Contractor China Overseas Engineering Nepal (Covec Nepal) averaged over 700m per month along the 12.2km drive using a 5.06m-diameter Robbins double shield TBM. The tunnel is located in the Siwalik Range, part of the Southern Himalayan Mountains, where geology consists of mainly sandstone, mudstone, and conglomerate. 

A large and well-attended ceremony featured a speech by the Prime Minister of Nepal KP Sharma Oli, where he praised the project and its success for the future of TBM projects in the country. “It is not just that new technology has entered Nepal; it is a matter of great gain. The government has plans to execute various other multipurpose projects such as the Sunkoshi-Marin Diversion Project.” 

When the BBDMP was fast-tracked as one of the country’s “National Pride Projects” feasibility studies showed that Drill & Blast excavation of the tunnel could take as long as 12 years. The DOI needed a faster option, and they found it in TBMs. 

Prajwal Man Shrestha, Robbins Representative in Nepal with MOSH Tunnelling said, “The country has received international attention and contractors and developers from around the world are now considering Nepal for future TBM projects.”

Once the BBDMP is operational, it will irrigate 51,000 hectares of land in the southern region of Nepal, and provide 48MW annual generating capacity. It will divert 42 cubic meters of water per second from Bheri River to Babai River under a head of 150m using a 15m tall dam, providing year-round irrigation in the surrounding Banke and Bardia districts.

The project was featured in Tunnels and Tunnelling International, April 2019.