(CNN) Environmental and Native American groups in Minnesota are gearing up to thwart the replacement of an aging pipeline that crosses the state.

The Minnesota pipeline at the center of this latest battle is a replacement for an existing pipeline called Line 3. Built in the 1960s, Line 3 transports crude oil 1,097 miles from Edmonton, Alberta, across northern Minnesota to Superior, Wisconsin.

Tribal and environmental groups opposed to the proposed Enbridge Line 3 project rally in September 2017 at the State Capitol in St. Paul, Minnesota.

The company that operates the pipeline, Enbridge Energy, says the old pipeline needs to be replaced for safety reasons.

In late June, the Minnesota Public Utilities Commission (MPUC) unanimously approved the pipeline proposal.

Enbridge said it has reduced the amount of oil flowing through the pipeline because of corrosion and other defects in the decades-old pipe. The replacement will allow them to transport more oil and address the safety concerns, the company said.

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