In a desolate area of central Indonesia where lush rainforest once stood, illegal miners on the frontline of a modern-day gold rush tear up the earth in the hunt for the precious metal.
Thousands of men use high-pressure hoses to blast tonnes of sand out of the ground daily in open pits around Kereng Pangi on Borneo island, before running it through filters to find specks of gold.
Aside from the environmental devastation, the workers there and at many similar sites across Indonesia are risking their health and poisoning communities by illegally using mercury to extract gold.
Mercury can cause serious neurological damage and gold miners who work for years burning the metal develop symptoms such as tremors and persistent coughing. The situation has been described as a “health timebomb” by Professor Marcello Veiga, an expert in the use of mercury in small-scale gold mining at the University of British Columbia in Vancouver. “They will die by the thousands,” he said.
Jakarta hopes that a landmark UN convention, signed this week in Japan aimed at reining in the use of mercury, will limit supplies of the metal for miners in Indonesia and help reduce the deadly practice. But others believe the treaty, signed near Minamata in southwest Japan where mercury pollution poisoned tens of thousands, is too weak to tackle a problem that has grown in tandem with the price of gold.
The United Nations estimates that up to 15 million so-called “artisanal small-scale gold miners” operate in 70 countries.
In Indonesia, the numbers have risen from an estimated 50,000 in 2006 to around 500,000, according to Abdul Harris, who heads a government-backed task force charged with tackling the issue.
The widespread use of mercury to extract gold has made mining the biggest single source of man-made releases of the highly toxic metal into the environment, according to the UN.
The growth in the practice is clear in Indonesia, where many who struggle to make a living are employed to crush rock ore and blast through sand at hundreds of sites in search of gold.
When mercury is mixed with the ore or sand mixture, the heavy liquid metal forms an amalgamate with the gold that allows it to be easily separated out.
It is the next part of the process that is dangerous. The mercury is burnt off, releasing neurotoxins that can cause irreversible neurological damage and harm vital organs.
“We do worry — but we worry more about not getting enough to eat,” said a gold miner, who declined to be identified, on the central island of Lombok.
In recent years, many shops where the amalgamate is burned off have had ventilation hoods fitted to suck up the dangerous fumes, but there is nothing to stop the burning that occurs in open fields. Rini Sulaiman, an advisory board member of Borneo-based development foundation Yayasan Tambuhak Sinta, said it is hard to monitor the health of people working in the industry as many are migrant workers.
When deaths do occur, the cause is rarely recorded for this group, making it difficult to know if mercury is a factor.
However some see a greater danger for communities surrounding the fields, as the toxic metal finds its way into the food chain.
It is a particular danger when it enters rivers, as it mixes with bacteria and forms “methylmercury,” which is more toxic than normal mercury.