EPA refuses to consider Alcoa expanding mining near dams

Within weeks, US miner Alcoa will open to the public what is likely to be one of the most controversial environmental approval processes ever seen in WA, that would see its strip mining expand northwards and consume 75 square kilometres of jarrah forest.

However, the assessment will not consider approving more mining in areas that pose the greatest risk to the water supply.

On Thursday, the WA Environmental Protection Authority published substantial changes to Alcoa's plans that were initially lodged almost four years ago.

In October, Alcoa told stakeholders it would defer expanding its Huntly mine into Reservoir Protection Zones (RPZ) that extend for two kilometres from the top water level of reservoirs and instead add a mine area called O'Neill to the east.

The $15 billion company's clearing of forest near Serpentine Dam poses a risk to water supply to the South West of WA.

Excessive runoff of sediment into the crucial Serpentine Dam could make its water treatment plant ineffective.

The runoff could also contaminate the water with toxic PFAS from firefighting foam once used by Alcoa or hydrocarbons from frequent spills from its heavy machinery.

In 2023, the Department of Water and Environmental Regulation opposed Alcoa's current mining "in its entirety" as there was a “foreseeable” risk that water from Serpentine Dam could become unusable.

Alcoa wanted an assessment of expanded mining in the RPZs deferred "to allow time for the long-term efficacy of current water management and drainage controls and practices to be determined," according to EPA.

The statement shows there are question marks over the effectiveness of the practices Alcoa uses in RPZs in its currently approved mining.

However, the EPA considered "mining within the RPZ to have been removed from the proposal’s content for the purposes of this assessment and any associated decisions."

If Alcoa wants approval to mine in the RPZs in the future, it may have to start a separate approvals process from scratch.

Continued permission to strip mine the jarrah forest is an existential issue for the US aluminium specialist. It mines about 75 per cent of its bauxite and makes about 70 per cent of its alumina in WA where it employs about 4000 people.

The $15 billion company is not only seeking a long-term expansion of its mining area but is also faced with an assessment of its current operations.

The EPA expects to issue Environmental Review Documents for both the expansion and its review of Alcoa's five-year mine plans to 2026 and 2027 "in the coming weeks" according to an email EPA chair Darren Walsh sent to stakeholders today and seen by Boiling Cold.

The plans would then be open for public comment for about ten weeks.

In December WA's other bauxite miner South32 received approval for a mine expansion for its Worsley alumina refinery 2½ years after it lodged the ERD.

Alcoa is predicting to complete the same process in just 12 months despite its activities being more controversial and environmentally sensitive due to the proximity to Perth's drinking water dams.

The Worsley process was slowed by South32 changing its plans five times after its ERD was issued.

Alcoa's amended expansion plan includes an increase in the annual production of toxic bauxite residue from 10.8 to 11.6 million tonnes a year. This is likely due to returning to the previously mined O'Neill area and mining low grade ore that was previously untouched.

Alcoa's WA mines already rely on one of the lowest grades of bauxite mined anywhere in the world.

The Huntly mine supplies Alcoa's Pinjara refinery and, until it was closed in 2024, its Kwinana refinery.

Alcoa's revised plan extended the mining period seven years to 2045 in case the Kwinana refinery does not reopen and it takes longer to remove all the bauxite it has targeted.

About 7500 hectares of jarrah forest will be cleared, equivalent in area to almost 19 Kings Parks.

After 62 years of mining in WA, Alcoa has yet to get a single hectare of mined land restored to meet the rehabilitation criteria it has agreed with the WA government.