Alcoa plans riskier mining near Serpentine Dam and massive new exploration

Alcoa’s future mining near Serpentine Dam is a greater threat to Perth’s biggest drinking water dam than its present work which is already worrying the West Australian government.

The US firm – that contests its plans pose a greater risk – is also asking for approval to explore more than 60,000 hectares of jarrah forest in a mine plan currently with the state government for review.

Government fears that heavy rain could cause so much sediment run-off from areas already cleared by Alcoa that water from Serpentine Dam would not be drinkable for months or even years were revealed by this masthead in February.

Alcoa’s future mining poses a significant increase in risk to the dam that supplied 18 per cent of Perth’s water in 2020, according to recent internal state government documentation obtained by this masthead.

The proposed clearing and earthworks – detailed in a five-year plan submitted to the Department of Jobs, Tourism, Science and Innovation and a longer-term expansion proposal lodged with the Environmental Protection Authority in 2020 – includes more mining on steep hillsides near the dam where uncontrolled runoff is more likely.

Alcoa intends to clear more than 60 per cent of the forest in some creek valleys, or subcatchments. Its 2023 to 2027 mine plan includes more than 1500 hectares near the dam, more than 70 per cent of which is in “constrained areas” of greatest risk, according to the government documentation.

Contrary to the state government assessment, Alcoa’s interim vice president of Australian operations, Rob Bear, said the company was not proposing to mine in more difficult areas around Serpentine Dam.

“We have extensive experience operating in areas with similar attributes to those being proposed, including proximity to the dam and the nature of the terrain,” he said.

Bear said Alcoa was working with regulators to improve its already stringent practices, including installing hundreds of additional water monitoring bores, and in 2022 reduced the number of drainage failures by 80 per cent.

“We are aligned with government on the need to maintain responsible and safe operations to protect drinking water,” he said.

In its 2023 to 2027 mining and management program, Alcoa also wants access to more than 60,000 hectares of jarrah forest for exploration, according to a person familiar with the plans who is not authorised to talk to the media. Not all of the area explored would be found suitable for mining.

In 2022, Alcoa extracted 31.4 million tonnes of bauxite from the jarrah forest, 75 per cent of the Pittsburgh-based aluminium giant’s global production.

The ore comes from two mining areas: Huntly, which encroaches on Serpentine Dam and supplied alumina refineries in Kwinana and Pinjarra, and Willowdale, which supports the Wagerup refinery. The alumina is shipped to smelters to make aluminium.

Due to delayed mining plan approvals in WA, Alcoa is now mining lower-grade bauxite which has increased production costs, according to Alcoa’s 2022 annual report.

Alcoa’s 2022 to 2026 plan was only approved by State Development Minister Roger Cook in September 2022 and the 2023 to 2027 plan remains under review, a JTSI spokeswoman said.

She said under the approved plan the miner could not work in higher-risk areas without submitting a method to manage those risks that is accepted by the Mining and Management Program Liaison Group, a committee of bureaucrats that approves Alcoa’s mining.

Higher-risk areas include anywhere with a slope greater than 16 degrees and subcatchments where Alcoa plans to clear more than 30 per cent of the vegetation.

Most mining in WA is assessed by the independent Environmental Protection Authority and regulated by the Department of Water and Environmental Regulation.

However, under a 62-year-old legislated agreement with the state, Alcoa’s mining is governed by the liaison group that is led by JTSI – the department tasked with promoting industry, not protecting the environment – and its plans are regarded by the government as commercial in confidence.

In late 2022, Cook gave Alcoa 12 expectations it had to meet to get future mine plans approved.

According to recent internal state government documentation obtained by this masthead, Alcoa then submitted a plan that inadequately addressed these expectations.

WA Forest Alliance convener Jess Beckerling said the level of risk and secrecy surrounding Alcoa’s mining has reached a tipping point and a full and transparent assessment was required.

Last week the alliance referred the 2022-2026 and 2023-2027 plans to the WA EPA, which has 28 days to decide whether it will investigate.

Alcoa’s operations in WA are 40 per cent owned by ASX-listed Melbourne company Alumina Limited.

Cook’s 12 expectations for future Alcoa mining plans

• Alcoa to submit a 10-year mine plan for assessment prior to its draft 5-year Mine Management Plan;
• Alcoa to submit a draft 5-year MMP to be assessed by the Mine Management Plan Liaison Group in consultation with the Mining Operations Group to determine the final boundaries (based on a 24-month mine schedule) of proposed native vegetation clearing under the MMP prior to submission of the final 5-year MMP.
• Alcoa to submit a final 5-year MMP to the Minister for State Development, Jobs and Trade based on a 24-month mine schedule, with other longer-term conceptual mining areas to be provided for context/information only
• The Minister will then seek concurrence from both the Minister for Water; Forestry and Minister for Environment that adequate consultation has occurred prior to any MMP approval; and
• Only after the Minister has approved the MMP, can Alcoa submit forest clearing advice submissions to MOG for endorsement where they comply with a prior approved MMP
• To avoid regulatory duplication and/or overlap, the MMP must not include native vegetation clearing proposed as part of any prevailing referral under Part IV of the Environmental Protection Act 1986
• The MMP must depict the final boundaries of proposed native vegetation clearing based on a 24-month mine schedule (that is, mining that will occur within 24 months after the MMP is approved)
• Include full mining cycle planning approach and methodologies that Alcoa will use to outline progress toward full cycle planning
• Include baseline data to support MOG assessment of impacts on native vegetation, catchment hydrology and water quality
• Provide an outline of Alcoa’s rehabilitation program, including:
  • The total area of native vegetation clearing to date, total area where rehabilitation is completed, total area where rehabilitation has commenced but is not yet completed and total area where rehabilitation has not yet commenced
  • The total rehabilitated areas accepted by the Department of Biodiversity and Attractions as meeting the completion criteria
  • The total rehabilitated areas where DBCA is yet to accept that the completion criteria have been met and an outline of what further work will be undertaken to meet these criteria; and
  • The methodology for completing future rehabilitation of cleared areas, including the strategy for reducing the total area cleared where rehabilitation has not yet commenced
• Demonstrate a formal reduction of open areas and increased rehabilitation rates to prevent an increasing forest clearing footprint within catchments supplying Perth’s Integrated Water Supply Scheme area.
• In addition the above, Alcoa to work collaboratively with the MMPLG to:
  • Reconstitute the Bauxite Hydrology Committee (BHC) or establish a similar independent scientific advisory committee, to collaborate/co-design a scientific research program to report to the MMPLG on matters concerning bauxite mining hydrology and catchment protection; and
  • Work with the MMPLG to design a full mining cycle planning approach and methodologies to ensure there is shared understanding as to the impacts of mining including risks associated with rehabilitation outcomes.

Source: Spokesman for State Development Minister Roger Cook

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