The freshest concerns were raised in government feedback to the 2023-27 plan, which advisers said had insufficient information to assess the risks to public drinking water catchments and dams, and was not backed by peer-reviewed science.

The list of expectations

The advisers raised further concerns about Alcoa’s responses to a list of 12 expectations placed on the company’s future mining operations by Cook in his September 2022 approval of last year’s plan.

These expectations included an obligation on Alcoa to submit a 10-year mine plan for assessment by the government panel and that future approvals must have concurrence from Cook, Environment Minister Reece Whitby, and Water Minister Simone McGurk.

Cook also wanted to re-establish a hydrology committee, shut down in 2015, that provided advice to the minister on bauxite mining’s impact on the movement of water in the Perth Hills.

This point was echoed by a spokeswoman from the Water Corporation, who said there was capacity for it to be reconvened.

Despite Cook’s stern expectations, the government’s advice trashed Alcoa’s response, claiming its latest plan was limited, incomplete and not subject to peer review.

Upper house Greens MP Brad Pettit questioned whether political pressure had a part to play in Alcoa’s mining plans being approved at the same time as bureaucrats warned of a major threat to Perth’s drinking water.

Cook, Whitby and McGurk met with Alcoa on December 15 last year, which followed a meeting between Premier Mark McGowan and Alcoa’s global chief executive Roy Harvey in November.

A state government spokesman said McGowan and the senior ministers made it clear in their meetings that risks to Perth’s water sources needed to be appropriately managed.

In addition to Cook’s 12 expectations, the spokesman said Alcoa’s 2022-26 mining plan was approved subject to conditions it did not mine higher-risk areas without submitting a revised risk management plan addressing the government’s concerns.

“To date, Alcoa has not satisfied those concerns and is not currently mining in these areas,” he said.

A JTSI spokesman said the government panel – known as the Mining and Management Program Liaison Group – would not recommend approval of mining in these higher-risk areas until it was satisfied the concerns were addressed.

An Alcoa spokeswoman said the company operated according to its mining and management programs, took its responsibilities seriously and its mining operations had never impacted drinking water supply.

“We continue to work cooperatively with relevant government bodies to address evolving expectations for environmental management,” she said.

Water Corporation tests of Perth dam water quality from 2019 to 2022 found no issues.

How does Alcoa get its approvals?

Alcoa’s approval to mine the Darling Scarp on a lease that spans from Collie to Gidgegannup stems from a State Agreement first inked by the Charles Court government in 1961.

It is this legislation and subsequent amendment acts that include the requirement to submit mining management plans annually, their assessment by the government panel, and approval requirements by the state development minister.

This panel is chaired by JTSI and comprised of public servants from Water Corporation; DWER; the departments of Mines, Industry Regulation and Safety; Biodiversity Conservation and Attractions; and Planning, Lands and Heritage.

The panel oversees all of Alcoa’s bauxite mining operations including vegetation clearing permits and mine design, but its decisions are not made public and there is no opportunity for public comment.