The search for six miners missing deep underground in the US was abruptly halted after a second cave-in killed three rescue workers and injured at least six others tunnelling through rubble to reach them.
The setback on Thursday came on the 11th day of the effort to find six miners who have been confined at least 450m below ground at the Crandall Canyon mine in Utah state. It was unknown if the six were alive.
"It just feels like a really hard blow to swallow after all we've been through the last week and a half and everyone trying to hope in their own individual way," Huntington Mayor Hilary Gordon said in a telephone interview on Friday with CNN's American Morning.
All rescue workers were evacuated from the mine on Thursday evening and work underground was stopped.
Asked whether the search would be suspended, Rich Kulczewski, a US Department of Labor spokesman, said: "That's something to be determined."
The cave-in at 6:39pm was caused by a mountain bump, in which pressure can force chunks of coal from walls of the mine with great force. Seismologists say such a bump caused the Aug. 6 cave-in that trapped the six men more than 4.8km inside the central Utah mine.
That led to the frenetic effort by rescuers to dig through the mine toward the men and drill narrow holes on top of the mountain to try to learn their whereabouts and perhaps drop down food and water.
It was not immediately clear where the rescuers were working or what they were doing when Thursday's bump occurred.
Underground, rescuers had advanced only 252m in nine days. Before Thursday's cave-in, workers still had about 365m to go to reach the area where they believe the trapped men had been working.
Mining officials said conditions in the mine were treacherous, and they were frequently forced to halt digging because of seismic activity.
"The mountain is still alive, the mountain is still moving and we cannot endanger the rescue workers as we drive toward these trapped miners," said Bob Murray, chief of Murray Energy Corp, the co-owner and operator of the mine.