Offshore deposits: the floating tin mines of Indonesia – in pictures

Wooden pontoons equipped to dredge the seabed for deposits of tin ore off the coast of Toboali.

From the shores of Bangka island, miners head out by boat every day to crudely built wooden pontoons dotted off the coast that are equipped to dredge the seabed for lucrative deposits of tin ore.

Willy Kurniawan/Reuters

Fri 18 Jun 2021 07.00 BST

Indonesia is the world’s biggest exporter of tin for use in everything from food packaging to electronics and green technologies.

Land-based deposits in the mining area of Bangka-Belitung have been heavily exploited, leaving parts of the islands off the south-east coast of Sumatra island resembling a lunar landscape.

Miners on the shore of Toboali, on the southern shores of the island of Bangka, have instead turned to the sea where there are far more reserves.

‘On land, our income is diminishing. There are no more reserves,’ said Hendra, 51, who shifted to offshore mining about a year ago.

Grouped together around underwater tin seams, the ramshackle pontoons emit plumes of black smoke from diesel generators.

Hendra operates six pontoons, each with three or four workers and pipes up to 20 meters (66 feet) long that suck up sand from the seabed.

The pumped mixture of water and sand is run across a bed of plastic mats that trap the glittery black particles of tin ore.

Amirudin, 43, a field supervisor of the state tin mining company PT Timah, rests on a makeshift hammock. The miners are paid about 70,000 to 80,000 rupiah (£3.50 to £4) per kilo of tin sand, and a pontoon typically produces about 50 kilos a day.

The state mining company, Timah, has increased production from the sea to the point that its proven offshore reserves were 265,913 tonnes last year, compared with 16,399 tonnes on land.

The huge expansion has heightened tension with fishermen, who say their catches have collapsed because of steady encroachment on their fishing grounds since 2014.

Fisherman Apriadi Anwar, out with his son Avanza, 12, and a friend, says fishing nets can get tangled up in offshore mining equipment, while trawling the seabed to find seams of ore has polluted once-pristine waters. ‘Fish are becoming scarce because the coral where they spawn is now covered with mud from the mining,” he says.

Apriadi said in the past his family earned enough to pay for his two younger siblings to go to university, but in recent years, they have barely scraped by. ‘Never mind going to university, these days it’s difficult to even buy food,’ he says.

The Indonesian environmental group Walhi has been campaigning to stop mining at sea, especially on Bangka’s western coast, where mangrove swamps are still relatively well-preserved.

‘The mangrove is an ecological fortress for the coastal area,’ says Jessix Amundian, the executive director with Walhi.

Authorities have cracked down on the tin industry from time to time, particularly illegal mining, and remaining land reserves are often hard to access or require heavy machinery to exploit.

Timah said it collaborates with fishing communities to help preserve their catches.