MARSHALL — Marshall Municipal Utilities is planning to replace two water mains that run under Minnesota Highway 23.

Later this month, the MMU Commission will meet to review bids for the project. The MMU Commission will hold the special meeting at noon on Feb. 28 in the MMU board room in Marshall.

MMU plans to bore under Highway 23 to replace two segments of water main in Marshall. The iron pipes in those locations are more than 60 years old, said MMU General Manager David Schelkoph.

One of the mains being replaced runs along part of Donald Street, and then under the highway to the Marshall water treatment plant. The other runs under the highway near Hawthorne Drive, and serves Marshall customers south of highway 23, Schelkoph said.

The fact that both water mains go under a state highway adds some complexity to the project, Schelkoph said. In order to protect the roadway from damage or collapse if the water mains fail, the new pipes need to have a steel casing.

“Essentially we will be putting two pipes under the highway,” Schelkoph said. In each location, a PVC pipeline will go inside a larger steel pipe.