A headline-grabbing rescue of 12 workers who were trapped in a tunnel at a hydropower plant project in the Central Highlands province of Lam Dong last Friday was widely applauded, but after the good news came, the questions about the safety of the project and others of the same kind still linger on.
The tunnel at the Da Dang - Da Chomo hydropower plant in Lam Dong's Lac Duong District was under construction when a section of it caved in 500 meters from its entrance at about 7 a.m. last Tuesday (December 16).
The tunnel was being built to bringing water from a dam to the hydropower plant.
Twelve workers, including one woman, were stuck inside the tunnel after the accident. They were brought to safety after all-out rescue efforts four days later.
Authorities are still investigating the cause of the collapse.
Truong Ngoc Ly, director of the provincial Department of Labor, War Invalids and Social Affairs, told Thanh Nien he thought that the contractor of the project made a mistake when they brought machines to dig up rocks and dirt to build the 700-meter tunnel.
They may have assumed that the dry season had come and it was safe to dig, but this year the rainy season lasted too long, according to Ly.
With heavy rains making the foundation weak, sinkages occurred in the tunnel, Ly said. And given the Central Highlands’ geological formations, digging up a big rock may lead to the whole tunnel’s collapse.
The designer of the tunnel is a Chinese company, and the contractor is Vietnam’s Song Da 505 Joint Stock Company.
Nguyen Van Yen, deputy chairman of Lam Dong Province People’s Committee, said sinkages had occurred several times in the tunnel before, and the contractor had reinforced the tunnel’s ceiling with steel frames.
“Authorities issued warnings and asked the investor of the project to pay attention to the problem in the rainy season, but the accident still happened,” he said.
Deputy Minister of Industry and Trade Do Thang Hai said the Da Dang-Da Chomo hydropower plant is just a very small-scale project and is not under its management, technically.
Another official of the ministry said the ministry is just in charge of licensing such projects, while local authorities must oversee them.
The Da Dang-Da Chomo plant is among 200 hydropower projects under construction in energy-hungry Vietnam.
A recently released report by the Ministry of Industry and Trade said it had revised and scrapped 15 “problematic’ small hydropower projects as of September this year.
It said investors of some small hydropower projects (having installed capacity under 30 megawatts) failed to meet requirements of dam safety.