Anticorrosion Treatment of the Dix-Rhône Head

Between March and August 2011, we started the anticorrosion treatment of the Dix-Rhone head. This stretches from the Grand Dixence dam to the River Rhone. It consists of an important project divided into 9 sections. Four of them were completed this year. Overall, 4.8 kms of pressure pipeline and lined basins (45,000 m2 of steel surface) will be treated by 2014.

These galleries leave from Louvie above Fionnay, pass over Peroua to end up at the Nendaz power station. We have taken over the management of the project, mandated by Grande Dixence SA. The work is being completed by sub-contractors chosen by ourselves: Isopermaproof AG, Marty AG and M. Grivetto SA. It has been divided into three phases :

• a robotised hydro-stripping, aimed at removing the old lining which dates from the 1950’s;
• a sand blasting stage in order to provide adequate roughness on the surface to be relined;
• application of the new lining in successive layers.

A particularity of the project: the sand blasting stage enables a prototype of robot developed by the Haute Ecole valaisanne (Valaisan Higher Education College) to be tested.

Specific know-how

This project requires our specific know-how in the domain of anticorrosion lining techniques. We have made a feasibility study of the project, and effected all the necessary measures and checks. In collaboration with our Expertise and Development department, we have examined the non-destructive control data and analysed the aptitude of the utilisation of the treated elements.

The project will be continued in 2013 (2 sections) to be completed in 2014 (3 sections).