In preparation of an in situ demonstration of the Belgian concept for the disposal of high-level radioactive waste, a mock-up experiment has been running for more than three years. It simulates a 5-m long section of a waste disposal gallery, and emphasis has been put on the engineered barriers. After hydration, the set-up was heated up to the level that we expect for the in situ experiment. Measurements and samples give us a view of the thermo-hydro-mechanical state, and of the geochemical and microbiological phenomena. To complete this view, we are currently preparing the dismantling of the mock-up, scheduled for the first trimester of 2002.