IT WAS always possible that the finger of sugar crystal dolomite stretching down to the alignment of the planned Gotthard base tunnel would prove to be a major obstacle when it came to serious digging. Just how tricky it may be to tunnel through this treacherous material in the Piora syncline was revealed at the end of March when Electrowatt submitted a detailed report to Swiss Federal Railways Chief Executive Dr Benedikt Weibel. This suggested that the cost of tunnelling through around 300m of the dolomite could reach SFr700m. The previous worst case estimate dating only from January was SFr300m.
Weibel reacted at once by calling for work to be halted on the access shaft further north at Sedrun and froze the SFr75m of funds that SBB has available for additional work there. Around 700m of the 990m horizontal gallery has been completed; this may still continue, but contracts are unlikely to be let as planned for the 780m vertical access shaft which needs to be built ahead of the main tunnel to allow intermediate faces to be opened up. Work would only resume at Sedrun after it has been established precisely what cutting through the sugar dolomite will entail - tunnellers have already bored a 5·5 km exploratory gallery from Faido and located the dolomite, but it is still not certain how far the strata extends.
In an interview with the Swiss media, Weibel attacked engineers suffering from a ’professional malady’ who say ’everything is possible’ without considering the cost. This is apparently not the reason for a decision by SBB’s AlpTransit project manager Peter Zuber to stand down at the end of the year.
When the parliamentary committee on transport met on April 7-9, it ruled that no further money would be freed for preliminary works until further geological investigation had determined the feasibility of the Gotthard bore - a process that could take two more years. This means that completion of the Gotthard base tunnel will only be possible in 2010-11 at the earliest.
Switzerland is meanwhile committed to transfer road transit traffic to rail by 2004, and it also has commitments with EC countries to provide adequate rail capacity. The result is that the L
