- Indonesia’s environment ministry has reapproved a controversial zinc and lead mine in North Sumatra, less than a year after the Supreme Court forced it to revoke the project’s earlier environmental approval over disaster-risk concerns.
- The revised environmental assessment replaces a proposed tailings dam with a plan to bury mining waste underground, but critics and independent experts say the mining company cannot realistically bury all of its waste and will still require a dangerous aboveground storage facility.
- Residents, activists and legal advocates argue the new approval is legally flawed because it relies on a framework already annulled by the Supreme Court, and say the company failed to conduct meaningful public consultation or provide key documents to affected communities.
- Communities opposing the mine say previous company activities have already caused environmental damage, flooding and water disruptions, and vow to continue fighting a project they fear could threaten lives and farmland in the earthquake-prone region.
JAKARTA — Indonesia’s environment ministry has issued a new approval for a controversial zinc and lead mine in an earthquake-prone region of Sumatra Island, less than a year after a Supreme Court ruling forced it to rescind its earlier approval. Critics of the project have slammed the U-turn, pointing out that nothing has fundamentally changed in that time.
The new approval was issued for an environmental impact assessment that updates the previous assessment produced by PT Dairi Prima Mineral (DPM) for the mine in Dairi district, North Sumatra province. That earlier impact assessment, known as an Amdal in Indonesian, was faulted by nearby residents and experts for a plan to hold mining waste sludge behind a dam — a recipe for disaster, they contended, in a highly earth-quake prone region.
The updated Amdal does away with the proposed permanent tailings dam, and instead proposes mixing the mining waste with cement and water and injecting it into mined-out voids underground, a process known as cemented paste backfill.
But residents who successfully petitioned Indonesia’s highest court to void the earlier Amdal say the new one changes nothing in terms of minimizing the risk that the mine and its waste will pose to nearby communities.
“I am disgusted,” said 65-year-old Rainim Purba from Pandiangan village in Dairi. “DPM is only hiding the same dangerous project in slightly different packaging.”
She said the Supreme Court ruling from 2024 was meant to ensure the mine didn’t get environmental approval. “So is the [environment] ministry not responsible for our existence in Dairi district? Is the community not recognized [by the ministry]?” she said.
Hydrogeologist and mining waste expert Steven Emerman, who reviewed the November 2025 update to the Amdal, called the project “the worst I’ve seen in all my years reviewing mining proposals around the world.”
He said he was perplexed by the environment ministry’s decision to approve the updated Amdal, saying DPM had provided no evidence it could backfill 100% of the tailings generated from the mine.
“Yet the Indonesian Ministry of Environment keeps providing approval to them. This can only be regarded as a failure to protect people and the environment,” Emerman said.
A mountain of waste in an earthquake zone
Villagers living within the DPM mine’s area of influence have for years petitioned against the project. Their main concern was the company’s initial plan to build a tailings dam to hold back the sludge left over after the valuable ore has been extracted.
David Williams, a tailings dam expert and director of the Geotechnical Engineering Centre at the University of Queensland in Australia, described the proposed mine site as one of the most dangerous possible locations for a project of this kind, citing high rainfall, frequent earthquakes, unstable volcanic ash deposits, and landslide risks.
Dairi lies in a seismically active part of Sumatra, near segments of the Great Sumatran Fault. Experts who have reviewed the project have warned that the combination of seismic activity and heavy rainfall could lead to a catastrophic breach of the tailings dam, putting downstream communities at risk of a torrent of toxic sludge.
Despite repeated warnings from experts and residents, the Indonesian Ministry of Environment approved the project’s Amdal in August 2022, putting DPM one step closer to being allowed to start mining.
Communities then challenged the approval in court.
In August 2024, the Supreme Court upheld the residents’ challenge and declared the environment ministry’s 2022 decision invalid, citing problems in the public participation process, zoning requirements, and disaster risk considerations. The court ordered the ministry to revoke the approval, which it eventually did 10 months later, in May 2025.
Low-key approval
It took another 10 months for the ministry to once again give DPM its stamp of approval. There was little fanfare around the issuance; it was issued on March 13, 2026, as “Environmental Feasibility Decree No. 1437/2026,” but residents and civil society groups only found out about it on May 5, when DPM and Dairi district government officials invited them to an event at a hotel in the district seat.
