(Adds Enbridge comment, paragraph 6)
By Nia Williams
CALGARY, Alberta, Sept 17 (Reuters) - The Minnesota Supreme Court declined on Tuesday to hear environmental and tribal challenges to Enbridge Inc's Line 3 oil pipeline, a decision that removes one potential obstacle for the already-delayed project.
The ruling means the Minnesota Public Utilities Commission (MPUC), the state regulator that approved the Line 3 project last year, will not have to consider additional environmental issues.
Line 3 is part of Enbridge's Mainline network that transports western Canadian oil to Midwest refineries. The replacement project would double capacity to 760,000 barrels per day, providing much-needed relief from congestion on existing Canadian pipelines.
Pipelines carrying Canadian oil have fallen short for years of meeting demand because of delays with Line 3, the Canadian government-owned Trans Mountain and TC Energy Corp's Keystone XL.
Line 3 was meant to be in service by the end of this year but has been delayed until the second half of 2020 because of issues with permitting.
"We agree with this decision from the Minnesota Supreme Court which now allows the Minnesota Public Utilities Commission to move forth with the permitting process for the Line 3 replacement," said Guy Jarvis, Enbridge's executive vice president of liquids pipelines. "We look forward to the MPUC providing their guidance on the remaining process and schedule."
The American Petroleum Institute also welcomed the court's decision. Erin Roth, executive director of API Minnesota, said Line 3 was the "most studied pipeline project in state history."
In June, the Minnesota Court of Appeals ruled that the Public Utilities Commission had failed to address how an oil spill from the line would affect Lake Superior within the project's environmental impact statement.
Groups including Honor the Earth and the Mille Lac Band of Ojibwe that oppose replacement of Line 3, which was built in the 1960s, petitioned for the state Supreme Court to review other aspects of the impact statement that the appeals court approved. Those petitions were denied on Tuesday.
"We are profoundly disappointed that the Minnesota Supreme Court felt more interested in siding with the rights of a Canadian corporation to proceed with a high-risk project than protecting the rights of the Minnesota Anishinabe and indigenous people and the rights of nature," Winona LaDuke, executive director of Honor the Earth, said.
Calgary-based Enbridge's shares closed up 0.15% on the Toronto Stock Exchange at C$46.70. (Reporting by Nia Williams in Calgary and Rod Nickel in Winnipeg; Editing by Leslie Adler and Peter Cooney)