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A view of the district of Laberinto, Peru, from the Inambari River.
A view of the district of Laberinto from the Inambari River. Over years of constant shifting, the river has transformed the area into a complicated landscape.

Located about an hour from the city of Puerto Maldonado, the capital of Madre de Dios, is Laberinto (or the Labyrinth) -– a gold mining district in the Peruvian Amazon, hidden by an immense canopy of vegetation.

A few months ago, a state of emergency was declared in Laberinto, along with other districts of Madre de Dios, due to concern about widespread mercury pollution caused by artisanal and small scale gold mining activities in the region.

But this problem is not restricted to Laberinto, Madre de Dios, or even Peru.

Worldwide, artisanal gold mining is responsible for over 30% of the world’s mercury emissions, or about 1,400 tons of toxic mercury released per year (according to UNIDO).

Peru is one of the countries in which Pure Earth is testing what is known as the Benguet method—a way of mining gold without the use of mercury.

The project in Peru is being implmented in collaboration with the local organization CREEH. Filipino miner Leoncio Na-Oy had rediscovered the traditional method, which was used by miners in his hometown of Benguet in the Philippines a century ago.

Now, Leoncio and his teammate Rudy work with Pure Earth to test and teach the method to local miners worldwide.

Members of the Pure Earth team
Members of the Pure Earth team (from left to right): Leoncio, Javier (Peruvian miner expert from CREEH), and Rudy.

Over the past year, the Pure Earth team has visited Bolivia, Mongolia, and Peru.

Earlier this year, together with the technical team from CREEH Peru, they demonstrated the technique to miners in Ollachea in the mountains of Peru before they headed down into the Labyrinth to teach miners in the rainforest how to stop using mercury.

Mercury Free With Minor Adjustments

Leoncio and his team have to test and adjust the way the Benguet method is used in every mining community they visit because different methods work at different locations.

For example, the Benguet method in Ollachea involves ore crushing and sluicing.

[See photos of Leoncio training miners in the mountains Ollachea]

In Laberinto, with its soft alluvium, ore crushing and sluicing is not needed.  Instead, Leoncio and his team determine that the key to going mercury-free in the Labyrinth is panning.

Instead of mixing the gold-rich alluvium with mercury, Leoncio instructs the miners in Laberinto to add water and pan. He tells the miners watching his demonstration that panning is like learning to drive.

“If you drive, you have to hold wheel. It’s the same with panning,” Leoncio says.

Leoncio with technical experts from CREEH teach miners in Laberinto how to pan

Leoncio shows the miners that what he gets with panning is a more concentrated gold mixture, which he then burns off using non-toxic borax rather than mercury.

Panning leaves behind a more concentrated solution of gold. This is what it looks like before it gets burned with non-toxic borax.

Borax lowers the melting temperature of the mixture, causing all the other materials to oxidize and break down, leaving behind pure gold.

Borax is a better option not only because it is a non-toxic substance, but it is also cheaper. Miners can buy a kilogram of borax for US$5 while a kilogram of mercury costs about US$300.

The mercury-free technique also does not require much investment in new equipment, which makes it easier for miners to adopt. All miners need to do is purchase a pan and practice panning.

These benefits were not lost on the miners.

Jose, head of the Laberinto Mining Association, has become a strong supporter of the effort to go mercury-free after seeing Leoncio’s demonstration and holding the mercury-free nugget of gold in his hand.

Jose, head of the Laberinto Mining Association, holds a nugget of mercury-free gold.
This could be one of the first grams of mercury-free gold in Laberinto, Madre de Dios.

“When we asked the miners why they used mercury, they told us that it was the only way gold had been processed for years in Laberinto. Nobody had showed them this method using borax before. But now that the miners know it is possible to extract gold without mercury, and that it can be cheaper, I think we will begin to see change,” says Pedro Sifuentes, Pure Earth’s project officer in Peru.

“There is still much work to do. But we are making great progress. Now there is a way forward.”



Pure Earth is working in Peru on a project funded by the U.S. Department of State to assist the Peruvian government and civil society in assessing artisanal gold mining sites, planning remediation efforts and strategies for alternative livelihoods, and sustainably restoring affected natural resources. Partners include  the Ministry of Environment (MINAM: Ministerio de Medio Ambiente) of Peru.

Pure Earth also works in many other artisanal gold mining areas around the world to reduce the impact of toxic mercury while maintaining livelihoods. Because different methods work at different sites, project teams test a variety of approaches; some that eliminate the use of mercury entirely, and others that use (and recapture) mercury.


In Photos: Teaching Artisanal Gold Miners To Extract Gold Without Mercury

In Peru – A Path Of Gold And Destruction

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