6 months of drilling to clear Deo Ngang tunnel through Hoanh Son range

On July 16, Song Da 10 Joint Stock Company detonated mines and demolished the last blocks of rock, officially opening the Deo Ngang tunnel. The technical opening of the Deo Ngang tunnel marks an important milestone in the construction process of the project connecting the two provinces of Ha Tinh and Quang Binh , now Quang Tri province.

The construction of the Deo Ngang tunnel is one of the items in the project to upgrade and expand a number of bridges and tunnels on National Highway 1 with an investment of nearly 2,000 billion VND. To serve the construction of the Deo Ngang tunnel, the two provinces of Ha Tinh and Quang Tri need to reclaim 5.5 hectares of agricultural land, convert the use of more than 3 hectares of forest, 3 plots of residential land and relocate a number of technical works.

In early January 2025, Song Da 10 Joint Stock Company gathered machinery and equipment to start the construction of Deo Ngang tunnel. On January 13, the contractor drilled the first drill bit to construct the Deo Ngang tunnel expansion.

At first, the construction encountered some difficulties, especially regarding the site. While Ha Tinh province basically completed the handover of the site, the handover of the old Quang Binh province, now Quang Tri province, was somewhat slower. Faced with this reality, the contractor proceeded with the construction at the North tunnel entrance.

Construction through the Hoanh Son mountain range with large rock blocks requires blasting. Before mass blasting, the contractor needs to conduct test blasting. However, because the Deo Ngang tunnel expansion construction site is close to important structures, especially the existing Deo Ngang tunnel and the 500kV circuit 3 power line, vibration measurement and impact level are more important.

The test blasting was carried out many times, and each time, the results were carefully calculated and measured by experts. The test blasting results were also sent to the provincial departments and agencies of Ha Tinh for appraisal and inspection. In early April, the mass blasting was approved by the authorities.

Mr. Nguyen Tuan Anh - General Director of Song Da Joint Stock Company said: To construct the Deo Ngang Tunnel expansion, the unit mobilized 130 officers, engineers, workers and 40 locomotives and modern equipment. The construction plan was calculated and planned by the unit specifically, suitable for each stage and time, especially to compensate for the time affected by the site and granting of permits for mass construction.

Mountain construction requires careful and meticulous calculations, especially regarding the safety of engineers and workers. The contractor always requires construction teams to strictly comply with labor safety procedures.

Mr. Mai Xuan Tan - Project Management Director (Railway Project Management Board - Ministry of Construction) assessed: The opening of Deo Ngang tunnel is of great significance, helping to coordinate personnel, vehicles, supplies, and materials to go through the tunnel instead of having to travel in a detour, contributing to shortening the progress, putting the project into operation in December 2025.

According to Mr. Tan, the drilling of Deo Ngang tunnel was one month ahead of schedule, in addition to the efforts of the contractor, there was enthusiastic support and assistance from provincial and local departments of Ha Tinh and Quang Tri provinces.

After drilling the tunnel, the contractor will continue to construct the tunnel lining concrete, install lighting systems, ventilation fans, fire protection systems, emergency exits, etc.