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In Brazilian Amazon, mining harm comes from beyond just the mines, study shows

There are signs of a new frontier of deforestation emerging in Autazes, as invaders descend on this slice of the Amazon. Indigenous leaders say the area is now plagued by illegal logging and land-grabbing. Much of it is related to speculation as a massive potash mining project awaits approval. Image by Ana Ionova for Mongabay

There are signs of a new frontier of deforestation emerging in Autazes, as invaders descend on this slice of the Amazon. Indigenous leaders say the area is now plagued by illegal logging and land-grabbing. Much of it is related to speculation as a massive potash mining project awaits approval. Image by Ana Ionova for Mongabay.

  • A new land-use-change model suggests that the indirect impacts of mining operations in the Brazilian Amazon have been grossly underestimated.
  • Impacts include not only deforestation but also loss of biodiversity, contamination of water sources, and health hazards for the Indigenous peoples living in the area.
  • The calculation comes after years of government attempts to change existing regulations on protected areas and open them up to exploration.
  • New roads opened for mining could cause 40 times more deforestation than the mines themselves, wiping out an area almost the size of Puerto Rico in the RENCA protected area in the northern Amazon.

Opening up protected areas to mining in the Brazilian Amazon could have an even bigger impact than previously thought, according to a study published in Nature Sustainability earlier this year. The study focused on the nine protected areas that make up most of the National Reserve of Copper and Associates (RENCA) in the Amazonian states of Amapá and Pará, and looked not just at the deforestation caused by creating new mines, but also by the new roads required to access them.

According to the study, while downgrading the protection in those areas with mineral deposits would cause 183 square kilometers (71 square miles) of deforestation, the roads would have an impact estimated at more than 40 times larger, leading to the loss of 7,626 km2 (2,944 mi2) of forest over the next three decades — an area nearly the size of Puerto Rico.

“There are lots of studies about the Amazon, about deforestation, about mining, and about roads in that region. Our aim was to show how everything correlates and should be taken into consideration when there is a debate about opening these areas for mining,” says Juliana Siqueira-Gay, an environmental engineer at the Escolhas Institute and the study’s lead author.

The research, she says, also brings to light the limitation of current analyses for obtaining licenses and permits even in legal mining projects in Brazil, which, according to Siqueira-Gay, could have grossly underestimated indirect environmental impacts. “It is often said that the deforestation caused by mining is relatively localized, because the mine itself is small,” she adds. “But on many occasions there are thousands of kilometers of roads needed to reach the deposits, and building them causes deforestation and forest fragmentation.”

In RENCA’s case, opening the entire 47,000 km2 (18,100 mi2) reserve to mining operations would require 1,463 km (909 mi) of new roads to access 242 mineral deposits, the study shows. RENCA was declared a mining reserve in 1984, which meant mineral exploitation was fully prohibited within its borders; the goal was to protect the area for government-led research, without the risk of commercial activity in the area. Ninety percent of the reserve overlaps with other types of protected areas, including Indigenous territories and conservation units — where mining is fully prohibited — to sustainable-use areas, where a limited degree of mining is permitted.

map mining Brazil
Scenarios of PAs downgrading in RENCA, alongside their respective road network required to access mineral deposits. Photo courtesy of the study’s authors.

Mining already occurs in other sustainable-use areas across the Brazilian Amazon, where the management plans for the proposed projects have been approved, and could also happen in RENCA if it no longer had reserve status. But there are currently no specific plans for exploiting the area.

The four existing sustainable-use areas within RENCA represent a potential 170 new mineral deposits for economic exploitation, and would need 752 km (467 mi) of new roads, according to the study. There’s also legislation currently working its way through Congress that could open up Indigenous territories to mining.

In 2017, then-president Michel Temer tried to suspend RENCA’s protection, which would have allowed mining in the reserve. However, he was forced to backtrack after public pressure, reinstating the protection a few months later. RENCA’s status has not changed since.

But the debate is still alive, and even with a nominally pro-environment government taking office in 2023, it’s not likely to go away. This is where scientific modeling that details the potential damage could help the next administration, Siqueira-Gay says. “The indirect impact caused by the roads in the Amazon is much bigger than anticipated,” she says. “It is something that wasn’t as clear before, when these propositions to open protected areas for exploration were discussed.”

Legislation to open protected areas to mining

RENCA isn’t the only reserve whose protections successive governments have sought to revoke to allow mining in the Amazon in recent years. Bill 191, introduced by the current administration of President Jair Bolsonaro in 2020, is perhaps the most notorious initiative in this regard. Part of what activists call a “death package” of anti-environment bills pushed by Bolsonaro and his allies, Bill 191 effectively seeks to override the constitutional ban on mining in Indigenous territories. But a wide range of critics, including even the Brazilian Mining Association (IBRAM), which represents the mining industry, have warned that Bolsonaro’s bill would create a scenario with little to no control over environmental impacts in currently protected areas.

