The fight over a Texas company's plan to build a $10 billion oil refinery in southeastern South Dakota is moving to court.
The state Board of Minerals and Environment recently issued a revised air quality permit for Hyperion Resources that also extended the deadline for starting construction until March 2013.
Opponents have asked a circuit judge to overturn the board's approval of the permit.
Circuit Judge Mark Barnett will hold a hearing in the case Thursday.
The proposed refinery would process 400,000 barrels of Canadian tar sands crude oil each day into low-sulfur gasoline, diesel, jet fuel and liquid petroleum gas.
Hyperion says the project would be the most environmentally sound refinery in the nation.
Opponents say the new permit does not do enough to cut air pollution.