The First Minister visited Skewen on Sunday to see the clean up operation after severe flooding caused families to be evacuated from their homes.
The Coal Authority, who are investigating the cause of the flood, said there had been a "build up of water in the mine-workings" above the flooded area from heavy rain brought by Storm Christoph.
It believes that pressure caused the water to blow out of the mine at weak point, "potentially an old mine shaft".
Stephen Morris who lives in Skewen previously told ITV Cymru Wales that homes in the area had been "totally wrecked" by floodwater and "it all happened so quickly, there was nothing we could do."
He described seeing flood water flowing into homes through the ground floor windows.
Mr Morris said the water "gushed down" the road and one of his neighbour's houses has been wrecked.
He added: "The drains couldn't take it. The back garden flooded as well, it was coming through his patio doors, through his kitchen door, the front door and there was about four foot of water on the ground floor.
"It's totally wrecked his kitchen, living room and the front room too."
He said now the "major worry" is that one of the other mine shafts in the area may collapse and cause more flooding.
The investigation into what caused the flooding is continuing and is being led by officials from the Coal Authority.
The Coal Authority says engineers have now determined the precise location and extension of the collapsed mine shaft which allows them to bring in larger equipment to investigate the wider mine workings and drainage channels in the area around it.
Engineers have also checked all recorded shafts in the immediate area and found them all to be safe and say work to check over a wider area is continuing in the days ahead.
The council says it is working closely with the Coal Authority to understand how residents will be impacted by the ongoing investigations.
The Coal Authority also says that it knows that people will want to get back to their homes but says it is not safe to do so over the next 24 hours.
It says the safety of residents continues to be our top priority and in the meantime we ask you to please be patient as the investigation continues.