Brazil Agents Raid Illegal Gold Mining on Isolated Tribal Land

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By Michael Kepp

Brazil said a government raid on illegal gold mining on an Amazon reservation of the Yanomami tribe resulted in “limited” success in fighting the cause of mercury poisoning and erosion along a major river.

Forty-five agents from IBAMA, the enforcement arm of the Environment Ministry; federal police; the federal Indian agency (FUNAI); and the Army conducted raids between March 27 and April 1 along a several-mile stretch of the 540-mile Uraricoera River in the Amazon state of Roraima, which runs through Yanomami land.

The agents arrested three people and destroyed 20 wooden-shack encampments, four river barges, hoses and other mining equipment, and seized a speedboat, IBAMA said.

Estimated 3,000 Illegal Miners

An estimated 3,000 miners on 60 barges are illegally mining gold along the Uraricoera, the longest river in the state, based on estimations from FUNAI plane flyovers, said Diego Bueno, an IBAMA coordinator of the operation.

Dozens of miners in the encampments fled into the rainforest when they heard helicopters and speedboats approaching. And the three arrested miners were released because there was no room in helicopters to take them, along with team members, back to the capital of Roraima state, a common practice in such busts, said Bueno.

“That’s why we measure the success of such an operation on how many miner barges and encampments we can destroy, not how many arrests we make,” he told Bloomberg BNA April 18. “And we destroyed four mining barges and 20 miner encampments on this operation, making it a limited success.”

Mercury Poisoning

Alluvial mining is illegal in Brazil.

Miners on barges use suction pumps and hoses on barges to bring riverbed ore to the surface. In nearby creeks, miners use pump-pressurized hoses to blast and destroy the banks, erosion that dries or silts-up the tributaries. Then miners transfer the slurry into sieve-bottomed sluices that separate soil from the heavier gold, Bueno said.

Mercury is used to remove impurities from gold-laden ore by creating an amalgam that, once heated, leaves only the gold. Heated mercury is a powerful neurotoxin, vaporizes and condenses in streams where it concentrates in fish, a main food source for Indians.

With 30,000 members, the Yanomami is the largest Amazon Basin tribe still isolated from much of modern society.

A study last year found unsafe levels of mercury in the bodies of more than 90 percent of Yanomami tribe members living closest to the illegal mining.

To contact the reporter on this story: Michael Kepp in Rio de Janeiro at

To contact the editor responsible for this story: Greg Henderson at

For More Information

An IBAMA statement is available, in Portuguese, at

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