tunnel boring machine
The contractors drilling a tunnel under downtown Seattle are closer to finding out what has blocked their boring machine.
The $80 million machine is designed to break up boulders, so what it hit is a mystery. It may be a huge boulder left by the last ice age. Others think it could be a buried rail car from pioneer days when the area was filled in.
Boring at Seattle’s $2 billion tunnel project has been delayed again until next week.
The world’s widest tunnel boring machine arrives in Seattle in pieces Tuesday aboard a ship from Japan.