Fix is on for Sappi waterline leak

The Lake Superior waterline to Cloquet "failed in spectacular fashion" earlier this month, but underwater pipe repairs are underway in the St. Louis River east of Duluth's Riverside neighborhood.

"We had a geyser in the river there the morning it came to light," said Cloquet public works director Caleb Peterson Wednesday afternoon. "It's been shut down for about a week and a half."

Peterson explained that the waterline pumps water from Lake Superior to Sappi. It is not used for potable drinking water and the leak that occurred was 100 percent raw lake water.

A dive team assessed the break Wednesday morning and determined an old repair had failed, Peterson said, causing the Aug. 1 leak. They planned to weld a patch on the pipe Thursday morning. The line is otherwise in good shape, he said.

"We're hoping we can be putting pressure back in the line late Thursday and maybe operating Friday morning," Peterson said. The line saga has been an evolving situation which "shifts by the hour," he said.

The 20-mile waterline transports untreated water from a spot in Lake Superior two miles out from Park Point to Cloquet, where more than 90 percent of the water is used by Sappi in its manufacturing process. In a 2023 letter to the state legislature - which later designated $5 million for waterline infrastructure improvements - mill manager Tom Radovich wrote that the mill could not run "without this line and the pumping stations running at full capacity to meet our 17 to 18 million gallons per day demand."

Peterson said the mill is "making do" for now with river water, but it's not a long-term solution.

"Even when the waterline is running, it doesn't supply enough to meet their entire water need," Peterson said. "So they draw from the river too."

Thomson Township is also tied into the waterline for its fire suppression system and WLSSD also draws cooling water from the line, which crosses the St. Louis River three times.