Enbridge has fought the shutdown order through the courts, and is pressing on with plans to bore a concrete-lined tunnel into the rock under the Straits of Mackinac, within which it would place the pipeline. Allowing the tunnel project would improve the safety of the pipeline by removing it from the lakebed, Enbridge says, as well as provide it with a 99-year extension of the Line 5 project, should it secure the needed state and federal permits.