Police say the death toll in a monthslong standoff between authorities and miners trapped while working illegally underground at an abandoned gold mine in South Africa has risen to at least 87.

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.

The prospectors were trapped underground for months as police, on orders from South Africa’s government, attempted to starve them out.