Top Seattle managers explain forced TBM shutdown - TunnelCast
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16 December 2013: An as yet unidentified blockage has brought the world's largest TBM, Bertha, to a standstill in Seattle. After making impressive progress of seven 2m wide rings in a 12 hour night shift to advance 243m (800ft) in the 10-week period from restarting mining after mucking away by barge from the waterfront resumed on 23 September 2013 to the point of current holdup at 300m (1,000ft) from the portal, the 17.5m diameter EPB machine met resistance to progress in the first week of December. Sterling Noren, TunnelTalk video reporter in Seattle, files interviews with Chris Dixon, Project Manager for the contractor Seattle Tunnel Partners (left), and Matt Preedy, Deputy Project Administrator, for the client WSDOT (right), who spoke to reporters with more detail on the current stoppage.