Theonila Roka Matbob

A Fraught History

Bougainville is the largest island in Papua New Guinea’s (PNG) Autonomous Region of Bougainville (ARB), covering about 3,600 square miles with an estimated population of 350,000. The island contains vast copper and gold reserves, fertile land for cocoa and coconut production, and extensive marine resources.

The Panguna copper and gold mine—located in a mountainous, rural region at the island’s center—was developed by Rio Tinto and operated through its subsidiary, Bougainville Copper Ltd, from 1972 to 1989, yielding approximately 3 million tons of copper, 306 tons of gold, and 784 tons of silver. During its lifespan, it was one of the world’s largest open-pit mines and accounted for an astounding 44% of PNG’s export revenue.

By 1988, the Panguna mine’s impact on the region was undeniable. It had brought persistent environmental destruction, steady streams of migrant labor, and unequal economic benefit to the surrounding communities—which received only 1.4% of revenues—and profoundly destabilized the community. The result was a local uprising that led to a brutal, decade-long civil war when national military forces were called in to quell the rebellion. Unable to continue operations in such a context, Rio Tinto permanently shuttered the mine in 1989.

The Lincoln Peace Agreement was brokered in 1998, ending the bloody conflict that killed 15,000 to 20,000 Bougainvilleans—largely civilians. The agreement established a permanent ceasefire, mandated withdrawal of PNG military forces, and set up a neutral peace monitoring group. In 2001, a second peace agreement granted Bougainville self-governing status, allowing the island to establish its own constitution, legislature, and president. Bougainville now has the right to pursue full independence from PNG, a move that is supported by the majority of its residents.

53 Years of Contamination

Over its 17 years of operation, the Panguna mine dumped an estimated 150,000 tons of tailings into nearby rivers each day—more than 1 billion tons over its lifetime—devastating the Jaba and Kawerong river systems and affecting thousands of people living downstream. Generations of residents report serious health issues as a result of the contamination, including skin diseases, gastrointestinal and respiratory infections, and pregnancy complications.

To date, there has been no remediation of the mine site nor official response to the extensive social and health-related impacts. Current residents describe a once-green landscape now utterly bereft of greenery, a desert of lifeless tailings waste covering previously fertile soil, and rivers that are still being poisoned by acid and heavy metals from the mine.

Rio Tinto, which is headquartered in Australia and the UK, was the majority owner of the mine throughout its construction and operation. When it first developed the site in the 1960s, environmental impact assessments were not legally required—and, therefore, not conducted. There was also no meaningful community consultation process yielding consent to the mine’s construction, which was bitterly opposed by many residents.

In 2016, Rio Tinto divested and transferred its shares to the governments of PNG and the ARB, renouncing responsibility for any environmental clean-up.

A Leader Emerges

Theonila Roka Matbob, 35, is an Indigenous Nasioi woman from the Basikang clan, whose early years were spent just minutes from the Panguna mine. Her childhood was profoundly marked by the twin impacts of the mine and the country’s civil war. As a small child, Theonila watched her father taken away by rebels, who later killed him. Her mother subsequently fled with the children to nearby Arawa, where Theonila spent the next six years detained in a refugee camp controlled by the PNG Defence Force. The mine and its echoes shaped her lifelong commitment to address its environmental and social harms. In 2013, she and her husband co-founded the John Roka Counselling & Learning Centre, an NGO providing education and trauma counseling for communities affected by the civil war.

In 2014, Theonila knew that she needed to do more. She had many unanswered questions about the civil war and the mine’s traumatic legacy that she wanted to explore. She wondered why no one outside of the community knew about what had happened and why there was no process of reconciliation or remediation in Bougainville. Into that void, she gradually assumed positions of leadership. In 2018, she took part in the Catholic Diocese’s Panguna Listening Project and, in 2019, worked with the Human Rights Law Centre (HRLC) to gather testimonies from villagers along the river valley, documenting ongoing and widespread environmental harm from mine waste, even decades after its closure. These accounts formed the basis of HRLC’s 2020 report, “After the Mine: Living with Rio Tinto’s Deadly Legacy,” which laid the groundwork for broader accountability efforts.

In September 2020, Theonila became the lead complainant in a landmark human rights complaint filed by HRLC against Rio Tinto with Australia’s National Contact Point for Responsible Business Conduct (AusNCP), alongside 155 other Bougainville community members. The complaint, which attracted global media attention, accused Rio Tinto of environmental and human rights violations linked to the Panguna mine’s toxic legacy—alleging that the company’s failure to remediate massive volumes of mine waste had poisoned water sources, flooded lands and sacred sites, and endangered livelihoods and health.

Further, the complaint asked Rio Tinto to acknowledge responsibility, fund an independent impact assessment, create a long-term remediation and compensation fund, and participate in a reconciliation process, according to Bougainvillean custom. The complaint framed the communities’ demands using international human rights and environmental standards, such as UN and OECD guidelines, putting public and shareholder pressure on Rio Tinto to act.

In 2020, Theonila ran for election to Bougainville’s house of representatives—and won, assuming office in October—in order to broaden the reach of her coalition and bring more allies to the table. (She would serve in that role through 2025.)

In 2021, after several months of negotiations launched by the complaint, Rio Tinto committed to funding an independent assessment of the mine’s legacy, called the Panguna Mine Legacy Impact Assessment. An oversight committee—including community and clan leaders, government representatives from ARB and PNG, Rio Tinto, Bougainville Copper Limited (BCL), HRLC, and Theonila representing the communities—would manage the study’s design and implementation. Led by independent technical consulting firm Tetra Tech Coffey, the impact assessment’s first phase (phase 1), which focused on identifying the most serious risks and impacts on communities, was launched in December 2022 and completed two years later.

A Breakthrough for Communities

In November 2024, in response to persistent community advocacy led by Theonila, Rio Tinto signed a landmark memorandum of understanding (MOU) with BCL and the autonomous Bougainville government to work together with affected communities to address the impact assessment’s findings and develop a remediation framework.

In signing the MOU, Rio Tinto recognized the gravity of the impacts caused by the mine, accepted the impact assessment’s findings, and committed to working with all stakeholders to ensure that the mine’s legacy is addressed in a fair and equitable manner for the benefit of impacted communities.

The MOU and ongoing remediation process have set a significant new precedent for communities devastated by mining, especially in the Pacific region.

Working closely with Theonila and the oversight committee, Rio Tinto funded the majority of the Panguna Mine Legacy Impact Assessment and, in collaboration with BCL and the government of ARB, has begun addressing some of the most urgent, life-threatening risks to community safety. To date, improvements include increased access to clean water for nearby communities; the start of work aimed at addressing unstable infrastructure and chemical threats; and the installation of an early warning system for geotechnical hazards.

Today, Theonila and other community leaders, together with HRLC, continue to negotiate the timeline for urgent remediation work, further investigations, and the establishment of a dedicated mechanism to support a wide range of long-term environmental, social, and health needs. While much work remains to be done, there are rays of hope on the horizon—thanks to Theonila’s dedication and leadership.