Rio Tinto agreed to examine the legacy of environmental damage and human rights abuses linked to a mine on the once war-torn Pacific island of Bougainville, the firm said Wednesday.

The Australian-based multinational said it had reached a landmark agreement to investigate the impact of the now-shuttered Panguna mine, which was at the centre of the brutal decade-long civil war in Bougainville, part of Papua New Guinea.

The mining giant has for years been accused of side-stepping responsibility for cleaning up poisonous waste at the vast mothballed copper and gold mine.

When it operated between 1972 and 1989, Panguna was one of the South Pacific's largest mines.

Bougainville voted for Independence from Papua New Guinea in a historic 2019 referendum Bougainville voted for Independence from Papua New Guinea in a historic 2019 referendum Photo: AFP / NESS KERTON

 

But anger among locals over the environmental damage and distribution of profits triggered an uprising that forced its closure.

The ensuing civil war left up to 20,000 people dead -- about 10 percent of Bougainville's population at that time.

Under legal pressure, and facing public and investor outrage for recently blowing up an ancient Aboriginal site in Australia, Rio Tinto said it would now "identify and assess legacy impacts" of Panguna.

"This is an important first step towards engaging with those impacted by the legacy of the Panguna mine," said company chief executive Jakob Stausholm.

"We take this seriously and are committed to identifying and assessing any involvement we may have had in adverse impacts."

Rebel leader Francis Ona led a secessionist rebellion over 10 years from his base near the defunct Panguna copper mine which left up to 15,000 people dead Rebel leader Francis Ona led a secessionist rebellion over 10 years from his base near the defunct Panguna copper mine which left up to 15,000 people dead Photo: THE NATIONAL / THE NATIONAL

 

As a first step, Rio Tinto will fund an independent "impact assessment" by international experts.

That report is likely to intensify calls for a fund to compensate victims and repair damage done.

Clean-up costs are estimated to be in the region of $1 billion.

Local activist and government official Theonila Roka Matbob welcomed the news.

"This is such an important day for communities on Bougainville. For so many years, the Panguna mine has poisoned our rivers with copper. Our kids get sick from the pollution," she said.

"These problems need to be urgently investigated so solutions can be developed."

Australia's Human Rights Law Centre, which helped organise legal action against Rio Tinto, said the news was "a major step forward".

The centre vowed "to ensure the assessment is followed up by swift action by Rio Tinto to address its disastrous legacy on Bougainville".

As part of a 2001 peace agreement that ended the civil war, Bougainville recently voted overwhelmingly to gain independence from Papua New Guinea.

The island's leaders have said full independence will be achieved by 2027, although lawmakers in Papua New Guinea's parliament could scupper that plan.