United Nations Environment Programme (UNEP)

Reducing Mercury Impacts in Small-Scale Gold Mining


Despite knowing full well the dangers of mercury, millions of small-scale gold miners across the globe continue to use the metal to separate gold from ore - usually because they have little other choice.

The mercury is mixed into ore and combines with the gold in a compound that can easily be scooped out and squeezed into a small bar of amalgam. This is then burned so that the mercury evaporates, leaving behind the gold. The dangerously toxic mercury vapour is often inhaled by the miners and their families, since these activities are usually conducted in their homes, or by the owners of gold shops who will process the amalgam for the miners before buying.

'When you burn off the amalgam - your head will feel like it's going to explode and you'll find it hard to breathe,' says Bapak Amit, a gold miner from Central Kalimantan, Indonesia.

However, introducing miners to simple recycling technologies can dramatically reduce the impact of mercury on human health and the environment. Amit is one of many who have benefited from a joint project between UNEP, the Blacksmith Institute and Yayasan Tambuhak Sinta, with funding from the US Environmental Protection Agency, to train miners to use better recovery techniques. The project also carried out awareness-raising events on the dangers of mercury and brought together representatives from across the sector and government to develop a national strategic plan. The end result is that mercury releases were reduced by an estimated 3,000 kg in one year.

Amit now uses a retort, a device which takes the mercury vapour up through a pipe and allows it to condense in a water tray. This means the toxic fumes are not released and the mercury can be used many times over, protecting the health of the miner and also bringing financial benefits.

'I wasn't even afraid of burning the amalgam inside my shed. It felt safe, as there were no symptoms like feeling hard to breathe,' says Amit. 'If there's smoke it's just the heat, the mercury stays in.'

In Indonesia, mercury costs 1,800,000 Rupiah (about US$150) per kilogramme. According to Abdul Samsuri, who runs a gold shop called Toko Huda, a kilogramme of amalgam can contain up to 500g of mercury. On average, he recovers around one kilogramme of mercury each month from the amalgam he burns.

Samsuri, who supports his wife and two daughters through his business, used to suffer from frequent headaches before beginning to use a water-box condenser, which traps the mercury fumes in a plastic box and condenses them back into the liquid form.

'It's good for our health and the mercury can be recycled,' he says. 'If they (miners) want to buy it we sell it cheaper; if they ask for it free, we give it to them.'

The savings in mercury point to the huge benefits that could be achieved by making such technologies an integral part of the small-scale mining process across Indonesia and the globe, thus helping nations to meet their obligations under the Minamata Convention.

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