Hsueshan Tunnel Breaks ThroughTaiwan's President Chen Shui-bian, Premier Yu Shyi-kun, and Minister of transportation and communications Lin Ling-san attended the breakthrough by a Robbins TBM of the last piece of rock at the eastern end of the Hsueshan tunnel at a ceremony held in Ilan on 20th October. Boring on the 5.7 km west end of the pilot tunnel at Pinglin in Taipei County was completed on 31st May this year.The 5 m-diameter pilot tunnel, some 750 m underground, is primarily designed to give engineers a total picture of the tunnel's complicated geology. So far the project has been slowed down by unexpected groundwater, intermittent flooding, mud and rock slides or broken layers of sedimentary rocks. Site investigations revealed the main faults, but not smaller breaks.The 12.9 km Hsueshan tunnel, also known as Shueishan (Snow Mountain), includes two separate two-lane tunnels. It is on the Beiyi freeway linking linking Pinglin in Taipei County with Toucheng in Ilan County. Most of the expressway is elevated in mountain terrain. State-owned RSEA Engineering Corp., the contractor, negotiated a contract for the pilot bore and another for the two main drives, set 60 m apart, with the Taiwan Area Expressway Engineering Bureau (TANEEB). The pilot bore began in 1991, partly to probe ahead for the main drives. Completion was expected in 1995, but the job has lasted 12 years.Ten engineers and workers have been killed and a 11.7 m-diameter TBM worth US$8.84 million was destroyed on the westbound drive of the main tunnel by the dozens of caves-in that have beset the ambitious project since it was launched in July 1991. In December 1997, water burst through the lining at 740 litres per second, burying the TBM in some 100 m of muck. A small bypass tunnel driven to the TBM for its rescue let tunnellers secure the face and begin scrapping. The contractor turned to drill/blast. To safeguard the eastbound drive, a similar bypass was driven so the top heading could be drilled and blasted. This lets TBM operators spot trouble ahead. Other crews are drilling and blasting both main tunnels from the opposite ends.With over 90% of the west drive and about 75% of the east one complete, final breakthroughs are due at fall next year, some six years late. Completion of the whole project is scheduled by the end of 2005. Click tw/14. Read E-News Weekly 12/2002. Visit www.robbinstbm.com 45/03.