Enbridge has failed to meet the Oct. 15 deadline for cleaning up the site of an aquifer ruptured during construction of its controversial Line 3 oil pipeline, the Minnesota Department of Natural Resources (DNR) reported Friday.

Meanwhile, the DNR is investigating two other sites where the company may have caused additional groundwater damage, the agency said in a statement. The DNR did not identify the locations of the other sites.

State regulators will require compensation for the loss of groundwater during the additional time it takes to stop the groundwater flow, the DNR said. And Enbridge also will be held accountable for any other violations.

While working on the pipeline in January, crews from the Calgary, Alberta-based Enbridge dug too deeply and punctured an artesian aquifer near Clearbrook, Minn. The damage caused the aquifer to leak at least 24 million gallons of groundwater, threatening to dry up a nearby rare and delicate wetland area called a calcareous fen.

The DNR learned about the leak in June after independent construction monitors reported water pooling in the pipeline trench. On Sept. 16, the department ordered Enbridge to pay $3.32 million for failing to follow environmental laws.

"Enbridge is fully cooperating with the Minnesota DNR in correcting uncontrolled groundwater flows at Clearbrook, and is working with the DNR as two other locations are being evaluated," company spokeswoman Juli Kellner said by e-mail Saturday.

Kellner did not give the locations of the two other sites but stressed they are not at Clearbrook.

Winona LaDuke, who heads the Honor the Earth Indigenous environmental group, called the company's failure to meet the deadline alarming.

"If Enbridge can't meet basic safety requirements, they should not be allowed to operate a pipeline," she said. "This is a deep concern, that they can't fix a problem they made. It doesn't bode well for the future."

Oil started flowing through the pipeline Oct. 1. Strongly opposed by environmental groups and some Ojibwe bands, the line carries a thick Canadian crude across northern Minnesota to the company's terminal in Superior, Wis.

Under the DNR's order, Enbridge put $2.75 million into escrow for restoration and damage to the fen. Enbridge could recover some of the escrow deposit if remediation costs less — or pay more if costs run higher.

Enbridge has paid an additional $40,000 as compensation to the state for the past 30 days of groundwater resources lost as a result of the uncontrolled aquifer leak and agreed to pay for additional future losses, the DNR said.

The state also fined Enbridge $20,000, the maximum allowed under state law. The fine would have been waived if Enbridge had fixed the problem by Friday's deadline.

The DNR has referred the matter to the Clearwater County attorney for possible criminal prosecution.

Enbridge will not contest the requirements set in the DNR's order, Kellner said. She said the company has provided all information and paid the penalty and mitigation amounts as required.

The aquifer breach is a significant error on one of the largest construction projects in the state's recent history. For months, it was largely out of public view because of its rural location and the company's failure to notify regulators.

Outraged environmental groups, scientists and Ojibwe bands who opposed the pipeline called the state's enforcement action in September too little, too late. They said the rupture was exactly the sort of problem they expected would happen in Minnesota's watery landscape.

Frank Bibeau, an attorney representing the White Earth Band of Ojibwe, said Saturday that the band wants to examine the length of the pipeline from the air using thermal imagery to look for other possible leaks. Water from an aquifer would be warmer than the surrounding ground, he said.

Members of the band have speculated that the ground surrounding the rupture is too saturated for Enbridge to make repairs.

"That's what we believe is happening and that's why they haven't met the cleanup deadline," Bibeau said. "Nobody's telling anybody anything. That's why we're setting up a flyover."

Staff writer Mike Hughlett contributed to this report.

Katy Read • 612-673-4583