Million tonnes of rock needed by BHP for work on non-compliant waste storage facility near WA town
Mining giant BHP has vowed to bring tailings dams at Kambalda and Prominent Hill into line with global standards after rating them a ‘high’ and ‘extreme’ risk to lives in the unlikely event of a failure.
BHP is hunting for a million tonnes of rock to reinforce an ageing tailings dam that the company admits does not meet global standards in another complication for the sale of its nickel business.
The substandard tailings dam sits on the doorstep of Kambalda in Western Australia, where BHP is looking to bolster its walls with waste rock – material removed to reach valuable ore bodies during mining.
The Kambalda tailings dam holds about 27 million cubic metres of waste built up over decades of nickel mining and processing. The facility is in fact four separate tailings dams covering more than 100 hectares with containment walls up to 30 metres high.
The tailings dam only partially meets the global industry standard on tailings management aimed at preventing catastrophic failure, according to BHP’s self-assessment.
The BHP finding has not yet been verified by an independent third-party. But in line with its commitment to the International Council on Mining and Metals, BHP has said it will seek third-party assessment “as soon as reasonably practicable”.
It is one of three BHP waste storage facilities in Australia that fall short of their benchmark. The tailings dam at the Prominent Hill copper-gold mine in South Australia is rated the most dangerous in the event of a catastrophic failure.
BHP rates the consequences of a major tailings dam incident at Prominent Hill “extreme” estimating the lives of more than 100 mine workers are at risk if the north or northwestern walls were to fail. Like Kambalda, Prominent Hill is partially compliant with global standards based on BHP self-assessment and awaiting third-party scrutiny.
International standards for tailing dams were raised in the wake of the Samarco disaster in Brazil. The Fundão tailings dam at the Germano iron ore mine in Minas Gerais – owned by BHP and Vale through joint venture company Samarco – collapsed in 2015, killing 19 people.
Two of the three non-compliant BHP waste storage facilities in Australia are part of the nickel operations it mothballed last year on the back of heavy losses. It is for sale.
The Kambalda tailings dam is 3 kilometres from a BHP-owned nickel concentrator that was being used to process ore from mines owned by Wyloo, a private company controlled by Andrew and Nicola Forrest. The Wyloo mines were shut last year as Australian nickel collapsed in the face of competition from Indonesia.
BHP rates the consequences of a Kambalda failure “high” based on the number of mine worker lives at risk (between one and 10) and threat to infrastructure, the environment and indigenous heritage.
The company’s fulsome public disclosures on tailings management reveal WA’s Department of Water and Environmental Regulation took no enforcement action over a breach in license conditions reported in 2024.
The other laggard is at Baldivis, an outer Perth suburb, and was used to store waste from a refinery near Kwinana from 1972 to 1995.
All the waste at Baldivis is stored below ground. The consequences of a failure are rated low, with the greatest concern around the potential for liquid to seep from the tailings into the surrounding environment.
The tailings dam at Prominent Hill, about 650km northwest of Adelaide, has been expanded four times and raised the height of the embankment walls to 25 metres. The tailings dam there covers about 240 hectares and currents holds more than 64 million cubic metres of waste.
The global standard classifications like ‘extreme’ for Prominent Hill and ‘high’ for Kambalda refer to potential consequences, not the likelihood of failure, and do not represent an assessment of current safety.
BHP said it was “committed to implementing the global industry standard on tailings management across all our tailings facilities”, including the three in Australia rated partially compliant.
“Over the past five years, we’ve worked to bring our 70 operated facilities into line within the agreed International Council on Mining and Metals time frames. The standard sets a high benchmark which we are firmly committed to meeting,” a BHP spokesman said.
BHP declined to respond to questions from The Australian on its efforts to secure a million tonnes of rock for the Kambalda tailings dam, or the nature of the work under consideration.
It is understood the potential upgrade involves the oldest of the four facilities and within the wider precinct that were not in use when BHP shut its concentrator in the town and Wyloo halted mining.
BHP declined to comment on whether potential buyers were being told about the works planned for the tailings dam as part of the nickel sale process.
The nickel assets carry closure and rehabilitation liabilities of at least $US900m.
The Australian reported on August 24 that the country’s largest miner had quietly put the business up for sale, and that when BHP last actively marketed the business about a decade ago, Glencore offered to take control for a nil premium.
Industry sources speculated that any interest from Glencore today would likely require BHP to pay out as much as $US300m to wash its hands of the business. Glencore said in August: “We don’t comment on rumour and speculation.”
Any interest from Wyloo is unclear, but appears limited to the Kambalda concentrator given Dr Forrest has been burned twice in nickel. It is understood ASX-listed IGO Limited is focused elsewhere and has no interest in the BHP nickel business.
The closure requirements BHP has outlined for the Kambalda tailings dam include a period of inactivity to enable long-term settling, consolidation and drying of waste for the safe movement of construction equipment onto the surface.
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