A conservation group is appealing a judge's order dismissing its lawsuit, which accused the Big Stone power plant of violating federal environmental laws by not installing modern pollution controls.
The Sierra Club complaint asked a judge to order the owners of the coal-fired plant to install equipment that would reduce pollution at the plant near Milbank in northeast South Dakota, before they build a second plant on the site.
The plant is owned by Otter Tail Power Co., MDU Resources Group Inc., and Northwestern Corp.
U.S. District Judge Charles Kornmann sided with the utilities and dismissed the lawsuit because it came after the statute of limitations expired.
He also refused to reconsider the case, so the Sierra Club appealed to the 8th U.S. Circuit Court of Appeals.