On October 9, 1984, Wolf Ridge Corporation (WRC), the holder of four federal sodium lease tracts within the Piceance Basin in northwest Colorado, submitted a mine plan to the Bureau of Land Management (BLM) for a commercial-scale nahcolite solution mine. Initial screening of the mine plan indicated that it represented a major federal action with the potential for significant impacts; therefore, pursuant to Section 102 of the National Environmental Policy Act of 1969 (NEPA), BLM determined that an environmental impact statement would be required in conjunction with approval of the mine plan.