In a written response to Mongabay, DPM said the approval had gone through “a transparent process,” including technical assessments and public consultation. The company said a public consultation was held on Nov. 27, 2025, involving representatives of surrounding communities, village officials, provincial agencies, the Dairi government, subdistrict and village administrations, environmental activists, youth forums, community leaders and local NGOs.
Hendra Sinurat, a lawyer with BAKUMSU, a legal aid organization representing communities opposed to the mine, disputed that account.
He said neither the plaintiffs in the previous lawsuit nor BAKUMSU, as their legal counsel, had been invited to the Nov. 27 consultation. He said two field-based organizations assisting affected communities, the Diakonia Pelangi Kasih Foundation and Petrasa, were invited, but attended online and submitted a letter rejecting the consultation process.
“Affected residents, especially those who oppose the project, as far as we know, were not invited to the public consultation,” Hendra told Mongabay.
He said this showed the Amdal revision process was not transparent.
“The community was never involved or asked for its opinion in the preparation of the Amdal,” Hendra said. “In addition, the affected communities would not give their consent to the mining activity, given the consequences of the major disaster risk, because Dairi is a disaster-prone area.”
DPM said the May 5 socialization was part of its transparency efforts and obligation to provide information about permits that had already been obtained. The company said the presentations covered underground mining technology, waste management, mine water management, potential negative impacts, mitigation measures, and potential benefits such as employment, business and partnership opportunities.
Environment ministry officials Mongabay contacted, including secretary-general Rosa Vivien Ratnawati and Sigit Reliantoro, the deputy for environmental management, declined to confirm the approval.
DPM has welcomed the decision, saying the waste disposal method it has proposed in its updated Amdal will reduce long-term environmental risk and support post-mining restoration.
“We hope this project can soon resume in the near future,” said chief operating officer Zhang Junming. “And we also affirm our full commitment to complying with all applicable regulations in Indonesia.”
Zhang added that DPM planned to begin several construction activities after obtaining government approval for the company’s work plan and budget.
‘Deceptive plans’
Critics say the updated Amdal fails to address the main shortcoming of the previous plan: what to do with the sheer volume of mining waste that will sit aboveground and pose a disaster risk.
DPM says the backfill method is in line with sustainable mining practices, which the Indonesian Mining Experts Association (PERHAPI) has echoed.
“This backfill method has been adopted domestically since 2015 and has proven to be more environmentally friendly,” Muhammad Toha, PERHAPI’s chair for downstreaming, said in a written statement on March 16, 2026.
However, Emerman said the issue isn’t about backfilling per se, but whether DPM can backfill all of its tailings — bury all its waste back underground — as its revised Amdal claims it will do.
“While that sounds good, it is an impossibility,” he said. “I should know — I am one of the U.S. representatives to the International Organization for Standardization’s Technical Advisory Group on Underground Mine Tailings Backfill.
“Industry experience around the world says only 50-60% of tailings can be backfilled, leaving 40-50% to be stored above ground,” Emerman said.
He added this range is consistent with current mining industry handbooks, which describe physical and operational limits on cemented paste backfill. These include the expansion of rock after blasting and grinding, the water and cement added to make the paste, the need to keep some underground openings accessible, and the difficulty of completely filling irregular underground voids.
With the backfill method, DPM said, it would not require a permanent land-based tailings storage facility, only a temporary tailings facility for plant maintenance or emergencies, with a maximum storage duration of 10 days.
The revised Amdal also refers to a temporary storage pond for tailings awaiting backfill with a total volume of 32,400 cubic meters and an effective volume of about 25,000 cubic meters.
Emerman said that if only part of the tailings can be returned underground, the pond could become a de facto permanent tailings facility, without being assessed or engineered as one.
“By excluding a tailings dam from their 2025 Amdal, DPM is admitting that any tailings dam in Dairi would be dangerous and result in a disaster. But under new, deceptive plans, a tailings dam for about 2.5 million tons of tailings will still be required,” he said. “Misinformation in an Amdal does not make a problem go away.”
Williams also questioned the company’s claim that it could backfill all of its tailings.
“No one has ever backfilled 100% of tailings,” he said. “In the DPM case, a 2.5-million-ton capacity tailings dam would be inevitable, and in Dairi, the consequences of a collapse would be extreme.”
Backfilling may also pose groundwater risks, including leaching of heavy metals into the water table, activists say. They argue these risks have not been assessed holistically in DPM’s Amdal.
DPM said expert studies and ministry technical approval supported the plan, but did not provide those studies to Mongabay or directly address the experts’ specific claim that 100% backfilling is technically unrealistic.
