Wirth TBM Breaks Through Sabugal-Meimoa Water TunnelA Wirth hard rock TBM broke though a tunnel on 23rd June for the Rural Development and Irrigation Institute under the Portuguese Ministry of Agriculture. The 4,122 m-long 3.6 m-diameter tunnel, built by Zagope, links the Sabugal and Meimoa dams and is designed for irrigation in the Cova da Beira region, east of Coimbra near Penamacor and Serra da Estrelha. Initially, the project was planned to be built by the drill/blast method but the contractor proposed a Wirth TB 360 H TBM to mitigate impact on the environment. Indeed, the downhill entrance of the tunnel is located in Serra da Malcata National Park. The drill/blast method was only used for the two portals. The machine is equipped with eight grippers, each delivering a pressure of 2 MPa approximately. Its thurst force totals 4,900 kN. Tunnelling took place from the uphill to the downhill portal. The tunnel has been supported with steel reinforcements and a primary shotcrete lining. The final lining will consist of a concrete shell. An 8-car muck train took the rock out of the tunnel. The total project cost is an estimated EUR16.7 million. The tunnel will be commissioned in June 2005. Visit www.wirth-europe.com 31-32/04.