A federal appellate court judge has denied a motion to stop construction of Enbridge's controversial Line 3 replacement, the second court ruling against pipeline opponents in the past week.

Two Minnesota Ojibwe bands and two environmental groups in December sued the Army Corps in U.S. District Court for the District of Columbia, asking for a preliminary injunction to halt construction of the 340-mile oil pipeline across northern Minnesota.

Judge Colleen Kollar-Kotelly Sunday denied a preliminary injunction, saying plaintiffs failed to show they would likely succeed on the merits of their case or that they will suffer "irreparable harm" if construction continues.

The Army Corps on Nov. 23 issued its permit for the discharge of dredged and filled material into U.S. waters during Line 3's construction. The permit was the last major approval Enbridge needed to begin construction on the $2.6 billion pipeline, which navigated the state and federal regulatory process for six years.

Construction began in December and Calgary, Alberta-based Enbridge has said the pipeline will take six to nine months to complete.

Enbridge, in a statement Monday, said it's "pleased with [the federal court's] decision that acknowledges the thorough, inclusive and science-based review of the Line 3 Replacement Project by the U.S. Army Corps of Engineers."

Darrell Seki, chairman of the Red Lake Band of Chippewa Indians, said in a statement: "We're disturbed that the court would not at least temporarily stop Enbridge from destroying the water and wetlands we have used and depended on since time immemorial."

Last week, the Minnesota Court of Appeals rejected a petition from the Red Lake band and the White Earth band of Ojibwe to halt construction. They tribes are appealing the approval of Line 3 by the Minnesota Public Utilities Commission (PUC).

The Red Lake and White Earth bands, along with the Sierra Club and the Indigenous environmental group Honor the Earth, also appealed the Army Corps' Line 3 approval to the D.C. court

They said the pipeline — which follows a new route — will open a new region of pristine waters to the prospect of oil spills, as well as exacerbate climate change by allowing for more oil production.

Enbridge said the new pipeline, which will transport oil from Canada, is a critical safety enhancement. The current Line 3 is so corroded it's running at only half of capacity. The new pipeline would restore full oil flow.

In the D.C. court case, tribes and environmental groups claim the Army Corps' permit violates multiple federal laws and treaties. They argued that the Corps failed to conduct a full environmental analysis — known as an environmental-impact statement (EIS) — to consider the risks and potential damage of oil spills from Line 3.

Instead, they claim the Corps relied "uncritically" on an EIS done by the Minnesota Department of Commerce.

The state's EIS was approved by the PUC in 2018, but was then rejected by the Minnesota Court of Appeals for a faulty analysis of potential oil spills in the Lake Superior watershed. The Commerce Department then retooled the EIS, which the PUC again approved along with Line 3 itself in February 2020.

Kollar-Kotelly agreed with the Corps' position that it took a "hard look" at oil spills. Also, she wrote that it "was appropriate for the Corps to evaluate and incorporate the state EIS into its findings, without needing to 'reinvent the wheel.' "

The tribes and environmental groups also argued that an injunction was necessary to stop irreparable damage to the environment and to Native Americans' cultural resources, including wild rice beds.

"If Enbridge is allowed to go ahead with construction, these water bodies on which [the Anishinaabe] rely for sustenance will be forever damaged or lost," Michaa Aubid, a member of the Minnesota Chippewa Tribe and teacher of Ojibwe language and history, said in a court affidavit in the case.

Kollar-Kotelly wrote that she's "sensitive" to plaintiffs' concerns. "But the record before the Court indicates that most of the environmental effects stemming from the construction of Line 3 will not be 'permanent or irreversible,' as the preliminary injunction standard requires."

The Army Corps argued that delaying construction — and thus continuing to rely on existing Line 3 — would put the environment and public safety at risk. In court filings, Enbridge argued the same, adding that the company would suffer $332 million in "economic harms" for a six-month delay in Line 3 construction.

"Overall, the Court finds the balance of harms and public interest considerations to be a close call," Kollar-Kotelly wrote. But the Army Corps' argument that the public is better served by a new pipeline is "persuasive," she wrote.

Mike Hughlett • 612-673-7003