The rusted air vent is deafening and a whoosh echoes around the pit. Copper-polluted water sits in a pool nearby and trees are starting to take over the graded hillside. Rocky, uneven ground is where locals pan for gold, hoping to find a few grams to make some money for families living in nearby villages. Seven kilometres wide at its broadest point, the Rio Tinto-controlled Bougainville copper mine in Papua New Guinea hasn’t been in operation for nearly 25 years, yet still dominates the local landscape.

Dozens of massive trucks lie inoperable. Oil drips from their engines and runs downstream. A loud, machine-like sound is heard in the pit. The vent is sucking air directly into a pipe that takes water outside the mine itself. It is this device that allows the mine not to fill up completely with water when it rains constantly during the rainy season. It has been making this booming sound 24 hours a day for the past two decades.