A movement is taking root in the small province of Benguet in the Philippines that might just revolutionize the artisanal gold mining industry and greatly reduce worldwide toxic mercury emissions. Gold miners there are rediscovering a century-old method of gold extraction that does not use toxic mercury.
If artisanal gold miners around the world can be convinced to go mercury-free, it would prevent the release of about 1,000 tons of toxic mercury a year – about 30% of the world’s mercury emissions.
We spoke with Leoncio Na-Oy, a gold miner in Benguet, about the method. Unable to find a job after graduating with a degree in history, Leoncio turned to gold mining and has since been a vocal supporter of a what’s been called “the Benguet method,” helping to spread the word to fellow miners in the Philippines and beyond.
He told us that elders in Benguet have been using this mercury-free technique to extract gold since the 1900s. But in the 1960s and 70s, large gold mining concerns came into the region and introduced mercury. However, Leoncio told us that many miners in Benguet have since gone back to using the traditional mercury-free method because it returns much more gold. This is what he told us:
There is a significant difference. For example, the percentage of purity of gold using the Benguet method is 15.8. If you use mercury, it is 14.8.
If miners see that the Benguet process is efficient and that they can recover more gold and earn more, they will learn the new process. That is the primary argument. For instance, we tell them that for 1 kilo of gold we will use only 400 grams of borax (used in the Benguet method), which can be bought at P40/kilo. However, we will need to use P30,000 worth of mercury to get 1 kilo of gold.
Miners in other areas are just not aware of the Benguet method. There was a group of miners from Compostela Valley Diwalway who came to Benguet to see us. When they saw the process they all were amazed that we could recover gold without mercury.
The miners are also unaware of the harmful effects of mercury. It was only brought to our attention in recent years by groups like BAN TOXICS. It was only when Peter Appel* came to the area that our Benguet method started to be promoted in other areas. We became volunteers to spread the method.
Now, the Benguet Federation of ASGM (artisanal gold miners) has a 15-year program to totally stop the use of mercury. All 15,000 affiliated members of the federation are now using the Benguet method. However, there are few rogue miners that still use mercury and we are trying to convince them to switch.
Update: Leoncio has been working with Pure Earth to test the method in artisanal gold mining communities in Bolivia and Mongolia.
Watch a video of gold mining without mercury.
* Peter Appel is a scientist at the Geological Survey of Denmark and Greenland in Copenhagen (GEUS), part of Dialogos, a Danish consortium, working with Ban Toxics, their local partner in the Philippines.