The National Disaster Response Force on Tuesday reached the final point of the Srisailam Left Bank Canal tunnel’s collapsed roof in Nagarkurnool district, where eight workers have been trapped since February 22, The Times of India reported.

A three-metre stretch of the under-construction tunnel collapsed on Saturday, injuring about a dozen workers. More than 50 persons were said to have been working at the site with a tunnel-boring machine when the accident took place.

The workers are believed to be trapped in the last 50 metres in front of the tunnel boring machine, the newspaper reported. This spot is about 14 km inside the tunnel.

Till Monday, the rescue teams were stuck 40 metres away from the last point of the collapsed roof.

Heavy flow of water and slush inside the tunnel have created hurdles for the rescue teams.

Telangana Irrigation Minister N Uttam Kumar Reddy, who visited the site on Tuesday, said that the tunnel around the collapse spot had become unstable, The Hindu reported. The extent of water seepage was assessed to be about 3,000 litres to 5,000 litres per minute and was creating a problem for rescuers, he was quoted as saying.

The Border Roads Organisation and the CSIR-National Geophysical Research Institute are expected to join the rescue operation on Wednesday. The Geological Survey of India is already part of the rescue efforts.

Despite efforts by the Indian Army, the National Disaster Response Force and other agencies, there has been no breakthrough in the rescue operations yet. The Indian Navy’s Marine Commandos also joined the operation with special equipment to trace those trapped inside.

On Monday, Telangana’s Tourism Minister Jupally Krishna Rao said that there were “very, very, very, very remote” chances of survival for the eight persons trapped inside the tunnel.

The eight individuals trapped in the collapsed tunnel have been identified as Manoj Kumar and Sri Niwas from Uttar Pradesh, Sunny Singh from Jammu and Kashmir, Gurpreet Singh from Punjab, and Sandeep Sahu, Jegta Xess, Santosh Sahu and Anuj Sahu from Jharkhand.

Two of them are engineers, two are operators and four are labourers.