Robbins model 105-144 drove 5.8 km of 6.2 km x 3 m internal diameter tunnel in volcanic tuff at 3,717 m elevation. Contractor Kunz experienced major crown fallouts at 5 km mark with ravelling ground and water. Some 1,200 cu m of material flowed into the TBM drive. Drill/blast relief heading from exit portal met struggling TBM after 400 m in May, 1990. See also Hall of Fame entry. October 1991.
