Gold prices have helped spur a renewed illegal mining rush across Brazil’s Amazon rainforest, accelerating deforestation inside protected areas and posing mercury contamination risks to waterways and food chains, officials and experts said. The renewed push is tied to a surge in gold prices in recent years, which prosecutors and researchers said has strengthened incentives for illicit extraction.
The new findings were released May 5 in a study by Amazon Conservation, working with Brazilian nonprofit Instituto Socioambiental, which examined how illegal mining sites have affected conservation areas in the Xingu region of Para and Mato Grosso. The study said it combined satellite imagery with ground research and linked illegal mining activity to clear-cutting within three conservation units.
Amazon Conservation reported that the Terra do Meio Ecological Station recorded its first illegal mining cases in September 2024. By the end of 2025, the study said mining-related deforestation there had spread to 30 hectares (74 acres).
At the Altamira National Forest, the study said illegal mining accumulated 832 hectares (2,056 acres) of deforestation between 2016 and September 2025. It also said a new mining front opened in 2024 and expanded to 36 hectares (89 acres) by October 2025, accounting for nearly half of mining-related deforestation recorded in the unit during that year.
Satellite monitoring also detected what the study described as a clandestine airstrip used by illegal miners at the Nascentes da Serra do Cachimbo Biological Reserve last year. It said illegal mining in the reserve grew from 2 hectares (5 acres) to at least 26.8 hectares (66 acres) in 2025.
The study added that mining remains a relatively smaller driver of overall deforestation in Brazil than agribusiness expansion, with official data cited for wider forest loss in 2025. Even so, Amazon Conservation estimated that 80% of mining-related deforestation in Brazil carries a high risk of being illegal, and it said mining often targets protected areas and Indigenous territories—conditions that researchers have described as crucial for slowing forest loss.
Protecting Indigenous territories is widely seen as an effective way to curb deforestation in the Amazon. Researchers have warned that continued forest loss could accelerate global warming, while the study’s authors and officials also said environmental damage from mining extends beyond clearing forest. They said illegal mining operations can dump mercury into rivers, contaminating waterways and accumulating in fish that riverine and Indigenous communities consume.
Prosecutors said enforcement efforts can reduce mining in some places but do not fully eliminate it. In 2023, Brazilian authorities launched a major crackdown on illegal gold mining in the Yanomami Indigenous territory in Roraima state, along the border with Venezuela, after a surge led to a humanitarian and health crisis. Amazon Conservation data cited in the report said annual growth in newly mined areas there fell sharply after that year, and it said nearly all deforestation inside Yanomami territory—about 5,500 hectares (13,590 acres)—had taken place by 2023.
Despite that, the report said miners can resume operations or relocate when officials leave. Federal prosecutor André Luiz Porreca, who investigates illegal mining in the western Brazilian Amazon, described enforcement as a “cat-and-mouse game.” He said, “Last year, I took part in an operation that destroyed more than 500 dredges on an Indigenous land,” and he added that “The following week, Indigenous people showed me photos proving the miners had already returned.”
Porreca said illegal gold mining is financed by Brazil’s largest criminal organizations, including the Red Command and the First Capital Command, or PCC, which he said operate in about a third of the cities in the Brazilian Amazon. He also said some dredges cost as much as 15 million reais, according to the report.
He said the gold-mining market dynamics also intersect with weaknesses in Brazil’s export controls, allowing laundering schemes that give illicit gold the appearance of legality. In April, Porreca submitted a report to the Inter-American Commission on Human Rights describing widespread mercury contamination in the Amazon, and he said the report cited a Fiocruz study. That study, as described in the report, found that 21.3% of fish sold in public markets across the Amazon exceeded World Health Organization mercury limits, and it said children ages 2 to 4 were consuming mercury at levels up to 31 times higher than the recommended maximum.
Brazil’s law prohibits mining on Indigenous lands, and the Ministry of Indigenous Peoples said combating illegal mining on Indigenous lands is a priority of President Luiz Inácio Lula da Silva’s administration. The ministry said mining invasions are sustained by criminal networks and that confronting them requires dismantling the economic and logistics chains. The Environment Ministry said mercury contamination remains persistent and is expanding scientific monitoring while supporting enforcement efforts, according to the report.
Authorities have faced continuing challenges tracking illicit extraction across remote regions, even as agencies and researchers monitor protected units and Indigenous territories. The report said Brazil’s Federal Police did not respond to requests for comment from The Associated Press.