MINNEAPOLIS (WCCO) — The Minnesota Court of Appeals has affirmed the Minnesota Pollution Control Agency’s approval of a key environmental permit in Enbridge Energy’s Line 3 pipeline replacement project.

In court papers filed Monday, the appeals court ruled the MPCA used “substantial evidence” in its decision to grant the pipeline’s 401 certification. A 401 certification is required whenever an activity results in any discharge into waters.

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Court papers show that the MPCA determined that the impacts of the project would result in “temporary, acute spikes” in TSS concentrations, which is a measurement of sediment and other organic matter that becomes mixed in with water during construction. The MPCA determined the spikes in TSS concentrations would not violate narrative or numeric water-quality standards.

The MPCA also said that the project wouldn’t result in long-term risks to aquatic life “due to the duration of the proposed construction activities and characteristics of the pollutants of concern.”

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On Friday, multiple protesters demonstrating against the replacement pipeline were arrested at the Minnesota State Capitol following a brief standoff with law enforcement. A group called the “Water Protectors” say they were in a religious ceremony, protected by treaty rights.

The protesters had been at the capitol since a large demonstration Wednesday, when more than 2,000 people gathered in opposition to the pipeline. Many indigenous elders say they’ll be there in ceremony for 40 days, or until the permits for the Line 3 pipeline are revoked.

The protesters say that the project is a threat to the environment and intrudes on indigenous land. On the other hand, Enbridge says that the pipeline is safe and is bringing jobs to northern Minnesota.

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The pipeline is expected to be operational by the end of the year after the Minnesota Supreme Court refused earlier this week to hear an appeal.