For additional insurance, the entrances to excavations are watched over by statues of St Barbara, patron saint of tunnelling.
There are no assurances that the northern part of the route, which will not be finalised until 2014, will see equivalent lengths of tunnelling.
During the second world war, hundreds of allied prisoners were held in the Stalag Luft III camp, which the Germans had built to be escape-proof, even planting seismographs in the ground to detect the sounds of tunnelling.
A recent report by Tongyang Securities, a broker, drew an explicit link between Korea's low equity valuations and the practices of "tunnelling" and "propping", which benefit insiders at the expense of smaller investors.Tunnelling is the awarding of contracts to firms owned by family members.
Mair and Williamson [4] performed centrifuge model tests regarding the effects of tunnelling beneath bored piles in clay.
One of the earliest proposed possibilities for FTL travel involved a hypothetical particle called a tachyon, capable of tunnelling past the speed of light barrier.
