The company that operates twin oil pipelines in the Straits of Mackinac says one of the lines suspected of being struck by a tugboat anchor was dented more than three-fourths of an inch.
Enbridge Inc. official Peter Holran told the Michigan Pipeline Advisory Board in Lansing Monday about the April 1 damage to the pipelines running between Lake Michigan and Lake Huron.
Continue Reading Below
Company spokesman Ryan Duffy says each pipeline is about 20 inches in diameter with walls nearly an inch thick — but the thickness of the walls did not decrease.
Holran says the other pipe suffered two dents of just under three-quarters of an inch and less than a half-inch.
The suspected anchor strike also caused about 600 gallons (2,270 liters) of mineral oil insulation fluid to leak from two electric cables.
Correction: A previous version of the story stated the thickness of the pipelines' walls decreased from the dents, with the first dent being two-hundredths of an inch from rupturing. The dents did not decrease the wall thickness; they only pushed the walls in.