Tarbela T-5 Crater Plugging in Full Swing
Work to plug the crater left by a rock collapse at the Tarbela fifth extension hydropower project is in full swing, with engineers and workers on site round the clock. The Tarbela T-5 crater plugging follows Monday’s collapse of a weak rock mass in the intake pit area, which sent water into the tunnel and the powerhouse area.
Officials say the concrete work to seal the hole and the dewatering of the under-construction powerhouse are likely to be completed within a week. The project team aims to keep the extension on schedule for commissioning, according to an official source at the site.
Tarbela T-5 crater: what happened on Monday
On Monday morning, a weak rock mass collapsed during excavation of the second bench connecting tunnel. Water from the intake pit entered the tunnel and the powerhouse area of the T-5 project, according to an official handout.
All workers in the area were evacuated safely. Officials and the Haripur district administration said water from the intake pit has now been completely drained. No further water is entering the downstream work sites, and dewatering of the under-construction powerhouse has started.
The collapse caused no damage to the main tunnel, the under-construction powerhouse, the tailrace culvert or the switchyard, officials said. Dawn reported the update on Friday.
Concrete work and the one-week target
After the intake pit was drained, consultants, contractors and the Wapda team assessed the incident before starting concrete work to plug the hole. The work continued until Dawn’s report was filed.
“The project staff has shifted its focus from routine work to the incident site and is busy 24/7 plugging the hole,” a source at the site said.
Heavy-duty pumps are dewatering the powerhouse. Reports are being compiled every six hours for stakeholders by teams from the seismology and geology departments, the contractors, the consultants and Wapda officials.
The initial incident report has already gone to the Wapda chairman and the Ministry of Water Resources. A final report on the causes and losses is likely to reach the Prime Minister’s Office, the ministry and other stakeholders in the next few days.
No human error, say geologists
Geologists from Wapda and the contractors, who compiled the initial assessment, denied any disruption or damage to the tunnel before or after the incident. They said the plug used to divert water from the intake pit to the tunnel was also fully intact.
“Only a weak rock mass situated some distance behind the plug somehow got damaged, but there was no human error or engineering flaw involved,” a source claimed.
The general manager of the T-5 project, Umair Manan, declined to answer detailed questions when contacted. “The time is too soon to answer your queries. Hope for the best from Allah Almighty, Ameen,” he said in a brief statement.
3,000 workers sent home for now
The general secretary of the Awami Labour Union at the Tarbela extension projects, Aslam Adil, said work to fill the hole and dewater the powerhouse continued day and night without interruption.
He said most of the 3,000 workers on the T-5 project had been asked to stay home until further notice. Only dumper and crane operators have been called to work for now.
Work on the project was suspended earlier in the week after the incident. Power cuts in Lahore have also been linked to Tarbela units going offline.
The incident matters beyond the dam site. Punjab and Sindh already face a 22 per cent water shortfall this Rabi season, and Tarbela is one of the country’s main reservoirs. Wapda’s handling of the dam has already drawn scrutiny this year. A swift repair would limit the delay to a project meant to add hydropower to the grid, at a time when the power sector is under strain as distribution companies face privatisation.
Frequently asked questions
What caused the crater at Tarbela T-5?
A weak rock mass collapsed on Monday morning during excavation of the second bench connecting tunnel. Water from the intake pit then entered the tunnel and the powerhouse area.
Was anyone hurt in the collapse?
No. All workers in the area were evacuated safely, and officials reported no damage to the main tunnel, the powerhouse, the tailrace culvert or the switchyard.
When will the repair work finish?
Officials say the concrete work to plug the hole and the dewatering of the powerhouse are likely to be completed within a week, after which project staff can return to routine work.
