Mercury use rising

It’s no easy task convincing the millions of artisanal gold miners across the globe that mercury, a substance they use routinely to extract fine gold from alluvial or lateritic ores, can be harmful to them, their families, and the environment.

Just ask Marcello Veiga, chief technical advisor to the Global Mercury Project (GMP) — a UN-funded program that aims to reduce mercury use and pollution by artisanal miners worldwide.

Although mercury poisoning can cause blindness, tremors, and neurological damage and accumulate in water, aquatic life and soil, workers with the GMP have faced challenges relaying those dangers to small-scale miners, Veiga says.

“Usually, the miners don’t believe in (mercury poisoning) because they don’t see it right now,” he says, adding that it’s a slow, accumulative process. “That’s one of the things — if you try to approach them just with health and environmental justifications for not using mercury or to use less mercury, it’s pretty difficult because they don’t believe — they don’t see the effects.”

Started in 2002, when a rising gold price spurred small-scale mining activity worldwide, the GMP was a response to the concerns of six countries in particular — Brazil, Tanzania, Sudan, Zimbabwe, Laos and Indonesia — about the amount of mercury being released into the environment by small-scale mining.

Mercury forms an amalgam with gold, and so is often mixed with ore to pick up fine gold. The silvery metal ends up in the environment when artisanal miners dump mercury-laden tailings into fresh water or burn the amalgam to concentrate the gold, vaporizing the toxic metal and leaving mostly gold behind.

A project of the United Nations Industrial Development Organization (UNIDO), the GMP initially focused on the environmental impact of mercury pollution — in particular, its effects on important water bodies and potential trans-boundary pollution. But over time, its focus has shifted, Veiga says.

“What we found is that the environmental effects are serious, but they’re not as serious as the health effect on the population living around mining sites,” he says. “We are seeing people dying. . . kids completely blind in Zimbabwe.”

Given the numbers — the GMP estimates that there are 10-15 million artisanal miners across the world, including 4 million women and 1 million children — the issue is critical to the health of millions.

Though health and environmental studies showed that mercury does accumulate in the environment, contaminating fish and soil, it is not as mobile through water as had initially been believed. Inhaling mercury vapour — which most artisanal miners and many of their families are often exposed to during the process of burning amalgam — was found to be much more damaging.

At the extreme, mercury poisoning can lead to death, but more commonly causes insomnia, concentration problems, lack of co-ordination, and among children, brain damage.

Local GMP campaigns focused on educating miners, women and children about the dangers of mercury exposure and teaching basic precautions such as using gloves when handling the liquid metal and never burning amalgam indoors. Miners also learned techniques such as using a retort — a simple device designed to collect the mercury vapour as amalgam is burned, and other technology to capture and recycle mercury — rather than trying to eliminate it altogether.

Artisanal miners are responsible for about 1,000 tonnes, or one-third of the mercury released into the environment each year through human activity, but Veiga says quashing the poverty-driven practice completely would be devastating to the roughly 100 million people who rely on it financially.

“We cannot cut the mercury completely,” says Veiga, who is also an associate professor at the University of British Columbia’s Department of Mining and Mineral Process Engineering. “It’s a very ancient technique, very obsolete. . . but it’s still very useful for them to capture fine gold.”

Originally from Brazil, Veiga says the GMP’s biggest success has been in his native country. In spite of an official ban on the use of mercury in mining in Brazil, the nation’s garimpeiros emit about 30 tonnes of mercury per year.

In the Rio Tapajos basin, the country’s main small-scale mining region, many miners dispose of tailings directly into local rivers. The local campaign was successful in getting the 5,000 miners it reached to use better methods that released less mercury and about half of them to move away from the water. About 40,000 miners work in the area.

Veiga attributes the success of the project to a high degree of support from the local government, as well as the ability of the local GMP team to demonstrate efficient techniques.

“When we demonstrate we can produce more gold in one site, then other miners. . . become interested,” Veiga says.

The GMP achieved encouraging results in Indonesia, largely because of the local knowledge and contacts of an exploration company — junior Kalimantan Gold (klg-v), Veiga says.

A community development organization founded and funded by Kalimantan Gold in 1997, Yayasan Tambuhak Sinta (YTS) was contracted to run one of two local campaigns in the country. The GMP found Indonesians tested in 2004 had the highest level of mercury contamination among all the project sites, owing to the common practice of burning amalgam indoors.

In the central Kalimantan region, where YTS conducted its campaign, the project targeted not miners, but the owners of gold shops in the local town of Kereng Pangi, who buy the gold-mercury amalgam from them and burn it in their shops. YTS introduced fume hood technology that captures the mercury vapour, allowing it to be reused and limiting emissions.

“We believe we are collecting and recycling ninety-five per cent of the mercury vapour in the shops that have adopted the technical modifications,” says YTS community and regional development manager Bardolf Paul, adding that 18 of 35 gold shops in town are using the inexpensive filter-condensor technology, with more coming on board. “We feel it has been pretty successful for just a nine-month run at the problem.”

YTS estimates that the local campaign has prevented the release of 600 kg of mercury into the environment annually.

Veiga has high praise for Kalimantan Gold, which has been exploring in Indonesia for copper and gold since 1997, as one of only two companies that participated in the project, and the sole junior. The YTS-led project is not on Kalimantan’s properties, which are in central and eastern Kalimantan, although there is likely some small-scale mining activity on the company’s concessions, says corporate relations manager Nick Cottam.

“You can’t ban artisanal mining altogether because it just happens — it’s a fact of life in that area,” he says.

AngloGold Ashanti (AU-N) was also involved in the GMP campaign in Tanzania, where it owns and operates the Geita gold mine.

Veiga believes that exploration and mining companies — which often have to deal with artisanal miners — have a role to play in the GMP, and hopes more will get involved in the next phase.

This summer marks the end of the first phase of the project, which has already seen 30,000 miners trained, with Veiga hoping to get funding for an extension into 20 more countries — which would receive funding for between three months and five years. The program requires a 30% contribution by participating countries.

A final study summarizing the progress made in the six countries that have participated so far, along with conclusions and recommendations, will be released in August.