The Mont Terri Project is an international research project for the hydrogeological, geochemical, and geotechnical characterisation of a clay formation (Opalinus Clay). Clay formations are being considered in various countries for the deep geological disposal of radioactive waste.

Opalinus Clay is the only host rock being proposed in Switzerland for disposal of high-level radioactive waste (Sectoral Plan for Deep Geological Repositories). This is the main reason why the Mont Terri rock laboratory is so important for the deep geological disposal programme.

swisstopo has the task of leading the international Mont Terri research project and operating the rock laboratory. The objective is to carry out the proposed research plans of Swiss and international partners under optimum conditions.

As a neutral centre of expertise within the federal government, swisstopo is in constant contact with all political, social and corporate stakeholders. The rock laboratory is dedicated solely to research (Questions). 

There is no question of radioactive waste being disposed of at Mont Terri. The research results from the past 25 years have clearly shown that the Mont Terri Project makes a key contribution to the safety and technical feasibility of deep geological disposal in an argillaceous rock (Opalinus Clay) (Core Messages).

The task is divided into three parts:

• As an centre of expertise and a neutral federal office, swisstopo runs the international Mont Terri project, which currently has 22 research partners from Europe, Canada, the USA and Japan.
• The Mont Terri rock laboratory provides the necessary infrastructure to allow the partners to carry out their experiments under optimum conditions.
• swisstopo operates the Mont Terri rock laboratory with expert personnel (Organisation). Priority is given to safety underground and the smooth operation of the rock laboratory.