Hyperbaric maintenance completed on SR99 TBM

20 January 2017


United States - Seattle Tunnel Partners resumed mining on Monday, January 17, following 10 days of hyperbaric maintenance on the SR 99 TBM.

Since the maintenance period began on January 5, crews replaced approximately 300 of the nearly 500 scrapers on the machine’s cutterhead and conducted other inspections and maintenance.

The Washington State Department of Transportation said there is about 25 per cent of the drive to be completed. Crews are less than 2,500ft (762m) from the receiving pit, with the top of the cutterhead located approximately 160ft (48.7m) below ground.