From the shores of Indonesia's Bangka island, miners like Hendra head out by boat every day to scores of crudely built wooden pontoons dotted off the coast that are equipped to dredge the seabed for lucrative deposits of tin ore.
Indonesia is the world's biggest exporter of tin used in everything from food packaging to electronics and now green technologies.
But deposits in the mining hub of Bangka-Belitung have been heavily exploited on land, leaving parts of the islands off the southeast coast of Sumatra island resembling a lunar landscape with vast craters and highly acidic, turquoise lakes.
"On land, our income is diminishing. There are no more reserves," said Hendra, 51, who shifted to work in offshore tin mining about a year ago after a decade in the industry.
Often grouped together around undersea tin seams, the ramshackle encampments of pontoons emit plumes of black smoke from diesel generators that rumble so loudly workers use hand gestures to communicate