Rio Tinto's abandoned Panguna mine in Bougainville is the site of actual and potential human rights violations, including risks to life, a preliminary study of the social and environmental impacts of the mine has found.

Despite being closed for more than three decades, the mine still has masses of waste and decaying infrastructure which continues to impact thousands of people in the area; The first assessment of the issues that stem from the mine site being the centre of a civil war in the region between 1988 and 1998, which saw an estimated 15,000 deaths.

Results from the Panguna Mine Legacy Impact Assessment (PMLIA) - undertaken by global environmental consulting firm Tetra Tech Coffey - will be publicly released next month, but the ABC reports the study found - in some sites - violations of Indigenous people's rights to water, education and culture has taken place.

The study coincides with a class action against Rio Tinto over the legacy of the mine, with the first hearings taking place last week in Port Moresby.

The lawsuit against Rio Tinto and BCL is seeking compensation for what the plaintiffs argue is the historic management of the mine between 1972 and 1989.

At least 71 local clan leaders support the class action, with the lead claimant named as former senior Bougainville political leader and chief of the Basking Taingku clan Martin Miriori.

However, there are also worries the class action will cause fragmentation in the community - despite being supported by many locals - and disrupt the independent assessment.

Speaking in May, ABG President Ishmael Toroama said the class action was the highest form of treason which was creating an obstacle to the economic independence agenda of the ABG.

"This class action is an attack on Bougainville's hard-fought unity to date," he said.

Bougainville government member and lead complainant in the human rights case, Theonilla Roka Matbob, told the ABC: "It is now time for Rio Tinto to come out public and make its commitment known to the people so that it can restore its trust as a company, as an institution."

"What's so hard about Real Tinto committing that same energy as it did some 34 years ago in [establishing the mine at] Bougainville, to also manage and control the damage that it has created?"

A spokesperson for Rio Tinto told National Indigenous Times they will "strongly defend its position in this case".

"Rio Tinto's focus remains on constructive engagement and meaningful action with local stakeholders through the Panguna Mine Legacy Impact Assessment," they said.

"Rio Tinto recognises the importance of understanding and addressing the environmental, and directly connected social and human rights impacts that have occurred since mining operations ceased abruptly in 1989 due to civil war."

In 2021, Rio Tinto agreed to take part in the PMLIA after the Human Rights Law Centre (HRLC) filed a complaint with the Australian government on behalf of 170 locals.

Funded by Rio Tinto, the assessment is supported by human rights groups and the Autonomous Bougainville Government (ABG).

In August, Rio Tinto signed a memorandum of understanding (MOU) with ABG and its subsidiary Bougainville Copper Limited (BCL) to address some of the ageing infrastructure.

"The primary objectives are to mitigate potential hazards and enhance community safety. To achieve these goals, the parties have scheduled work on these structures to begin in the fourth quarter of 2024," the company's website states.

It alleged serious impacts to the safety of the community, as well as the health and safety of local livelihoods caused by close to a billion tonnes of mine waste that had been left when it was abandoned in 1989.

The ABC reports the results of the PMLIA found parts of the mine pit, levee, roads, and old buildings were at extreme risk of collapse. This had the potential to cause death, as well as cutting off access to medical care for locals.

It also said toxic chemicals were present in old fuel storage tanks, shipping containers and a sewage treatment plant, as well as in some soil samples.

One expert with intimate knowledge of the situation and speaking on condition of anonymity said Rio Tinto attempted to "wipe their hands" of the situation when they gave their stake in the mine to the Bougainville and PNG governments.

"It's the complaint from the Human Rights Law Centre that has pulled them [Rio Tinto] back in again," they told National Indigenous Times.

"Once that claim was accepted, it was very difficult for Rio Tinto not to respond to it, and their response has been to fund this legacy impact assessment."

They added the significant levels of rainfall in Bougainville made the risk of levee collapse a significant concern.

"If you got a really big rainfall event, the levees could collapse, and there would be significant numbers of people at risk if that happened," they said.

The Human Rights Law Centre said a failure to clean up the mine site and contribute to a remedy would have "major reputational and financial implications" for Rio Tinto, arguing it had struggled to establish its environmental, social, and governance credentials since the Juukan Gorge disaster in 2020.

"In the meantime, people in Bougainville are continuing to live in a volatile and increasingly dangerous situation," HRLC said.

Asked if they had engaged with locals since some of the findings were shared in community consultations over the last week, the Rio Tinto spokesperson referred to a section of their statement, titled "collective remedy".

"Rio Tinto is seeking to partner with key stakeholders, such as the ABG and BCL, to design and implement a remedy framework to respond to the impacts identified through the Independent Legacy Impact Assessment," the spokesperson said.

"This will include targeted engagement with impacted stakeholders, such as representatives from communities in the river tailings area, to ensure community concerns are incorporated into the remedy framework."