Expert miners start HS2 tunnel emergency cross passages - Construction Enquirer

As TBMs reach 4-mile mark under the Chilterns, work starts to dig 38 cross passages between main tunnels

The 15m-20m long escape tunnels are bored every 500m to connect the two main running tunnels around 40m below the surface. An expert team of miners are using a remotely controlled excavator to break… [+1778 chars]

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