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 bodies of 100 men remain trapped in the Stilfontein mine, according to the Mining Affected Communities United in Action (MACUA), who told CNN that nine bodies were pulled out of the shaft on Monday, along with 20 survivors.

Meshack Mbangula, head of the Mining Affected Communities United in Action (MACUA), told CNN Tuesday that the men had possibly died from hunger and dehydration.

While there are varying reports on how many men have been trapped, Mbangula estimated that 500 people are still underground. Conditions in the shafts, which are several kilometers deep, are continuing to deteriorate, he said.