Recently, a Ninth Circuit Court of Appeals’ panel ruled that the Office of Surface Mining (OSM) wrongly approved an expansion of Signal Peak’s Bull Mountain longwall mine near Roundup, Montana. In its ruling, the court said OSM largely ignored the fact that the proposed 175-million-ton expansion would release 240 million tons of greenhouse gas pollution over 11 years. In a 2-1 decision, Judges Morgan Christen and Johnnie Rawlinson ruled OSM “hid the ball” about the climate and environmental impacts of expanding the mine. Judge Ryan D. Nelson dissented.

In 2017, a federal judge ruled in favor of environmental protections and required OSM to conduct a proper analysis of the mine’s climate impacts. In the previous ruling, the court found OSM had put its “thumb on the scale’” by only considering the benefits of the mine and not the cost.

OSM’s subsequent 2018 environmental assessment (EA) concluded the mine’s emissions would be insignificant because the greenhouse gases emitted from the mine would appear small when compared to global greenhouse gas emissions. The 9th Circuit panel agreed with conservation groups, saying this type of analysis would “predestine that emissions would appear relatively minor, even though, for each year of its operation, the coal from this project is expected to generate more GHG emissions than the single largest source of GHG emissions in the United States.”

The case was remanded to District Court to determine the appropriate legal remedy.