Deforestation and gold mining in Brazilian Amazon.
Deforestation and gold mining in Brazilian Amazon. Image by Fabio Nascimento for Mongabay.

“There is a lot of pressure for new mining legislation,” says Suely Araújo, a senior public policy specialist at the Climate Observatory, a civil society coalition focused on climate change. “Since Bill 191 was introduced by the [administration], we expect that it will be removed from discussion when president-elect Luiz Inácio Lula da Silva takes over. However, the future Congress remains highly conservative, and it will not become pro-environment overnight. The pressures will continue to exist.”

Soon after winning the presidential election runoff by a narrow margin on Oct. 30, Lula, who served two terms as president, from 2003-2010, pledged to end deforestation in the Amazon, reiterating one of his key campaign promises. In Lula’s first stint as president, the annual deforestation rate in Brazil dropped by about 67%, according to data from the National Institute for Space Research (INPE), which keeps track of forest destruction using satellite imagery. Under Bolsonaro, who took office at the start of 2019, the rate picked back up, with a Connecticut-sized 13,000 km2 (5,000 mi2) of deforestation in 2021 — almost triple the record low of 4,500 km2 (1,700 mi2) in 2012.

To keep his promise, observers say, Lula will need to work on alliances in a more hostile Congress than the one he faced when he took office for the first time 20 years ago. “At least, we expect that pro-environment representatives will have support from the Ministry of the Environment,” says Araújo, who headed IBAMA, the federal environmental protection agency, for three years under Lula. “With Bolsonaro, the ministry itself wanted to put an end to protective legislation.”

Illegal mining a persistent problem

Researchers like Araújo also argue that, while more robust regulation is necessary, there needs to be an effort to curb land-grabbing and illegal artisanal mining as well. According to a 2020 report by the Escolhas Institute, which advocates for sustainable development of natural resources, around 17% of Brazil’s gold exports were illegal, extracted without permits or any registration of origin. “While illegal mining doesn’t affect deforestation as much, it still has potential for a huge impact on biodiversity, because it contaminates the water resources,” says Ane Alencar, the scientific director at the Amazon Environmental Research Institute (IPAM), a Brazilian NGO.

President Jair Bolsonaro has been criticized for dismantling IBAMA, Brazil's environment agency. In this photo IBAMA agents remove deforestation machinery from the forest. Image by Vinícius Mendonça/Ibama [CC BY 2.0.]
Jair Bolsonaro administration has encouraged mining in the Amazon, while watering down environmental monitoring. Image by Vinícius Mendonça/Ibama [CC BY 2.0.]

During his term in office, Bolsonaro has publicly defended illegal artisanal miners, and even tried to “stimulate” their activity with decrees. “There was also an astronomical growth in illegal mining by invaders in Indigenous lands” in recent years, Alencar says. She cites the cases of the Munduruku and Yanomami peoples, who suffer from mercury contamination, damage worth hundreds of millions of dollars, and even getting violence and death from direct confrontation both with artisanal miners and land grabbers invading their territories to clear pasture for cattle ranching.

“When it comes to legal mining operations, the migration of workers also needs to be counted among the impacts,” Alencar tells Mongabay. Beyond the roads being opened to reach the mineral deposits, there’s also the building of structures for accommodation and, sometimes, even power plants and associated infrastructure.

“There is no mining activity without environmental impact,” Araújo says. “But with the right licensing this impact can be manageable.” That’s where more complex modeling, like the one proposed by Siqueira-Gay, could become useful tools for assessing more precisely the real consequences of opening up new territories for exploration.

Siqueira-Gay says the modeling cannot be extrapolated across the entire Amazon, due to regional differences in landscape, hydrography and transportation. However, with a few tweaks in the parameters, it could help similar calculations in areas of deep forest as remote as RENCA, and not just in Brazil. “Many areas of tropical forest around the globe could benefit from a similar analysis, particularly where there is interest to develop mining projects,” Siqueira-Gay says.


Siqueira-Gay, J., Metzger, J. P., Sánchez, L. E., & Sonter, L. J. (2022). Strategic planning to mitigate mining impacts on protected areas in the Brazilian Amazon. Nature Sustainability, 5(10), 853-860. doi:10.1038/s41893-022-00921-9

Banner image: In protected areas, opening roads to mining sites could prove more harmful than mine themselves. Image by Ana Ionova for Mongabay.

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Relevant reading:

Road network spreads ‘arteries of destruction’ across 41% of Brazilian Amazon

Report offers a road map to restore the rule of law in the Brazilian Amazon

The Amazon will reach tipping point if current trend of deforestation continues

Brazil leads Amazon in forest loss this year, Indigenous and protected areas hold out


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