Picture 1. The Surge Chamber of CHMC Laos Nam Ngum 4 Hydropower Station Project, Was Smoothly Threaded Together

On May 8, 2020, With the last blast, a ray of sunlight went into the headrace tunnel. The surge chamber of the Laos Nam Ngum 4 Hydropower Station Project contracted and constructed by CHMC, was smoothly threaded together.

The surge chamber of the Laos Nam Ngum 4 Hydropower Station Project was 121 meters in length, and the maximum excavation diameter was 24 meters. The complex and diverse rock conditions (mainly comprised by the carbonaceous slate and mudstone), added difficulties to the construction. CHMC Project Department overcame difficulties, such as: the back-hole drilling hard to form a hole, the artificial guide shaft excavation, the fracture treatment of the shaft wall, as well as the impact of the new coronary pneumonia epidemic. Even though, CHMC finally completed the excavation of the surge chamber.

In order to guarantee the surge chamber to be smoothly threaded together, CHMC Project Department organized the thematic meetings for several times, discussed the solutions for the construction difficulties, actively communicated and coordinated with the local government, opened up a 'Green Channel' to ensure the orderly entry of personnel, materials and equipment to the Site, and to ensure the construction safety and quality, while well implementing the epidemic prevention measures. 

Currently, the epidemic continued to spread overseas, and the prevention and control situation was getting worse. The smooth threading together of the surge chamber of the Nam Ngum 4 Hydropower Station Project, greatly inspired the confidence of the project participants, laid a solid foundation for the Project to be completed on schedule.