Deliveries resumed Wednesday through both pipes in Enbridge Inc.’s 540,000 b/d Line 5 across the lake floor of the Straits of Mackinac in Michigan, after a safety examination shuttered one of the conduits for 11 weeks.

The Pipeline and Hazardous Materials Safety Administration (PHMSA) allowed the Calgary-based operator to restore full capacity. The Michigan Circuit Court also lifted an oil traffic restraining order obtained by Gov. Gretchen Whitmer and Attorney General Dana Nessel in June.

The PHMSA said neither staff nor an independent expert retained for additional checks detected a threat of a leak from a damaged underwater pipe support anchor, which triggered the prolonged safety review.

“We continue to work toward and look forward to the day when a replacement for the Line 5 dual pipelines is encased safely in a tunnel below the waters of the Straits of Mackinac,” Enbridge stated.

Preparations have begun for the $500 million construction project. However, Democrats Whitmer and Nessel still oppose the Enbridge tunnel agreement that was put in place during the previous Republican administration. Whitmer and Nessel lost a Line 5 skirmish in the Michigan Court of Appeals, which rejected their claim that the tunnel deal was unconstitutional.

A verdict still is expected from Michigan’s Ingham County Court on another lawsuit that seeks to cancel a 1953 easement by the state, which enabled construction of the four-mile Line 5 leg between Lake Michigan and Lake Huron.

In addition to court challenges, Enbridge faces a long Line 5 regulatory proceeding. The Michigan Public Service Commission last month began a tunnel project review on a schedule that stretches out contested hearing dates until next May.