America’s Biggest Coal Discovery Ever — 1 TRILLION Tons

The Powder River Basin in northeastern Wyoming holds 1.07 trillion tons of coal, making it the largest coal deposit ever measured in the United States. This video explores how a trillion tons of coal ended up under a quiet stretch of Campbell County grassland, starting with Highway 59 near Gillette and the town of Wright, which had only two buildings before the discovery. The US Geological Survey confirmed the massive resource sitting beneath the surface in 11 stacked layers, some up to 100 feet thick. We trace the geologic story back roughly 57 million years to a swamp that never flooded or dried out, a sinking trough between the Bighorn Mountains and the Black Hills, and the absence of sulfur from a retreating sea that made Powder River coal remarkably clean. In the late 1960s, Atlantic Richfield drilled 312 core holes and realized the scale of what lay underground. The Black Thunder mine opened in 1977, connected by 127 miles of Burlington Northern rail, and went on to ship over a billion tons of coal. The 1971 EPA sulfur rule made low-sulfur Wyoming coal suddenly priceless, turning this empty land into the backbone of American power generation and one of the most productive coal fields in the country.