Fears ‘toxic’ fracking wastewater ponds could overflow into Kimberley river

Fracking wastewater ponds could overflow under higher-than-average rainfall conditions that are common in the Kimberley, environmental groups warn, as new documents raise fresh fears of a contamination threat to a nearby major waterway.

Texan mining company Black Mountain Energy’s proposed Valhalla Gas Project in the Kimberley includes plans to drill and frack up to 20 exploration wells, which WA’s Environmental Protection Authority approved in January.

However, new evidence submitted to the WA Appeals Convenor shows Black Mountain Energy’s own modelling found wastewater ponds at the project could overflow into the Martuwarra Fitzroy River.

While evidence of that potential was submitted to the federal Environmental Protection Authority by the mining company, it was not included in submissions to the state body which approved the project.

The Appeals Convenor is now reviewing more than 8000 submissions made following that decision.

Lock the Gate Alliance WA coordinator Simone van Hattem said the group had submitted the company documents regarding potential flooding to the state EPA as part of the appeals process.

She said the documents raised questions about whether wastewater ponds could safely contain fracking water full of “toxic chemicals”.

“Black Mountain Energy’s modelling, which was completed after the state’s environmental watchdog assessed the project, shows that if two wells were fracked in the same year and 70 per cent of fracking water returned to the surface, ponds would overflow in any year with higher-than-average rainfall,” she said.

“The modelling only assessed up to a 0.5 per cent Annual Exceedance Probability flooding scenario, equivalent to a one-in-200 year event, but didn’t model worst-case scenarios, such as what occurred during ex-Tropical Cycle Ellie in 2022.

“The Kimberley is vulnerable to increasingly frequent extreme rainfall and flooding events. If fracking water ponds overflow, they could release contaminated water into waterways connected to the Martuwarra Fitzroy River.”

In its submission to the Appeals Convenor, Lock the Gate also supplied data about the quality of fracking water from two wells previously drilled in the area, published by Buru Energy in 2018.

The Valhalla project was previously held by Buru Energy and Mitsubishi, with fracking wells already drilled.

The data from Buru Energy showed extremely high salt concentrations that were toxic to land and aquatic animals, and high levels of the metals boron and barium, Lock the Gate’s submission stated.

A Black Mountain quarterly activities report from April 2023 also stated the area in and around Project Valhalla “experienced catastrophic flooding in early January 2023”.

“It is expected that river and soil moisture levels will remain high longer than typically occurs making access to the full survey area unlikely until later in the year,” the report reads.

In response to questions from this masthead, a Black Mountain Energy spokesperson said the company’s Valhalla Project had undergone a “comprehensive” assessment by the WA EPA, which recommended its approval.

“The project is also currently being assessed through the Commonwealth environmental approvals process,” they said.

“Black Mountain sets its own high standards for environmental management and sustainability and is committed to developing the Valhalla Project responsibly.

“We continue to work cooperatively and transparently with the relevant State and Commonwealth authorities and respect the statutory approvals processes currently underway.

“We will continue to provide any information regulators require and allow those processes to take their course.”

Environs Kimberley director Martin Pritchard said an oil and gas wastewater pond had overflowed in the Kimberley before at a well site.

“We cannot risk this in the catchment of the National Heritage-listed Martuwarra Fitzroy River catchment,” he said.

“Potentially radioactive wastewater laden with heavy metals would be a disaster for the river.”

The EPA said it was unable to comment given the appeals process remains ongoing.

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Holly Thompson is a journalist with WAtoday, specialising in education and the environment.Connect via X or email.AdvertisementAdvertisement