A gold mining site collapsed Tuesday in the western part of Central African Republic, killing at least 30 miners and leaving others trapped, authorities and residents said.

The low-tech, artisanal mine collapsed Tuesday morning in the Abba region of the Nana-Mambere prefecture, according to Florian Gaguende, one of the surviving miners. He said rescuers were searching for additional miners believed trapped, but that the chance of finding them alive “is getting slimmer.”

The sub-prefecture’s deputy mayor, Souleymane Bi, said rescuers and residents managed over several hours to pull 30 bodies from the collapsed mine, and that injured miners were receiving treatment.

“It is horrible and we are calling for help from organisations and all people of good will to help pull from the hole those who are unable to do so,” Bi said.

Artisanal mine collapses are common in the Central African Republic, where several thousand people work in small-scale extraction mining. The work is risky because miners typically do not have enough protection.