Hendra of BAKUMSU said the shift from a tailings storage facility to backfilling is not a minor revision.
He said the change goes to the core of the project’s waste management system, and that this should not have been allowed as a mere revision of the previous Amdal. Instead, he said, a change of this scale should have triggered a new environmental impact assessment process entirely.
In fact, Rosa, the environment ministry’s secretary-general, had stated during the May 2025 revocation that DPM would have to start from scratch if it sought a new environmental approval.
“The previous permit was annulled, so they can’t rely on it [for a new approval],” she said at the time.
Hendra contended the new approval is legally flawed on these grounds, because it’s based on a framework the Supreme Court had already quashed.
“When the ministry tried to issue a new decree on a legal foundation that had already been revoked, this automatically violated legality, because it had already been revoked and annulled. Therefore, the new Ministry of Environment decree has no legal force,” he said.
Even if the ministry used the mine’s original Amdal, submitted in 2005, as the basis for the new approval, that would still be problematic because more than two decades had passed and environmental conditions in Dairi had likely changed since then, Hendra said.
As such, he said, both the revised Amdal and the new environmental approval must be considered legally flawed.
‘Things being covered up’
Juniaty Aritonang, director of BAKUMSU, the legal aid group, said some community members have expressed their intent to challenge the new environmental approval in court.
“We will support them,” she said. “They have a right to be safe from dangerous and dishonest mining companies. If the Ministry of Environment will not do their job, we and the courts have to do our jobs — again. It’s such a waste of time when this mine and this company are so obviously dangerous.”
Local activists say the mining company and the government effectively sucker-punched them with the new approval. They say they were invited to the May 5 event at the hotel in Dairi, where the approval was made public, only the day before the event.
Tioman Simangunsong, a 67-year-old resident of Silima Pungga-Pungga subdistrict, said she was one of the very few people opposed to the project who was invited; most of the other attendees supported the mine.
Rohani Manalu, an activist with the Diakonia Pelangi Kasih Foundation, said residents and civil society representatives asked for copies of the latest Amdal and environmental approval documents at the event, but were turned down.
“In several of our experiences attending DPM socializations, they did not involve residents who would be directly affected, and they did not provide documents,” she said. “What is there to discuss if we are not given the Amdal document and the environmental feasibility decree?”
Fitrianto, a Dairi district councilor who attended the event, described it as “nothing more than a formality.”
He said it appeared to be organized merely to fulfill administrative requirements, with one-way information dissemination rather than meaningful engagement with affected communities and stakeholders.
“We saw an imbalance. This socialization does not reflect an effort to seek the truth, because there are things being covered up,” Fitrianto said.
He also highlighted the absence of representatives from the environment ministry’s relevant directorate general and from the provincial government, who had been expected to provide technical explanations regarding the new approval.
A number of civil society representatives walked out of the event, also citing a lack of meaningful engagement and transparency.
DPM said a copy of the revised Amdal had been submitted to the Dairi government, the Dairi environmental agency and other relevant departments in accordance with the recipient list issued by the environment ministry.
The company did not say whether copies were provided directly to residents or civil society representatives who requested them at the May socialization.
Resistance continues
Residents opposed to the mine say it threatens farming communities who depend on rice, coffee, cacao, durian and other crops.
Tioman said that even though the mine wasn’t operational yet, DPM’s activities in the area had already disrupted their lives. In January 2012, drilling by the company reportedly resulted in a waste leak that contaminated rice fields and a river.
The company has also carried out forest clearing to build its waste containment ponds. Residents blame this deforestation for exacerbating flash floods that hit Silima Pungga-Pungga subdistrict in 2018, devastating homes, farmland and village facilities. Six residents were swept away and killed.
Tioman said residents also experienced water disruption after the 2018 flash floods, leaving some communities without drinking or piped water for nearly two months.
“We were sad. Since DPM came, we have suffered,” she said. “There is no water. Our rice fields have dried up since 2018 until now. We can no longer plant rice.”
Rainim said she would continue resisting the project.
“We will fight this,” she said. “DPM is again proposing a mine that will kill us. They are trying to divide our community. But we know what DPM is doing, and we will fight this mine until we die.”
Banner image: Villagers of Dairi stage protest in front of the Chinese Embassy in Jakarta in June 2024. Image by Falahi Mubarok/Mongabay Indonesia.
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