The TBM, nicknamed Moley, and three other machines – Holey, Yorkie and Torkie – were supplied by Caterpillar Tunneling to the project owner, Toronto Transit Commission, in 2010. Work included 10 TBM drives totalling 13.4km of tunnels and were awarded to two contractors, MKA Joint Venture, consisting of McNally, Kiewit and Aecon, and OHL-FCC JV.
MKA was assigned Holey and Moley to mine 5.8km 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 4 June 2012, at the Keele Street extraction shaft. After being moved back to Sheppard West launch shaft, it started its 1.32km southbound drive and reached the final breakthrough on 5 March 2013. The Cat TBM has bored 2.89km 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 in December 2012.