Rescuers are racing against time to bring out the eight workers trapped for over 48 hours in a collapsed tunnel in Telangana. A state minister has warned that their survival chances are “very, very remote” as a pileup of muck and water hinders the rescue mission.

The tunnel, proposed to be 44-km-long – behind the Srisailam dam in Nagarkurnool collapsed Saturday morning when some workers were inside repairing a leak. While most of them managed to escape, eight got trapped and have been out of contact since Saturday.

Four of them are labourers and four are employees of the construction company, said state minister Krishna Rao, who is overseeing the rescue efforts.

Army, National Disaster Response Force and state agencies are already engaged in the rescue operation while Navy commandos have also arrived to assist them. Six members of the heroic team behind the 2023 Silkyara tunnel operation in Uttarakhand have also joined the rescue efforts.

The collapse occurred at least 13 km from the mouth of the tunnel and the rescuers have reached the final 100 metres, but the minister said water and muck are impeding the rescue operation.

“Muck has piled up too high inside the tunnel which has made it impossible to walk. The rescuers are using rubber tubes and wooden planks to navigate. The chances of survival are very, very remote, but we are hopeful and not sparing any effort,” said Mr Rao.

The rescuers have also flagged the need for more equipment as they fight the odds to bring out the trapped workers. A report yesterday said there were cracks on the walls of the tunnel from where water was gushing out and needed de-waterisation.

Another concern was the noises of shifting boulders that indicated the roof in the collapsed portion of the tunnel was still unstable.

The situation is being monitored round the clock at central and state levels.

Leader of Opposition Rahul Gandhi, whose Congress party holds power in Telangana, dialled Chief Minister Revanth Reddy yesterday to enquire about the rescue operation while Prime Minister Narendra Modi has assured full assistance.