It has been reported that 12 workers were trapped after the tunnel at the Da Dang-Da Chomo Hydropower Plant in Lam Dong Province suddenly collapsed on December 16.

The site of the collapsed tunnel

According to Song Da 505 Corporation, rocks and dirt fell down onto a construction unit around 7am. The collapsed section is located 300 to 500 metres from the entrance.

Initially it was believed that the collapsed portion of the tunnel was about 6 metres, however, rescue workers have not been able to reach the workers even though 10 metres of pipe has been inserted through the rubble.

Rescue teams attempt to reach the workers.

Police, rescue workers and emergency workers were immediately sent to the scene. They have started pumping oxygen into the tunnel and trying to find ways to get access to the workers. Heavy rains and difficult terrain is making the job more difficult.

An iron pipe of 60 centimetres in diameter will be used to vacuum out the rubble and hopefully make it possible for the workers to escape through the pipe. 

By 4.45pm, rescue teams were pumping oxygen through a hole into the section of tunnel where the workers are thought to be trapped. However, they still have been unable to pin down their exact location. They are now planning to cut through the concrete to allow rescue workers access to the victims.

At 8:00 pm, rescue forces made contact with trapped workers.

The 12 victims, including one woman, are all in good health, the rescue forces said, adding that they have managed to clear the site where the workers are being trapped, about 500m from the hatch, and will install a pipeline to provide oxygen for them.

Colonel Hoang Cong Thao from the provincial police said rescue work will be continued overnight until the victims are brought to the hatch.

Earlier, Prime Minister Nguyen Tan Dung dispatched an urgent note requiring all necessary measures to rescue the trapped workers.

Right after the incident, the province has mobilised more than 100 firefighters, rescue workers, traffic police and medical staff to join the rescue mission.

The Da Dang-Da Chromo Hydropower Plant cost VND475 trillion and was funded through Build-Own-Operate scheme.