Production and Delivery of Microtunnelling Cutter Head Takes only 33 DaysOn 12th December, only 33 days after receiving the order, TunnelTec delivered a microtunnelling cutter head with a diameter of 2,220 mm to the tunnelling division of Zueblin. Further to receiving the order in the first half of November, TunnelTec was able to develop, manufacture and deliver a complete mixshield cutter head for the east collector (Sammler Ost) project in Hamburg, Germany in record time.Since 900 mm boulders and a very high strength had already been found in the first section of the tunnel, it was decided to design a new cutter head for the subsequent sections. The result was the development of a cutter head with four twin-disc cutters in the face area and additional cutting tools for face and gauge. ln total, approximately 80 TunnelTec tools were installed. The cutting head will be dressed with gauge cutters and scrapers, face ripper, face scraper, cleaning tools and have a special centre assembly. Additionally, protective wear plates for the rim and rear structure of the cutter head were added. For the east collector project, Zueblin has still to excavate four tunnel sections with an enlarged Herrenknecht AVN 1600 D machine. The geology in this area consists of glacial loam and marl or glacial river sands. Basin sediments in the form of sand, loam or silt must be expected as well. Big boulders will also be expected for the further drives. This was already the second delivery of a microtunnelling cutter head to Zueblin by TunnelTec in 2007. Visit www.tunneltec.de or www.tunneltec.com 05/08.