"‘It’s our garden’: PNG villages fight to prevent mine waste dumping in the sea", 13 June 2025

Three communities in Papua New Guinea are waiting for the country’s Supreme Court to decide whether their concerns about the dumping of mine waste in the sea near their homes merit cancellation of an environmental permit for mining that the government issued in 2020.

U.S.-based Newmont Corporation and South Africa’s Harmony Gold Ltd., the partners in the development of the Wafi-Golpu copper and gold mine in Morobe province, want to pipe a slurry of leftover sediment, known as tailings, through a 103-kilometer (64-mile) pipeline...

The method is known as deep-sea tailings placement (DSTP), and in December 2020, PNG’s Conservation and Environmental Protection Authority (CEPA) approved the plan laid out in the companies’ environmental impact statement (EIS).

That approval triggered a series of legal battles beginning in 2021 that questioned whether Huon Gulf communities had been adequately informed of the risks of DSTP. Most recently, three leaders representing the villages of Labu Butu, Wagang and Yanga, located near the pipeline, sued CEPA’s leader and the government. Initially, the lawsuits aimed to stop the government from issuing a permit for large-scale mines called a “special mining lease” that would allow the project to move forward, citing the possibility of “catastrophic and irreplaceable damage to the marine environment and the eco-system of the Huon Gulf.” (In a separate 2021 case, a Supreme Court justice said the issuance of the environmental permit may have violated PNG’s 2002 Environment Act, based on evidence that communities weren’t apprised of these risks, and he temporarily suspended the permit.)

But, in November 2024, a national court judge ruled the villages weren’t in immediate danger and rejected their request to block the lease. Now, their hopes hinge on the Supreme Court ruling that the environmental permit isn’t valid because it didn’t adequately take into account the potential dangers of DSTP. The hearing had been scheduled for February 2025, but was delayed several times before happening on June 12. A decision is expected in July.

CEPA did not respond to Mongabay’s requests for comment.

For nearly a decade, a coalition of organizations has mounted a campaign to prevent the use of DSTP at the Wafi-Golpu mine. Over the mine’s anticipated 28-year life span, roughly 360 million metric tons of tailings and chemicals would be dumped in this part the Coral Triangle, a global hub of marine biodiversity, and the proposal has raised concerns about damages to the ecosystem. Opponents of DSTP say fisheries could also suffer, threatening the livelihoods of some 400,000 people in the region who depend on resources from the sea.

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The dumping of waste into Australia’s waters ... is heavily regulated.

In public documents, the companies dispute the coalition’s claim that DSTP is illegal in Australia. They also say sites in Australia are generally less conducive to DSTP owing to a relatively shallow continental shelf that makes accessing the deep ocean difficult.

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Communities also weren’t adequately informed of the risks of DSTP, he added.

In 2022, the coalition filed a human rights complaint with the Organisation for Economic Co-operation and Development (OECD), an intergovernmental policy forum. But at the same time, the companies, with apparent support from parts of the government, have continued to seek the special mining lease that would allow them to begin operations.

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The site of the proposed mine, which reportedly would be the largest underground mine in Papua New Guinea, sits about 65 km (40 mi) from Lae, PNG’s second-largest city. Newmont and Harmony say transporting the waste to the sea is less harmful to the people, environment and cultural heritage of the area than getting rid of it on land, and that tailings wouldn’t impact marine life in the gulf.

The companies, through the Wafi-Golpu Joint Venture, declined to comment on the court hearing because they are not a party to the case. A representative of the venture did not respond to other questions about the companies’ plans.

At a 2022 annual general meeting, Sandeep Biswas, then the CEO of Australia-based Newcrest Mining Limited (Harmony’s original partner on the project, which was acquired by Newmont in 2023), said the companies had determined DSTP would be the safest option after vetting 45 potential disposal sites. The EIS points out that the region is earthquake-prone and receives high rainfall, making land-based tailings disposal risky.

Biswas also said the Markham River already carries tens of millions of tons of silt from farther inland into the Huon Gulf every year that “is not dissimilar to the tailings” the mine would produce.

A video posted on Harmony Gold’s website citing the companies’ EIS suggests that the top 60 m (about 200 ft) of water in the Huon Gulf, where “most fish life” lives, won’t mix with the tailings expelled from the tailpipe at 200 m down. Instead, it says currents will carry most of the sediment — 60%, according to the EIS — down to eventually settle in the depths of Markham Canyon, 700 m (2,300 ft) below the surface.

Critics of DSTP point to byproducts and chemicals from mining, such as lead, manganese and mercury, that will tag along in the slurry emptied into the Huon Gulf. They note how little scientists know about the deep ocean and how sediment plumes might affect life there.

“The science hasn’t caught up,” said Ellen Moore, interim mining program co-director at Earthworks. What’s more, we know little about life in the deep sea, she added.

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An independent review of the EIS commissioned by CEPA, the government’s environment agency, found that the deep sea near the planned outflow is rich in biodiversity, and the results conclude that more of the sediment would end up suspended in the water column than the EIS reported. Still, CEPA issued an environmental permit allowing the mine to go forward in late 2020 — according to the coalition, in spite of those findings. The issuance helped prompt the communities’ legal action against the government in early 2021, in part, for failing to take the potential environmental damage into account.

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