Shishir Prashant

Dehradun, Feb 10 (IANS): Even as rescuers raced against time to look for survivors in a blocked tunnel of Tapovan Vishnugad project on Dhauliganga river in Chamoli district of Uttarakhand, a helicopter fitted with remote sensing equipment made repeated sorties overhead to map the structure to help authorities plan their moves accordingly.

The sorties were made since Tuesday as the chopper took pictures of the disaster-hit tunnel snaking through the tough hilly terrain in order to help rescuers make way forward.

"We are doing geographical mapping of the disaster-hit tunnel, which will help us in the search and rescue operation," State Disaster Response Force DIG Ridhim Agarwal said.

SDRF officials also sent a remote-controlled drone to take pictures of the insides of a section of the tunnel that had been cleared of debris and mud brought down to the spot by flash flood on Sunday.

"In addition, thermal and laser scanning will also be used, if need be," Agarwal added.

"We are using both drones and helicopters to take quick decisions as we are running against time," said DGP Ashok Kumar.

"We will explore all possibilities to save the lives of people trapped inside," the DGP assured.

The rescuers also consulted NTPC officials to understand the tunnel design.

The rescue work had slowed down on Tuesday due to presence of heavy silt inside the tunnel of the hydroelectric project.

Rescuers are toiling to save 25-35 persons still feared trapped inside the tunnel of NTPC 520-MM Tapovan Vishnugaud project. No contact had been made with the trapped people so far.

After digging for two consecutive days, jawans of the Army, ITBP, NDRF and SDRF managed to clear a sizeable portion of the tunnel till Wednesday morning. However, the presence of huge amount of silt inside the tunnel was hampering rescue work, top government officials admitted.

The state government had earlier said that around 200 persons had gone missing after Sunday's disaster and 32 bodies had been recovered so far.