One of the most difficult pumped media to deal with in mining is abrasive slurry. It often contains toxic chemicals that are extremely hazardous to people and the environment. It has a sandpaper-like effect and moves at high speed. This slurry is transported through various process steps, before being finally stored in tailing ponds. Knife gate valves used in these applications must therefore remain absolutely bubble-tight, even under extreme conditions – without interruption in either direction and with a long operational life-cycle. This is because the intervals between maintenance are very long – a challenge that we gladly accept and more than meet.