Rosyth, Scotland, was the destination of a DOSCO refurbished Lovat TBM at the beginning of last month, in preparation for a US$10.9M sewer project for Scottish Water.

The Dunfermline duplication sewer involves a 2.3km bored tunnel through glacial till, sandstone, mudstone and dolerite, and a 600m of cut+cover tunnel. The TBM will erect a pre-cast, segmental lining, using bolted, fibre-reinforced concrete segments. Contractor Amco Donelon will also construct three access shafts, two control chambers, one railway crossing, one river crossing and 420m of cut+cover pipework.

Mott MacDonald reviewed and evaluated the designs, which comprised the 2.1m i.d. sewer and ancillary works. The scheme will intercept a nearby existing main trunk sewer to safely process overflows during storm conditions. The majority of wastewater will be directed to upgraded treatment works at Queensferry. The new tunnel will also act as a storage area during peak periods, in line with Scottish environment regulations.

Tunnelling started 19 September, with completion set for mid 2003.