South African police lowered a camera down more than a mile (1.5 km) underground into an illegal gold mine on Thursday to ascertain if any survivors or corpses were still there after a months-long siege by authorities in which at least 78 miners died.

The South African government has launched a rescue operation at an abandoned gold mine in the country’s North West province, where at least 109 men have died, a group representing the miners said, after local authorities cut off vital supplies in a dramatic bid to crack down on the country’s illegal mining trade.

Arguing that the miners had entered the mine without permission, authorities reportedly cracked down by cutting off their access to food and water.