BRUMADINHO, Brazil — One woman searching for her husband collapsed on the floor. Another clutched a photo of her missing daughter and a third shouted at volunteers: “To you, he is just someone you can substitute. But he is my husband, the father of my daughter!”

Scenes of desperation played out at a local school on Saturday in the Brazilian town of Brumadinho where hundreds of people waited as rescue workers dug through mud and sludge searching for survivors a day after a mining dam collapse in southeastern Brazil left at least 34 dead and almost 300 missing.

More than 24 hours after one of the deadliest mining accidents in Brazil’s history, official information was scarce. The Civil Defense office said 199 people had been rescued by emergency workers, but only 23 of their names were tacked on the walls of the makeshift crisis center.

“I’m anxious, despaired, because there is no news,” said Lucilene Ferreira, 37, who was looking for her husband Emerson José. “Sometimes, I think everything will be all right. And sometimes, I think the worst.”