Xe-Pian Xe-Namnoy TBM starts work

15 April 2015

Laos – March saw the start of TBM tunnelling works on the 11.8km-long, low-pressure headrace tunnel for the Xe-Pian Xe-Namnoy Hydropower Project.

A ceremony was arranged and attended by officials from Xe-Pian Xe-Namnoy Power Company, SK Engineering & Construction, Seli Overseas and TBM manufacturer Terratec.

The TBM had begun to advance through a 500m of tunnel adit excavated by drill and blast as T&T went to press. Once the TBM reaches the tunnel face, it will commence work on the main 11.3km bore.

The machine is a 5.74m diameter double shield hard rock TBM designed and manufactured by Terratec. It will have to excavate through two main geological formations, the Tholam Formation consisting of mudstones and siltstones and the Champa Formation including siltstones, sandstones and conglomerates.

The TBM was tested and accepted at the factory in December. Since then, it was dismantled, transported to site and re-assembled within approximately three months, which according to the manufacturer was logistically challenging due to the remote location of the site.

The project also calls for the construction of two central cored rock fill dams, waterway tunnels with a vertical shaft and a powerhouse generating capacity at 410MW