A water-passage tunnel in Ethiopia’s Gilgel Gibe 2 hydropower project collapsed in February.

Some 15km of the 26km long tunnel collapsed just ten days after its inauguration, shutting down operations indefinitely.

The construction company behind the project, Salini said in a statement that the site will be under maintenance for about two months to allow the necessary repairs to take place.

Salini sub contracted the tunnel works to Seli.

Seli said in a statement that the collapse was caused by a “geological event” that saw a large quantity of rock and mud fall into the tunnel.

The client Epco will leave Salini, Seli and a team of expert consultants to investigate the exact cause of the collapse and the repair measures needed to see the plant fully operational in the shortest time possible.

The $512.5M project is Ethiopia’s biggest power plant. The project channels the water discharged from the Gilgel Gibe 1 Dam through a long tunnel and a steep drop directly to the valley of the Omo River.

from Tunnels & Tunneling