forest since 1963, but no area has yet been rehabilitated to the completion criteria agreed with the WA government.

Despite this, in the past week, Alcoa has been advertising that "75 per cent has already been rehabilitated."

The truth is that Alcoa has started, not finished, the rehabilitation process on 75 per cent of its cleared area.

Alcoa's large area of cleared land threatens Perth's water supply as it increases the risk of water in Serpentine Dam - Perth's largest - being contaminated by PFAS and hydrocarbons spilled by Alcoa..

Even uncontaminated soil washing into the dam after heavy rainfall could render the water undrinkable, as the current water treatment plant is ineffective above a certain level of sediment.

State-owned utility Water Corporation ranks bauxite mining as "the single most significant risk to water quality in Perth and the South West”.

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Alcoa Australia president Elsabe Muller said that since 2020, the company has refined its plans on environmental and social grounds.

The company's expansion plan has deferred mining in Reservoir Protection Zones that cover forest within two kilometres of a dam. This does not exclude Alcoa wanting access to those areas later.

Muller said Alcoa had a long and successful track record of responsible operation in the northern jarrah forest.

Alcoa employs about 3800 people in WA.

The Greens spokeswoman on Forests Jess Beckerling said Alcoa's proposals were outrageous.

"This would be the final nail in the coffin for the forest’s climate resilience and the endangered wildlife who rely on these forests," she said.

"It simply cannot proceed."

The EPA is working towards publishing a single assessment report by March 2026, with sets of recommendations for both the current mining operations and the expansion.

That report would then be open for public comment for three weeks.

The comments are then considered by the Appeals Convenor, who makes a report to the environment minister, who decides whether the two proposals can go ahead, and if so, under what conditions.

In 2024, a ministerial decision for the similar but less controversial expansion of bauxite mining for South32's Worsley Alumina took five months after appeals closed.