First Section of Pajares Tunnel is CompletedOf the five machines used to bore the Pajares high speed rail tunnels in Spain, the NFM Technologies 9.88 m-diameter hard rock tunnel boring machine used on Lot 1, which runs from Pola de Gordon to Folledo, is the first to complete its task. The TBM put the last of 6,565 rings in place on 5th June, 2007. The machine successfully drilled a total of 9,860 metres in the east tunnel in just 20 months and nearly two years ahead of schedule (April 2009), despite complex geological problems, such as the presence of methane pockets and groundwater, which caused prolonged downtime. The performance of the NFM TBM was appreciated by the client, a joint venture of Acciona and FCC, as the tunnel was completed two months quicker than the parallel, west tube. The contractors have excavated already 97.9% of the west tunnel (10,086 metres). In the completed east tunnel of Lot 1, the TBM achieved an average advance rate of 16.26 daily metres, with a maximum daily advance peak of 51 metres. Visit www.nfm-technologies.comExcavation of the Pajares tunnel is a great technical and engineering challenge with respect to the ground that has to be crossed, characterised by the complexity of the local geology. The completed tunnel crosses a geological bedrock named Somiedo-Correcilla, belonging to the Pliegues and Mantos region which forms part of the Cantabrian zone, the most outer part of the northern leg of the Iberian hercinic massif. The main challenges that the TBM had to cope with include abundant lithology alterations, shifting from competent ground (sandstone, limestone and quartzite) to incompetent rock (lutites) and very geomechanically weathered rock, featuring high fracturation levels in the excavated material, due to the successive tectonic phases. This continuous alternation of materials along with the numerous contact zones and faults resulted in the formation of ground zones with very poor ground quality both geotecnically and geomechanically, which greatly complicated the excavation works. The TBM has now finished its part of the job but is currently still within the mountain and will not come to daylight until the other TBM from the other side makes the junction. The TBM will now be dismantled in the tunnel. To do this, a cavern will be dug behind the shield, the back-up train will then be removed in order to allow the shield to slide to the front of the cavern, thus making it possible to completely dismantle the machine. The machine will subsequently be transferred to another site to excavate a new high speed rail tunnel near Vigo and the Portuguese border.Already 29 kilometres of tunnels, or 53% of the total, has been excavated. The project is almost fully complete in Leon but advances more slowly in Asturias. Whilst advance rates have been faster than expected in Leon, ground instability and safety measures to protect workers in Asturias, where tunnelling began later, have slowed down the construction process. To date, the TBM of Lot 2 in Leon province has excavated 5,450 metres of the access tunnel (99.1%) and has only 50 metres to go to finish the access tunnel prior to commencing its 3.9 km segment of the east tunnel. Read E-News Weekly 10/2007, 22/2006 & 5/2006. Click es/55. 25/07.