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Tunnelling update - January 2014
Corrib Tunnel reaches the half way mark
The half way stage of the Corrib tunnel under Sruwaddacon Bay was reached just prior to Christmas 2013.
The tunnel boring machine (TBM) ‘Fionnuala’, which weighs almost 500 tonnes and is 140m in length has been excavating under Sruwaddacon Bay in North West Mayo since January 2013. The work continues 24 hours per day seven days per week. During this time, Fionnuala has excavated almost 75,000 tonnes of material and has installed 2300 concrete rings, which line the inside of the tunnel.
Paul Hughes, Shell Tunnel Construction Manager, said: “It is great to have passed the half way mark. The construction of the tunnel remains a significant engineering challenge and we look forward to making safe and steady progress over the coming months.”
As part of the tunnelling process, the cutter head at the front of ‘Fionnuala’ breaks the rock and gravel that it meets while tunnelling. This material is then pumped in a suspended mixture back through the tunnel to the surface at Aughoose where it is separated.
Tunnelling is expected to be completed later this year after which the 20-inch (50cm) diameter gas pipeline will be installed together with a number of service and control lines.
Once completed, the Corrib tunnel will be longer than the Dublin Port Tunnel and also the longest gas pipeline tunnel in Europe.