On October 19th, 1#-2# Section of Diversion Tunnel of Laos Nam Ngum 4 Hydropower Station of China National Heavy Machinery Corporation was successfully dug through the hill.

The 1#-2# Section of Diversion Tunnel of Laos Nam Ngum 4 Hydropower Station is 3067 meters in length, the longest of its kind since the project was started. As the diversion tunnel mainly consists of IV2 silty slate which is relatively soft and vulnerable to cracks and local collapse, so it is challenging for the construction of this diversion tunnel in practice.

Many measures were taken in this project to ensure the construction proceed in a secure and orderly way. For example, firstly, precautionary step was taken in augmenting the support in the construction; secondly, reviews were made in the open tunnel to ensure there is no deviation from the tunnel axis; thirdly, close link was established between two working surfaces of the 100-meter section. Under the scientific management of the project department, the diversion tunnel was smoothly dug through, which further encouraged the project workers in building a solid foundation for its continuous work and completion on time.