Big Robbins breaks out at Niagara The 14.4 m-diameter Robbins Main Beam TBM, the largest of its type ever produced and affectionately known as Big Becky, has broken through at Niagara. The 10.143 km-long drive officially completed the mining phase of the tunnel project. The breakout was witnessed by Ontario Premier Dalton McGuinty, along with the CEOs of owner Ontario Power Generation and contractor Strabag AG. The cutterhead will be retained and put on display in the city of Niagara Falls as a permanent memorial of this epic feat. Read the Robbins press release and review project history at tunnelbuilder archive ca/13. Visit www.niagarafrontier.com/tunnel.html and www.robbinstbm.com. 21/11. Mike Kolenich, Gilles Moffat and Lok Home celebrate Niagara triumph