On March 5, 2013, a 6.12-meter Cat EPB Tunnel Boring Machine (TBM) broke through the headwall of Downsview extraction shaft in Toronto, Canada. This is the second Cat TBM that has completed its mission in the construction of the Toronto-York Spadina Subway Extension Project.
The TBM, nicknamed Moley, and three other machines (nicknamed Holey, Yorkie and Torkie) were supplied by Caterpillar Tunneling to the project owner, Toronto Transit Commission, in 2010. The contract works include 10 TBM drives totaling 13.4 km of tunnels and were awarded to two contractors, MKA Joint Venture (McNally, Kiewit and Aecon) and OHL-FCC Joint Venture.
MKA was assigned Holey and Moley to mine 5.8 km tunnels in four drives between Finch West Station in the north and Downsview Station in the south. Moley was launched in the fall of 2011 and finished its first northbound drive on June 4, 2012, at the Keele Street extraction shaft. After being moved back to Sheppard West launch shaft, it started its 1.32 km-southbound drive and reached the final breakthrough on March 5, 2013. The Cat TBM has bored 2.89 km of tunnels and installed 1,813 segment rings through glacial till, sand, silt and clay grounds under Toronto.
The other Cat TBM operated by MKA, Holey, completed its mission late last year, and the final breathrough took place December 7, 2012.
For more details, see the TBM article from December 2012 http://www.tunnelingonline.com/full-speed-ahead/