Wirth Exports its Tunnel Bore Extender to JapanTo protect an endangered species of hawk during expansion of the Tokyo Metropolitan Expressway, a 1,000 m-long tunnel is not being blasted but bored with a Wirth Tunnel Bore Extender (TBE). Thanks to its long experience in hard rock boring, the Wirth Group was first choice for Japanese contractor Hitachi Zosen. Two tunnel boring machines are working in parallel on the Tokyo site, widening from 5 to 12.97 m the two portal sections, which were bored with a 5 m shield machine. As already successfully done in Chinese projects, the core components of the TBEs are produced in Erkelenz, Germany and by Japanese partner GTM (Geological Technology & Machinery), a company affiliated to Hitachi Zosen. The TBE units pre-assembled at the Wirth and GTM plants were finally assembled on site and put into operation. This enabled the client's ambitious project targets to be met two months ahead of time. Visit www.wirth-europe.de, www.hitachizosen.co.jp and www.geo-machine.comThe contract was signed in November 2004 and boring commenced in September 2005. Breakthrough was scheduled for March 2006. The machines feature the following main technical parameters: 12.94 m boring diameter, 100 m length, 1,500 tonnes each, total installed power (basic machine without backup) of 3,000 kW, cutter head drive power of 2,550 kW, boring speed comprised between 1 and 2.20 mph, cutter head torque of 6,500 kNm, cutter head speed of 3.6 rpm and main thrust of 17,500 kN. To know more about the TBE, click here. 17/06.