Large quantities of fibre waste are produced during paper production. These are dried and burned and the energy released during combustion is used as process heat or to generate electricity. The ash is stored in high silos to be later used as an additive in the building materials industry. When the ash silo is filled, a great amount of noise and dust is generated and the material forms large angles of repose and overhangs. Filling, emptying and transportation logistics are controlled through the level measurement system.