Sludge squirts to surface from WA tunnel drilling
Thursday, October 6, 2011
SEATTLE (AP) -- It looked at first like a sludgy, gray geyser when witnesses say liquid began shooting five feet into the air at an intersection on Seattle's Capitol Hill. The eruption later subsided to a slow, bubbling ooze.
Sound Transit spokesman Bruce Gray says Thursday's problem right above his agency's Capitol Hill tunnel route was material escaping through a vertical well that had been used for soil sampling -- and should have later been filled with concrete. He says as the tunneling machine grinds forward, it squirts a "soil conditioner" compound ahead of the cutting blades to soften the soil. Grays says when the drill passed through the sampling well, soil conditioner squirted 85 feet up to the surface.
The Seattle Times says the transit agency gave free carwash vouchers to vehicle owners whose parked cars were coated.
The work is part of a $2 billion light rail extension.