Narayan Singh was working in a 3.3 km long tunnel under construction between Dodawali and Raita in Jhadol Tehsil of Udaipur district when it collapsed trapping him on one side, officials said.
The tunnel was part of a project to solve the drinking water problem in the city.
On Friday, a pipe was passed through the tunnel and contact was established with him, they said, adding yesterday the District Collector Hemant Gera spoke to him through the pipe and assured that he would be rescued soon.
As part of the rescue effort, another tunnel is being dug with the help of a special Hydraulic machine brought from Delhi.The Irrigation Department, which is part of the rescue mission has assured people that although the operation might take some more time, Narayan Singh was in no immediate danger.
Oxygen cylinders are being used to pump in air to the victim and food and water are also being supplied to Singh through the pipe and his health was constantly being monitored, the officials said.