A proposal by Canadian oil giant Enbridge to construct a new four-mile pipeline beneath the Straits of Mackinac in Michigan has cleared another legal hurdle, with the state Court of Appeals upholding the legality of a 2018 state deal approving the project.

Enbridge claims the $500-million tunnel is needed to replace the existing underwater dual-pipe segment of Line 5, a nearly 70-year-old, 30-in. dia pipeline that transports up to 540,000 barrels per day of crude oil and natural gas liquids 645 miles between Superior, Wis., and Sarnia, Ontario.

在2018年会议结束时，密歇根州立法机关授权该公司与即将离任的里克·斯奈德（Rick Snyder）（R）之间的协议，以在狭窄海峡下建造隧道，将该州的上半岛分隔开。

Pipeline opponents critical of the expedited approval received a boost from incoming Gov. Gretchen Whitmer (D), whose administration claimed enabling legislation violated the state constitution because it contained a provision transferring project oversight to another governing authority, which exceeded the scope described in its title.

In its June 11 decision, the three-judge appeals panel upheld a 2019 ruling by Michigan’s Court of Claims that the act properly authorizes the tunnel to proceed; Michigan’s Attorney General plans to appeal the case to the state Supreme Court.

With a busy docket, observers say the court is not likely to hear the appeal until after work has already begun. Public hearings for construction permits start this summer，，，，

The ruling was Line 5’s second legal victory in as many months.

5月初，当所有原告退出案件时，驳回了螺钉锚作为现有部门维护计划的一部分的诉讼。尽管Enbridge声称现有的海峡穿越状况处于“良好”状态，但在60多年的运营中没有记录泄漏，但该公司在5月下旬争先恐后地修理了四个磨损到裸机的保护性涂层区域。

According to an Enbridge statement, the worn areas ranged in size from .07 to .43 sq ft. Pending state and federal permit approvals, Enbridge plans to begin tunneling for the new Straits of Mackinac crossing next year, which is set to operate in 2024.

Meanwhile, Wisconsin’s Dept. of Natural Resources is weighing Enbridge’s request to re-route about 42 miles of Line 5 in three counties. Indigenous groups have opposed the project, with the Bad River Band of the Lake Superior Tribe of Chippewa Indians suing successfully in 2019 to remove the pipeline entirely off its reservation.

根据该机构的说法，重新路线将通过开放式挖沟或挖泥影响109英亩的湿地和87水道。

Jay Dee Contractors Inc., Livonia, Mich. and the U.S. unit of Japanese giant Obayashi Corp. were named in March to build the tunnel through a joint venture called Great Lakes Tunnel Constructors to be the principal construction contractor.

恩布里奇还聘请了伦敦的Arup为设计师。