Herrenknecht Separation Plants are optimally adapted to the requirements of the tunnelling process. They separate the slurry suspension continually from the loaded solid particles in the slurry circuit. A powerful and efficient combination of state-of-the-art screening technology and hydro-vacuum cyclones with high g-forces and low cut points results in depositable excavated material with low water content. The lower the water content and thus the weight of the excavated material, the lower the costs for disposal and recycling. Very fine particles that remain in the suspension have a significant impact on parameters such as excavation speed and daily advance rate. Additional equipment and fine treatment devices like filter presses and centrifuges are necessary to keep the suspension from thickening and the TBM performance high.