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Michigan legislators last week gave final approval to plans that will build an oil pipeline tunnel under the Straits of Mackinac for the Enbridge Line 5 crossing.
The concept for that tunnel originated with a group of Michigan Tech students who presented their design to legislators after an oil leak that occurred earlier this year in the Straits.
“Back in April, there was an anchor strike that hit an Enbridge line and tore the ATC transmission line, which leaked hundreds of gallons of their fluid. So we have seen that this thing is a very feasible issue. It’s something that could happen,” said MTU Graduate Student Michael Prast.
Currently the line crosses the Straits in two parallel tubes about 3 miles west of the Mackinac Bridge. Once construction of the tunnel is completed, those lines would be removed from the lake bed and placed in the tunnel where they would be isolated from the natural waters, theoretically preventing a disaster, if a line failure were to occur in the crossing. Prast said, “It wouldn’t leak out or at least into the environment and they could easily clean it up with in a contained tube basically.”
While conducting their research, Prast and his team discovered that there are other things that cross the straits in that area as well, and the design that they presented legislators would allow for safe crossing of those lines through the same tunnel. Prast said, “There are many electrical lines, there’s a natural gas line and there’s the Enbridge oil line and so there are quite a few down there that would be good to encapsulate them all so we don’t have any leakage of any of them.”
Currently those lines are simply lying on the lake floor and building such a tunnel is unchartered territory in the Straits. The only known bedrock borings are more than sixty years old, from the construction of the Mackinac Bridge’s tower bases.
“We took the borings that we knew of and stuff on the surface and we tried to predict what it would be like. The team that did that did a very good job. They went down there on a surface visit with Enbridge, because they were doing surface borings on the land. They were able to confirm that what they predicted was very close. So it was cool to figure out what was down there and from there we could figure out the tunnel structure and how strong it needs to be and how good the rock is down there,” Prast said.
Although it’s likely that Enbridge will alter the design, or create a different blue print altogether, Michael and his teammates are proud to have played a part in creating a solution to environmental concerns that come with pumping million of gallons of crude oil across the Straits of Mackinac each day.
“I think it’s really cool for me, a student, to have worked on something that maybe my direct engineering isn’t going to be implemented, but the concept and the idea that it kind of started it all. I think it’s really cool to see how it’s progressed. We had a pretty big part in it, and my entire team should be proud of that,” said Prast.
